Analysis of antigenic determinants of structural polypeptides of avian type C tumor viruses

Radioimmunoassays were developed for the 19,000, 15,000 and 12,000 molecular weight polypeptides of avian myeloblastosis virus and for the 19,000 and 12,000 polypeptides of RAV O, a subgroup E avian tumor virus. Each polypeptide was shown to possess both group and type specific antigenic determinants, in contrast to the 27,000 mol wt polypeptide, which contained only group specific determinants. The corresponding low molecular weight polypeptides of subgroup A, B, and E viruses were shown to be immunologically indistinguishable. The findings that low molecular weight polypeptides of subgroup C and D viruses reacted very differently in immunoassays for the respective polypeptides of avian myeloblastosis virus or RAV O suggest that subgroups C and D may have evolved differently from subgroups A, B, and E.