<p>VC5 and MC2 cells were cultured in E<sub>2</sub>-depleted media followed by transfection with CIITA pIV luciferase constructs. On the following day, cells were treated with vehicle (ethanol), E<sub>2</sub> (10<sup>−9</sup> M) and/or ICI (10<sup>−6</sup> M), and stimulated or not with IFN-γ (100 U/ml) for 12 hours. Data are expressed as fold induction over the PGL2 Basic empty plasmid after controlling for transfection efficiency using cells dual transfected with GFP (Green Florescent Protein). The effect of ERα on the transcription activation of CIITA PIV was determined from relative luciferase activities in transfected MC2. Error bars represent the mean ± SEM of three independent experiments (**p<0.01).</p