Enterotoxigenic Escherichia coli surface antigens and enterotoxins (ETEC surface antigens and enterotoxins)

Enterotoxigenic Escherichia coli (ETEC) surface antigens and enterotoxins are the primary virulence factors responsible for ETEC-mediated diarrheal disease, a leading cause of morbidity in children in developing countries and travelers (CDC, 2024). The surface antigens, collectively termed colonization factors (CFs), are diverse proteinaceous structures such as fimbriae (e.g., CFA/I, CS1-CS6) that enable the bacteria to adhere to and colonize the small intestinal mucosa (UniProt, 2024). Once colonized, ETEC secretes heat-labile (LT) and/or heat-stable (ST) enterotoxins; LT is a multisubunit protein that activates adenylate cyclase, while ST is a small peptide that activates guanylate cyclase C (GC-C) (PubMed, PMID: 29330113). These antigens and toxins serve as the principal targets for vaccine development, where the goal is to induce mucosal IgA antibodies that neutralize the toxins and block bacterial attachment (WHO, 2023). Current therapeutic approaches include oral inactivated whole-cell vaccines like ETVAX and recombinant toxin subunits designed to provide broad protection against the numerous ETEC serotypes (PubMed, PMID: 31606314).

Other names

Colonization factorsCFsHeat-labile enterotoxinLTHeat-stable enterotoxinSTCFA/ICS1CS2CS3CS4CS5CS6Bacterial adhesins

Induction of mucosal IgA antibodies to neutralize enterotoxins and inhibit bacterial adhesion to the intestinal epithelium (PubMed, PMID: 29330113).