Induction and Specificity of Antisera from Mice Immunized with Syngeneic UV-Induced Tumors

Abstract

Abstract Sera from mice inoculated with syngeneic fibrosarcomas induced by ultraviolet light (UV) were tested to determine if antibodies specific for the immunizing tumor were present. The assay used for this determination involved indirect immunofluorescence binding of anti-sera to tissue culture cells derived from the appropriate UV-induced tumor. The degree of binding of a given antiserum was determined by either fluorescence microscopy or quantitative cytofluorometry. Antisera specific for the syngeneic UV-induced tumor used for immunization were produced. Binding by such antisera was tumor specific and was not due to the presence of contaminating antibodies directed against AKR murine leukemia viruses (MuLV). Only two instances of cross-reactivity were observed, and these involved allogeneic UV-induced tumors. These sera did not react with embryonic fibroblasts, tail skin epidermal cell lines, methylcholanthrene (MCA)-induced fibrosarcomas, or spontaneous fibrosarcomas. On the other hand, anti-UV-tumor sera, which also contained antibodies that react with MuLV, were cross-reactive with a number of tumors. Upon removal of anti-MuLV antibodies by appropriate adsorptions, the cross-reactive activity of these sera was lost, but the specific activity against the immunizing UV-induced tumor remained. We conclude that syngeneic mice challenged with UV-induced tumors can make a tumor-specific humoral immune response to individual tumors.