Structural proteins of classic and variant strains of infectious bursal disease viruses

Abstract

Structural polypeptides of six tissue-culture-origin (BGM-70 continuous cell line) infectious bursal disease viruses representing classic and variant strains of serotype 1 and one serotype 2 strain were analyzed and compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Additionally, two of the variant strains were propagated in vivo in bursa of Fabricius and compared with those grown in cell culture. Differences among the structural proteins of serotype 1 viruses were minor and probably of no value in differentiating these viruses. However, distinct differences were observed between serotype 1 and 2 viruses. The bursa-derived viruses were different from those propagated in cell culture in molecular weights and in proportions of the proteins. The bursa-derived strains had protein migration patterns similar to those described for tissue-culture-incomplete virus particles.