Epithelial Defence by γδ T Cells

γδ T cells constitute a separate lineage of T lymphocytes which differ from conventional αβ T cells with regard to T cell receptor (TCR) repertoire and tissue localization. In murine skin, γδ T cells expressing a canonical Vγ5 TCR are abundant and contribute as so-called dendritic epidermal T cells to local immune surveillance. In humans, major subsets of γδ T cells are recognized on the basis of their TCR Vδ usage. While Vδ2 cells dominate in the peripheral blood, Vδ1 cells are preferentially localized in mucosal tissue including the intestinal epithelia. In this article we summarize basic features of intraepithelial γδ T cells and discuss their possible role in epithelial defence.