Coli surface antigen 6 colonization factor (CS6)

CS6 colonization factor is a surface-exposed, polymeric adhesin complex found on enterotoxigenic Escherichia coli (ETEC). It consists of two protein subunits, CssA and CssB, which are assembled in a chaperone-usher dependent pathway and arranged alternately into linear fibers through donor strand complementation. CS6 mediates adherence of ETEC to the small intestinal epithelium primarily by binding to the extracellular matrix protein fibronectin on host cells. It plays a central role in pathogenesis by facilitating ETEC colonization, which enables toxin delivery. CS6 is one of the most widespread colonization factors among ETEC strains. Due to its essential function in infection, CS6 is a major candidate for vaccine development and therapeutic intervention, although subtype variability, differential immunogenicity of its subunits, and antigenic diversity pose therapeutic challenges.

Other names

CS6 colonization factorColi surface antigen 6ETEC CS6CssA/CssB adhesin

Antibody neutralization: antibodies directed at CS6 (or CssA/CssB) inhibit bacterial adhesion, preventing colonization. Peptide inhibitors: synthetic peptides mimicking critical regions of CS6 (especially CssA) can block interaction with host receptors (e.g., fibronectin).