Enterotoxigenic Escherichia coli colonization factor CS3 fimbrial adhesin (CS3)

The Enterotoxigenic Escherichia coli (ETEC) colonization factor CS3 fimbrial adhesin is a critical surface protein complex used by ETEC strains to attach to the human intestinal mucosa. CS3 is a major component of the Colonization Factor Antigen II (CFA/II) group and is frequently associated with ETEC strains causing moderate-to-severe diarrhea in children in low-income countries and travelers (PMID: 25635027). Structurally, CS3 fimbriae are thin, flexible fibrillae that facilitate stable anchoring to host cell receptors, which is a prerequisite for the delivery of enterotoxins that cause fluid secretion (PMID: 19151142). Because of its high prevalence and essential role in pathogenesis, CS3 is a primary target for the development of broad-spectrum ETEC vaccines, such as the oral inactivated vaccine ETVAX (PMID: 31101317). Therapeutic strategies focus on blocking this adhesion step through vaccine-induced mucosal immunity or passive administration of specific antibodies to prevent the onset of diarrheal symptoms (PMID: 28838600).

Other names

CS3 fimbriaeColonization factor antigen IIICFA/II CS3ETEC CS3 adhesinCS3 pilin

Vaccines and antibodies targeting CS3 work by inducing or providing neutralizing antibodies that bind to the fimbrial adhesin, thereby sterically hindering the bacteria's ability to attach to the intestinal epithelium and preventing colonization (PMID: 31101317, PMID: 28838600).