Establishment and characterization of a human leukemic cell line (SR-91) with features suggestive of early hematopoietic progenitor cell origin.

The characterization of a cell line (designated SR-91) from a patient with clinical and morphological diagnosis of acute lymphoblastic leukemia (CD3-, CD2+, CD7+, germline TCR genes) who relapsed early after allogeneic bone marrow transplantation, is reported. The line was established from blood cells obtained at diagnosis and placed in suspension culture with medium conditioned by 5637 cells. SR-91 cells are negative for lymphoid surface markers (CD3-, CD2-, CD7-) but positive for markers indicative of myeloid progenitor cells, such as CD33 and CD34. It is likely that the conditioned medium has induced myeloid differentiation from a lymphohematopoietic progenitor cell. After establishment, cells proliferated in response to GM-CSF stimulation but they are not factor-dependent and do not produce GM-CSF. No proliferative response to IL-1, IL-2, IL-3, IL-4, IL-6 or M-CSF was observed. Cells were completely resistant to anti-proliferative effects of tumor necrosis factor-alpha and interferon-alpha or -gamma, and showed no lysis after incubation with freshly isolated natural killer cells or IL-2-activated natural killer cells.