Escherichia coli 987P fimbrial antigen (F6) (F6)

The Escherichia coli 987P fimbrial antigen, also known as F6, is a filamentous proteinaceous surface appendage found on certain strains of enterotoxigenic Escherichia coli (ETEC) that primarily infect neonatal piglets [1, 2]. These fimbriae are critical virulence factors that mediate the initial attachment of the bacteria to the small intestinal epithelium, a process essential for colonization and the subsequent delivery of enterotoxins that cause severe diarrhea [9, 10]. The 987P fimbria is a heteropolymeric structure composed of a major structural subunit, FasA, and minor subunits including the tip adhesin, FasG, which recognizes host receptors such as sulfatides and histone H1 proteins [6, 13, 15]. Because of its essential role in pathogenesis, the 987P antigen is a primary target for veterinary vaccines, which aim to induce maternal antibodies that are transferred to piglets via colostrum to block bacterial adhesion [1, 7, 10]. These vaccines, such as Porcilis Coli and Gletvax 6, have been highly effective in reducing the incidence of neonatal colibacillosis in swine [10]. Therapeutic strategies focusing on this target include the development of multivalent vaccines and potential anti-adhesion agents designed to disrupt the interaction between the fimbrial adhesin and the host cell surface [3, 12, 18]. A significant challenge in targeting 987P is the phenomenon of phase variation, where bacteria can switch the expression of fimbriae on or off in response to environmental conditions [8, 11]. Additionally, the diversity of fimbrial types among ETEC strains necessitates the use of multivalent formulations to ensure broad protection [10, 16].

Other names

987P fimbriaeF6 antigen987P piliFasAFasGF6 fimbriae

Induction of neutralizing antibodies (IgA and IgG) that bind to the fimbrial subunits, particularly the FasG adhesin, thereby preventing bacterial attachment to host intestinal receptors [1, 7, 10].