EL4 cells are not susceptible to an IFN-γ–mediated antiproliferative effect.

(A) A FACS profile showing expression of IFN-γ receptor on EL4 cells. EL4 cells stained with anti-CD119 (IFN-γ receptor α chain) and isotype control mAb are presented as filled and open histograms, respectively. Results from one representative experiment of 3 are shown. (B) Proliferation of EL4 and WEHI-279 cells cultured in medium containing various concentrations of IFN-γ. Data are presented as the mean ± SD (cpm) of triplicate cultures in each culture condition. Results from one representative experiment of 3 are shown. (C) Lack of inhibitory activity on the proliferation of EL4 cells in allogeneic mixed lymphocyte reaction supernatants. EL4 cells were cultured inside tissue culture inserts placed in 24-well plates containing responders (BALB/c splenocytes) and stimulators (irradiated B6 splenocytes) (▪) or stimulators only (■) (see “Materials and methods”). Three wells from each group were harvested at each time point and the number of viable EL4 cells in each well was counted. Data are presented as the mean ± SD (cell number/well) of triplicate samples.