Antigenic Properties of Lymphomas Induced by the Moloney Agent2

Abstract

Mouse lymphomas induced by the Moloney agent were strongly antigenic in isologous hosts, as indicated by transplantation and serologic tests. Specific transplantation resistance was established by pretreatment of the recipients with homografts of other Moloney lymphomas, small isografts of the same lymphoma, or virus-containing lymphoma homogenates. Extensive cross-resistance was demonstrated between different Moloney lymphomas, while there were no certain cross-reactions between Moloney lymphomas and lymphomas induced by the Gross virus, or between Moloney lymphomas and a number of long-transplanted lymphomas. Total-body X irradiation with 400 r reduced the minimum number of cells required for the take and growth of Moloney lymphoma cells after inoculation into untreated isologous recipients. Establishment of specific transplantation resistance by one of the procedures mentioned was paralleled by the appearance of humoral antibodies in the serum, detectable by the indirect fluorescent-antibody reaction and by cytotoxicity in the presence of complement. The fluorescence test was specific for Moloney, while the cytotoxic test indicated certain cross-reactions. Moloney target cells were killed only by anti-Moloney sera, but some hyperimmune anti-Moloney sera also killed cells of Gross lymphomas and some long-transplanted lymphomas. Preliminary absorption tests indicated efficient and complete removal of the activity directed against the Moloney lymphomas by absorption with Moloney cells and no removal, or partial removal, with the cross-reacting lymphomas of other types. Thus, all experiments indicated that lymphomas induced by the Moloney agent differ from lymphomas of other types with regard to their antigenic specificity, but the possibility that the difference may be quantitative rather than qualitative cannot be excluded.