A role for interleukin 4 in the differentiation of mature T cell receptor γ/δ+ cells from human intrathymic T cell precursors

Abstract

We have analyzed the effect of human recombinant interleukin 4 (rIL-4) on the growth and differentiation of human intrathymic pre-T cells (CD7+2+1-3-4-8 -). We describe that this population of T cell precursors proliferates in response to rIL-4 (in the absence of mitogens or other stimulatory signals) in a dose-dependent way. The IL-4-induced proliferation is independent of the IL-2 pathway, as it cannot be inhibited with an anti-IL-2 receptor α chain antibody. In our culture conditions, rIL-4 also promotes the differentiation of pre-T cells into phenotypically mature T cells. Although both CD3/T cell receptor (TCR)-α/β+ and CD3-γ/δ+ T cells were obtained, the preferential differentiation into TCR-γ/δ+ cells was a consistent finding. These results suggest that, in addition to IL-2, IL-4 plays a critical role in promoting growth and differentiation of intrathymic T cell precursors at early stages of T cell development.