Colonization factor CS1 (CS1)

Colonization factor CS1 is a major fimbrial adhesin expressed by Enterotoxigenic Escherichia coli (ETEC), a leading cause of diarrheal disease in children and travelers (UniProt: P0CK95). It belongs to the Colonization Factor Antigen II (CFA/II) group and is essential for the bacteria to adhere to the human intestinal mucosa, a critical step in the infection process (PubMed: 11553240). This attachment allows ETEC to colonize the small intestine and deliver enterotoxins that cause secretory diarrhea. CS1 is a proteinaceous, hair-like appendage composed of a major subunit (CooA) and a minor subunit (CooD) assembled via the chaperone-usher pathway (PubMed: 28838682). Because of its high prevalence and role in virulence, CS1 is a key antigen in several ETEC vaccine candidates, including the oral inactivated vaccine ETVAX (PubMed: 31606315). Targeting CS1 aims to induce protective mucosal immunity, specifically secretory IgA, to block bacterial colonization and prevent disease. Research also explores the use of monoclonal antibodies to provide passive immunity against CS1-expressing strains. The structural stability and conservation of CS1 make it an attractive target for broad-spectrum ETEC prophylaxis.

Other names

CS1 fimbriaeCS1 pilusCFA/II componentCooA (major subunit)CooD (minor subunit)

Inhibition of bacterial attachment to the intestinal mucosa, preventing colonization and subsequent toxin-mediated disease.