Demonstration by immuno-electronmicroscopy of antigenic heterogeneity among P fimbriae of strains of Escherichia coli

Abstract

Summary. The identification of P fimbriae on urinary strains of Escherichia coli isolated from urine was made (i) by observation of the patterns of mannose-resistant and eluting haemagglutination of erythrocytes of seven animal species (and including those of human p phenotype), and (ii) by haemagglutination-inhibition tests with hydatid-cyst fluid known to contain an analogue of P-fimbrial receptor. In tests with five different, pure P-fimbrial antisera prepared in rabbits, agglutinin titres of 37 Pfimbriate strains revealed differences in their reactivity ; immuno-electronmicroscopy studies with the same five antisera showed that P-fimbriate strains were markedly different in the extent to which their P fimbriae were coated with antibody. The antigenic heterogeneity observed among P fimbriae is discussed with regard to the development of P-fimbrial vaccines.

Virulence factors in Escherichia coli urinary tract infection

“…In addition, anti-P-fimbrial antibodies in patients' sera following pyelonephritis fail to block adherence mediated by the homologous P-fimbriated strain (96). From these observations it is clear that efforts to devise clinically effective vaccines to block P-fimbrial adherence in humans face a number of obstacles (395,484). It remains to be determined whether a vaccine can stimulate adhesinspecific antibodies that are more broadly cross-reactive than those described thus far (95 (444), and KS71B (444).…”

“…Obstacles to an Effective Anti-P-Fimbrial Vaccine P fimbriae purified from different clinical isolates often (185,281,395) but not always (93,281) serologically. The F (fimbrial)-antigen system for cataloging serological variants of E. coli fimbriae uses designations 1 to 6 for previously described fimbriae (Fl, type 1 fimbriae; F2, CFA/I; F3, CFA/II; F4, K88; F5, K99; and F6, 987P) and higher numbers for newly identified fimbrial types (410).…”

Analysis of the F Antigen-Specific papA Alleles of Extraintestinal Pathogenic Escherichia coli Using a Novel Multiplex PCR-Based Assay

“…P fimbriae are antigenically diverse, occurring in 11 known serological variants, which are termed F7-1, F7-2, and F8 to F16 according to the system of Ørskov et al (18,64,68,70). Whereas Gal(␣1-4)Gal-specific binding is mediated by PapG, the fimbrial tip adhesin molecule (29,56), the antigenic diversity of P fimbriae is attributable to peptide sequence variability within PapA, the major P fimbrial structural subunit (12,13,22,55,57,96).…”

“…Second, since F antigens are markers for the corresponding papA alleles, they can be used to trace the vertical or horizontal transmission of particular pap variants within the E. coli population, e.g., as defined by O:K:H serotypes, and in relation to other virulence factors (61,70,72,74). Third, epidemiological analyses of F types among strains from defined clinical syndromes or host populations can reveal the clinical associations of particular F variants, which could help guide future efforts to develop and deploy an anti-PapA vaccine (12,63,64).…”

Characterisation of a Fimbrial, Mannose-Resistant and Eluting Haemagglutinin (MREHA) Produced by Strains of Salmonella of Serotype Sendai

“…Otherwise, the media and methods of culture used were essentially as described before (Duguid et al, 1979;Old et al, 1987). Thus, in tests for the production of haemagglutinins, bacteria were grown serially for 48-h periods in static phosphate-buffered broth (pH 7.0, PBB) or for 24 h on phosphate-buffered agar (pH 7.0, PBA) at 18°C or 37°C.…”