Figure 2. Cross-talk in epidermal γδ T cell activation.

γδ DETC recognize stress or damage signals delivered by keratinocytes. This recognition involves the coordinated interaction between the TCR and its unknown ligand, together with the costimulatory molecules, JAML and NKG2D, with their keratinocyte ligands, CAR and H60c/RAE 1, respectively. Additional signals are generated through CD100 on DETC and plexin B2 on keratinocytes to initiate DETC rounding prior to complete activation. Activated DETC exhibit a round morphology and secrete KGFs (KGF-1 and KGF-2) that facilitate keratinocyte proliferation and re-epithelialization. Simultaneous secretion of a battery of cytokines and chemokines ensures an appropriate effector response and recruitment of inflammatory cells. Together, these coordinated events allow the efficient functioning of all facets of the wound-repair process.