File:Complement evasion strategies of Escherichia coli.jpg

English: To overcome complement attack, E. coli has evolved diverse immune evasion strategies: (A) capsular polysaccharide may confer resistance to complement-mediated killing. (B) E. coli proteases such as Pic and extracellular serine protease P (EspP) may cleave complement components of all three pathways or, in the case of StcE, may recruit C1 inhibitor (C1-INH) to the surface of target cells, locally downregulating complement activation by the classical pathway. (C) cquisition of the soluble complement regulators FH and C4b-binding protein (C4BP) by outer membrane protein W (OmpW) and by outer membrane protein A (OmpA)/new lipoprotein I (NlpI) may allow downregulation of the alternative and the classical/lectin pathways of complement, respectively.