FHR-5, Human, mAb clone 5.1

Anti-FHR-5; clone 5.1 is a mouse monoclonal antibody recognizing human full length Complement Factor H-related protein 5 (FHR-5), a glycoprotein belonging to the family of complement regulatory proteins. It is synthesized and secreted primarily by the liver but also by immune cells such as monocytes, macrophages, and dendritic cells. FHR-5 has an approximate molecular weight of 65 kDa. Structurally, FHR-5 shares homology with Complement Factor H (CFH), a key regulator in the complement system. Also FHR-5 is part of the complement regulatory network, predominantly within the alternative pathway (AP) of the complement system. Many host ligands have been identified for FHR-5, such as C3b, heparin, CRP, PTX3 and components of the extracellular matrix. Various reports show that FHR-5 enhances the promotion of AP activation on cell surfaces. Surface-bound FHR-5 serves as a platform for the assembly of the AP C3 convertase. In addition, FHR-5 may compete with FH binding to certain surface ligands and inhibit FH regulatory activities. With regards to its role disease, (rare) genetic variants in the CFHR5 gene have been found in patients with atypical hemolytic uremic syndrome (aHUS) and age-related macular degeneration (AMD) and may contribute to the disease. In addition, circulating and glomerular FHR-5 associates with IgA nephropathy (IgAN) and familial C3 glomerulopathy (C3G). However, contradictory outcomes have been reported regarding FHR-5’s involvement in these diseases and other genes may also play a role, emphasizing the need for further research.