Serological relatedness of mouse-virulent Yersinia enterocolitica

Abstract

An antiserum (WA-SAA) was produced which agglutinated specifically with mouse-virulent but not with avirulent strains of Yersinia enterocolitica. Expression of the antigenic determinant(s) reacting with WA-SAA was temperature dependent; for growth temperatures of 20 to 40°C, agglutination titers were lowest for cultures grown at 20°C and highest for cultures grown at 35 to 40°C. Addition of Ca2+ (2.5 to 10 mM) to the growth medium had little effect on the agglutination titer, and gel diffusion studies with monospecific anti-V serum indicated that V antigen was not likely to be the determinant reacting with WA-SAA. Immunohistological studies of Peyer's patches of mice infected with Y. entero(olitica WA revealed that the antigenic determinant(s) reacting with WA-SAA was expressed in vivo. The strong correlation of agglutination titer with mouse virulence and the expression in vivo of the antigenic determinant(s) reacting with WA-SAA suggest that the antigen(s) may be associated with the pathogenicity of Y. enterocolitica. Yersinia enterocolitica is a widely distributed organism which may be isolated from a variety of foods. Examples include milk (17, 30), fish (20), porcine tongues (12), chicken (23), lamb (15), beef (15), oysters (1, 25), shrimp (25), crab (25), and vegetables used in salads (1). Although the organism is often present in foods and the environment, a large number of the strains isolated from these sources are apparently avirulent (21, 28, 29). Hence, it would be useful to identify characteristics common among virulent Y. enterocolitica that may be used as determinants for developing methods to differentiate virulent from avirulent strains. Several established or presumed virulence determinants have been associated with Yersinia pestis. Included are the ability to produce V and W antigens, capsular or fraction 1 antigen, pesticin, coagulase, and fibrinolysin, and the capacity to absorb hemin (5). Carter et al. (11) have shown that mouse-virulent Y. enterocolitica WA produces V and W antigens that are immunologically identical to the V and W antigens of Y. pestis. These are the only virulence determinants known to be common to these two species; however, it is not known whether V and W antigens are common among all strains of mouse-virulent Y. enterocolitica. Interestingly, although not a determinant of virulence, susceptibility to pesticin, a bacteriocin produced by wild-type strains of Yersinia pestis (4), is also a characteristic common among strains of Y. enterocolitica that are lethal to mice (16). We report here a serological test that identi

Identification of specific outer membrane polypeptides associated with virulent Yersinia enterocolitica

“…This procedure removes most of the antibodies to common surface antigens and retains antibodies specific to virulent WA cells. As expected, cells of the avirulent strain WA-ETBR did not agglutinate, nor did they stain in immunohistochemical assay with antiserum WA-SAA (8). Three major polypeptides and possibly four (Ti, T5, T6, and T7) were identified as virulence-associated polypeptides among the virulent but not the avirulent isolates of Y. enterocolitica.…”

“…In conclusion, our study identified specific polypeptides in the outer membrane of virulent strains of Y. enterocolitica that are likely expressed in vivo in infected mice (8). These polypeptides, unlike the V and W virulence antigens of yersiniae (5), were unaffected by calcium concentration and were produced under conditions in which V antigen could not be detected (8).…”

“…We reported previously an antiserum (WA-SAA) that agglutinates specifically with virulent strains of Y. enterocolitica (8). This differential reaction suggests differences in the composition of surface antigens.…”

“…MATERIALS AND METHODS Cultures. Strains of Y. enterocolitica used for this study were detailed in our previous report (8). Y. enterocolitica WA 20+ was obtained from N. Stern (15).…”

“…Antibody-binding assay. The preparation of specific absorbed antiserum to strain WA of Y. enterocolitica (WA-SAA) and agglutination assay have been described previously (8). Western blotting from an SDS gel was accomplished by diffusion transfer and assayed by the method of Chang et al (6) with the following modifications.…”