Daan Pieren

95 Compromised DNA repair promotes the accumulation of regulatory T cells Total splenocytes of WT young (n=6) and aged (n=6) mice, and Ercc1 +/+ (n=5), Ercc1 -/ Δ 7 (n=7), and Ercc1 -/ Δ 7 mice treated with rapamycin (n=3-6) were exposed to anti-CD3 alone or in combination with anti-CD28 or IL-2 for four days. Bar graphs show Th- and Tc-cell proliferation of ( A,B ) Ercc1 -/ Δ 7 and Ercc1 -/ Δ 7 mice and of ( C,D ) WT young and aged mice. Bar graphs show CD25 expression by Th and Tc cells of ( E,F ) Ercc1 -/ Δ 7 and Ercc1 -/ Δ 7 mice and ( G,H ) WT young and aged mice . Bar graphs show mean ± SD; * p < 0.05, ** p < 0.01, *** p <0.001, **** p < 0.0001 ns = not statistically significant for the difference between groups using parametric one-way ANOVA corrected with Holm-Sidak correction for multiple comparisons. Due to the low number of eRapa-fed Ercc1 -/ Δ 7 mice (n=3), statistical significance of this group was determined by non- parametric Mann-Whitney U Test. 3