Establishment of an in vivo human myeloid leukemia model in the SCID mouse

We succeeded in establishing a human myelogenous leukemia model in severe combined immunodeficient (SCID) mice by transplanting 2 x 10(7) ML-2 cells intraperitoneally (i.p.) with cyclophosphamide (CTX) pretreatment. Two months after transplantation, 9 of 10 mice developed leukemia and leukemia cells were detected in the peripheral blood (PB) and bone marrow (BM). The main findings at autopsy were peritoneal and pleural effusions and large tumor masses involving the peritoneal organs. However, successful transplantation required injection of a large number of cells. We therefore established a new cell line, ML-2S, from the PB of a mouse with ML-2 leukemia. Although only 2 x 10(6) ML-2S cells were inoculated, ML-2S induced the same pattern of leukemic dissemination reminiscent of the parent ML-2 cells. Compared to ML-2, progression of ML-2S was slow, suggesting that ML-2S is suitable as a leukemia model to study treatment. Furthermore, we confirmed that ML-2S cells are of human origin using isoenzyme analysis and also that ML-2S and ML-2 cells have the same phenotypic character by cell surface marker analysis.