LPS-induced IFNγ in mouse splenic lymphocytes is promoted by estrogen at the posttranscriptional level. (A) ELISA analysis of IFNγ levels in supernatants from 5 × 10⁶ freshly isolated (t0) splenocytes and those stimulated with LPS (500 ng/mL, the same concentration was used in all the experiments in this study) for 6 hours. The graphs show the means plus or minus SEM (n = 4 each). (B) Total RNA was prepared from freshly isolated splenocytes and from those stimulated with LPS for 6 hours. IFNγ mRNA expression levels were determined by real-time RT-PCR. The graphs show the relative mRNA expression levels with the means plus or minus SEM (n ≥ 3). *P < .05.