Coli surface antigen 2 (CS2) (CS2)

Colonization factor CS2, also known as Coli surface antigen 2, is a fimbrial adhesin expressed on the surface of Enterotoxigenic Escherichia coli (ETEC) [1, 8]. ETEC is a major bacterial cause of watery diarrhea in children in low-income countries and is the most frequent cause of traveler's diarrhea worldwide [3, 6]. CS2 is a key component of the Colonization Factor Antigen II (CFA/II) complex, which facilitates the initial attachment of the bacteria to the human intestinal epithelium, particularly in the small intestine [2, 14]. This adherence is a prerequisite for colonization and the subsequent delivery of enterotoxins that disrupt fluid homeostasis [6, 24]. As a critical virulence factor, CS2 is a primary target for the development of prophylactic vaccines and therapeutic antibodies [24, 29]. It is included in several multivalent vaccine candidates, such as the live attenuated ACE527 and various multiepitope fusion antigens (MEFAs), which aim to induce mucosal IgA and systemic IgG antibodies [30, 31]. These antibodies function by binding to the CS2 fimbriae, thereby blocking bacterial adhesion and preventing the onset of diarrheal disease [2, 32]. Research into the structural subunits of CS2, including the major subunit CotA and the tip adhesin CotD, continues to inform the design of broad-spectrum interventions against ETEC infections [22, 25].

Other names

Colonization factor CS2CS2 fimbriaeCS2 piliCFA/II componentCotA (Major subunit)CotD (Tip adhesin)

Inhibition of bacterial adhesion to host intestinal epithelial cells by inducing or providing neutralizing antibodies (IgA/IgG) that target the CS2 fimbriae, thereby preventing colonization and subsequent enterotoxin-mediated diarrhea [2, 31, 32].