Study of the Antigenic Specificity of Graffi

Rauscher, and Gross leukemias were studied by serologic methods (in vitro cytotoxicity, immunoRuorescence reactions, and absorption tests). Leukemias of the four types were serially transplanted in CBL57/6 mice, and antisera were prepared in the same mice and in rats. The immunity induced against isotransplants of Graffi and Moloney leukemias was also studied. A cross-reactivity between Graffi leukemias and leukemias of the Friend-Moloney-Rauscher antigenic group is evidenced. The immunologic classification of murine leukemias is brieRy discussed.-JNat Cancer Inst41: 743-750,1968. A SPECIFIC antigenicity was found on the membrane of leukemic cells induced by Gross, Graffi, Moloney, Rauscher, and Friend viruses (1-6), and two different systems were identified: the "G " antigen found at the surface of Gross-induced leukemic cells (2) and the "FMR" antigen, a common cross-reacting antigen distinct from G, present at the surface of leukemic cells induced by Friend, Moloney, and Rauscher viruses (1). In addition, Graffi lymphoma cells share a similar antigen, probably different from G (3, 7). The relationships between G and FMR are not well known. The present study concerns antigens on Graffi leukemic cells and their relation-ships to the other antigens already described in virus-induced leukemias. Evidence is presented that Graffi antigens are closely related to the FMR antigen group