Which of the following immunoglobulin is a pen tamer?
IgG
IgA
IgM
IgD
ANSWER: (C) IgMREF: Jawetz, Melnick, & Adelberg's Medical Microbiology, 24TH edition Chapter 44 Chapter 8Repeat in December 2010See APPENDIX-20 below for "IMMUNOGLOBULINS"Note: 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 a pentamer composed of five H..L. units (each similar to one IgG unit) and one molecule of J (joining) chain. APPENDIX - 20Immunoglobulins IgGIgAIgMIgDIgEHeavy chaingaudePercentage75-85 (max)7-155-100.30.019 (min)Carbohydrate %41010.71212serum half-life (days)21 (max)6532 (min)Concentration12 mg/ml2 mg/ml1.2 mg/ml0.03 mg/ml0.00004 mg/mlMolecular formmonomerSerum IgA = monomerPentamerMonomerMonomer Secretory IgA = Dimer Molecular weight150,000(lightest)Serum IgA = 160,000950,000(heaviest)175,000190,000Secretory IgA = 400,000SubclassesIgGl > IgG2 > IgG3 > IgG4IgAl = circulatory, IgA2 = secretoryMl, M2nonenoneComplimentactivationClassical ++ G4 subclass= alternateAlternate (only IgAl fixes complement)Classical +++AlternateAlternate or NoneSedimentationcoefficient7SMonomer = 7S7S7S8SDimer = 15SPlacental crossingYesNoNoNoNoPresence in milkPresentPresentAbsentAbsentAbsentCompartmentEqual in intravascular (45%) and extravascular(55%)compartmentMostly extravascular (Minimum intravascular distribution)mostlyintravascular MostlyextravascularHeat stabilityStableStableStableStableHeat labileAlso know- Producessecondaryresponse - First to appear in fetus (20 wk)- Producesprimaryresponse Homocytotropic
Anitibody