Identification of some antigenically related outermembrane proteins of strains of Vibrio cholerae 01 and non-01 serovars involved in intestinal adhesion and the protective role of antibodies to them

Abstract

Summary. Outer-membrane proteins (OMPs) of Vibrio cholerae strains of 0 1 and non-0 1 serovars were studied. Marked similarity was found in the OMP profiles of different V. cholerae 0 1 strains but the OMP profile of a non-01 strain was somewhat different. Antigenic relatedness between the OMPs of different V. cholerae strains was established by enzyme-linked immunosorbent assay (ELSA). Immunoblotting experiments demonstrated that at least two OMPs of 36 and 25-26Kda were immunogenic and common to strains of 0 1 and non-01 serovars. Antiserum raised against the outer membrane of a V. cholerae strain, and rendered specific for its OMP by absorption with lipopolysaccharide, inhibited in vitro the intestinal adhesion of the homologous and heterologous strains of V. cholerae irrespective of their biotype, serotype and serovar. Furthermore, antiserum to OMPs induced passive protection against vibrio challenge in rabbit ileal loop experiments. These results suggest that the OMPs may be useful in immunoprophylaxis against cholera.

A 20-kDa pilus protein with haemagglutination and intestinal adherence properties expressed by a clinical isolate of non-01 Vibrio cholerae

“…The strain belonged to 034 serovar [8] and was negative by the cholera toxin (CT) gene probe assay (kindly tested by Dr. T. Shimada, NIH, Japan). Other 01 and non-01 strains used for comparative studies have been described elsewhere [9,10]. The V. cholerae 01 strain 0395 was kindly made available to us by Dr. J.J. Mekalanos, USA.…”

“…cholerae cells were grown either in TSB, pH 7.4, or in 'T'-medium, pH 7.4, for 16 h at 37°C and harvested bacteria were disintegrated in an Ultrasonic disintegrator (Labsonic 2000, Braun). The crude envelope fraction was collected from the clear supernatant by centrifugation at 104,000 x g for 1 h at 4°C [9]. The outer membrane (OM) part was isolated from the crude envelope fraction by selective solubilisation of the inner membrane with 0.5% (w/v) Sarkosyl (Sigma) solution [12].…”

“…Lipopolysaccharides were extracted from acetone dried ceils of non-01 V. cholerae strain 10325 by the phenol-water extraction method. Any residual protein remaining was removed by proteolytic digestion [9].…”

Immunogenicity and protective role of an IgA reactive 31-kDa antigen of Vibrio cholerae O139

“…As the WCS antigens were used in SDS-PAGE in this study, it is likely that the predominant proteins were from the outer membrane. Remarkable similarities have been shown previously among the OMP pro®les of various V. cholerae O1 strains belonging to both biotypes and serotypes [11,17]. A comparison of envelope and OMP pro®les between O1 and O139 isolates also failed to show any signi®cant differences [3].…”

Expression of antigenically distinct fimbriae with hemagglutination and HeLa cell adherence properties by an enteroaggregative Escherichia coli strain belonging to the enteropathogenic serogroup

“…Lipopolysaccharides (LPS) were obtained from acetone dried E. coli cells of DS92 by the phenol-water extraction method [24]. Any residual protein remaining in the LPS preparation was removed by protease digestion [25].…”