TBPP_Immunoglobulin

5 isotypes (IgM, IgD, IgG, IgA, IgE), 4 IgG subclasses (1-4) and 2 IgA subclasses (1-2), isotype switching: change of constant domains while retaining the variable domains = change of effector function (depending on pathogens). Hinge regions in IgD, IgG, IgA but not in IgM and IgE, different glycosylation patterns (N- and/or O-)

joined by J-chain (protein), f.e. pentameric IgM (with J-chain), hexameric IgM (without J-chain), dimeric IgA (50% in the body, the rest monomeric, with J-chain), secretory IgA (with J-chain and secretory component, more stable)

ribbon structure, used in all Ig's, building blocks, for IgG1: 2xVL, 2xCL, 2xVH, 2xCH1, 2xCH2, 2xCH3 and hinge-region, IgM and IgE: 4 CH-domains, IgG and IgA: 3 CH-domains

treatment with papain: Fab and Fc, treatment with pepsin: F(ab')2 and peptide fragments, special effector functions for therapeutical use (f.e. Fab in Lucentis, prevents tumours from growth)

antigen, C3a, C3b, FcyR, FcRn, CDR

large amount of variability caused by V-D-J rearrangement (changes in parts of light and heavy chain, different combinations)

hypervariable stretches in VL and VH chains, responsible for specific contact to antigens, can be edited to increase binding affinity, create a shape putting AS together

IgG most abundant of Ig's, longest half life (21 days), IgD and IgE in lowest amounts available