Preparation of syngeneic tumor regressor serum reactive with the unique determinants of the Abelson murine leukemia virus-encoded P120 protein at the cell surface.
Antisera reactive with the Abelson murine leukemia virus (A-MuLV)-specified P120 (anti-AbT sera) were produced in C57L/J mice. Of many strains tested, only C57L/J reproducibly rejected syngenic A-MuLV-induced tumor cells; after multiple immunizations their sera would immunoprecipitate both P120 and Moloney-MuLV (M-MuLV) proteins. Using labeled A-MuLV-induced nonproducer cells, only P120 could be detected by anti-AbT sera, suggesting that it may be the only A-MuLV-specified protein. Reactivity of anti-AbT sera with P120 was not blocked by M-MuLV virion proteins, implying that the sera recognize a portion of P120 that is not homologous to any M-MuLV product. Anti-AbT sera stained the surface of live, A-MuLV-transformed nonproducer cells in a two-stage immunofluorescence assay, and such staining was not blocked by M-MuLV protein. Also, intact A-MuLV-transformed cells absorbed much of the reactivity of certain anti-AbT sera for P120. Thus a portion of P120 appears to be exposed on the surface of transformed cells. P120 lacks detectable carbohydrate, is not affected by endoglycosidase H, and cannot be labeled by lactoperoxidase-catalyzed iodination. Thus P120 is an unusual surface protein.
D000011:Abelson murine leukemia virus / Q000276:immunology*; D000818:Animals; D000912:Antibodies, Neoplasm / Q000096:biosynthesis; D000914:Antibodies, Viral / Q000096:biosynthesis; D000918:Antibody Specificity; D000954:Antigens, Surface / Q000032:analysis*; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D002472:Cell Transformation, Viral; D000939:Epitopes; D007106:Immune Sera; D009052:Leukemia Virus, Murine / Q000276:immunology*; D051379:Mice; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000276:immunology; D051381:Rats; D014764:Viral Proteins / Q000276:immunology*
D000912:Antibodies, Neoplasm; D000914:Antibodies, Viral; D000954:Antigens, Surface; D000939:Epitopes; D007106:Immune Sera; D014764:Viral Proteins