title: In vivo antigenic modification of tumor cells. I. Introduction of murine leukemia virus antigens on non-virus-producing murine sarcomas.
abstract: Murine oncovirus antigens represent excellent targets for immune recognition, and virus-associated tumors are generally susceptible to various immunotherapy protocols. Virus-negative tumors, however, are nonimmunogenic and refractory to immunologic control. Therefore, the feasibility of the introduction of antigens onto non-virus-expressing tumors in situ in inbred C57BL/6J mice by systemic administration of nononcogenic murine retroviruses was investigated. Two classes of murine fibrosarcomas were studied: a 3-methylcholanthrene-induced fibrosarcoma syngeneic to C57BL/6 mice (MCA-FS) and a Harvey murine sarcoma virus-transformed, nonproducer fibrosarcoma syngeneic to C57BL/6 mice (H-NP). Both were found to be devoid of infectious ecotropic murine leukemia virus (MuLV) or MuLV antigens. A single dose of Friend murine leukemia virus (F-MuLV) was used to superinfect MCA-FS- and H-NP-induced tumors in vivo and converted these tumors to a highly productive, virus-positive state. In vivo superinfected tumors were indistinguishable from their preinfected counterparts by competition radioimmunoassays for the virion's major envelope glycoprotein, gp71, and its group-specific antigen, p30, and by assays for infectious virus. Analysis of virus from tumor extracts proved that the antigenic specificity of the superinfected tumor was provided by F-MuLV administered systemically to the animals. Finally, an immunoperoxidase technique, applied to tumor cross sections, demonstrated the uniform appearance of viral antigens in the superinfected tumors.
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000032:analysis*; D002460:Cell Line; D005354:Fibrosarcoma / Q000150:complications / Q000276:immunology* / Q000382:microbiology; D005622:Friend murine leukemia virus / Q000276:immunology / Q000302:isolation & purification; D051379:Mice; D008815:Mice, Inbred Strains; D011863:Radioimmunoassay; D012513:Sarcoma, Experimental / Q000150:complications / Q000276:immunology / Q000382:microbiology; D014412:Tumor Virus Infections / Q000150:complications*
chemical_list: D000956:Antigens, Viral