Phosphoprotein profile analysis of ruminant respiratory syncytial virus isolates

Abstract

Abstract Objective To determine the apparent molecular weight for 24 ruminant respiratory syncytial viruses (RSV) on the basis of differences in the electrophoretic mobility of the phosphoprotein (P protein). Procedure 29 bovine RSV (BRSV), 20 of which were not previously tested, 3 ovine RSV, and 1 caprine RSV isolates were selected for determination of electrophoretic mobility of the P protein. Virus radiolabeled with [35S]methionine was immunoprecipitated with polyclonal antiserum to BRSV and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Results On the basis of apparent molecular size of the P protein, all isolates could be categorized into 2 electropherotypes, low molecular size of 36 kd and high molecular size of 38 kd. Twenty-three BRSV, the 3 ovine RSV, and 1 caprine RSV isolates had a high molecular size P protein; 6 BRSV isolates had a low molecular size P protein. Conclusions The apparent molecular size of the P protein of the ruminant RSV strains is greater than that of the human RSV subgroups, providing further evidence of their distinctiveness. Whether categorization of electrophoretic mobility of the P protein of BRSV underlies distinct antigenic subgroups, as it does in human RSV, requires further antigenic and genetic analysis. Clinicai Relevance Antigenic subgroups of ruminant RSV may have relevance in the development of new vaccines for control of the disease. (Am J Vet Res 1997;58:478–481)