Radioimmunoassay of mammalian type‐c polypeptides. IV. Characterization of woolly monkey and gibbon viral antigens

The ˜30,000 dalton woolly and gibbon type‐C viral polypeptides have been isolated and characterized immunologically. By radioimmunoassay, antibody prepared in rabbits to the woolly and gibbon “gs” protein show only low‐level cross‐reactions with other mammalian type‐C viral gs antigens and their antisera. The woolly and gibbon ˜30,000 dalton polypeptides are highly related on the basis of both serum and antigen titrations, confirming previous studies with the viral reverse transcriptases. The woolly gs assay using a double antibody radioimmunoassay can detect less than one nanogram of purified woolly or gibbon viral protein, and the same protein also reacts in the interspecies of gs‐3 radioimmunoassay indicating that the primate “gs” proteins also contain both species‐specific and interspecies reactivities on the same polypeptide. To establish that the woolly and gibbon type‐C viruses represented distinct isolates with a close immunological relationship and to eliminate the possibility of laboratory contamination, original woolly and gibbon material was studied for antigen. Both the original woolly monkey fibrosarcoma and two separate gibbon lymphoid tumors contained high levels of type‐C interspecies and woolly viral antigen by radioimmunoassay, indicating that natural tumors from distinct species of primates contain immunologically related viral antigen.