Table 5-5

CR1

CR1

clears immune complexes, enhances phagocytosis, regulates C3 breakdown

CR2

enhances B-cell activation, B-cell coreceptor, and retention of C3d-tagged complexes

CR3

binds adhesion molecules on leukocytes, facilitates extravasation, iC3b binding enhances opsonization of immune complexes

CR4

iC3b-mediated phagocytosis

CRIg

iC3b-mediated phagocytosis and inhibition of alternative pathway

C1qRp

induces T-cell activation, enhances phagocytosis

SIGN-R1

enhances opsonization of bacteria by MZ macrophages

C3aR

induces degranulation

C5aR

induces degranulation, chemoattraction, acts with IL-1B and TNF-a to induce acute response, induces respiratory burst in neutrophils

C5L2

uncertain, but likely down-regulates proinflammatory C5a