The present study describes the establishment of the cell line Pre-Alp from the bone marrow of a pediatric patient with a t(1;19) pre-B acute lymphoblastic leukemia (ALL) at diagnosis. Proliferation of leukemic blasts was found to be initially dependent on the presence of autologous stromal cells. However, after five weeks of culture, the stromal cells were no longer necessary and cells began to grow autonomously, with a doubling time of approximately 24 hours. The established Pre-Alp cell line displays a pre-B cell phenotype (CD19+, CD10+, CD34-, c mu+, s mu-), with immunoglobulin (Ig) light chain DNA in germline configuration, and carries a (1;19)(p23;q13.3) chromosomal translocation identical to the freshly-isolated leukemic blasts. A unique feature of this cell line is represented by its ability to respond to interleukin 7 (IL-7). Thus, IL-7 enhances 3H-thymidine uptake by Pre-Alp cells in a dose-dependent manner, under conditions of low cell density and serum concentration, and increases cell recovery. Finally, Pre-Alp cells were found to remain at a pre-B stage even upon addition of various cytokines, which failed to induce a transition to surface Ig+ cells. The presently described cell line should constitute a useful model of t(1;19) pre-B ALL and permit the study of IL-7 dependent signal transduction in human pre-B cells.