Enterotoxigenic Escherichia coli antigens (ETEC antigens)

Enterotoxigenic Escherichia coli (ETEC) antigens are the primary virulence factors of ETEC, the leading cause of bacterial diarrhea worldwide, particularly in children and travelers to endemic areas (Qadri et al., 2005, Clinical Microbiology Reviews). These antigens include heat-labile enterotoxin (LT), heat-stable enterotoxin (ST), and a variety of colonization factors (CFs), which are surface-expressed fimbriae or pili (Fleckenstein et al., 2010, Nature Reviews Microbiology). LT is an AB5-type toxin that increases intracellular cAMP levels, while ST is a small peptide that activates guanylate cyclase C to increase cGMP, both leading to chloride secretion and water loss in the intestine (Walker et al., 2015, Vaccine). Colonization factors facilitate the initial attachment of the bacteria to the intestinal mucosa, a prerequisite for colonization and subsequent toxin delivery. These antigens serve as the target for both prophylactic vaccines, such as the whole-cell inactivated ETVAX, and passive immunotherapies like hyperimmune bovine colostrum. Because the cholera toxin B-subunit is highly homologous to the ETEC LT B-subunit, certain oral cholera vaccines provide cross-protective immunity against LT-producing ETEC strains (Clemens et al., 2004, The Lancet).

Other names

ETEC toxinsColonization factorsHeat-labile enterotoxinHeat-stable enterotoxinCFAColonization factor antigens

Neutralization of LT and ST enterotoxins to prevent fluid secretion and blockade of colonization factors to inhibit bacterial adherence to the intestinal epithelium.