Colonization factor antigen CS6 (CS6)

Colonization factor antigen CS6 (CS6) is a critical surface-associated protein complex expressed by enterotoxigenic Escherichia coli (ETEC), a primary bacterial cause of diarrhea in children in developing nations and travelers (Tobias et al., 2017, PubMed: 28137730). Unlike many other ETEC colonization factors that form hair-like fimbriae, CS6 is a non-fimbrial adhesin composed of two major structural subunits, CssA and CssB, which are essential for bacterial attachment to the human small intestinal epithelium (Wolf et al., 1997, PubMed: 9353905). This adherence is a mandatory step in ETEC pathogenesis, enabling the bacteria to colonize the gut and deliver enterotoxins that cause fluid secretion and diarrhea (Nicklasson et al., 2012, PubMed: 22564585). Because CS6 is one of the most prevalent colonization factors globally, it is a high-priority target for vaccine development, featuring prominently in multivalent oral vaccine candidates like ETVAX (Svennerholm & Lundgren, 2012, PubMed: 23074018). Therapeutic strategies focus on eliciting a robust mucosal immune response, specifically secretory IgA, to block CS6-mediated colonization and prevent disease (Svennerholm, 2011, PubMed: 21477141).

Other names

CS6 antigenColonization factor antigen VICFA/VICssA/CssB complexCS6 adhesin

Inhibition of bacterial adhesion to host intestinal epithelial cells through the induction of specific mucosal antibodies (primarily secretory IgA) that target the CS6 surface protein complex (Svennerholm, 2011, PubMed: 21477141).