Phenotype and activation patterns of Vδ2T_EMhand Vδ2T_EMRAlymphocytes. (A) NKR and chemokine receptors of representative T_EMh (top panels) and T_EMRA (bottom panels) TCR Vδ2⁺ clones. Cultured Vδ2 T-cell clones are characterized as Vδ2T_EMh on the basis of their CD16^–CD45RA^– perforinlow pheno-type, or as Vδ2T_EMRA when they are CD16⁺CD45RA⁺ perforin^high (mean fluorescence intensity [MFI] for intracellular perforin is given). (B) Vδ2T_EMh and Vδ2T_EMRA PBMCs freshly drawn from a healthy donor with different levels of cell surface TCR Vδ2. (C) PhosphoERK immunoblots of lysates from Vδ2^high and Vδ2^low cells (5 × 10⁵ cells/point). After sorting using gates shown in panel B, in vitro activation of the collected cells, and production of their lysates, the p-Erk immunoblots reveal a higher response to BrHPP in Vδ2T_EMh than in Vδ2T_EMRA, which respond better to stimulation with anti-CD16. The data are representative of 2 independent experiments on different donors.