Factor I Antibody (Monoclonal - #2)

Factor I is one of the complement proteins which is unique to the Alternative Pathway. It is a 88 kD glycoprotein composed of heavy (50 kD) and light (38 kD) chains linked by disulphide bonds. Factor I is a highly specific serine protease which cleaves the alpha chain of C3b and C4b leading to the formation of iC3b and C3f, followed by C3c and C3d, g. It does not function effectively without a cofactor, such as Factor H, CR1, MCP or CR2. The concentration of Factor I in human serum/plasma is ~34 μg/ml. The Alternative Complement Pathway provides innate protection against microbial agents in the absence of specific antibodies. The activation of this complement pathway can be triggered by a variety of substances, including microbial polysaccharaides or lipids, gram-negative bacterial lipopolysaccharides, and surface determinants present on some viruses, parasites, virally infected mammalian cells, and cancer cells. In autoimmune diseases, the Alternative Complement Pathway may contribute directly to tissue damage.