Recognition of Blood Group ABH Type 1 Determinants by the FedF Adhesin of F18-fimbriated Escherichia coli

F18-fimbriated Escherichia coli are associated with porcine postweaning diarrhea and edema disease. Adhesion of F18-fimbriated bacteria to the small intestine of susceptible pigs is mediated by the minor fimbrial subunit FedF. However, the target cell receptor for FedF has remained unidentified. Here we report that F18-fimbriated E. coli selectively interact with glycosphingolipids having blood group ABH determinants on type 1 core, and blood group A type 4 heptaglycosylceramide. The minimal binding epitope was identified as the blood group H type 1 determinant (Fuc alpha 2Gal beta 3GlcNAc), while an optimal binding epitope was created by addition of the terminal alpha 3-linked galactose or N-acetylgalactosamine of the blood group B type 1 determinant (Gal alpha 3(Fuc alpha 2)Gal beta 3GlcNAc) and the blood group A type 1 determinant (GalNAc alpha 3(Fuc alpha 2)Gal beta 3GlcNAc). To assess the role of glycosphingolipid recognition by F18-fimbriated E. coli in target tissue adherence, F18-binding glycosphingolipids were isolated from the small intestinal epithelium of blood group O and A pigs and characterized by mass spectrometry and proton NMR. The only glycosphingolipid with F18-binding activity of the blood group O pig was an H type 1 pentaglycosylceramide (Fuc alpha 2Gal beta 3GlcNAc-beta 3Gal beta 4Glc beta 1Cer). In contrast, the blood group A pig had a number of F18-binding glycosphingolipids, characterized as A type 1 hexaglycosylceramide (GalNAc alpha 3(Fuc alpha 2)Gal beta 3GlcNAc beta 3Gal beta 4Glc beta 1Cer), A type 4 heptaglycosylceramide (GalNAc alpha 3(Fuc alpha 2)Gal beta 3GalNAc beta 3Gal alpha 4Gal beta 4Glc beta 1Cer), A type 1 octaglycosylceramide (GalNAc alpha 3(Fuc alpha 2)Gal beta 3GlcNAc beta 3-Gal beta 3GlcNAc beta 3Gal beta 4Glc beta 1Cer), and repetitive A type 1 nonaglycosylceramide (GalNAc alpha 3(Fuc alpha 2)Gal beta 3GalNAc alpha 3-(Fuc alpha 2)Gal beta 3GlcNAc beta 3Gal beta 4Glc beta 1Cer). No blood group antigen-carrying glycosphingolipids were recognized by a mutant E. coli strain with deletion of the FedF adhesin, demonstrating that FedF is the structural element mediating binding of F18-fimbriated bacteria to blood group ABH determinants.