Complement Factor H is a 155kD glycoprotein that provides critical negative regulation to the alternative pathway of complement cascade. It is secreted by Kupffer cells, hepatocytes, vascular endothelial cells, and platelets, and circulates in the serum at high concentration. Complement Factor H is composed of 20 SCRs (short consensus repeats), each of which consists of ~60 amino acids with four invariant Cys residues. Alternate splicing generates a Complement Factor H isoform that is truncated following SCR7. Complement Factor H interacts with cell surface polyanions including heparin and sialoglycoproteins, and immobilized Complement Factor H supports the CD11b/CD18 integrin-dependent adhesion of neutrophils. It prevents local complement activation by sequestering complement component C3b, accelerating the decay of C3 and C5 convertases, and functions as a cofactor for the C3b inactivator, Factor I. Short consensus repeats 15-20 (SCR15-20) encompass the primary binding sites for heparin and C3b, as well as for the peptide hormone adrenomedullin. Within SCR15-20, human Complement Factor H shares 60% and 63% amino acid sequence identity with mouse and rat Complement Factor H, respectively. Dozens of mutations clustered in SCR15-20 are associated with atypical hemolytic uremic syndrome, a disorder characterized by anemia, thrombocytopenia, and renal failure. Binding of Complement Factor H to tumor cell-associated dentin matrix protein 1, bone sialoprotein, or osteopontin results in the protection of that cell from complement-mediated lysis. A variety of pathogenic microbes also express Complement Factor H binding molecules that interfere with immune clearance of the infection.
Intended Use:This BioAssay™ ELISA Development kit isdesigned for the analysis of cell culture supernates. Other sample types, such as serum and plasma, need to be validated prior to use in this kit. Each kit contains sufficient materials to run ELISAs on ~fifteen 96-well plates, provided that the following conditions are met: The assay is run as summarized in the General ELISA protocol. The recommended microplates, buffers, diluents, substrates, and solutions are used.
Storage and Stability:Store other components at 4°C. Stable for at least 6 months For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
