Enterotoxigenic Escherichia coli colonization factor antigen (CFA, or CS)

Enterotoxigenic Escherichia coli surface antigens denote a highly diverse group of surface-exposed proteins critical for the initial binding and colonization of the human small intestine by ETEC. The best-characterized among these are the colonization factors (CFs) or coli surface antigens (CSs), which include several families of pili/fimbriae (such as CFA/I, CS3, CS23, CS26), assembled via the chaperone-usher pathway, as well as afimbrial adhesins. These antigens function primarily as adhesins, facilitating ETEC attachment to intestinal epithelial cells—an essential prerequisite for the subsequent delivery of enterotoxins (heat-labile and heat-stable toxins) that cause secretory diarrhea. Targeting these surface molecules has driven modern ETEC vaccine development, with antigens like CFA/I tip adhesin (CfaE) and YghJ being explored for recombinant subunit vaccines. Due to their central role in pathogenesis and immunogenicity, ETEC surface antigens are considered premier targets for both prophylactic and therapeutic interventions, although high antigenic variability and presence in nonpathogenic strains complicate universal targeting

Other names

Coli surface antigen(s)Colonization factor(s)Adhesive fimbriaePili/fimbriae (ETEC-specific)Molecular names (e.g., CFA/I, CS3, CS23, CS26)

Vaccines/antibodies: Block bacterial adhesion to host epithelial cells and prevent colonization and subsequent toxin delivery Transcriptional inhibitors (experimental): Block expression of CF antigens by targeting regulatory proteins (e.g., Rns via decanoic acid)