Escherichia coli F41 pilus antigen (F41)

The Escherichia coli F41 pilus antigen is a fimbrial adhesin found on the surface of specific enterotoxigenic Escherichia coli (ETEC) strains, which are major causes of neonatal diarrhea (colibacillosis) in calves and piglets. This filamentous protein structure mediates the initial attachment of the bacteria to receptors on the host's intestinal epithelial cells, such as glycophorin AM, which is a critical step for bacterial colonization and the subsequent delivery of enterotoxins. F41 is frequently co-expressed with other fimbriae, most notably K99 (also known as F5), and its presence is highly correlated with virulence in young livestock. As a key virulence factor, F41 serves as a primary target for veterinary vaccines designed to immunize pregnant dams. These vaccines induce high titers of F41-specific antibodies in the colostrum, which, when ingested by the newborn, provide passive protection by sterically hindering the bacterial pilus from binding to the gut wall, thereby preventing infection and the associated diarrheal disease.

Other names

F41 fimbriaeF41 adhesinF41 antigenF41 pilusF41 major fimbrial subunit

Induction of maternal antibodies (IgG and IgA) that are transferred to neonates via colostrum to provide passive immunity by blocking the adhesion of F41-expressing E. coli to the intestinal mucosa.