IL2 and melanoma: However, exposure of DAB/IL2 to proliferating human melanoma cells in vitro at a concentration 15-fold higher than the obtainable peak plasma concentration of DAB/IL2 in humans (0.3 μg/ml) had no effect on cell viability or proliferation (0.05–5 μg/ml × 48 hours; vehicle control, 7.12 ± 0.13 × 105 cells; + 5 μg/ml DAB/IL2, 7.35 ± 0.37 × 105 cells; p value = 0.444).