A Safety Catch on Immune Response

摘要

The complement system is an integral part of the innate immune system. When triggered, it initiates a cascade that marks intruders for elimination and stimulates immune responses. The key amplification step is cleavage of a complex comprising the complement fragment C3b and factor B (C3bP" by factor D (FD). Forneris ef al. (p. 1816) now describe the cr al structure of C3bB and its complex with FD.