Figure 4.

Reduced IAβ and IEβ mRNA expression in bone marrow macrophages from aged mice after IFN-γ stimulation. Macrophages from aged and young mice were treated with IFN-γ (300 U/ml) for the indicated times. The 18S RNA was used as an internal control of RNA load and was not affected by the treatment. The upper panel is representative of six independent experiments, all of which showed the same level of basal expression in young and older macrophages. In the lower panels, data are represented as the mean ± SD of six experiments. For IAβ, after 24, 48, and 72 hours, and for IEβ, after 48 and 72 hours of IFN-γ treatment, there was a significant difference (P < 0.01) between young and aged macrophages.