IFNG and neoplasm: Next, antigen-specific reactivity against EGFRvIII was determined in co-culture assays; while EGFRvIII+ CAR T cells did not secrete observable levels of the type 1 cytokine interferon-gamma (IFN-γ) in response to the U87MG (EGFRvIII-) tumor cell line, they did produce IFN-γ in the presence of the U87MG.ΔEGFR (EGFRvIII+) cell line as measured by intracellular staining (ICS) (Fig. 2c; P = 0.0004; two-way ANOVA).