Xenogenization of rat erythroid cells by lymphatic leukemia virus: its role in induction of autoimmune hemolytic anemia.

Newborn rats given injections of low doses of Friend lymphatic leukemia virus subsequently developed hemolytic anemia characterized by production of antierythrocyte autoantibody. Electron microscopy showed C-type virus particles budding from the cell membrane not only of lymphoid cells but also of erythrocyte percursor cells in bone marrow and spleen, suggesting that the erythroid cells were infected by the virus. In addition, erythrocyte precursor cells expressed virus-induced cell surface antigens detected by cytotoxicity tests. Normal syngeneic rats preimmunized with a Friend lymphatic leukemia virusinduced tumor and subsequently inoculated with bone marrow, spleen cells, or reticulocyte-rich fraction derived from other rats injected with high doses of the virus at birth produced cytotoxic antibody to the virus-induced tumor and antierythrocyte autoantibody. In contrast, rats subsequently inoculated with virus-infected thymus or lymph node cells produced cytotoxic antibody but not antierythrocyte autoantibody. These results indicate that "xenogenization," previously shown for tumor cells and normal lymphoid cells, is also observed for rat erythroid cells and, further, that xenogenization of erythroid cells by Friend lymphatic leukemia virus is one of the most important factors in induction of autoimmune hemolytic anemia.