Skin γδ T-cell functions in homeostasis and wound healing

There is a resident population of T cells found in murine skin that expresses an invariant V gamma 3V delta 1 T-cell receptor (TCR), and these cells are significantly different from lymphoid gamma delta T cells and alpha beta T cells in terms of ontogeny, tissue tropism, and antigen receptor diversity. These dendritic epidermal T cells are derived from fetal thymic precursor cells, are in constant contact with neighboring epidermal cells, and express a monoclonal gamma delta TCR only found in the skin. Skin gamma delta T cells have been shown to play unique roles in tissue homeostasis and during tissue repair through local secretion of distinct growth factors including keratinocyte growth factors and insulin-like growth factor-1. In this review, we discuss evidence supporting a role for cross talk between skin gamma delta T cells and keratinocytes that contributes to the maintenance of normal skin and wound healing.