C4A/C4B polyclonal antibody

The complementcomponent proteins C3, C4 and C5 are potent anaphylatoxins that are released during complement activation, a system of ligand-surface protein interactionsspecificto cells of hematopoieticlineage. These proteins belong to theα2-macroglobulin family, but retain distinctive featuresincluding an anaphylatoxin domain and a netrin (NTR) domain. The human C4 gene is polymorphic at two loci, C4A and C4B,mapping to chromosome 6p21.32. C4A
expressesthe Rodgers(Rg) blood group Ag, while C4B expressesthe Chido(Ch) blood group Ag. C4 is expressed as a precursor that iscleaved into α, β and γ chains, all ofwhich are non-identicalcleavage products. Theαchain of C4may be cleaved to produce an acidicisotype, C4a,which reactswith amino groups, and a basicisotype, C4b,which reactswith hydroxyl groups. Deficiency in the C4 gene is associatedwith autoimmune or immune complex disorders, such assystemiclupus erythematosus.