anti-Complement C3, mAb (10A1)

Human Complement C3 (C3) is synthesized as a single-chain pro-molecule (185 kDa) that then suffers several post-translational modifications. Before being secreted as a mature protein, C3 is split into β-chain (645 residues and 70 kDa) and α-chain (992 residues and 115 kDa) and forms a rare internal thioester bond. C3 plays a central role in the activation of all the three pathways of complement activation i.e. the classical, alternative, and lectin pathway. As C3 is the major complement component and participates in several stages of the immune response, its deficiency generally associated with higher susceptibility to severe bacterial infections and in some cases with autoimmune diseases such as systemic lupus erythematosus. C3 plays a central role in the activation of the complement system. Its processing by C3 convertase is the central reaction in both classical and alternative complement pathways. After activation C3b can bind covalently, via its reactive thioester, to cell surface carbohydrates or immune aggregates. Derived from proteolytic degradation of complement C3, C3a anaphylatoxin is a mediator of local inflammatory process. It induces the contraction of smooth muscle, increases vascular permeability and causes histamine release from mast cells and basophilic leukocytes.