VARIABLE EXPRESSION AND GEOGRAPHIC-DISTRIBUTION OF MYCOPLASMA-AGALACTIAE SURFACE EPITOPES DEMONSTRATED WITH MONOCLONAL-ANTIBODIES

Species-specific monoclonal antibodies (MAbs) were developed against M ycoplasma agalactiae reference strain PG2 and French isolate P89 to st udy the in vitro expression of surface epitopes and to probe the antig enic profiles of 245 field isolates originating from 10 different coun tries. Colony immunostaining with MAbs on clonal lineage showed that 4 out of 9 species-specific epitopes exhibited a high rate of variation , demonstrating that M. agalactiae possesses a capacity for phenotypic diversification of its surface antigenicity. The emphasis was on dot immunobinding screening of the Geld isolates with MAbs recognizing per manently expressed epitopes. Eight different profiles could be defined . Great differences in epitope conservation were demonstrated with som e area-specific strains completely lacking certain specific determinan ts. These results indicate that the antigenic variability of M. agalac tiae relies not only upon surface switching mechanisms but also upon t rue epitope differences, partially related to the geographic origin of the isolates.