<prompt> Pentameric antibody with a J chain is?IgAIgGIgMIgE  <response>: ANSWER: C IgMREF: Jawetz, Melnick, Adelbergs Medical Microbiology, 24 11 edition Chapter 44 Chapter 8 See APPENDIX-20 below for IMMUNOGLOBULINSNote: Both secretory IgA dimeric and IgM pentameric have J chainsIgM is the main immunoglobulin produced early in the primary immune response. IgM is present on the surface of virtually all uncommitted B cells. It is composed of five H..L-, units each similar to one IgG unit and one molecule of J joining chain. APPENDIX - 20Immunoglobulins IgGIgAIgMIgDIgEHeavy chaingaudePercentage75-85 max7-155-100.30.019 minCarbohydrate 41010.71212serum half-life days21 max6532 minConcentration12 mgml2 mgml1.2 mgml0.03 mgml0.00004 mgmlMolecular formmonomerSerum IgA monomerPentamerMonomerMonomer Secretory IgA Dimer Molecular weight150,000lightestSerum IgA 160,000950,000heaviest175,000190,000Secretory IgA 400,000SubclassesIgGl IgG2 IgG3 IgG4IgAl circulatory, IgA2 secretoryMl, M2nonenoneComplimentactivationClassical G4 subclass alternateAlternate only IgAl fixes complementClassical AlternateAlternate or NoneSedimentationcoefficient7SMonomer 7S7S7S8SDimer 15SPlacental crossingYesNoNoNoNoPresence in milkPresentPresentAbsentAbsentAbsentCompartmentEqual in intravascular 45 and extravascular55compartmentMostly extravascular Minimum intravascular distributionmostlyintravascular MostlyextravascularHeat stabilityStableStableStableStableHeat labileAlso know- Producessecondaryresponse - First to appear in fetus 20 wk- Producesprimaryresponse Homocytotropic 