Upregulation of T Cell Receptor γ Chain Transcription by Interleukin-2

Signals involved in TcR gene rearrangement and expression are poorly understood. The ability of interleukin 2 to control TcR γ gene expression was examined. Precursor thymocytes grown in the presence of IL-1 and Con A develop to CD3+ T cells that express either the TcR α/β or γ/δ complex on the cell surface (1). We show here that a major subpopulation of these cells are CD4-/CD8-, γ/δ cells expressing only low levels of TcR γ transcripts, compared to TcR δ mRNA or to TcR γ, mRNA of γ/δ cells grown from precursor thymocytes with IL-2 and Con A. The cells cultured with IL-1 and lectin then strongly reacted to IL-2 by upregulating the steady-state level of TcR γ mRNA. Our findings indicate that IL-2 upregulates TcR γ transcription by transcriptional regulatory effects in this in vitro system.