Figure 5.

Recognition of γδ TCR ligands requires a cell stress context. (a) Recognition of EPCR requires co-stimulatory ligands on the surface of the target cells, and accessory molecules on the surface of the T cell. (b) Both hMSH2 and MIC A become upregulated and ectopically expressed in response to cell stress stimuli and are dually recognised by NKG2D and TCR. The sequential model of recognition implies that the initial contact provided by a transient high-affinity NKG2D–ligand interaction (1) is followed by formation of a stable low affinity TCR-ligand complex (2).