Host control of susceptibility to erythroleukemia and to the types of leukemia induced by Friend murine leukemia virus: initial and late stages.

The genetic control of the susceptibility to early erythroleukemic induction by helper-independent Friend murine leukemia virus was determined to be due to the presence of a single dominant resistant locus. This locus, (termed Fv6), however, governs only resistance to early erythroleukemia, since other types of leukemias developed late in the resistant mice: myelomonocytic leukemia (approximately 70%), T-lymphoid leukemia (approximately 25%) and late erythroleukemia (approximately 10%). Data also indicated that mice with higher DBA/2 (resistant strain) genetic background had an increased frequency of myelomonocytic leukemias. Studies of the hemopoietic modulations indicated that mice that developed early or late erythroleukemia had dramatic increases in erythroid bursts, suggesting that the leukemic blocks are at the level of BFU-E or earlier. High levels of the granulocytic progenitor colonies were also found in mice with late erythroleukemia and myelomonocytic leukemia. Analysis of these leukemias indicate that they are multistage diseases.