Host Antigens on Avian Oncoviruses: Evidence for Virus Envelope Antigens Related to Specific Chicken Erythrocyte Membrane Antigens

Abstract

SUMMARYAvian sarcoma viruses (ASV) of subgroups A to D, produced by chick embryo fibroblasts (CEF), are inactivated to a high degree by rabbit antisera to the membrane antigens of adult chicken and chick embryo erythrocytes, notably by antisera to an antigen of embryo erythrocytes, which is lost by adult erythrocytes and to another antigen specific to the latter erythrocytes. Contrary to virus inactivation by anti-CEF serum reported earlier, virus inactivation by the antisera to these two age-specific antigens does not require complement and is not paralleled by virolysis but by aggregation of virions.The two antigens related, or identical, to the age-specific erythrocyte membrane antigens thus shown to be present on the virus envelope do not pre-exist, or preexist only in a low amount, on the CEF membrane, since the virus-inactivating capacity of their antisera is not removed by absorption with CEF. Their appearance on the virus does not depend on cell transformation but only on infection, since both antigens are found on a ts ASV mutant produced at restrictive temperature by untransformed CEF and the virus-inactivating capacity of their antisera is removed by absorption with CEF infected with Rous-associated virus (RAV-I). These findings suggest that infection of CEF by avian oncoviruses may elicit the appearance, or enhance the expression at the cell surface of antigens characteristic of another cell type which may contribute to the formation of specific virus budding sites.

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

“…This inactivation is paralleled by virolysis, and is due to the presence on the virus envelope of a host cell surface antigen (CEF HCSA) which is neither an antigen of the endogenous virus (chjO of CEF, nor Forssman antigen (Aupoix & Vigier, 1975). ASV produced by CEF are also inactivated to a high degree by rabbit antisera to the membrane antigens of adult chicken and chick embryo erythrocytes, notably antisera to an antigen of embryo erythrocytes which is lost by adult erythrocytes and to another antigen specific to the latter erythrocytes (Aupoix et al, 1980). Virus inactivation by both antisera occurs either with or without C', and inactivation in the absence of C' is not accompanied by virolysis but by aggregation of virions.…”

“…The immune sera to CEF and to the chicken erythrocyte membrane antigens were the same as for earlier studies (Aupoix & Vigier, 1975;Aupoix et al, 1980). The anti-erythroeyte sera were either unabsorbed and called anti-AE (unabsorbed antiserum to chicken adult erythrocytes) or anti-EE (unabsorbed antiserum to chicken embryo erythrocytes), or absorbed with the heterologous erythrocytes (EE for AE and vice versa) and called anti-AE/EE (anti-AE serum absorbed on chicken embryo erythrocytes; detects essentially the adult-specific membrane antigen or anti-EE/AE) (anti-EE serum absorbed on adult chicken erythrocytes; detects essentially the embryo-specific membrane antigen).…”

“…We therefore METHODS Viruses, cells and media. The ASV used in these experiments were the subgroup C, D and E Rous sarcoma virus (RSV) strains which were used in earlier studies (Aupoix & Vigier, 1975;Aupoix et al, 1980), plus the subgroup C virus B77 (Simkovic et al, 1969). The subgroup C and D viruses were passaged on the same Brown Leghorn CEF, cultivated in the same media as in earlier studies (Aupoix & Vigier, 1975).…”

“…Absorption of antisera with erythrocytes or on cell monolayers were performed as described earlier (Aupoix et al, 1980). Virus inactivation tests.…”

“…Virus inactivation tests. These tests were performed as described previously (Aupoix & Vigier, 1975;Aupoix et al, 1980).…”