IFNγ induced cytotoxicity. Cytotoxicity of IFNγ was evaluated by lactate dehydrogenase (LDH) release from IFNγ-treated BON cells. A: After 48 h of incubation, IFNγ induced a dose-dependent increase in LDH release. B: MIBG-treatment (48 h) also induced cytotoxicity in BON cells in a dose-dependent manner. C: Interestingly, co-treatment of BON cells with IFNγ and MIBG resulted in an over-additive LDH release. Black bars indicate the calculated additive values of LDH release of either combination. Data are given as the relative increase in LDH release compared to untreated controls (means ± SEM of 4 independent experiments). *, statistical significance (p < 0.05) compared with untreated controls.