BIOL 2005 Lecture Notes - Macrophage, Polysaccharide, Heparin
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30 Jan 2013
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EFFECTOR FUNCTIONS OF ANTIBODIES
determined by constant regions of HC
Ig’s in body fluids:
IgG – internal
IgA – external (on mucosal surfaces)
IgM – first one made in reponse to antigen
NO hypermutation low overall affinity
10 binding sites high AVIDITY
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
IgE – heavily glycosylated; mediates allergic reactions
Isotype Dependent Effector Functions (depends on HC)
- Transport
oIgA- mucosal
oIgG – placental
- Non-inflammatory
oall but IgE (neutralization and blocking adherence)
- Inflammatory
oIgG – phagocytosis/opsonization
oIgM/IgG – complement activation
oIgE – mast cell activation
oIgG - cytotoxicity