PATHOLOGY

Detailed explanation-1: -The human C3b receptor (CR1) is a polymorphic glycoprotein which functions regulating the complement system by inhibiting the activation of C3 and C5, through its effect on their convertases, and serving as cofactor for factor I in mediating the degradation of C3b to its inactive fragment C3bi and further to C3d-g.

Detailed explanation-2: -Generally, these studies supported a possible role of C3b as a ligand that enhances immune adherence of opsonized particles in the vicinity of cells, facilitating their phagocytosis via other mechanisms mediated by iC3b or IgG.

Detailed explanation-3: -We show that purified C3b can potently trigger phagocytosis and killing of bacterial cells via Complement receptor 1.

Detailed explanation-4: -These complement receptors bind pathogens opsonized with complement components: opsonization of pathogens is a major function of C3b and its proteolytic derivatives.