Abstract
The occurrence of antigenic variation among nine isolates of bovine respiratory syncytial virus (BRSV) was determined by examining their reaction patterns to human respiratory syncytial virus (HRSV) subgroup A and B monoclonal antibodies (MAbs) by enzyme immunoassay and radioimmunoprecipitation with fractionation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis by using MAbs and polyclonal antisera to HRSV and BRSV. Shared epitopes were demonstrated on four of five structural proteins between BRSV and both subgroups A and B of HRSV. The nine isolates of BRSV showed different patterns of reactivity in enzyme immunoassays with panels of MAbs to HRSV subgroups A and B. Major variations in the molecular weights of the P (phosphoprotein) and F (fusion protein) proteins were demonstrated among the BRSV isolates tested. These results suggest that BRSV belongs to a different antigenic grouping than HRSV and that BRSV is composed of two distinct subgroups.