Homing of a γδ thymocyte subset with homogeneous T-cell receptors to mucosal epithelia

IN mice γδ T-cell populations with distinct T-cell receptor (TCR) repertoires and homing properties have been identified. Diversified populations are found in lymphoid organs 1–3 and intestinal epithelia 4,5 . By contrast, the γδ T-cells Is that have been found in the murine skin are homogeneous. They express a TCR consisting of one particular V γ 5 and one particular V81 chain 5,6 and seem to originate from early fetal thymocytes 6,7 . We have now systematically analysed many tissues by immunohistochemistry and TCR gene sequencing aided by the polymerase chain reaction. These studies revealed a second homogeneous γδ T-cell subset in epithelia not of the intestine and skin, but of the vagina, uterus and tongue. The TCR expressed by this γδ T-cell subset consists of the same Vδ1 chain. Cells that express this particular TCR have previously been shown to be positively selected in the late fetal thymus 7 .