In vitro characterization of an avian reovirus vaccine strain

In vitro studies were performed to characterize the vaccine strain, designated P100, derived from the arthrogenic reovirus isolate, S1133, by cold adaptation. P100 appeared to be temperature sensitive, shown by a marked drop in titer and efficiency of plaquing after incubation at 41 degrees. Studies indicated that genomic double-stranded RNA and protein synthesis were severely restricted at the elevated temperature. Differences in the growth behavior of P100 and S1133 at 37 degrees were also noted. The vaccine strain seemed to be more cell associated than S1133. Three outer coat proteins of P100 grown at 37 degrees displayed mobilities different from those of S1133 by PAGE. It is possible that alterations in these proteins may have some relationship to the growth characteristics observed for the P100 strain.