Poor peripheral T cell proliferation defect in aged mice.

<p>CD4+ or CD8+ T cells from naïve <i>FoxN1 K14KO</i>, aged and young control mice were isolated from spleens by positive immunomagnetic selection, stained with CFSE and stimulated with suboptimal concentrations of anti-CD3 and anti-CD8. Two, 3 and 4 days after stimulation, proliferation of CD4+ (A) and CD8+ (B) T cells were measured by flow cytometry. Three mice/group were used in two independent experiments.