Cell lines

B16-F10 cells were purchased from the American Type Culture Collection (ATCC Cat# CRL-6475, RRID:CVCL_0159). B16-GVAX and B16-OVA cells (RRID:CVCL_WM78) were a gift from Glenn Dranoff. Cells were cultured in RPMI 1640 medium (Gibco) supplemented with 10% heat-inactivated FBS (Omega Scientific catalogue # FB-11), 2 mM L-glutamine (Gibco), penicillin G sodium (100 U/mL, Gibco), streptomycin sulfate (100 μg/mL, Gibco), 1 mM sodium pyruvate (Gibco), 0.1 mM nonessential amino acids (Gibco), and 0.1 mM β-mercaptoethanol (Sigma). Cells were passaged 2–6 times prior to use and were used for experiments at 80–90% confluency. Mycoplasma testing was performed by Charles River Laboratories every 6 months and was negative for the entire course of this study. No further authentication was performed. HEK 293T cells (ATCC Cat# CRL-3216, RRID:CVCL_0063) were purchased from ATCC and cultured in DMEM medium (Gibco) supplemented with 10% heat inactivated FBS, 2mM L-glutamine and 100 U/ml penicillin G.