Fig. 3

Expression of SIRT1 in non-stimulated and stimulated CD56dim and CD56bright cells of the young, old and the oldest. Data are presented as means ± SEM and show expression of the studied protein in NK cell subsets demonstrated as the percentage of cells with the expression of a particular protein (%) and mean fluorescence intensity (MFI). The same symbols over bars (^#, *^, ^) denote statistically significant differences between similarly treated CD56dim or CD56bright cells, i.e. respectively non-stimulated or stimulated by IL-2, LPS or PMA with ionomycin compared between: young vs. old (marked with ^#), young vs. oldest (marked with *) and old vs. oldest (marked with ^). 3 symbols denote p < 0.001; 2 symbols denote p < 0.01; 1 symbol denotes p < 0.05. Horizontal lines above paired bars denote statistically significant differences between respectively CD56dim or CD56bright cells non-stimulated vs. stimulated by IL-2, LPS or PMA with ionomycin within the same age group. a Expression of SIRT1 in CD56dim cells (%). b Expression of SIRT1 in CD56bright cells (%). c Expression of SIRT1 in CD56dim cells (MFI). d Expression of SIRT1 in CD56bright cells (MFI)