Dose-dependent effect of IFN-γ on monocyte apoptosis and IL-10 secretion. Monocytes were cultured for 24 hours in the presence of medium alone or of various concentrations of IFN-γ. (A) Each histogram represents the percentage of apoptotic cells in response to a different concentration of IFN-γ assessed by flow cytofluorimetry analysis using the acridine orange nuclear dye. (B) Each circle represents the amount of IL-10 secreted in response to a different concentration of IFN-γ.