<prompt> Secretions are rich in which immunoglobulin?IgGIgAIg MIg D  <response>: ANSWER: B IgAREF: Wintrobes clinical haematology, 12th edition volume 1 page 440, Jawrett s 24th edition Section II. Immunology Chapter 8. ImmunologySee APPENDIX-20 for IMMUNOGLOBULINS 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 