P-antigen-recognizing fimbriae from human uropathogenic Escherichia coli strains

Abstract

P-antigen-recognizing fimbriae (P fimbriae) from four pyelonephritogenic Escherichia coli strains and type 1 fimbriae from an E. coli strain and a Salmonella typhimurium strain were purified. The P fimbriae were morphologically similar to type 1 fimbriae. The purified P fimbriae agglutinated neuraminidase-treated human P1 and P2k erythrocytes but not p erythrocytes, which lack all P-blood group-specific glycosphingolipids. However, coating of neuraminidase-treated p erythrocytes with globoside rendered such erythrocytes agglutinable by the P fimbriae. The hemagglutinations were in all instances fully inhibited by the synthetic alpha-D-Galp-(1-4)-beta-D-Galp-1-O-Me glycoside. The binding specificity of the P fimbriae could also be demonstrated by using fimbriae coated onto latex particles and nontreated erythrocytes. It was thus concluded that the P fimbriae recognize and bind to the alpha-D-Galp-(1-4)-beta-D-Galp carbohydrate sequence occurring in the series of P-blood group antigen-specific glycosphingolipids. In contrast to both type 1 fimbriae, all four P fimbriae preparations showed multiple bands in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Antisera were raised in rabbits against the various E. coli fimbriae. In enzyme-linked immunosorbent assays each one of the antisera to the P fimbriae reacted to titers of log 4 to 7 with both the homologous and the heterologous P fimbriae, but not with the type 1 fimbriae of E. coli. In a reciprocal fashion, the antiserum to the type 1 fimbriae of one E. coli strain reacted only with the homologous type 1 but not with any of the P fimbriae preparations.