Cross-talk between intraepithelial γδ T cells and epithelial cells.

Intraepithelial γδ T cells play pivotal roles in homeostasis, tissue repair, inflammation, and protection from malignancy. In some tissues, γδ T cells are the only resident T cell population, whereas in others, they coexist with αβ T cells and other lymphocyte populations. γδ T cell function in the epithelium requires constant communication between cells in the form of cell-to-cell contacts and cell-to-matrix interactions. These interactions coordinate with the timely production of specific cytokines, chemokines, growth factors, and glycosaminoglycans, which have specialized effects on neighboring epithelial cells. Antigens that activate these T cells are not well-defined, and they do not express classic costimulatory or coreceptor molecules. As such, an understanding of the mechanisms used by epithelial γδ T cells to maintain homeostasis and facilitate wound repair has necessitated the identification of novel molecular interactions between γδ T cells and their neighboring epithelial cells.