5: Complements

where are complement proteins synthesized?

liver

which complement proteins cause vasodilation via histamine release?

C3a, C4a, C5a

deficiency in formation of the membrane attack complex (C5b-C9) will result in increased susceptibility to which bacteria?

Neisseria meningitidis

what is the primary function of the C1-like complex in the lectin pathway?

splitting C4 and C2

what forms C3 convertase in the classical and lectin complement pathways?

C4b2b

which steps are common to all complement pathways?

• cleavage of C3 by C3 convertase

• formation of C5 convertase

• formation of the membrane attack complex (MAC)

C4b2b3b forms what in the classical and lectin complement pathways?

C5 convertase

what is the activating step of the alternative pathway?

direct binding of C3 to the microbial cell surface

what can activate the classical complement pathway?

IgM or IgG

what is the primary function of C3b?

opsonization

which complement protein is able to stimulate neutrophil chemotaxis and increase histamine release from mast cells?

C5a

what causes the prevention of the cleavage of C2 and C4?

C1-esterase inhibitor (C1inh)

which complement pathway is activated by the binding of mannose?

lectin