Host antigens on avian oncoviruses: presence on viruses produced by quail, duck and rat cells of antigens related to membrane antigens of chick embryo fibroblasts and chicken erythrocytes.

Avian sarcoma viruses (ASV) produced by Japanese quail embryo fibroblasts (QEF) were inactivated to the same degree as ASV produced by chick embryo fibroblasts (CEF), with or without complement, by rabbit antisera to CEF and to membrane antigens of chick embryo and adult chicken erythrocytes, in particular their unique age-specific antigens. ASV produced by duck embryo fibroblasts (DEF) were only inactivated by the antisera to the chicken erythrocyte antigens. Hence, viruses produced by QEF and DEF bear on their envelope antigens related to the chicken antigens picked up by ASV in CEF. These antigens are presumably coded by the quail and duck cells, since antigens related to the chicken antigens were found on QEF and on quail and duck erythrocytes. Antigens related to the chicken antigens have also been found on ASV shed in low amounts by semi-permissive rat sarcoma cells (line 17RBI77) and on the surface of these cells, as well as on that of another semi-permissive cell line (RBH) originating from a hamster sarcoma produced by inoculation of the rat cells. The origin of these antigens, which may play a role in semi-permissiveness, remains to be explained since they do not appear to be normally expressed by rat or hamster cells. It was also found that, contrary to an earlier conclusion and in agreement with a recent report, uninfected CEF bear on their membrane an antigen that is related or identical to the specific antigen of chick embryo erythrocytes. Therefore, only the antigen related to the adult-specific chicken erythrocyte antigen does not pre-exist on CEF.