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 leuke mia (CD3-, CD2+, CD7+, germline TCR genes) who relapsed early after al logeneic bone marrow transplantation, is reported. The line was establ ished from blood cells obtained at diagnosis and placed in suspension culture with medium conditioned by 5637 cells. SR-91 cells are negativ e for lymphoid surface markers (CD3-, CD2-, CD7-) but positive for mar kers indicative of myeloid progenitor cells, such as CD33 and CD34. It is likely that the conditioned medium has induced myeloid differentia tion 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 comp letely resistant to anti-proliferative effects of tumor necrosis facto r-alpha and interferon-alpha or -gamma, and showed no lysis after incu bation with freshly isolated natural killer cells or IL-2-activated na tural killer cells.