Dose-dependent inhibition of the cytotoxic effect of IL-1β to A375.S2 cells. (A)% levels of inhibition under varied inputs of the fusion protein, IL-1ra, and HSA. (B) Inhibition of IL-1β-induced cytotoxicity to A375.S2 cells as shown by photomicroscopy. Cells were incubated in the presence of 32 nM fusion protein (1), 1 ng/ml (0.06nM) IL-1β alone (2), 0.06nM IL-1β plus 2 nM fusion protein (3), and 0.06nM IL-1β plus 32 nM fusion protein (4). There is no difference: between (1) and cells with medium alone (not shown); between (2) and the cells in 0.06nM IL-1β plus 32 nM HSA (not shown).