Definition:

Membrane immune adherence receptor that plays a critical role in the capture and clearance of complement-opsonized pathogens by erythrocytes and monocytes/macrophages. Mediates the binding by these cells of particles and immune complexes that have activated complement to eliminate them from the circulation. Acts also in the inhibition of spontaneous complement activation by impairing the formation and function of the alternative and classical pathway C3/C5 convertases, and by serving as a cofactor for the cleavage by factor I of C3b to iC3b, C3c and C3d,g, and of C4b to C4c and C4d. Also plays a role in immune regulation by contributing, upon ligand binding, to the generation of regulatory T cells from activated helper T cells.; (Microbial infection) Acts as a receptor for Epstein-Barr virus.