CS3 fimbrial subunit (CS3)

The CS3 fimbrial subunit is a critical surface protein found on Enterotoxigenic Escherichia coli (ETEC), one of the leading causes of bacterial diarrhea worldwide (WHO, 2023). It is a component of the Colonization Factor Antigen II (CFA/II) complex and functions as an adhesin, mediating the attachment of the bacteria to the human intestinal mucosa (UniProt: P0CK95). This attachment is a prerequisite for the delivery of enterotoxins that cause fluid secretion and diarrhea (Qadri et al., 2005). Because of its prevalence in clinical ETEC isolates and its essential role in pathogenesis, CS3 is a primary target for the development of vaccines, such as the oral inactivated vaccine ETVAX (Lundgren et al., 2014). Therapeutic strategies focus on neutralizing CS3 to prevent bacterial colonization and reduce the global burden of diarrheal disease (Svennerholm, 2011). Targeting this subunit aims to provide broad protection against a significant proportion of ETEC infections globally.

Other names

CstHCS3 pilinColonization factor antigen II component CS3CFA/II CS3

Vaccines and antibodies targeting the CS3 fimbrial subunit work by inducing or providing immunity that blocks the attachment of Enterotoxigenic Escherichia coli (ETEC) to the intestinal epithelium, thereby preventing colonization and subsequent toxin-mediated diarrhea (Qadri et al., 2005; UniProt: P0CK95).