INTERLEUKIN-7 RECEPTOR MEDIATES THE ACTIVATION OF PHOSPHATIDYLINOSITOL-3 KINASE IN HUMAN B-CELL PRECURSORS

Interleukin 7 appears to be central to promoting growth and differentiation of lymphocyte precursors. Pro-B cells, as well as pre-pre-B cells, but not mature cells express the IL-7 receptor suggesting an important role for IL-7 during these early stages of B cell maturation. Indeed, IL-7 was shown to promote not only growth but also immunoglobulin gene rearrangement in these cells. However, the mechanism by which IL-7 receptor transduces these growth signals remains elusive. In an attempt to characterize a pathway of signal transduction via the IL-7 receptor, we have demonstrated here that ligation of the IL-7 receptor is associated with increased activity of PI-3 kinase. PI-3 kinase products were detected by TLC and their identity confirmed by HPLC. Further, by in vivo labeling intact cells we have shown that IL-7 receptor mediates the activation of PI-3 kinase. © 1993 Academic Press, Inc.