Scientists claim they are one step closer to creating a drug that can cure HIV . A team of researchers has been customising a defence system used by bacteria and training this scissor-like machinery to recognise the HIV virus . In their tests , they found that the technique could completely remove up to 72 per cent of cells that had been infected with HIV . A team of researchers has been customising a defence system used by bacteria and training this scissor-like machinery to recognise the HIV virus ( pictured ) CRISPR technology precisely changes target parts of genetic code . Unlike other gene-silencing tools , the Crispr system targets the genome 's source material and permanently turns off genes at the DNA level . The DNA cut – known as a double strand break – closely mimics the kinds of mutations that occur naturally , for instance after chronic sun exposure . But unlike UV rays that can result in genetic alterations , the Crispr system causes a mutation at a precise location in the genome . When cellular machinery repairs the DNA break , it removes a small snip of DNA . In this way , researchers can precisely turn off specific genes in the genome . 'Evolution has led to some of the most astonishing mechanisms for protecting organisms against their natural pathogens , ' says Juan Carlos Izpisua Belmonte , a professor of Salk 's Gene Expression Laboratory in California . 'Understanding the immune responses by which bacteria protect themselves against viral infections has allowed us to engineer novel platforms for the targeting of devastating viruses , such as HIV , in human patients . ' When a copy of the HIV virus sneaks into a human cell , it can cause havoc . It takes control of the cell 's own molecular machinery to made copies of the virus 's genetic material and then buries these copies in the cell 's own genes . From there , the host 's cell becomes an HIV factory , making new copies of the virus to spread throughout the body . Existing HIV drugs target individual steps of this lifecycle ; some stop the virus from integrating into cells ' DNA , for instance , while others try to stop the affected cells from producing more virus . The problem with these drugs , explains Hsin-Kai Liao , a research associate in the Izpisua Belmonte lab , is that they do n't actually remove the copies of the virus that are hidden within cells ' DNA . These copies can remain dormant for years and then activate again . 'Patients normally need to take drugs every day or every week for their whole lives , because of the HIV that can be latent , ' says Professor Liao . 'This costs money , time and effort . ' To combat this problem , the team turned to a molecular defence system called CRISPR that bacteria use to cut up foreign DNA at specified spots . Since its recent discovery , scientists have started using CRISPR to edit genes . But the researchers were also intrigued by its defensive ability and wondered if CRISPR could be programmed to slice and destroy viruses inside human cells . The new Salk study showed that the method is effective against active , full-length HIV rather than a shortened , inactive version of the virus . Pictured are the study team , from left : John Martlett , Juan Carlos Izpisua Belmonte , Hsin-Kai Liao , Yuta Takahashi , Concepcion Rodriguez Esteban , Tomoaki Hishida and Mo Li . CRISPR uses bits of genetic material called guide RNAs to dictate its cuts , so the scientists developed guide RNAs that bound to unique spots on the HIV virus . They added CRISPR , the guide RNAs and other molecules needed for the system to work to immune cells that had been infected with HIV . They found that CRISPR successfully cut the right spots in HIV 's genes , inactivating the virus . This resulted in the virus being completely removed from up to 72 per cent of cells . Not only did CRISPR chop up loose copies of the virus as they initially infected the cell , but it also cut up HIV that was hidden and dormant within the cells ' DNA . While other research groups have taken similar approaches in targeting CRISPR to HIV , the new Salk study showed that the method is effective against active , full-length HIV rather than a shortened , inactive version of the virus . The Salk team also illustrated in a more complete way how CRISPR targets HIV in living human cells , verifying that it works both before and after the virus is embedded in the genome . Not only did CRISPR chop up loose copies of the virus as they initially infected the cell , but it also cut up HIV that was hidden and dormant within the cells ' DNA . 'CRISPR can actually excise the virus out of the human genome , ' Liao says . Next , Liao and his colleagues tried adding the CRISPR system to human cells before they becoming infected with HIV . 'Having the system in place , they showed , prevented an infection–CRISPR chopped up any copies of the virus before they could start replicating . More research is needed to determine how the technology could be used in human patients and whether HIV will quickly evolve to escape CRISPR . With that in mind , the team is studying the effectiveness of adding more guiding RNAs to the CRISPR mix so that the defence simultaneously recognizes more areas of the virus . 'The HIV virus can mutate very quickly , ' says Liao . 'If we target multiple regions at the same time , we reduce the chance that the virus can develop resistance . '
Scientists trained scissor - like machinery of bacteria to recognise HIV . They ##PR method successfully cut HIV 's genes , destroying the virus . This resulted in the virus being removed from up to 90 per cent of cells . CRISPR method also cleaned up HIV that was dormant within the cells ' DNA . Latest study shows the method is effective against active , full - length HIV rather than a shortened , inactive form of the virus .