CHARACTERIZATION OF A T(1-19) PRE-B ACUTE LYMPHOBLASTIC-LEUKEMIA (ALL) CELL-LINE WHICH PROLIFERATES IN RESPONSE TO IL-7

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 acut e lymphoblastic leukemia (ALL) at diagnosis. Proliferation of leukemic blasts was found to be initially dependent on the presence of autolog ous stromal cells. However, after five weeks of culture, the stromal c ells were no longer necessary and cells began to grow autonomously, wi th 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 config uration, and carries a (1;19)(p23;q13.3) chromosomal translocation ide ntical to the freshly-isolated leukemic blasts. A unique feature of th is cell line is represented by its ability to respond to interleukin 7 (IL-7). Thus, IL-7 enhances H-3-thymidine uptake by Pre-Alp cells in a dose-dependent manner, under conditions of low cell density and seru m concentration, and increases cell recovery. Finally, Pre-Alp cells w ere found to remain at a pre-B stage even upon addition of various cyt okines, 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 transducti on in human pre-B cells.