IL-7 induces proliferation, variable cytokine-producing ability and IL-2 responsiveness in naive CD4(+) T-cells from human cord blood

We investigated the effects of IL-7 on the proliferation and acquisition of cytokine-producing ability of naive CD4(+) T-cells from human cord blood. Naive CD4(+)CD45RA(+) T-cells from human cord blood expressed CDw127 (IL-7R) at higher levels than adult CD4(+)CD45RA(+) T-cells and produced IL-2 and a small amount of IFN-gamma upon stimulation with PMA and ionomycin. IL-7 induced IL-2-independent proliferation and both Th1- and Th2-type cytokine-producing abilities in cord blood CD4(+)CD45RA(+) T-cells without stimulation via TCR. These results suggest that this IL-7-induced antigen-independent activation mechanism could contribute to maintaining the clonal size of naive T-cells with the potential to differentiate into either Th1 or Th2 cells at the sites of IL-7-expression. (C) 1997 Elsevier Science B.V.