IFNG and neoplasm: Next, to evaluate TIL activity, we co-cultured TIL alone, with autologous tumor digest, or with autologous tumor digest treated with W6/32 antibody to block MHC class I. Increased IFNγ, TNFα, and Granzyme B were measured after a 24-hour co-culture, which was decreased with an MHC class I blocking antibody, confirming MHC class I-directed TIL reactivity against autologous tumor (Figure 4e).