This was done as we previously described [24 (link), 33 (link), 44 (link)]. Cells were harvested at day 7 after culture and stained with Pacific blue-conjugated anti-CD3 (Clone SP34-2, BD, Franklin Lakes, NJ), PE conjugated anti-CD4 (clone OKT4, eBioscience, San Diego, CA), FITC-conjugated Vγ2 (Clone 7A5, Pierce, Rockford, IL) and purified Vδ2 (clone 15D, Pierce) in combination of allophycocyanin-conjugated goat anti mouse IgG (Dako, Carpinteria, CA). After staining, cells were fixed with 2% formaldehyde-PBS (Protocol Formalin, Kalamazoo, MI) and subjected to run on a CyAn ADP flow cytometer (DakoCytomation, Carpinteria, CA). Lymphocytes were gated based on forward- and side-scatters, and pulse width and at least 40 000 gated events were analyzed by using Summit Data Acquisition and Analysis Software (Dako Cytomation). Further special gates and quadrants for data analysis were determined on nonstaining, specific antibody staining, and isotype control antibody background staining.