Unformatted text preview: C3 is central to both the classical and alternative pathways. In classical, C4b2b convertase cleaves C3 into C3a/b. C3a is a potent anaphylatoxin. C3b combines with C4b2b to form C4b2b3b complex that is a C5 convertase. C3b can also bind directly to cells making them susceptible to phagocytosis. C5 is converted by C5 convertase (i.e. C4b2b3b) to C5a/b. C5a has potent anaphylatoxic and chemotaxic activities. C5b functions as an anchor on the target cell surface to which the lytic membrane-attack complex (MAC) forms. MAC includes C5b, C6, C7, C8 and C9. Once C9 polymerizes to form a hole in the cell wall, lysis ensues....
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- Fall '10
- Microbiology, C3 convertase, convertase (i.e., actual recognition portion