Cytomegalovirus and tumor stress surveillance by binding of a human γδ T cell antigen receptor to endothelial protein C receptor

T cells bearing gamma delta T cell antigen receptors (TCRs) function in lymphoid stress surveillance. However, the contribution of gamma delta TCRs to such responses is unclear. Here we found that the TCR of a human V(gamma)4V(delta)5 clone directly bound endothelial protein C receptor (EPCR), which allowed gamma delta T cells to recognize both endothelial cells targeted by cytomegalovirus and epithelial tumors. EPCR is a major histocompatibility complex-like molecule that binds lipids analogously to the antigen-presenting molecule CD1d. However, the V(gamma)4V(delta)5 TCR bound EPCR independently of lipids, in an antibody-like way. Moreover, the recognition of target cells by gamma delta T cells required a multimolecular stress signature composed of EPCR and costimulatory ligand(s). Our results demonstrate how a gamma delta TCR mediates recognition of broadly stressed human cells by engaging a stress-regulated self antigen.