A floor runner with electrical and/or electronic or data outlets provides a low-profile, unobtrusive power and/or data source along a floor or other support surface. The electrical floor runner may be a one-piece unit of substantially any desired length, and typically includes a power cord with plug or connector at one end for coupling to a wall outlet or the like, and a power/data block at the other end for receiving power and/or data couplers for other devices, such as computers and electronics, lighting, etc. A middle portion is a strong, low-profile region that houses and protects electrical wiring held internally, and that is minimally intrusive for use in walking areas. Optionally, the floor runner may be modular so that its overall length or configuration (e.g., straight or angled) can be changed as desired.

Extension cords are commonly used for temporarily routing electricity or electrical signals from a power or data source to a different area or location, such as in a home or office building. When extension cords are laid across flooring or walking areas, floor runners or cord protectors may be used to temporarily house the extension cord in an effort to reduce tripping hazards.


One example provides, on a scanning mirror display system, a method for communicating timing information for light samples that are scanned to form a displayed image. The method comprises, for a line of light samples, encoding timing information for a first light sample of the line of light samples using a first, greater number of bits to form encoded timing information for the first light sample. The method further comprises encoding timing information for a subsequent light sample of the line of light samples by computing a derivative based upon a timing of the subsequent light sample compared to a prior light sample, encoding the derivative using a second, lesser number of bits to form encoded timing information for the subsequent light sample, and sending the information for the first light sample and the subsequent light sample across the communications channel.

In a scanning display system, laser light is reflected by a scanning mirror system to scan a projected image. Laser pulses are synchronized with the motion of the scanning mirror to display pixels of the image. In some such devices, the scanning of the mirror may be performed via harmonic oscillation at a resonant frequency of the mirror.

Derivative-based encoding for scanning mirror timing


A motor stop mechanism for a motor including an output shaft includes a motor mounting surface to which the motor is attachable and a threaded drive shaft fixed to and rotatable with the motor output shaft. A trunnion threaded on the threaded drive shaft is displaceable between a retracted position and an extended position by forward and reverse rotation of the threaded drive shaft. A housing surrounds the threaded drive shaft and the trunnion, and a stop limit fixed to the housing defines the extended position of the trunnion. In use, when the trunnion reaches the stop limit, the motor is stopped.

The invention relates to slide-out rooms for recreational vehicles and the like and, more particularly, to a motor stop for a through-frame slide out system. The application is related to U.S. application Ser. No. 16/708,619, the contents of which are hereby incorporated by reference.
In order to increase available interior space of recreational vehicles, e.g., motor homes and trailer homes, slide-out rooms or sections have been provided. During transit, these rooms are retracted and stored in the interior of the vehicle or trailer, with the exterior end wall of the slide-out room approximately flush with the adjacent exterior wall of the vehicle or trailer. To use the slide-out room, the vehicle is parked and leveled. The slide-out room is then slid outward from the vehicle, using the slide-out room support system, thereby increasing the interior space of the vehicle.
An exemplary support and drive system is described in U.S. Pat. No. 6,109,683, the contents of which are hereby incorporated by reference.
Existing drive and support systems include a motor-driven shaft that runs perpendicular to a rack and pinion driven frame on which the slide-out room rides. There has been an issue with existing designs with respect to effectively getting a through-frame system to stop at the desired points while preventing the room from running off its track and out of the vehicle.

Motor stop for a through-frame slide out system


A driving unit for a liquid crystal display device is provided. The driving unit includes a first group of driving stages and a second group of driving stages. A first driving stage of the first group receives a first gate start voltage. The first group of driving stages sequentially outputs scan signals according to a first clock signal. The scan signal outputted by one driving stage of the first group is sent to a next subsequent driving stage of the first group. A first driving stage of the second group receives a second start voltage. The second group of driving stages sequentially outputs the scan signals according to a second clock signal. The scan signal outputted by one driving stage of the second group is sent to a next subsequent driving stage of the second group. The driving stages of the first group and the second group alternately output the scan signals.

1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device and a driving unit thereof, and particularly, to a liquid crystal display (LCD) device and driving unit capable of facilitating application of high resolution and improving image quality.
2. Description of the Background Art
Recently, since information was visually embodied, display devices which act as an interface between human being and information have been widely utilized. More particularly, because of the superior characteristics of liquid crystal display (LCD) devices such as clear image quality, low power consumption, light weight and the like, the LCD devices have been gradually utilized as a next-generation display device which can substitute for widely used Cathode Ray Tubes (CRTs).
FIG. 1 schematically illustrates a typical liquid crystal display device. As illustrated in FIG. 1, a LCD device includes a liquid crystal display (LCD) panel 1 formed by attaching a thin film transistor array substrate 2 and a color filter substrate 3 to each other with a constant cell-gap, a plurality of data lines 15 and gate lines 16 arranged perpendicularly and longitudinally on the thin film transistor array substrate 2, a plurality of pixels P defined by crossing the data lines 15 and the gate lines 16, a data driving unit 20 for transferring image information to the pixels P through the data lines 15, and a gate driving unit 30 for applying scan signals to the pixels P through the gate lines 16.
The thin film transistor array substrate 2 on which the pixels P are arranged in a matrix has an image display unit 10 composed of the pixels P, for substantially displaying images thereon.
The data driving unit 20 is electrically connected to the image display unit 10 by the data lines 15, while the gate driving unit 30 is electrically connected to the image display unit 10 by the gate lines 30. The gate lines 16 and the data lines 15 are respectively electrically connected to the pixels P to form the image display unit 10.
The gate driving unit 30 sequentially outputs scan signals to the gate lines 16 and applies the scan signals to the pixels P connected to the gate lines 16. Thin film transistors TFTs provided to each pixel P are turned on by the scan signals. During this period for turning on the TFTs, the data driving unit 20 applies image information, i.e., data signals, to the pixels P through the turned-on TFTs.
The pixels P are provided therein with storage capacitors, by which a voltage of the image information, which has been applied to the pixels P when the TFTs are turned on by the scan signals, is charged to keep driving the pixels P for one frame when the TFTs are in an off state.
A plurality of driving voltages and control signals are inputted to the gate driving unit 30, which is then controlled by the control signals to sequentially output scan signals to the gate lines 16. As will be explained in FIG. 2A, the gate driving unit 30 is provided with a shift register unit for sequentially generating signals every horizontal period to thereby output the scan signals in sequence.
FIG. 2A illustrates the shift register unit of the gate driving unit 30, and FIG. 2B shows the timing sequences of the signals shown in FIG. 2A. The shift register unit is driven by inputting a gate start voltage Vst, and is provided with a plurality of stages ST1 to STn for outputting scan signals Vout1 to Voutn according to a plurality of clock signals C1 to C4.
Four clock lines CL1 to CL4 are provided at one side of the shift register unit. The stages ST1 to STn are electrically connected to one of the four clock lines CL1 to CL4. A high potential voltage Vdd and a low potential voltage Vss are commonly applied to the stages ST1 to STn. The shift register unit may only use two clock lines CL1 and CL2.
An output side of each of the stages ST1 to STn is electrically connected to its next preceding stage as wells as to its next subsequent stage. Although not shown, each of the stages ST1 to STn has one-to-one connection with its respective gate line.
The stages ST1 to STn are preset by the gate start voltage Vst to be in a state of immediately outputting the scan signals Vout1 to Voutn by inputting the clock signals C1 to C4. The gate start voltage Vst is inputted only to the first stage ST1 and outputted to a timing controller. In each of the other stages ST2 to STn, the scan signals Vout1 to Voutn−1 of the next preceding stages ST1 to STn−1 perform a function as same as that of the gate start voltage Vst. That is, the scan signals Vout1 to Voun−1 of the next preceding stages ST1 to STn−1 are inputted to the next subsequent stages ST2 to STn to preset the corresponding stages ST2 to STn. Accordingly the corresponding stages ST2 to STn are synchronized with the clock signals C1 to C4 to be in a state that the scan signals Vout2 to Voutn can immediately be outputted.
On the other hand, each of the scan signals Vout2 to Voutn is applied to the next preceding stages ST1 to STn−1 to stop the output of the next preceding stages ST1 to STn−1. In addition, the scan signals Vout1 to Voutn are outputted to only one of the stages ST1 to STn.
FIG. 2B illustrates the timing sequences of the clock signals C1 to C4 applied to the shift register unit and of the scan signals Vout1 to Voutn controlled by the clock signals C1 to C4. When the gate start voltage Vst is firstly inputted and the clock signals C1 to C4 are then sequentially inputted to the stages ST1 to STn, the scan signals Vout1 to Voutn are sequentially outputted from the stages ST1 to STn. The scan signals Vout1 to Voutn are generated every horizontal period H.
FIG. 3 illustrates an exemplary circuit configuration of the shift register unit shown in FIG. 2A. As illustrated in the drawing, the shift register unit is provided with a plurality of flip-flops FF1 to FF3 for outputting the scan signals Vout1 to Vout3 by inputting the clock signals C1 to C3 in a state that the gate start voltage Vst has been applied thereto. Each output side of the flip-flops FF1 to FF3 has one-to-one connection with the gate lines GL1 to GL3 arranged on a substrate in a lateral direction.
Each of the flip-flops FF1 to FF3 includes: a second transistor T2 turned on by a high potential voltage Vdd, for charging a second Node ND2; a first transistor T1 turned on/off by the gate start voltage Vst, for discharging the second Node ND2 and for charging a first Node ND1; a seventh transistor T7 electrically connected to one side of the charged first Node ND1 and turned on/off by a voltage charged in the first Node ND1, for outputting scan signals Vout1 to Voutn according to clock signals C1 to C4; a fourth transistor T4 turned on/off by signals outputted from a next subsequent flip-flop, for discharging the first Node ND1 and recharging the second Node ND2, and an eighth transistor T8 turned on/off by a voltage charged in the second Node ND2, for lowering the voltage level of the scan signals Vout1 to Voutn to a low potential voltage. The first to eighth transistors T1 to T8 are all N-type.
The first Node ND1 electrically connects a source electrode of the first transistor T1, a gate electrode of the seventh transistor T7 and a drain electrode of the fourth transistor T4. The second Node ND2 electrically connects a source electrode of the second transistor T2 and gate electrodes of the eighth and third transistors T8 and T3.
The output of the flip-flops FF1 to FF3 is controlled by potentials of the first Node ND1 and the second Node ND2. That is, when the first Node ND1 is in a high potential, the seventh transistor T7 is turned on to transit the scan signals Vout1 to Vout3 into high potential levels, while transiting the scan signals Vout1 to Vout3 into low potential levels when the eighth transistor T8 is turned on.
The scan signals Vout1 to Vout3 of the flip-flops FF1 to FF3 are supplied to the gate lines GL1 to GL3 and simultaneously applied to the next subsequent flip-flops FF2 to FF4 (not shown) to thereby perform a function as same as that of the gate start voltage Vst applied to the first flip-flop FF1. That is, the first transistor T1 of the current flip-flops FF1 to FF3 is turned on to charge the first Node ND1. Furthermore, the scan signals of the flip-flop FF2 to FF4 are transferred to the next preceding flip-flops FF1 to FF3 to discharge the first Node ND1 of the next preceding flip-flops FF1 to FF3. If the first Node ND1 of the next preceding flip-flops FF1 to FF3 is not completely discharged, when the current flip-flops output scan signals, minute signals can still be outputted from the next preceding flip-flops. In other words, an abnormal output of the scan signals of the next preceding flip-flops FF1 to FF3 can be prevented by completely discharging the first Node ND1. Thus, the scan signals of the current flip-flops control the output of both the next preceding and the next subsequent flip-flops.
Recently, LCD devices with large dimension and high resolution have been developed. In order to make the devices lighter, a driving unit which has been installed in a LCD panel as IC chip (Integrated Circuit Chip) type is integrated with the LCD panel. Thus, the driving circuit integrated with the LCD panel is generally formed of amorphous silicon transistor.
On the other hand, because the number of pixels is increased to enhance the resolution of screen, the number of the gate lines is also increased to control the increased pixels. Accordingly, more flip-flops should be formed corresponding to the increased number of gate lines. Since the number of the gate lines is increased, the scanning frequency has to be increased. In other words, a horizontal period for applying scan signals to each gate line for one frame is reduced.
When the horizontal period for applying scan signals to each gate line is reduced, a time assigned to each flip-flop for outputting scan signals is also reduced. Therefore, it would be difficult to ensure a sufficient time for charging the first Node ND1. In the state that the first Node ND1 is not enough charged, a gate voltage for turning on the seventh transistor T7 is lowered, and accordingly current flowing through the seventh transistor T7 is also reduced. As a result, potential levels of the scan signals rise at a lower speed, which requires a longer time period (rising time) to raise the scan signals up to high potential levels. That is, pulses of the scan signals fall with delay.
Similarly, when the horizontal period is reduced, it is difficult to ensure a sufficient time taken by charging the second Node ND2. As a result, the eighth transistor T8 is not completely turned on, which causes limitation on electric charge which is discharged through the eighth transistor T8, thereby taking a longer time period (falling time) to lower the potential levels of the scan signals. Furthermore, resistance and capacitance elements of the increased gate lines increase a load in the shift register unit to lengthen the rising time and the falling time of the scan signals. That is, pulses of the scan signals Vout1 to Vout3 fall with delay.
Thus, when the pulses of the scan signals Vout1 to Vout3 fall with delay by the incomplete charging of the first Node ND1 and the second Node ND2, each flip-flop outputs the scan signal which does not have desired potential level for the gate line. Accordingly, when the scan signals are applied to the gate lines, image quality of the LCD device may be degraded. Especially, in the driving circuit-integrated LCD panel applying amorphous silicon transistor thereto, due to its lower electron mobility, the rising time and the falling time of the scan signals may be longer.
Moreover, when the rising time or the falling time of the scan signals is lengthened, waveforms of the scan signals fall with delay to maintain high potential levels for a long time, thereby unnecessarily turning on TFTs. In this case, image information may be applied to pixels through the TFTs which should have been turned off. This may cause degradation of image quality. In addition, when the waveforms of the scan signals fall with delay, the time period for outputting the scan signals have to be further reduced to prevent adjacent scan signals from being overlapped with one another, which makes it difficult to fabricate a LCD device with high resolution.

Liquid crystal display device and driving unit thereof


According to one embodiment, a memory system includes a nonvolatile memory and a controller configured to control the nonvolatile memory using first data. The controller is configured to write either the first data or second data into the nonvolatile memory based on a total write amount of user data into the nonvolatile memory. The second data is compressed data of the first data.

As a memory system, a solid state drive (SSD) on which a nonvolatile semiconductor memory such as a NAND flash memory is mounted is known. For example, an SSD is used as an external storage device for various computers. In the SSD, a system data nonvolatilization in which system data for managing the SSD is written into a NAND flash memory per predetermined period of time is execute to store the system data.


A method for secure storage and distribution of account tokens includes: storing blockchain data comprised of a plurality of blocks, each block including at least a block header and one or more data values, where each data value includes at least an identification value, an account token, and one or more usage rules; receiving a login request including at least a specific identification value and a set of credentials; identifying a specific data value included in the blockchain data where the included identification value corresponds to the received specific identification value; validating the set of credentials based on the identified specific data value and access to the account token included in the specific data value based on the included one or more usage rules; and transmitting the account token included in the identified specific data value in response to the login request upon successful validation.

A goal of many websites on the Internet is to make things as easy as possible from a user standpoint, to encourage user registration and increase user retention. Many websites offer personalized experiences to users, which require the users to register with the website or otherwise provided personal information that can be used to tailor the experience to the user or otherwise provided personalized services to the user. However, in many instances, a complicated or time-consuming registration process may discourage the user from participating and result in the user leaving the website. Thus, websites are often seeking ways to make the registration process as quick and easy as possible for users.
One method that has become prevalent is the use of third-party services to log in to a website. In such a method, the website provides a link to the third-party service, which will ask permission from the user to share their information with the website in a single prompt, and then provide such information to the website upon acceptance by the user. The result is that the user is registered with the new website, and the new website has received their personal information, in as little as two clicks. These services, such as those offered by Facebook® or Google®, enable websites to offer personalized experiences to users while minimizing user impact, and also providing peace of mind to users that trust these third party services but may be wary of providing an e-mail address and password to the website.
However, while these services make it easier for a user to register or log in to a website, they often require the user to give up a level of control over their information. Traditionally, third party services operate by providing an account token, a digital data file that includes unique identification of the user and any other information necessary for the third party to identify the user's account information, to the website, which the website can present to the third party any time account information is desired. There arises a technical problem in that these account tokens are typically shareable and do not expire except as subject to any agreement between the website and the third party service. This enables websites that use the account tokens to identify common users via their tokens and share the tokens with other websites that have not been explicitly authorized. In addition, current processes make it difficult and time consuming for a user to control authorization of their account tokens, requiring the user to navigate to the third party service, log in, identify settings that enable the user to change permissions, identify the website for which the user would like to change permissions, and then actually change the permissions. This is a problem with the technology being employed, and it is a time consuming, and often confusing, process for users, which ends up discouraging the user from controlling access to their own personal information. Thus, there is a need for a technical solution to provide better user access and control over their account tokens and the usage thereof at websites.

Method and system for enhanced login credential security via blockchain


A deadman brake assembly incorporating a turnover spring in a link mechanism thereof to exert a spring force in a direction in which a seat supporting plate is kept in a state it enters when a driver sits on the driver's seat and to exert the spring force in another direction in which the seat supporting plate is lifted when the driver leaves the driver's seat, suppressing as much as possible the lifting force acting on the driver's seat when the driver sits thereon.

1. Field of the Invention
The present invention relates to cargo vehicles such as fork lift trucks. More particularly, it relates to a deadman brake assembly which automatically works when the driver is not on his seat.
2. Description of the Prior Art
FIG. 5 shows a typical conventional deadman brake provided on a cargo vehicle such as a fork lift truck. As illustrated, the deadman brake assembly comprises a seat supporting plate 2 for supporting a driver's seat 1 and a brake bar 4 of a drum type brake device 3 connected by a link mechanism 5. When the driver is not on the driver's seat 1, the seat supporting plate 2 pivoted on a bracket 7 of a vehicle frame 6 is tilted forward (the direction of the arrow A) as a result of the action of a tension spring 8, and a brake shoe 9 sandwiches a brake drum 10 on both sides thereof to exert a braking action on the brake drum 10. When the driver sits on the driver's seat 1, the seat supporting plate 2 is tilted against the spring force of the tension spring 8 to the position indicated by the dotted chain line so that the brake drum 10 is released from the state in which it is sandwiched by the brake shoe 9.
As will be apparent from the above, in the deadman brake, the driver's seat 1 always has a tendency to tilt forward as a result of the action of the tension spring 8. However, since the tension spring 8 has a maximum tensile force when the driver sits on the driver's seat 1, the lifting force exerted on the driver's seat when the driver sits on the seat is greater than that exerted when the seat is not occupied. This has resulted in problems that, even when the driver sits on the driver's seat, the seat can be shaky during driving depending on the posture of the driver and the driver can have a sense of floating.

Deadman brake assembly for cargo vehicles

Kabushiki Kaisha Toyoda Jidoshokki Seisakusho


A tape recording system is provided for coupling the angular velocities of a pair of roller guides disposed one on either side of a head assembly. In one embodiment, the roller guides each comprise cylindrical first and second surfaces wherein the first surfaces guide a tape over the head assembly. An idler bearing comprising a cylindrical ring having an inside diameter surface engages in rolling contact the second surfaces of the pair of roller guides, thereby coupling the angular velocities of the pair of roller guides. In another embodiment, an idler bearing comprises a roller having an outside diameter surface that engages the surfaces of a pair of roller guides on each side of the head to couple the angular velocities of the pair of roller guides.

1. Field of the Invention
The invention relates to the field of recording tape transport mechanisms and more particularly to a tape recording system having a mechanism to couple the rotation of roller guides adjacent to a tape head assembly.
2. Background Information
Magnetic tape storage systems are widely used in computer systems for storing and retrieving large amounts of data. Current systems typically read and write from parallel tracks on the tape which vary in number based on the design of the system. Each track of the head has a read and a write magnetic transducer (head) arranged in tandem so that the data written by the write head can be verified by the read head. The head pairs may be alternated so that one set of the tracks are written and read when the tape travels in one direction and the other set is used when the tape is moving in the opposite direction.
Some tapes are written with magnetic servo information thereon to allow positioning of the heads in relation to the tracks. All tapes have a magnetic noise floor which is present even when the tape is erased. Therefore, even a tape with no data recorded thereon will generate a media noise signal in the read heads and tapes with servo information will also generate signals corresponding to servo information.
For high density recording the tape must be precisely positioned and tensioned as it moves across the head assembly. The tape is typically supported and positioned by support surfaces, for example cylindrical rollers or posts or guides disposed on each side of the head. The support surfaces may be positioned to form the wrap angles which are the angles of the plane of the tape with respect to the air bearing surfaces of the head. Precise wrap angles are necessary for optimum performance.
Therefore, there is an ongoing need for improved tape support and positioning systems to reduce damage to the recording tape and to provide precise stability and tracking of the tape relative to the recording head during operation.

International Business Machines Corporation


A computing device has a storage volume, a file system managing the storage volume, and a file stored on the storage volume and accessed by such file system. The file system receives an open command for the file from an application, notes that the file has been ghosted in that data of the file has been moved to an alternate location, and returns an error. The returned error is intercepted and the file system is commanded to retrieve ghosting information from the ghosted file. A handle corresponding to the ghosted file is delivered to the application, and a read command for the file is received from the application, including the handle, an offset, and a read length. Reconstituting of the ghosted file is initiated based on the data thereof at the alternate location, and after reconstituting the read command is responded to with the data requested.

In a computing device such as a personal computer, a computer server, or the like, and as is known, data is typically persistently stored on the computing device in the form of local computer files resident on one or more local storage volumes of the computing device. Each such storage volume may reside on a hard drive of the computing device or the like, and such storage volume may be organized by, accessed through, and otherwise controlled by a file system running on the computing device, as is also known.
At times, it can be the case that some, many, and perhaps even most of the computer files on the storage volume are not of interest and can be considered to have become 'cold'. That is to say, such cold files have not been accessed for some extended length of time and/or likely will not be accessed for some extended length of time, for example, and therefore have little if any real value in remaining on the volume.
Of course, such cold files could simply be deleted from the storage volume, especially if there is a need for space on such volume. However, it is to be appreciated that most users are loathe to delete files simply to create space. In addition, it is considered bad practice to delete a cold file merely because of perceived disuse. At any rate, it can and likely will be the case that a cold file though not considered needed and not foreseen as needed may nevertheless become needed at some future point.
In such a situation, then, it would be useful to be able to create space on the volume by moving data from such cold files to an alternate location, while still allowing such cold files to maintain a presence on the volume. That is, it would be useful to be able to 'ghost' a cold file by moving data from such cold files to the alternate location or to copy the entire file to the alternate location, while leaving the cold file in a smaller, 'ghosted' form on the volume. Thus, if in fact the ghosted file is needed on the computing device, the data for such ghosted file may be retrieved from the alternate location, the ghosted file may be reconstituted based on thereon, and such reconstituted file may then be employed.
In another scenario, it can be the case that data files of an organization or the like are to be replicated at multiple branch locations of the organization, perhaps from a central location such as a hub. For example, an architectural design firm may wish to have all architectural design files thereof available at any one of several branches of such firm.
In such a situation, a networked system can be constructed to replicate a copy of each file to each branch, and to keep all files at all branches current. In such a system, for example, a centralized hub server would store each such file, and a replication service would be employed to distribute a copy of each file at the hub over a network to a branch server or the like at each branch. However, it is to be appreciated that as the number of files of the organization increases, and as the size of each file increases, and as the number of branches increases, the amount of traffic over the network also increases, perhaps to a point that exceeds available bandwidth. Moreover, as the overall size of all the files at the hub server increases, it may in fact become the case that each branch server does not have enough space available thereon to store all of such files as replicated from the hub server.
Similar to the previous scenario, though, it can be the case that some, many, and perhaps even most of the computer files on the branch server of a particular branch are not of interest and can be considered to be superfluous. Such superfluous files may for example relate to matters that are not relevant to the particular branch, likely will not be accessed through the particular branch, and therefore have little if any real value in being replicated on the branch server for the particular branch. For example, a branch office of an architectural design firm in Wilkes-Barre, Pa. likely has very little if any need to have architectural design files relating to a project handled by a branch office of the firm in Boynton Beach, Fla.
In such a situation, then, and similar to previous scenario, it would be useful to be able to wholly store on a branch server of a particular branch only those files relevant to the particular branch, while only partially storing on such branch server of such particular branch all other non-relevant files as available from the hub server for the organization. Thus, in a manner akin to that of the previous scenario, it would be useful to be able to 'ghost' the non-relevant files at the branch server of the particular branch, such that each non-relevant file remains on the branch server in a smaller, 'ghosted' form. Thus, and again, if in fact the ghosted file is needed at the branch server, the data for such ghosted file may be retrieved from the hub server, the ghosted file may be reconstituted based on thereon, and such reconstituted file may then be employed.
Accordingly, a need exists for a method and mechanism by which a file at a source such as a local volume or a branch server may be replicated or ghosted such that the data thereof is stored at a sink such as an alternate location or a hub server, and the file at the source is thus in a reduced or ghosted form that can be reconstituted if need be. In particular, a need exists for such a method and mechanism by which such a ghosted file may be formed and reconstituted, as necessary.

Moving data from file on storage volume to alternate location to free space


The invention relates to Infectious Bursal Disease Virus (“IBDV”) and vaccines therefor. Provided are infectious recombinant Infectious Bursal Disease Virus (“rIBDV”) essentially incapable of growing in a cell that is not derived from a bursa cell, or an infectious rIBDV having retained at least part of the very virulent characteristics of a very virulent Infectious Bursal Disease Virus (“vvIBDV”).

Infectious bursal disease ("IBD"), an infectious disease among young chickens, was first recognized in 1957 in Gumboro, Del., USA, and formally documented by Cosgrove (Cosgrove, 1962; Lasher and Shane, 1994). As a result, the disease is often referred to as "Gumboro". Not long after IBD was first reported, it was recognized in poultry populations throughout the world (Lasher and Shane, 1994). IBD is caused by a virus ("IBDV") classified as a Birnavirus (Dobos et al., 1979).
Two different IBDV serotypes exist: serotypes I and II (Jackwood et al., 1982; McFerran et al., 1980). Isolates belonging to serotype I are highly pathogenic for chickens. Serotype II isolates, which are mainly recovered from turkeys, have not been reported to induce clinical signs in chickens and are regarded as apathogenic (Ismail et al., 1988). Infectious bursal disease or Gumboro is a highly contagious disease for young chickens and is responsible for severe losses in the poultry industry. In birds surviving an acute infection, lymphoid cells in the bursa of Fabricius are destroyed, resulting in B-cell-dependent immunodeficiency. This causes increased susceptibility to disease caused by otherwise harmless agents. A central role in the pathogenesis of Gumboro is played by the bursa, which is representing the target organ of the virus.
IBDV infections were initially recognized by whitish or watery diarrhea, anorexia, depression, trembling, weakness, and death. This clinical IBD was generally seen in birds between three and eight weeks of age. The course of the disease runs approximately 10 days in a flock. Mortality usually ranges from 0–30 percent. Field reports suggest that leghorns are more susceptible to IBDV than broiler-type chickens. Subclinical IBD was later recognized and is generally considered a greater problem in commercial poultry than the clinical disease. It is generally seen in birds less than three weeks of age. This early infection results in a B-lymphocyte depletion of the bursa of Fabricius. The bird is immunologically crippled and unable to respond fully to vaccinations or field infections. In susceptible chickens, damage caused by IBDV can be seen within two to three days after exposure to virulent virus. Initially, the bursa swells (3 days post-exposure) with edema and hemorrhages and then begins to show atrophy (7–10 days). IBD virus is especially cytopathic to certain B-lymphocytes. The highest concentration of these specific B-lymphocytes is found in the bursa. Destruction of the B-lymphocytes by IBD field virus may result in an incomplete seeding of these cells in secondary lymphoid tissue. As a result of the depletion of B-lymphocytes, surviving birds are immunocompromised during the remainder of their lifetime.
IBDV is found worldwide, and IBDV-specific antibodies have even been found in Antarctic penguins (Gardner et al., 1997). The prevalence of clinical IBD is relatively low compared to the prevalence of subclinical IBD. IBDV is very resistant to common disinfectants and has been found in lesser mealworms, mites, and mosquitoes. These facts correlate with field experience of reoccurring IBD problems on a farm, despite clean-up efforts. Infection with IBDV results in a strong antibody response against IBD, which is capable of neutralizing this virus. Most likely as a result of vaccination, antigenic variant isolates of serotype I were isolated in the Delaware area (USA). These isolates have been shown to cause bursa atrophy in as little as three days post-infection without inflammation of the bursa. Despite their change in antigenicity, these antigenic variants do not form a distinct serotype. After the occurrence of antigenic variant IBDV isolates in the USA, the poultry industry in European countries was hit by outbreaks of IBD caused by a very virulent serotype I IBDV (vvIBDV) (Berg et al., 1991; Chettle et al., 1989; Kouwenhoven and Van den Bos, 1995). These very virulent field isolates were capable of establishing themselves in the face of high levels of maternal antibodies which normally were protective. These vvIBDV cause more severe clinical signs during an outbreak and are now found globally (e.g., Europe, Japan, Israel and Asia).
IBDV belongs to the family of Birna viruses which include Infectious Bursal Disease Virus (IBDV) isolated from chickens, Infectious Pancreatic Necrosis Virus (IPNV) isolated from Fish, Drosophila X Virus (DXV) isolated from fruit fly, and Tellina Virus (TV) and Oyster Virus (OV) both isolated from bivalve molluscs (Dobos et al., 1979). Birna viruses have a dsRNA genome which is divided over two genome segments (the A- and B-segment). The A-segment (3.3 kbp) contains two partly overlapping open reading frames (ORFs). The first, smallest ORF encodes the non-structural Viral Protein 5 (VP5, 17 kDa). The second ORF encodes a polyprotein (1012 amino acid, 110 kDa), which is autocatalytically cleaved. The exact positions of these cleavage sites are unknown.
From SDS-Page analysis of in vitro translated IBDV RNA, it is known that the polyprotein is rapidly cleaved into three proteins: pVP2 (48 kDa), VP4 (29 kDa) and VP3 (33 kDa). During in vivo virus maturation, pVP2 is processed into VP2 (38 kDa), probably resulting form site-specific cleavage of the pVP2 by a host cell-encoded protease (Kibenge et al., 1997). VP2 and VP3 are the two proteins that constitute the single shell of the virion. The B-segment (2.9 kbp) contains one large ORF, encoding the 91 kDa VP1 protein. This protein contains a consensus RNA-dependent RNA polymerase motive (Bruenn, 1991).
Furthermore, this protein has been reported to be linked to the 5′-ends of the genomic RNA segments (Viral Protein genome-linked, VPg). The nucleotide sequence of internal parts of a large number of IBDV isolates of classical, antigenic variant or very virulent origin has been determined and deposited in several databases such as GenBank. Furthermore, Mundt and Muller (Mundt and Muller, 1995) have determined the 5′- and 3′-termini of several IBDV isolates (CU-1, CU-1M, P-2 and 23/82), and by combining the internal and terminal sequences, Mundt and Muller established the complete nucleotide sequence of a serotype I A-segment (3261 bp) and B-segment (2827 bp). This provided the way to generate an infectious (recombinant) copy (rIBDV) of IBDV serotype I, by knowing the complete sequence dsRNA sequence of IBDV genome and by using one of several methods to generate infectious copy virus (see, for example, Boyer et al., Virology 198:415–426, 1994). Mundt and Vakharia indeed produced infectious rIBDV serotype I from cDNA (Mundt and Vakharia, 1996). Full-length cDNA of a serotype I IBDV, preceded by a T7 promoter, was thereby used as a template for T7 RNA polymerase using a method described by Weiland and Dreher (Weiland and Dreher, 1989). The in vitro-generated mRNA, containing a cap-structure at its 5′-end, was subsequently transfected into eukaryotic cells (VERO cells) using a liposome formulation (Lipofectin, GibcoBRL). The supernatant of the transfected cells contained infectious rIBDV after incubation during 36 h in the CO2 incubator at 37° C. (Mundt and Vakharia, 1996; (WO 98/09646)). In addition, Lim et al. introduced two amino acid mutations (D279N and A284T) into the cDNA of vvIBDV isolate HK46 (Lim et al., 1999). These mutations were most probably based on data of Yamaguchi et al. (Yamaguchi et al., 1996), which showed that these specific mutations were found in two independent experiments in which very virulent IBDV isolates lost their very virulent character by adaptation and growth on primary CEF cells. Lim et al. obtained an rIBDV isolate which possessed the phenotype of a CEF-culture adapted isolate, i.e., an rIBDV isolate which can be propagated, i.e., is able to infect, multiply and be released for further replication, in vvIBDV non-permissive cells such as CEF cells. Noteworthy, Lim et al. were unable to produce an infectious vvIBDV isolate using the unmodified cDNA of the HK46 isolate (Lim et al., 1999). Furthermore, although cDNA of IBDV can be used to produce infectious IBDV, the exact mechanism of replication has not been elucidated yet. Data exist which are in support of a semi-conservative genome replication model for Birnaviradae (Bernard, 1980; Mertens et al., 1982).
Now and then, IBDV variants are detected in the field or are created in cell cultures in the laboratory (Muller, 1987) that are genetic re-assortments of serotype I and II strains of IBDV, in that they contain one genomic segment derived from the one serotype and another segment derived from the other serotype. Such segment re-assorted (srIBDV) strains (also called chimeric IBDV) not only occur in nature, but have recently been generated from cDNA as a well, by Vahkaria and Mundt (WO 98/09646).
Vaccination using attenuated field isolates worked sufficiently well until antigenic derivatives were found in the Delaware region of the USA starting in 1985 (isolates Del A, D, G and E) (Snyder, 1990). These field isolates were missing an important virus-neutralizing epitope. The change of this epitope is characterized by the lack of binding of the virus-neutralizing monoclonal antibody (Mab) B69 (Snyder et al., 1988a). The antibodies induced by vaccination with classical IBDV vaccines appeared to be less protective against these antigenic IBDV variants. Inactivated vaccines based upon antigenic IBDV variants were subsequently produced and were found to protect effectively against these antigenic variants of IBDV. After the Delaware variant, a second antigenic variant IBDV was isolated. This variant was recovered from the Delmarva region (USA) and was referred to as the GLS variant. The GLS variant is characterized by the absence of epitopes for both the virus-neutralizing Mab B69 and R63 (Snyder et al., 1988b). After identifying these antigenic variants, a large survey was performed within the USA by using a panel of nine Mabs against IBDV. This survey yielded an additional antigenic variant: the DS326 variant. This antigenic variant is characterized by the absence of epitopes for Mab 179 and BK44, in addition to those for Mabs B69 and R63 (Snyder, 1990). No further reports of antigenic variants have been published in the USA or in other parts of the world. Whether this is due to non-existence of new variant IBDV isolates or whether new antigenic variants just have not been detected due to the lack of extensive surveys or the lack of discriminating monoclonal antibodies is unclear.
The nucleotide sequence of the polyprotein-encoding part of the A-segment of the Del, the GLS and the DS326 antigenic variant IBDV isolates has been determined (Vakharia et al., 1994). Most of the amino acid changes were found in a specific region of the VP2 protein, the so-called hypervariable region. Furthermore, it was found that the epitopes which are capable of inducing neutralizing antibodies are conformation dependent and are clustered in the hypervariable region. This region consists of a domain with a high hydrophobicity index (amino acids 224 to 314 of pVP2, corresponding with amino acids 224 to 314 of the polyprotein) which is flanked by two small hydrophilic regions, each spanning about 14 amino acids (Vakharia et al., 1994; Heine et al., 1991). Amino acid substitution both within the hydrophobic region and within the hydrophilic regions might be involved in the antigenic variant character of these isolates.
After the problems caused by the antigenic variant IBDV isolates in the USA, the poultry industry in Europe was affected by very virulent IBDV (vvIBDV) isolates (Berg et al., 1991; Chettle et al., 1989). The vvIBDV isolates cause more severe clinical signs during an outbreak and are able to break through levels of antibodies which are protective against classical IBDV isolates. The molecular determinants which distinguish vvIBDV from classical IBDV isolates are not exactly known. It is known, however, that the pathogenicity of cell culture adapted very virulent IBDV isolates is severely reduced, compared with the non-adapted parental isolates (Yamaguchi et al., 1996). The correlation between CEF-adaptation and loss of the very virulent phenotype is likely to be due to the change in target cell tropism of the adapted virus. This change in cell tropism may be due to the loss of bursa cell receptor binding capability of the cell culture adapted very virulent IBDV isolate. Another possibility is that the cell culture adapted very virulent IBDV isolate is able to infect non-bursa cells, resulting in large reduction of IBDV load in the primary target cells (bursa cells). From the published results (Yamaguchi et al., 1996), it is clear that a recombinant IBDV (rIBDV) which is based upon the cDNA of a cell culture adapted very virulent isolate will never yield a vaccine which meets the demands of being able to break through high levels of maternal antibodies and induce a high enough immune response.
No specific antibodies that exclusively recognize the vvIBDV isolates have been described yet (Eterradossi et al., 1997). The lack of discriminating antibodies makes direct diagnosis difficult. Most attention has been given to sequence comparison between the hypervariable region of VP2 of classical isolates and of very virulent isolates. Sequence analysis of the vvIBDV isolate UK661 showed that only three unique (i.e., not found in non-vvIBDV isolates) amino acid substitutions are present within the hypervariable region of the VP2 protein. One amino acid substitution is present within the remaining part of the pVP2 protein, while 5 unique amino acid mutations are present within the VP4-encoding part of the polyprotein and 6 in the VP3-encoding part (Brown and Skinner, 1996). The smaller ORF of the UK661 isolate A-segment, encoding the VP5 protein, contains 2 unique amino acid substitutions. Additionally, 16 unique amino acid substitutions were found in the VP1 protein encoded by the B-segment of this vvIBDV isolate. The virulent phenotype of the vvIBDV might be influenced by each of the found amino acid substitutions, and even (silent) nucleotide substitutions within the coding or non-coding parts of either the A- or B-segment may contribute to the altered phenotype of the vvIBDV isolates in comparison with the classical or antigenic variant isolates. Serial passage on embryonated eggs of a vvIBDV isolate (OKYM) resulted in the appearance of a derivative isolate (OKYMT) which is able to grow on Chicken Embryo Fibroblast (CEF) cells and has lost its virulence. This adaptation was reported to be the result of 7 nucleotide substitutions in the polyprotein encoding part of the genome. Whether additional nucleotide substitutions (or deletions) were present in remaining parts of the A- or B-segment (e.g., untranslated regions, VP1-encoding region, and VP5-encoding region) was not determined (Yamaguchi et al., 1996). The reported nucleotide substitutions result in 5 amino acid substitutions. Three of these amino acid substitutions were located in the hydrophobic part of the hypervariable region (I256T, D279N, A284T) of VP2, one in the hydrophilic part located downstream of the hypervariable region (S315F) of VP2, and one in VP3 (A805T) (Yamaguchi et al., 1996). In an independent experiment, Yamaguchi et al. found that the adaptation of vvIBDV isolate TKSM into TKSMT resulted also in the A284T and D279N substitutions. The A284T substitution correlated in their analysis completely with adaptation onto CEF cells and loss of virulence. The D279N substitution was also present in both CEF-adapted vvIBDV isolates (OKYMT and TKSMT) and is potentially also important for growth on CEF cells and loss of virulence. The non-CEF adapted, classical IBDV isolate GBF-1 has, on the other hand, an asparagine at position 279, in combination with alanine at position 284, and cannot grow on CEF cells, so the single substitution D279N does not account for loss of virulence and growth on CEF cells. The amino acid changes in the VP2 apparently allow the modified IBDV to propagate on cells which do not have a receptor for wild-type IBDV. Cells possessing a wild-type IBDV receptor such as bursa cells are susceptible for classical and vvIBDV isolates. Recently, it was shown that amino acid substitution, A284T in combination with D279N, is indeed enough to turn a non-CEF-adapted very virulent IBDV isolate into a CEF-adapted isolate. Lim et al. introduced these two amino acid substitutions into the A-segment cDNA of vvIBDV isolate HK46 (Lim et al., 1999). After transfection of this cDNA, Lim et al. obtained an rIBDV isolate which possessed the phenotype of a CEF-culture-adapted isolate, i.e., an rIBDV isolate which is able to infect and multiply in CEF cells. The virulence of this rIBDV isolate was not assessed in chickens. Noteworthy, Lim et al. were unable to produce a recombinant infectious vvIBDV isolate using the unmodified cDNA of the HK46 isolate (Lim et al., 1999).
The goal of vaccination against IBD is prevention of subclinical and clinical IBD and the economic aspects of each. Effective vaccination for IBD can be divided into the following categories:
Protection of the developing bursa in broilers, breeders and layers.
Prevention of clinical disease in broilers, breeders and layers.
Priming and boosting of breeders.
To minimize the immunosuppressive effects of IBDV, the young chick must be protected. Protection of the very young can be achieved through high enough levels of maternal antibodies passed from the breeder hen to her progeny. Vaccination of the very young chick itself may not be successful since onset of protection after vaccination is between three and five days. When a bird, lacking maternal antibodies against IBDV, is exposed to a pathogenic IBDV field strain, damage will occur within 24–48 hours.
Generally, the early vaccinations of the breeders serve as priming. In most situations, this single vaccination is not considered to be adequate. "Boosting" is the term commonly associated with the administration of a final IBDV vaccination prior to the onset of lay. This is done to increase the circulating antibody in the hen and hence the maternal antibodies in the progeny. Both inactivated (oil emulsion vaccine) and live vaccines (IBDV) have been used for this purpose. The use of a live vaccine in an older bird will result in an increase of antibodies; however, large variations in antibody titers are often seen. These variations result in progeny becoming susceptible to field challenge from as early as a few days after hatching to 21 days after hatching. The use of inactivated IBDV vaccines gives a higher antibody titer as well as a decrease of variation between antibody titers of birds belonging to the same flock. The levels of maternal antibodies necessary to neutralize IBD vary with the invasiveness and pathogenicity of the field strain. In practical terms, if a very virulent IBDV isolate is present, higher maternal antibody levels are desired (see Table 1 for an overview of virulence of field isolates and strength of vaccines). Yet, for effective vaccination, avoiding interference with maternal antibodies is needed to induce a good immune response. Clinical IBD is typically seen between three and six weeks of age. The immune response of the chick must be stimulated as the passive protection is declining. The timing of the active vaccination may be estimated by the breeder or chick titer and the half-life of antibodies of approximately 3.5 days (De Wit and Van Loon, 1998; Kouwenhoven and Van den Bos, 1995). The levels of maternal antibodies tend to vary within a population. This variation might be a result of variation in the antibody levels of the breeder hen. Also, the mixing of progeny from several breeder flocks (e.g., combination of breeders of different age; breeders vaccinated with live vaccine and those with oil emulsion vaccine) results in variation of IBDV antibodies between chicks belonging to the same flock. If the coefficient of variation (CV) in mean maternal antibody titers is too wide, it may be recommended to vaccinate twice (with a 10 day interval) or to vaccinate early with a hot vaccine (in the presence of a high antigenic pressure).
The average titer of antibody against IBDV in a flock will decline in time (FIG. 1). As a result of the decrease in average antibody titers, an immunity gap will occur. The best results are obtained if the immunity gap is as short as possible and is as early as possible, within a minimum of 2 weeks after hatching. There should be at least sufficient immunity after active vaccination at the age of 4 weeks, since many handlings occur in the houses from that time point with risks of introducing field virus. Therefore, farmers like to vaccinate at 2 weeks or even before. Intermediate vaccines are often unable to break through the average IBDV antibody titer of the broiler at two weeks after hatching (FIG. 1). If there is a high variation in mean maternal antibody titers, some chicks will be effectively vaccinated with intermediate vaccines, others not. To circumvent those problems, hot vaccines are being used. A drawback of usage of hot vaccines is that the bursa of chickens with low-to-moderate maternal antibody titers will be (partly) damaged.
There is a wide variety of IBDV vaccines available. Important aspects in vaccination strategies are the ability of the virus to replicate in the face of maternal antibody (invasiveness of the vaccine) and the spectrum of antigenic content (including antigenic variants). The ability of a vaccine virus to replicate in the face of maternal antibodies allows live vaccines to be categorized into three main groups: mild, intermediate, and intermediate plus or hot vaccines (see Table 1).
The initial vaccines for IBD were derived from classical IBDV isolates. These vaccines were moderately pathogenic IBDV strains with low passage numbers in embryonated eggs. These were often used in breeder programs to induce high levels of circulating antibodies. However, when given to a young bird with moderate or low levels of maternal antibodies, these vaccines could cause extensive bursal atrophy resulting in immunosuppression. Mild vaccines were subsequently developed to be used in these young birds. The attenuation of classical IBDV was done in tissue culture systems. Traditionally, attenuated strains for vaccines are generated by adapting IBDV strains to chicken embryoblast (CEF) cells or other appropriate cells or cell lines through serial passages. These vaccines are not immunosuppressive even when used in birds having no maternal antibodies. However, moderate and high levels of antibodies easily neutralize them. As breeder programs developed (including the use of adjuvant, inactivated vaccines), higher levels of maternal antibodies were generated in progeny. This reduces the effectiveness of these mild vaccines.
Intermediate-strength vaccines were to overcome the inadequacies of the mild vaccines. Some of the intermediate-strength vaccines were developed by cloning a field isolate on chicken cell cultures. Intermediate-strength vaccines are capable of establishing immunity in birds with moderate levels of maternal antibodies. These vaccines will cause some bursal atrophy in birds without maternal antibodies, but are considered not immunosuppressive.
Hot (strong) or intermediate plus vaccines were developed after the first outbreaks with vvIBDV. These vvIBDV isolates could break through higher levels of maternal immunity than the vaccines that were on the market at that time. Vaccination with intermediate vaccines always came too late in situations with high infection pressure with vvIBDV. Hot vaccines consist of vvIBDV strains with low-to-moderate passage in embryonated eggs or bursa-derived IBDV of chickens infected with vvIBDV isolates. Adapting vvIBDV on cells traditionally used for the generation of vaccines in general fails, since either these cells are non-permissive for vvIBDV or, when adapted to the cells, the vvIBDV in question had lost its very virulent character, making it useless for hot or intermediate plus vaccines. Hot or intermediate plus vaccines are desirably able to circumvent maternal immunity at an earlier age than intermediate vaccines but spread more within a flock. If intermediate plus and hot vaccines are used in chickens with moderate-to-high levels of maternal antibodies, there is no negative side effect on the bursa (Kouwenhoven and Van den Bos, 1995). If these vaccines are used in chickens with low-to-moderate levels of maternal immunity, this causes depletion of lymphoid cells in the bursa and a severe depletion of peripheral blood-B cells is found (Ducatelle et al., 1995). Although a recovery of bursal function has been observed, these vaccines should be used with precautions.
Live vaccines must be given in a way in which the virus will preferably reach the bursa, where it will quickly multiply and induce an immune response. Possible routes for application of live vaccines include drinking water, spray, subcutaneous and in ovo. Inactivated IBD vaccines are used in broiler breeders. They differ in some of the same ways as live vaccines. Their efficacy depends upon the spectrum of antigens they contain. Injectable oil-emulsion products may be given subcutaneously or intramuscularly.
A continuous monitoring of the field situation using an integrated quality control scheme including serology can be a valuable tool for continuously adapting preventive vaccination programs to changing epidemiological conditions. Also, a continuous follow-up of the epidemiological situation will allow anticipation of the development of major epidemics (Ducatelle et al., 1995). However, the ability of diagnostic laboratories to monitor IBD with meaningful definitive data is difficult. Serology is important but can be confusing when all birds monitored from commercial broiler flocks have high levels of the same spectrum of circulating antibodies. Field evaluations of broilers to monitor the status of IBD are highly subjective: it is difficult to discriminate antibody titers obtained after vaccination from those induced by IBDV field infections. If it were possible to discriminate between IBDV antibody response to field virus and IBDV vaccination, it is possible to have "early warning" systems and to start IBDV eradication programs if desired. Only when there is a known difference between the antibody response to the used IBDV vaccine and IBDV field isolates, defined conclusion about whether (sub)clinical signs of IBDV are the result of live IBDV vaccination or of IBDV field isolates can be made.
The invention provides infectious recombinant Infectious Bursal Disease Virus (rIBDV) essentially incapable of growing in a cell that is not derived from a bursa cell or another cell comprising a wild-type IBDV receptor (a non-bursa cell). A bursa is a lymphoid organ, mostly comprising cells that are related to the immune system. In particular, it comprises lymphocytes or lymphocyte precursor cells of sometimes the T-cell but mainly the B-cell-type, and cells derived thereof, in close relation with monocytes or monocyte-derived cells such as macrophages, and also with follicular dendritic cells and antigen-presenting cells. In particular, the invention provides rIBDV that is essentially incapable of growing in a cell not listed among the above-identified bursa cells or cells derived thereof, such as dendritic cells, monocytes, lymphocytes or cells derived thereof. Herewith, the invention provides an rIBDV having retained an important characteristic, in that in comparison with commonly attenuated IBDV strains, it cannot or only little grow in non-bursa cells, such as the well-known CEF, QM5 or VERO cells, or other cells that are commonly used for propagating attenuated strains of IBDV. In particular, the invention provides an rIBDV essentially incapable of growing in a non-B-cell-derived cell. Essentially incapable of growing herein means that the isolate in question is not or only little capable to infect, multiply or be released for further replication. No such rIBDV isolates existed prior to this invention; all previously known rIBDV isolates grow in non-bursa cell-derived cells such as CEF cells (WO98/09646; Lim et al., 1999), thereby, for example, having lost those very virulent characteristics essential for maintaining in a vaccine strain designed to face the above-identified problems.
In a preferred embodiment, the invention provides are infectious rIBDV having retained at least part of the very virulent characteristics of a very virulent Infectious Bursal Disease Virus (vvIBDV) needed to provide protection against vvIBDV. In particular, vvIBDV is provided that is essentially incapable of growing in a non-bursa cell-derived cell. In particular, as, for example, demonstrated in the detailed description, the invention provides an rIBDV essentially incapable of growing in a CEF cell, a VERO cell or a QM5 cell, except, of course, in those CEF, VERO, QM5, or related cells having been provided with the necessary means (such as a transgenic receptor or replication system derived from a bursa cell or other characteristic of B-lymphoid cells which support the propagation of IBDV in an essentially non-lymphoid cell if this characteristic is present in such a non-B-lymphoid cell) needed for replication of classical or very virulent IBDV.
Furthermore, the invention provides an rIBDV wherein the amino acid sequence of protein VP2 comprises no asparagine at amino acid position 279, but, for example, comprises an amino acid particular for a strain with a very virulent character, such as with aspartic acid at amino acid position 279. Such rIBDV strains as provided by the invention have retained at least part of the very virulent characteristics of vvIBDV, as well as an rIBDV according to the invention wherein the amino acid sequence of protein VP2 comprises no threonine at amino acid position 284, but, for example, comprises an amino acid particular for a strain with a very virulent character, such as with alanine at amino acid position 284.
In a preferred embodiment, the invention provides an rIBDV according to the invention wherein the amino acid sequence of protein VP2 at least comprises a stretch of amino acids from about position 279 to 289, preferably from about position 229 to 314, most preferably from about position 214 to 328 as found in a vvIBDV isolate such as shown in Table 8.
The invention furthermore provides a method for obtaining an infectious recombinant copy of Infectious Bursal Disease Virus (rIBDV) essentially incapable of growing in a non-bursa cell-derived cell or having at least part of the very virulent characteristics of a very virulent Infectious Bursal Disease Virus (vvIBDV) comprising transfecting at least one first cell with a nucleic acid such as a cDNA or RNA comprising an IBDV genome at least partly derived from a vvIBDV, incubating the first cell in a culture medium, recovering rIBDV from the transfected first cell or culture medium, and propagating recovered rIBDV in at least one second cell which is permissive for vvIBDV. A vaccine derived from the recombinant virus as described is also part of this invention. Also, a vaccine comprising a chemically or physically inactivated recombinant virus or parts thereof is part of this invention.
Also, the attenuated derivatives of initially produced recombinant very virulent IBDV are part of this invention. Such a virus can be attenuated by known methods including serial passage, removing specific nucleic acid sequences, or site-directed mutagenesis. Physiologically acceptable carriers for vaccines of poultry are known in the art and need not be further described herein. Other additives, such as adjuvants and stabilizers, among others, may also be contained in the vaccine in amounts known in the art. Preferably, adjuvants such as aluminum hydroxide, aluminum phosphate, plant and animal oils, and the like, are administered with the vaccine in amounts sufficient to enhance the immune response to the IBDV. The vaccine of the present invention may also contain various stabilizers. Any suitable stabilizer can be used including carbohydrates such as sorbitol, mannitol, starch, sucrose, dextrin, or glucose; proteins such as albumin or casein; and buffers such as alkaline metal phosphate and the like. A stabilizer is particularly advantageous when a dry vaccine preparation is prepared by lyophilization. The vaccine can be administered by any suitable known method of inoculating poultry including nasally, ophthalmically, by injection, in drinking water, in the feed, by exposure, and the like. Preferably, the vaccine is administered by mass administration techniques such as in ovo vaccination, by placing the vaccine in drinking water or by spraying the animals' environment. When administered by injection, the vaccines are preferably administered parenterally. The vaccine of the present invention is administered to poultry to prevent IBD anytime before or after hatching. Poultry is defined to include but not be limited to chickens, roosters, hens, broilers, roasters, breeders, layers, turkeys and ducks. Examples of pharmaceutically acceptable carriers are diluents and inert pharmaceutical carriers known in the art. Preferably, the carrier or diluent is one compatible with the administration of the vaccine by mass administration techniques. However, the carrier or diluent may also be compatible with other administration methods such as injection, eye drops, nose drops, and the like.
As explained above, there is need for an IBDV vaccine that can protect against field infections with IBDV, and preferably against very virulent IBDV (vvIBDV). It is clear that vaccines derived from attenuated classical strains and not from very virulent strains will not be able to sufficiently protect. However, as explained above, simply adapting and cultivating a vvIBDV strain on a cell or cell-line, such as VERO, CEF or QM5, as one skilled in the art would first do in order to obtain a vaccine strain from a vvIBDV strain, reduces it virulent phenotype such that no sufficient protection is to be expected. Therefore, a vaccine strain is needed that has at least partly maintained the very virulent or hot character, in order to provide sufficient protection; however, paradoxically, such a desirable vaccine strain would most likely not be able to be sufficiently or substantially propagated on appropriate cells, such as non-bursa cell-derived VERO, CEF or QM5, deemed needed to obtain the vaccine. In a preferred embodiment, the invention provides a method wherein the first cell is a non-bursa cell-derived cell non-permissive for vvIBDV, preferably wherein the first cell has additionally been provided with a helper virus or a viral protein (herein T7-polymerase is used) derived thereof. With the help of such a cell comprising a properly selected helper virus, e.g., expressing distinct IBDV or Birna virus viral proteins, or of a cell expressing IBDV or Birna virus viral proteins, (also called a complementary cell) also now defective or deficient rIBDV can be made.
The invention therewith also provides a method to generate Infectious Bursal Disease Virus, by combining cDNA sequences derived from very virulent IBDV (vvIBDV) isolates with cDNA sequences derived from either serotype I classical attenuated IBDV isolates, serotype I antigenic variants of IBDV, or serotype II IBDV isolates, wherein the infectious copy recombinant Infectious Bursal Disease Virus, having retained at least part of the very virulent characteristics of a very virulent Infectious Bursal Disease Virus, has at least retained the incapacity to substantially be propagated on a vvIBDV non-permissive cell such as a QM5 or CEF cell.
Preferably, a method as provided by the invention provides a vaccine comprising an IBDV genome wherein parts of segments A and/or B derived from a vvIBDV are used combined with parts of segments A and/or B derived from an attenuated IBDV, such as attenuated serotype I or I IBDV. Such an rIBDV is herein also called a mosaic IBDV (mIBDV). Herein we show that (mosaic) vvIBDV can be generated from cDNA by transfection of non-susceptible cells followed by amplification of the cDNA-derived rIBDV on susceptible cells. The invention provided herein provides a method to generate vvIBDV from the cloned, full-length cDNA of a vvIBDV isolate (see Table 5 and 6). After transfection of QM5 cells with cDNA of vvIBDV, it is essential that propagation of the generated vvIBDV virus takes place on cells which are permissive for vvIBDV. These permissive cells can, for example, be found among bursa cell-derived cells such as primary bursa cells, in chicken in embryo cells, chicken embryo's, or young chickens. Using the method described herein we have, for example, produced recombinant D6948 (rD6948) using the cDNA derived from the very virulent D6948 IBDV isolate. This rD6948 isolate has the same virulence as the parental D6948 isolate (Table 6).
Preferably, the invention provides a method wherein a permissive second cell is a primary bursa cell, thereby allowing initial propagation of the desired vaccine virus. As explained above, there is a need for a vaccine capable of breaking through maternal immunity of young chickens at an early stage. A desired vaccine should preferably be able to induce a high level of protection in vaccinated young chickens, and should, therefore, be as immunogenic as very virulent viruses or be almost as immunogenic.
The invention furthermore provides a method to engineer recombinant mosaic IBDV (mIBDV) vaccine which has one or more of the desired phenotypes, i.e., i) being able to break through high levels of maternal antibodies in young chickens and being highly immunogenic, and ii) having a reduced pathogenicity compared to wild-type very virulent IBDV isolates. In one embodiment, the invention provides an infectious mosaic IBDV (mIBDV) comprising an rIBDV wherein at least one genome segment comprises nucleic acid derived from at least two different Birna virus isolates. It is preferred that at least one of the isolates is a vvIBDV characterized by its incapacity to substantially be propagated on a vvIBDV non-permissive cell, such as a VERO, QM5 or CEF cell and/or characterized by its capacity to substantially be propagated on a vvIBDV-permissive cell, such as a primary bursa cell. For example, the invention provides mIBDV which consists partly of the genome derived from a classical attenuated isolate (such as CEF94) and partly derived from the genome of a vvIBDV isolate (such as D6948). A recombinant mosaic IBDV (mIBDV), made on the basis of infectious cDNA derived from a very virulent IBDV isolate (D6948) and combined with defined parts of cDNA derived from a cell culture adapted, serotype I, classical IBDV isolate (CEF94), results in an mIBDV isolate which has a reduced pathogenicity compared to wild-type vvIBDV isolates which are essentially not replicating on non-B-lymphoid-derived cells.
Furthermore, specific nucleotide substitutions which either do or do not lead to amino acid mutations, or deletion of specific parts of the IBDV genome, again lead to an altered phenotype of the generated mIBDV. For example, the replacement of the pVP2-coding region of CEF-94 cDNA with the corresponding region of cDNA of D6948 yielded plasmid pHB36-vvVP2. This plasmid was subsequently transfected into FPT7-infected (Britton et al., 1996) QM5 cells in combination with pHB-34Z. Supernatant of these transfected QM5 cells was subsequently transferred to fresh QM5 cells. None of these QM5 cells reacted positively in an IPMA using specific antibodies for the VP3 protein of IBDV. On the other hand, primary bursa cells, after being overlaid with supernatant of the transfected cells, reacted positively in the same IPMA. The functional feature of being able to enter permissive cells such as QM5 cells is apparently located in the pVP2 coding region of the A-segment. This invention provides a method to generate recombinant vvIBDV (such as rD6948) having a pVP2 sequence exactly as found in a wild-type vvIBDV (here D6948). All very virulent isolates of which the pVP2 sequences have been described thus far have an alanine at position 284 and cannot or only little be propagated on CEF cells (see Tables 7 and 8). On the other hand, when a threonine is present at position 284, propagation on CEF cells is possible, but this is associated with the lack of a very virulent phenotype (see Tables 7 and 8). Herein we describe a method to generate infectious recombinant IBDV (rIBDV) having the nucleotide sequence of a wild-type very virulent IBDV isolate, including the alanine codon for amino acid 284 and being unable to be propagated on CEF cells. Furthermore, in our rD6948 isolate we have an aspartic acid present at position 279 instead of an asparagine commonly found for virulent IBDV isolates which can be propagated on CEF cells (Tables 7 and 8). The rD6948 is truly a very virulent rIBDV, as it is unable to grow on CEF cells (Table 5) and induces similar clinical signs and mortality as wild-type very virulent D6948 isolate (Table 6). Although mIBDV isolate (mCEF94-vvVP2) did not cause any mortality or body weight loss in a 9-day course, in contrast to the D6948, rD6948 and srIBDV-DACB isolates (also having a functional VP2 protein derived from vvIBDV, see Table 6), it caused the same reduction in bursa weight after 9 days post-infection as the wild-type very virulent D6948 isolate.
In yet another embodiment, the invention provided a mosaic IBDV according to the invention wherein at least one of the isolates is a serotype II IBDV. Such an mIBDV, preferably lacking at least one immunodominant epitope specific for a serotype I IBDV as well, is an (r)D6948-derived vaccine virus such as mD6948-s2VP3C1, also having a functional VP2 protein derived from vvIBDV, allowing vaccination with a marker vaccine. Vaccination with an IBDV marker vaccine and subsequent testing with a corresponding diagnostic test enables the discrimination between antibodies induced by the vaccine and by infection with IBDV field isolates. This mIBDV can be differentiated from all other known wild-type IBDV isolates, either belonging to serotype I or serotype II, for example, by using a specific set of monoclonal antibodies. The generation of mIBDV from serotype I and II cDNA provides such an mIBDV marker vaccine that induces a serological response in chickens that can be differentiated from the serological response induced by IBDV field strains. The marker vaccine provided by the invention, lacking at least one immunodominant epitope, preferably a serotype I epitope, enables the discrimination between vaccinated and infected animals by means of a diagnostic serologic test. Such an mIBDV marker vaccine is preferably based upon vvIBDV and contains specific sequences originating from classical serotype I or serotype II IBDV. Such an mIBDV marker vaccine has one or more of the following characteristics: i) It induces a protective immune response against vvIBDV field viruses despite high levels of maternal antibodies. ii) It has a reduced pathogenicity compared to vaccines based upon wild-type vvIBDV. iii) It, for example, misses at least one serotype I-specific antigen which enables the serological discrimination of the mIBDV marker vaccine from all serotype I IBDV isolates.
Also, the invention provides a method to produce or generate tailor-made vaccines against specific antigenic variants of IBDV by incorporating the specific amino acid changes in an mIBDV vaccine virus. Depending on the composition, these mosaic IBD viruses (mIBDV) possess different phenotypes and different antigenic properties. A specific mutation in one of the viral proteins can have a profound effect on IBDV viability. We found that this is true in the case of a single nucleotide substitution, leading to a single amino acid mutation in VP4 (V582A). No rIBDV could be rescued from cDNA when this particular nucleotide substitution was present. Not only mutations within the VP4-encoding region itself, but also mutations or deletions in the region of the cleavage sites (pVP2-VP4 and VP4-VP3) may have a negative effect on replication of rIBDV. Mutations in the other viral proteins, or even deletion of an entire viral protein (i.e., VP5), influence the replication and or virulence as well. Two groups have constructed a VP5 minus rIBDV isolate, by introducing mutations in the cDNA of a CEF-adapted D78 IBDV isolate (Mundt et al., 1997; Yao et al., 1998). Apparently, the VP5 protein, which is a non-structural protein, is also a non-essential protein. Yao et al. reported that inactivation of the ORF for VP5 (replacement of the start codon by a stop codon) yielded infectious rIBDV (rD78NS which grows to slightly lower titers (in vitro) than rD78), while Mundt et al. reported that inactivation of the ORF for VP5 (replacement of the start codon by an arginine codon) yielded an rIBDV (IBDV/VP5−) which is able to grow to the same titers (in vitro) as the parental isolate. Furthermore, Yao et al. reported that rD78NS has decreased cytotoxic and apoptotic effects in cell culture (in vitro) and has a delay in replication compared to the parental isolate (in vivo), and failed to induce any pathological lesions or clinical signs of disease in infected chickens.
Mutations or deletions in the mIBDV cDNA yields an mIBDV with a desired phenotype, i.e., mIBDV which is based on a very virulent isolate but which has a reduced ability to replicate and hence a reduced pathogenicity. The introduction of cDNA sequences from a serotype II, cell culture adapted, IBDV isolate (TY89) into the mosaic virus gives us yet another opportunity to generate marker mIBDV vaccine which can be discriminated from wild-type serotype I IBDV, for example, by using specific monoclonal antibodies. Such mIBDV can be used to induce an antibody spectrum, which differs from the spectrum induced by IBDV field isolates. This enables the development of a serologic test to determine whether IBDV antibodies are the result of live mIBDV vaccination or of infection with IBDV field isolates. For example, the mCEF94-s2VP3C virus is recognized by serotype II-specific VP3 antibody (Mab T75), while it is also recognized by a serotype I-specific VP2 antibody (Mab 1.4). This particular rIBDV is, on the other hand, not recognized by a serotype I-specific VP3 antibody (Mab B10). No apparent difference is present between the replication of mCEF94-s2VP3C and rCEF94, indicating that the exchange of the VP3C-terminal part does not lead to major changes in replication ability in QM5 cells. When, on the other hand, the complete VP3-encoding region was exchanged, we observed a severe reduction in replication ability of the resulting virus (mCEF94-s2VP3). On the other hand, mCEF94-s2VP3N was not reacting with Mab C3 (VP3, serotype I) while it is fully reacting with Mab B10 (VP3, serotype I) and only partially with Mab T75 (VP3, serotype II. Replication of this mosaic IBDV on CEF cells is reduced compared to rCEF94. From the generated mIBDV, based on cDNA derived from serotype I (CEF94) and serotype II (TY89), it is clear that a serological marker based on VP3 has been identified. The replacement of the cDNA of (part of) VP3 of serotype I for the corresponding part of serotype II leads to a unique combination of IBDV antigens within one mIBDV isolate. An mIBDV isolate based on this combination of antigens can be used as an IBDV marker vaccine.
The introduction of the VP3 C-terminal part of TY89 (Serotype II) into the cDNA of D6948 yielded a mosaic IBDV (mD6948-s2VP3C1) which has a reduced virulence (no mortality, no body weight loss) compared to D6948 or rD6948 (Table 6). This mIBDV, or a comparable isolate which is more or less virulent, is also advantageously used as an IBDV marker vaccine to prevent infections with very virulent IBDV field isolates.
Furthermore, the invention provides using site-specific mutagenesis techniques to introduce any desired nucleotide mutation within the entire genome of mIBDV. Using this technique allows adapting mIBDV vaccines to future antigenic variations by including any mutation that has been found in antigenic variant IBDV field isolates. Furthermore, it is provided by the invention to exchange part of the genomic sequence of IBDV with the corresponding part of a Birna virus belonging to another genus (e.g., DXV, EPNV, OV, TV). Herewith, the invention provides new mosaic Birna (mBirna) viruses which have new characteristics resulting in new recombinant vaccines for IBDV or other Birna viruses. Also, the use of cDNA of other Birna viruses (e.g., DXV, IPNV, OV or TV) leads to new IBDV vaccines. In this approach, one or more of the IBDV immunodominant or neutralizing epitopes are exchanged with the corresponding parts of the protein of another Birna virus.
Of course, the invention also provides a method for producing an rIBDV according to the invention, the vector comprising heterologous nucleic acid sequences derived from another virus, or (micro)organism, whereby r- or mIBDV serves as a vector. For example, a method is provided to generate an infectious copy IBDV which expresses one or more antigens from other pathogens and which can be used to vaccinate against multiple diseases. Such an infectious copy IBDV, for example, comprises a heterologous cDNA encoding a heterologous protein obtained from a pathogen, for example, poultry pathogens. Also, a method is provided to generate a conditional lethal IBDV deletion mutant which can be used as a self-restricted, non-transmissible (carrier) vaccine. Such an IBDV deletion mutant is unable to express one of the IBDV proteins, and is phenotypically complemented by supplying the missing protein by other means.
The invention is further explained in the detailed description without limiting the invention thereto.

Mosaic infectious bursal disease virus vaccines

ID-Lelystad, Instituut voor Dierhouderij en Diergezondheid B.V.


An apparatus, system, and method are disclosed for providing parallel access to a data set configured for automatic recovery. The apparatus includes an access module, a conversion module, a recovery module, and a restore module. The access module establishes parallel access to a data set configured for “pair and a spare” automatic recovery. The conversion module converts access to the data set from parallel access to single point access in response to an application instance detecting an error in the data set. The recovery module recovers the data set using an automatic recovery process initiated by the application instance that detects the error. The restore module restores access to the data set from single point access to parallel access in response to successful recovery of the data set. Providing parallel access to a data set configured for automatic recovery ensures that data transactions are performed swiftly, reliably, and efficiently.

1. Field of the Invention
This invention relates to data transactions and recovery, and more particularly relates to providing parallel access to a data set configured for automatic recovery.
2. Description of the Related Art
Application processing systems such as Information Management System (IMS®) from IBM of Armonk, N.Y. generally handle extremely important data. As a result, users of an IMS® often require rapid and uninterrupted access to highly reliable data. Consequently, IMS® systems are implemented with backup capabilities and with a redundant architecture. Users of the IMS® data typically include executable computer applications.
In the current implementation of an application processing system, a critical data set can be accessed by multiple systems. There is typically a component in each system that manages the data set and processes requests from other components. Processing of these requests involves one or more accesses to the data set to read or update the data. As commonly implemented, access to the data set is serialized such that one system has exclusive access to the data set at a time while processing a request.
One architecture typically implemented for greater reliability in serialized access systems includes two physical data sets and a third spare data set ('a pair and a spare' architecture). Software duplexing is used to maintain the two data sets as active dual copies of the same logical data. In the event of a media failure on one of the two active physical data sets, the failed data set is removed from the physical data set configuration and the remaining active data set is copied into the spare to maintain dual data sets. A request is then made of an administrator to create a new spare data set. Alternatively, the new spare data set is generated automatically. Typically, the recovery process can be performed automatically. Although the "pair and a spare" architecture is highly reliable, it is conventionally just implemented in serialized systems due to the many complexities involved in coordinating the recovery process while allowing multiple systems to access the data.
Although the "pair and a spare" architecture provides increased reliability, a bottleneck can be created between application instances constantly accessing the data set serially that hinders performance. To eliminate contention resulting from data set level serialization, it would be desirable to allow multiple systems to access the data set and process requests concurrently.
One solution implemented to allow parallel access to multiple application instances concurrently is implemented in a system using a data set backup and forward recovery logging. In a backup and forward recovery solution, multiple application instances may access the data set in parallel. However, if recovery is required, all access to the data set may be suspended while the backup data set is copied over and the forward recovery is implemented. Forward recovery logging is required to capture updates made to the data set between backup and time of failure. Implementation of this backup scheme requires that the data set be taken offline for the duration of the recovery. Additionally, typical systems require manual operation of the backup procedure. Recovery using backup and forward recovery can be prohibitively time consuming. The primary drawbacks of this system include increased system down time, and an inability to perform the recovery process automatically.
From the foregoing discussion, it should be apparent that a need exists for an apparatus, system, and method that provide parallel access to a data set configured for automatic recovery. Beneficially, such an apparatus, system, and method would overcome the many complexities of providing multiple systems access to a data set configured for high-speed automatic recovery and high availability. Information system reliability and performance will be increased without typical tradeoffs required by standard system architectures.

Apparatus, system, and method for providing parallel access to a data set configured for automatic recovery


A container for transporting laboratory-type animals comprises a base and a lid, wherein the base and the lid when assembled define a volume for receiving one or more laboratory animals therewithin. The base includes a flange for contacting the lid, wherein the lid is removably attached to the flange of the base with removable stitching.

This invention concerns containers for transporting animals, especially laboratory animals.
Smaller laboratory animals such as mice, rats, rabbits, hamsters, gerbils, and the like are generally shipped from a supplier to a laboratory in shipping crates formed of cardboard and lined with wire mesh. For example, Charles River Laboratories regularly uses crates constructed of die cut corrugated cardboard and metal screen materials and secured by metal staples. The constructed crates include six side-positioned vent areas covered with an air-filtration material which is permeable to air and minimizes passage of airborne contaminates into the crates. The crates are designed with slant-in sidewalls to enable air passage between crates that are stacked on pallets during transport.
Typical crates are sized about 24.5 inches in length, 16.5 inches in width, and 5.5 inches in height for transport of up to about thirty mice or up to about eight rats. A higher crate--about 10 inches in height--is typically used for the transport of up to two guinea pigs. In general, crates are sized to maximize transport efficiency on pallets.
The crates are also designed to properly support animal health during the shipping period. While shipping periods are variable, proper design generally assumes a period of at least 72 hours, even though most deliveries will be completed within a 48-hour period.
As noted above the crates are typically corrugated cardboard. An interior lining or coating is generally provided to make the crate impervious to animal wastes. A further interior lining is generally provided to prevent the animals from gnawing or chewing through the container.
The crates are constructed from two exterior parts: a base and a lid. The lid will usually be partially attached to the base before introducing animals for shipment. After the animals are loaded the remainder of the lid is attached to the base. When unloading the animals after shipment, the process is reversed.
A principal difficulty with the crates currently in use is that they are difficult to open. One method for attaching the lid of the container to the base is stapling. However, not only is the stapled container difficult to open, the staples protruding around the edges of the opened container are hazardous to both the animal and its handler. Another method is to add a perforated tear-strip along the top, front edge of the crate. However, the strip often does not function properly or easily and, to complete opening from the end to the mid-crate area, the two side edges of the lid must be lifted against the strength of the stapled corrugated materials, resulting in torn corrugated and uneven tear lines.

Container and method for transporting laboratory animals