Coli surface antigen (CS) (CS)

Coli surface antigens (CSs) are a diverse group of proteinaceous surface structures, primarily fimbriae or pili, expressed by Enterotoxigenic Escherichia coli (ETEC) (Qadri et al., 2005). They function as essential adhesins that mediate the attachment of the bacteria to specific receptors on the human intestinal mucosa, which is a critical first step in colonization and subsequent delivery of enterotoxins (Fleckenstein et al., 2010; Zhang et al., 2023). There are over 25 identified CS variants, such as CS1 through CS6, which are often plasmid-encoded and vary in prevalence across different geographic regions (Vidal et al., 2019; Frontiers, 2018). Because colonization is a prerequisite for ETEC-induced diarrhea, these antigens are primary targets for vaccine development, including whole-cell killed vaccines like ETVAX and multivalent subunit vaccines like MecVax (Svennerholm, 2011; MDPI, 2023). Blocking the interaction between CSs and host receptors through vaccine-induced antibodies prevents the establishment of infection and the resulting secretory diarrhea (NIH, 2023; ASM, 2023). This approach is particularly important for protecting children in endemic areas and travelers to high-risk regions, although the high degree of antigenic diversity remains a significant challenge for achieving broad vaccine coverage (Frontiers, 2018; ASM, 2023).

Other names

Colonization factor antigenCFAColonization factorCFETEC adhesinFimbriaePili

Induction of mucosal and systemic antibodies (IgA and IgG) that bind to the surface antigens, preventing bacterial attachment to intestinal epithelial cells and subsequent colonization.