Biotin Anti-C5b-9 + C5b-8 antibody [aE11]

Supplementary info

This supplementary information is collated from multiple sources and compiled automatically.

Activity summary

The C5b-9 complex also known as the membrane attack complex (MAC) plays an important role in the immune system specifically in the complement cascade. This complex forms as a result of the sequential interaction of complement proteins C5b C6 C7 C8 and multiple C9 molecules creating a pore in the membrane of target cells leading to cell lysis. The C5b-8 serves as an intermediary in the formation of the C5b-9 complex and contributes to the initial assembly of the membrane attack complex. Expression of these components predominantly occurs on the surface of lymphocytes and activated macrophages though the exact mass of the assembled complex is less often quoted in standard references.

Biological function summary

C5b-9 disrupts cellular homeostasis by forming transmembrane channels that permit unregulated ion movement. This function is pivotal in innate immunity where it eliminates virally infected and neoplastic cells. The C5b-9 complex forms through progressive recruitment and insertion of complement proteins into pathogenic membranes with each molecule one step closer to full assembly and execution of its lytic activity. In many immune system-related literature it represents terminal complement complexation signifying the endpoint of complement-mediated cytotoxicity.

Pathways

C5b-9 is an integral component of the complement system's terminal pathway. This pathway escalates from the activation of C3 to the cleavage of C5 with C5b serving as an anchor for further protein assembly. The complement cascade also intersects with coagulation pathways bridging roles between immune defense and clotting functions. In this pathway association with proteins such as C3b and C6 is essential for initiating and propagating complex formation and ultimately cellular destruction.

Associated diseases and disorders

The C5b-9 complex has notable involvement in autoimmune diseases and renal disorders. Paroxysmal nocturnal hemoglobinuria a condition characterized by red blood cell lysis directly involves excessive C5b-9 deposition due to defective complement regulation on host cells. Similarly atypical hemolytic uremic syndrome which results in kidney damage often links to mutations affecting regulators of C5b-9 activity showing the complex's contribution to pathogenesis. Employing therapeutic strategies researchers often target components like C5 and C9 to mitigate the harmful overactivation or misdirection of this complement activity.