Human Complement Factor H-related 5/CFHR5 Antibody

The human complement factor H protein family consists of the complement and immune regulators factor H, the factor H‑like protein 1 (FHL-1) and five factor H‑related proteins (FHR-1 to -5) (2). Members of this family are exclusively composed of individually folded protein domains, termed short consensus repeats (SCRs) or complement control modules. The genes of this family have been located in human chromosome 1q32, which is known as the regulator of complement activation (RCA) gene clusters (3). FHR-5 has been identified initially as a universal component of complement deposits (1), and detected in glomerular immune deposits (4). The pattern of deposits is similar to other complement components, suggesting that FHR-5 may play a role in complement activation and regulation. It is synthesized in the liver and consists of 9 SCRs. Its biological function is not understood fully. FHR-5 exhibits similar characteristics as those of factor H in heparin binding, CRP binding, and lipoprotein association (5). Weak factor I-dependent cofactor activity for C3b cleavage has also been observed (5).