Evaluating Cytotoxicity of Vγ9Vδ2 T Cells

CytoTox 96^® Non-Radioactive Cytotoxicity Assay kits (Promega), which are based on the colorimetric detection of the released enzyme lactate dehydrogenase (LDH), was used to determine specific cytotoxicity. Vγ9Vδ2 T cells (Effector, E) were co-cultured with LX-2 cells (Target, T), which were pretreated with N-BPs for 4 h at specific E/T ratios for 4 h (indicated in figure captions). In some cases, after 4 h co-cultured, the number and area of Vγ9Vδ2 T cells clusters were determined using IncuCyte (Essen BioScience) image analysis software. Three different locations per well were imaged with a 10 × objective lens. Clusters were defined as cell aggregates occupying an area at least 300 µm² and were displayed as the number and area of clusters per well. In some experiments, Transwell^® units (pore size 0.4 µm, Corning) were used to separate Vγ9Vδ2 T cells from LX-2 cells. In some cases, the neutralization antibodies anti-NKG2D (10 µg/mL, BD), anti-FasL (10 µg/mL, Biolegend), anti-TRAIL (10 µg/mL, Biolegend), anti-TCR γδ (10 µg/mL, Biolegend), and their relevant isotype controls, were individually added in the co-cultures to block the NKG2D-, FasL-, TRAIL-, and TCR γδ- mediated pathways. To block perforin and granzyme B pathways, the perforin inhibitor Concanamycin A (CMA, Selleck) (1 µg/mL) and granzyme B inactivator BCL-2 (1 µg/mL, R&D Systems) were used (15 (link)).