Primary cells and cell lines

PBMCs and monocytes were obtained from Human Immunology Core at the University of Pennsylvania, which were obtained from healthy donors. For γδ T-cell expansion, PBMCs were cultured with RPMI1640 media supplemented with 10% FBS (HyClone; GE Healthcare, Utah, USA), 100 U/mL penicillin–streptomycin, 2 mM L-glutamine, 1/1000 2-mercaptoethanol (2-Me) (Gibco; Thermo Fisher Scientific, Massachusetts, USA) (or without 2-Me as indicated) and 200 units/mL of recombinant human interleukin (IL)-2 (PeproTech, New Jersey, USA) in 24-well microplates, new media added and supplemented every other day. γδ T cells were expanded in 24-well tissue culture treated microplates that were coated with mouse-monoclonal anti-pan-TCR γδ antibody (1.0 μg/mL in phosphate-buffered saline (PBS); IMMU510, IM1349, Beckman). For naive γδ T-cell isolation, PBMCs were purified using a commercial human TCR γ/δ T-cell Isolation Kit (Miltenyi Biotec, Germany). Purified naive γδ T cells routinely exceeded >95% concentration by flow cytometry. Human melanoma cell lines A375, A2058, WM9, 903 were obtained from Meenhard Herlyn’s laboratory (The Wistar Institute, Philadelphia, Pennsylvania, USA), and they were routinely tested for mycoplasma and DNA fingerprinted.17 Lung cancer cell line H1975, colon cancer cell line HT-29, and gastric cancer cell line NCI-N87 were purchased from American Type Culture Collection (ATCC). Daudi cells were obtained from Andrei Thomas-Tikhonenko Lab at the University of Pennsylvania and Children’s Hospital of Philadelphia, K562 cells were obtained from Michael Milone Lab at the University of Pennsylvania. BRAF inhibitors (BRAFi) and MEK inhibitors (MEKi) combination therapy-resistant (CR) cell lines WM9-CR and A2058-CR were generated as described before.18