A new subpopulation of intestinal intraepithelial lymphocytes expressing high level of T cell receptor gamma delta.

Abstract

The murine intestinal epithelium contains T cell receptor (TcR) gamma delta-bearing T cells in high frequency. In the present report, we showed that TcR gamma delta-bearing intestinal intraepithelial lymphocytes (IEL) from C3H/He (H-2k) mice can be divided into two subpopulations based on TcR expression level; a subpopulation with a remarkably high level of TcR expression and a subpopulation with a moderate level of TcR expression, designated as TcR gamma delta hi IEL and TcR gamma delta mod IEL, respectively. In flow cytometric analysis, the TcR gamma delta hi IEL expressed a high level of TcR (mean fluorescence channel 518) when compared with the TcR level of TcR gamma delta+ T cells in other lymphoid organs (mean fluorescence channel 88). The TcR gamma delta hi IEL were detected in IEL from mice of H-2k and H-2k/b haplotypes but not in H-2b and H-2d haplotypes. V delta 4, which was reported to be frequently expressed in IEL of H-2k mice, was preferentially expressed by TcR gamma delta hi IEL. These results suggested that the existence of the TcR gamma delta hi population is related to the high frequency of V delta 4 in H-2k mice.