Tumor antigens on the cell surface of thymic lymphoma cells from chemical- and virus-induced lymphomas of C57BL mice and virus-induced tumors of Wistar-Furth rats have been studied with the use of immunofluorescence on viable cells with rat, rabbit, and monkey antisera. In young mice given intrathymic injections of a murine leukemia virus, a new cell surface antigen can be detected as early as 2 to 4 days postinjection in some thymuses. Rat antisera to virus-induced rat thymic lymphoma cells gave a precipitin line in Ouchterlony double diffusion analysis when tested with virus isolated from plasma of tumor-bearing rats or from mouse lymphoma extracts. This reaction is due to the group-specific (internal) antigen of the murine leukemia viruses, since ether treatment of the virus preparations was required to obtain it. The results indicate that both radiation and certain chemicals may “activate” the same leukemia virus, which is endemic in this low leukemia strain.
This investigation was supported by USPHS Research Grant CA 08914 from the National Cancer Institute and Training Grant AI 82-12 from the National Institute of Allergy and Infectious Diseases.