Pathogenic Potency and Host Range of the Mouse Leukemia Virus

Abstract

The passage A leukemic virus, isolated from spontaneous Ak mouse leukemia, and then passed serially through newborn C3H mice, induces a high incidence of leukemia in several inbred strains of mice, including random-bred Swiss mice, and also in rats. This virus induces in most instances the lymphatic form of leukemia or stem-cell leukemia, but in certain strains of mice, such as BALB/c, and also in rats, it may induce a relatively high incidence of myeloid leukemia. Following thymectomy in mice of strains C3H and C57 Brown, the passage A virus may induce a relatively high incidence of myeloid leukemia and in C3H mice also chloroleukemia, and occasionally either the monocytic or the erythroblastic form. The passage A leukemic virus induces in most of the leukemic animals a rapidly progressing anemia, accompanied in some instances by extramedullary hematopoiesis. Leukemic virus strains could also be isolated from radiation-induced leukemia, and from a number of transplanted mouse tumors. Such leukemic viruses induce in mice and rats forms of leukemia very similar to those induced with the passage A virus. The question is discussed whether these virus strains are distinct, or whether they represent isolation from different sources of the same, or of a closely related, virus.