Complement receptor 2 in the regulation of the immune response

Antigens coated with split products of C3, the result of complement activation, are capable of crosslinking the complement receptor 2 (CR2, CD21) and the antigen receptor on the surface of B cells simultaneously. This dual recognition leads to increased cell proliferation and differentiation and enhanced antibody production. CR2 is also considered to be a regulator of the B cell response to antigen. In this review we summarize the biology of the CR2 and focus on its essential role in generating an effective B cell response to antigenic stimuli. The involvement of CR2 in the pathophysiology of infectious and autoimmune diseases is also discussed.