BLG 307 Lecture Notes - Polysaccharide, Zipper, Macrophage
Document Summary
Effector functions of antibodies determined by constant regions of hc. Igm first one made in reponse to antigen. Igg 4 subclasses (varying hinge region flexibility, glycosylation sites) some respond to t-independent antigens (lps) - igg2, igg4 otherwise, predominant reponse is from igg1. Iga monomer in serum; active as a dimer on mucosal surfaces held together by j-chain and secretory component. Transport: iga- mucosal, igg placental. Non-inflammatory: all but ige (neutralization and blocking adherence) Inflammatory: igg phagocytosis/opsonization, igm/igg complement activation, ige mast cell activation, igg - cytotoxicity. Mucosal transport 3g of iga made daily; very little enters systemic transport submucosal lymphoid follicle secretes iga (trachea, for example) No change in serum iga, igm levels dimerization: J-chain: connected to iga c 3 by disulphide bonds made in b cells. Sc (secretory component) produced by mucosal epithelium. Sc1 non-covalently binds c 3 of dimeric iga (or igm) Sc5 disulphide bonds to c 2 cytoplasmic tail targeting secreted on basolateral surface of epithelium.
