Complement component 5 alpha chain (C5)

Complement component 5 (C5) alpha chain is a critical structural and functional component of the C5 protein in Mus musculus, serving as a central node in the terminal pathway of the complement system (UniProt: P06684). Upon activation by C5 convertases, the alpha chain is proteolytically cleaved into two distinct fragments: C5a, a potent anaphylatoxin that mediates chemotaxis and inflammatory cell recruitment, and C5b, which initiates the assembly of the membrane attack complex (MAC) (PubMed: 11544334). In mice, the C5 alpha chain is a primary target for studying complement-mediated pathologies, including glomerulonephritis and rheumatoid arthritis, often utilizing the BB5.1 antibody as a surrogate for human therapeutics (PubMed: 8225556). Pharmacological inhibition of this target prevents the downstream formation of MAC and the release of C5a, effectively mitigating tissue damage in various autoimmune and hemolytic disorders. While highly effective in controlling complement-driven diseases, targeting C5 significantly increases the risk of infections by encapsulated bacteria, necessitating prophylactic measures in clinical and experimental settings.

Other names

C5aC5bComplement C5 alpha chainHcHemolytic complementCPAMD4

Inhibition of C5 cleavage into C5a and C5b by C5 convertase, preventing the formation of the membrane attack complex and the release of proinflammatory anaphylatoxins.