Antigen heterogeneity among isolates of Mycoplasma bovis is generated by high-frequency variation of diverse membrane surface proteins

Abstract

The protein and antigen profiles of 11 isolates of Mycoplasma bovis were compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analysis of whole organisms. The isolates examined included the type strain PG45 and 10 other filter-cloned strains or purified isolates both from animals without clinical signs and from clinical cases of bovine mastitis, arthritis, or pneumonia. While the overall protein patterns visualized by silver staining were very similar, marked differences in the antigen banding profiles were detected by rabbit antiserum prepared against whole organisms from one of the strains analyzed. This antigenic heterogeneity was shown to be independent of the geographical origin, the type of clinical disease, and the site of isolation and was also observed among serial isolates from a single animal. Antigen profiles were further monitored throughout sequentially subcloned populations of the PG45 strain. This clonal analysis revealed a high-frequency variation in the expression levels of several prominent antigens. All of these variable antigens were defined by detergent-phase fractionation with Triton X-114 as amphiphilic integral membrane proteins. A subset of different-sized membrane proteins was identified by a monoclonal antibody raised against a PG45 subclone expressing a 63- and a 46-kDa variant antigen within that set. The selective susceptibility of these proteins to trypsin treatment of intact organisms and their ability to bind the monoclonal antibody in colony immunoblots demonstrated that they were exposed on the cell surface. In addition, their preferential recognition by serum antibodies from individual cattle with naturally induced M. bovis mastitis or arthritis confirmed that they were major immunogens of this organism. These studies establish that the apparent antigenic heterogeneity among M. bovis isolates reported here does not represent stable phenotypic strain differences generated from accumulated mutational events but reflects distinct expression patterns of diverse, highly variable membrane surface proteins.

Mycoplasma hyorhinis vlp gene transcription: critical role in phase variation and expression of surface lipoproteins

“…PolyA tract mutations appear not to be coupled to high rates of vlp gene transcription (Selby and Sancar, 1993), since no major transcript is present in the OFF configuration which mutates to the ON configuration. The mutational processes contributing to surface antigenic diversity in M. hyorhinis may be indicative of several emerging systems of antigenic and phase variation in mycoplasmas (Wise et aL, 1992;Dybvig, 1993;Behrens et al, 1994;Rosengarten et aL, 1994;Yogev et aL, 1994;Markham et aL, 1994;. Additional mechanisms, including DNA methylation and rearrangement have been proposed in some species (Dybvig, 1993).…”

Outbreak of Streptococcus equi subsp. zooepidemicus infections in cats

“…Anaerobic bacteria were identified with API ID32A (bioMerieux, France). BAL, swab and lung specimens were inoculated in Mycoplasma broth (Rosengarten et al, 1994) under 37 8C, 5% CO 2 for 48 h, and plated onto Mycoplasma agar (Rosengarten et al, 1994) afterwards. Mycoplasma agar plates were incubated in a moist chamber under the same conditions and observed for Mycoplasma colonies growth every 2 days for up to 10 days.…”

Mycoplasma Mastitis: A Review of Transmission and Control

“…However, others report outbreaks of much longer duration, from several months (Jasper et al, 1966;Bicknell et al, 1983;Brown et al, 1990;Jackson and Boughton, 1991) to several years (Bayoumi et al, 1988). Rosengarten et al (1994) studied the antigenicity of Mycoplasma sp. strains from isolates from clinical cases of bovine mastitis, arthritis and pneumonias.…”