Membrane attack complex (MAC) in complement system is -

Ans. is C. C5-9 Components of complement cascade mediate various biological responses o C5a, C3a, to a lesser extent C4a - are called anaphylotoxin because they have effects similar to those of mast cell mediators that are involved in the reaction called anaphylaxis. These effects are due to stimulation of histamine release by these anaphylotoxin. The effects are increased vascular permeability and vasodilatation. o C5a is a powerful chemotactic agent o C3b, C3bi act as opsonin and enhance phagocytosis. o C5-9 called membrane attack complex (MAC). It forms channel in the lipid membrane and causes cell lysis (including bacteria).