Friend leukemia virus-induced leukemogenesis in fully H-2 incompatible C57BL/6-->C3H radiation bone marrow chimeras

Resistance and/or susceptibility for Friend leukemia virus (FLV)-induced leukemogenesis was examined in the fully H-2 incompatible C57BL/6 (B6)-->C3H radiation bone marrow chimeras (RBMC). The results indicated that B6-->C3H chimeras never developed FLV-induced leukemias when infected with FLV 4 months after bone marrow transplantation (BMT). Spleen cells from B6-->C3H chimeras that were preimmunized with 100 Gy-irradiated FBL-3 cells (FLV-induced leukemic cell line originated from B6 mice) were shown to generate anti-FBL-3 specific T-cell proliferation as well as cytotoxic T cells. We also found that when bone marrow cells from B6 mice were mixed with those from C3H mice and then grafted into supralethally irradiated C3H mice, resulting chimeras whose peripheral blood contained less than 30% C3H-derived (susceptible) cells were refractory to FLV-induced leukemogenesis. On the other hand, when C3H mice were infected with FLV and then supralethally irradiated 5 days later and grafted with bone marrow from B6 donors, they developed leukemias which were of B6 origin. Athymic nu/nu mice of B6 background were again shown to develop leukemia following infection with FLV. Possible implication of these findings on the role of T cell-mediated immune response in resistance to FLV-induced leukemogenesis and the immunocompetent nature of fully H-2 incompatible RBMC were discussed.