Interleukin 7-induced expression of specific T cell receptor γ variable region genes in murine fetal liver cultures

Abstract

We previously reported that culture of murine fetal liver (FL) cells with interleukin 7 (IL-7) results in expression of high levels of T cell receptor (TCR) γ transcripts by a population of cells expressing Thy-1 and Pgp-1, suggesting that IL-7 promotes the growth and/or differentiation of pre-T cells. We demonstrate herein that culture of FL cells for 7 d with IL-7 caused the rearrangement and expression of TCR γ variable (V) region genes Vγ4 and Vγ6, but not Vγ5 or Vγ7. Since this effect was not blocked by hydroxyurea, it appeared to represent induction of expression of these genes by IL-7 rather than expansion of a preexisting positive population. We also show that IL-7 induced RAG-1 and RAG-2 mRNA expression by FL cells. These data provide evidence that specific TCR γ/δ V region genes can be rearranged and expressed by T lineage cells before their migration to the thymus, in response to IL-7.