IFNG and neoplasm: When co-culture with tumor cells, IFN-γ secretion was lower in Jurkat cells co-cultured with HK2 overexpressing-A549 cells (“HK2 vector”) than in Jurkat cells co-cultured with empty vector transfected-A549 cells (“empty vector”) in both direct and transwell co-culture systems (p < 0.05; Fig. 5a).