Expression of Bcl-2 and Bax in the U-266-1970 cells in the absence or presence of anti-Fas MoAbs (CH-11; 100 ng/mL). Cells were incubated in the presence of IL-6 (20 U/mL) without or with IFN-γ (100 U/mL) for 96 hours. Cells were then subjected to double-staining for TUNEL and Bcl-2 or Bax expression and flow cytometry analysis. The population of TUNEL⁺/Bcl-2⁺ and TUNEL⁺/Bax⁺ cells was gated in the analysis by the use of RPE-conjugated mouse IgG1/FITC-conjugated mouse IgG1 and RPE-conjugated mouse IgG1/FITC-conjugated antirabbit IgG, respectively.