The anaphylatoxin C5a: Structure, function, signaling, physiology, disease, and therapeutics

The complement system is one of the oldest known tightly regulated host defense systems evolved for efficiently functioning cell-based immune systems and antibodies. Essentially, the complement system acts as a pivot between the innate and adaptive arms of the immune system. The complement system collectively represents a cocktail of similar to 50 cell-bound/soluble glycoproteins directly involved in controlling infection and inflammation. Activation of the complement cascade generates complement fragments like C3a, C4a, and C5a as anaphylatoxins. C5a is the most potent proinflammatory anaphylatoxin, which is involved in inflammatory signaling in a myriad of tissues. This review provides a comprehensive overview of human C5a in the context of its structure and signaling under several pathophysiological conditions, including the current and future therapeutic applications targeting C5a.

Automated summary

The complement system is an ancient host defense system that regulates the immune response. It acts as a bridge between innate and adaptive immunity. The complement system consists of various glycoproteins that control infection and inflammation. C5a is the most potent proinflammatory anaphylatoxin and plays a role in inflammatory signaling in different tissues. This review provides a comprehensive overview of human C5a, including its structure, signaling, and potential therapeutic applications.