Natural cytotoxicity receptors are selectively expressed on proliferating Vδ1⁺ T cells. (A) γδ PBLs were labeled with CFSE and cultured as described in Figure 1, or in the absence of T cell mitogens (ie, IL-2 alone). Flow cytometry analysis of CFSE dilution and Vδ2 TCR expression after 7 days in culture. (B) Percentage of Vδ1⁺ or Vδ2⁺ cells among total γδ PBLs cultured up to 19 days with PHA and IL-2. Error bars represent SD (n = 3). (C) NKp30 expression in PHA and IL-2–activated γδ PBL subsets. Vδ1⁺ or Vδ2⁺ cells were FACS-sorted from peripheral blood, labeled with CFSE and cultured with PHA and IL-2 for 7 days. Percentages refer to NKp30⁺ cells within each cell division (according to CFSE levels and indicated by vertical rectangles). (D) Expression of NKp30, NKp44 and NKp46 in Vδ1⁺ T cells after 19 days of PHA and IL-2 stimulation. Isotype mAb control stainings are also shown. Data in this figure are representative of 2-3 independent experiments with similar results.