Colonization factor antigen I fimbrial subunit E (CfaE) (CfaE)

CfaE is the minor, tip-localized adhesive subunit of the Colonization Factor Antigen I (CFA/I) fimbriae, which are archetypal Class 5 fimbriae found in Enterotoxigenic Escherichia coli (ETEC). It is a critical virulence factor that mediates the initial attachment of the bacteria to the human intestinal epithelium, a prerequisite for colonization and subsequent toxin delivery. Structurally, CfaE is composed of two domains: an N-terminal adhesin domain that contains the receptor-binding site and a C-terminal pilin domain that anchors the protein to the fimbrial shaft. The receptor-binding pocket of CfaE, particularly involving the conserved Arg181 residue, is the primary site targeted by neutralizing antibodies. As ETEC is a leading cause of traveler's diarrhea and childhood mortality in developing countries, CfaE has become a high-priority target for vaccine development. Current therapeutic strategies include the use of CfaE-based subunit vaccines, fusion proteins like CfaE-dmLT, and monoclonal antibodies designed to block bacterial adhesion. By preventing the binding of ETEC to host cells, these interventions aim to provide broad protection against infections caused by CFA/I-expressing strains.

Other names

CFA/I tip adhesinCfaE tip subunitMinor fimbrial subunit CfaEColonization factor antigen I tip adhesinCFA/I fimbrial subunit E

Inhibition of bacterial adhesion to host intestinal epithelial cells by neutralizing the tip adhesin; induction of protective mucosal and systemic antibodies (IgA/IgG) against the receptor-binding domain.