DC maturation is affected by aging.

<p>(A and B) Young and old mice were intravenously injected with 100 μg polyU/DO. Eighteen hours later, expression levels of CD86, CD40, MHC II (A) and PDL-1 (B) were determined in DC subsets by flow cytometry. Total (C) or CD8α⁺ (D) cDCs purified from the spleen of young and old mice were stimulated with 20 μg/mL polyU/DO and then supernatants were assayed for cytokine production by ELISA. (D) Spleen DC subsets from young and old mice were purified and total RNA of 1x10⁶ DCs was extracted. Relative mRNA levels for <i>Tlr7</i> were quantified by qPCR and normalized to <i>Hprt1</i>. Data show the mean ± SEM. Results are representative of 3 independent experiments (3–4 mice/age group/experiment). *p < 0.05, **p < 0.01, ***p < 0.001.