Complement receptors on the surface of leukocytes bind complement proteins CR2:surface of B cells and dendritic cells. Binding of activated complement fragments to CR2 amplifies antigen-induced cellular activation provides a link between the innate and acquired immune systems. Complement receptors on the surface of leukocytes bind complement proteins CR2: surface of B cells and dendritic cells. Binding of activated complement fragments to CR2 amplifies antigen-induced cellular activation - provides a link between the innate and acquired immune systems