Fig. 2.

Expression of SIRT1 and intracellular HSP70 in non-stimulated and stimulated NK cells of the young, the old aged under 85 and the oldest seniors (aged over 85). Data are presented as means ± SEM and show expression of the studied proteins in NK cells demonstrated as percentages of cells with the expression of a particular protein (%) or mean fluorescence intensity (MFI). The same symbols over bars (^X, ⁺, ^o, ^#, *, ^, ^Δ, ^Y) denote statistically significant differences between similarly treated NK cells of different age groups (i.e. young vs old; young vs oldest or old vs oldest). Horizontal lines above paired bars denote statistically significant differences between treated and untreated NK cells of the same age group (i.e. non-stimulated vs stimulated with IL-2, LPS or PMA with ionomycin). a Expression of SIRT1 (%): ^X, ^#, ^, ⁺, *, ^Yp < 0.001; ^op ≤ 0.01. b Expression of SIRT1 (MFI): ^#, ⁺, *, ^Yp < 0.001; ^, ^Xp < 0.01; ^Δp < 0.05. c Expression of HSP70^{intracellular} (%): ^X, ⁺, ^Yp < 0.001; ^#, *, ^Δp < 0.01; ^ p < 0.05. d Expression of HSP70^{intracellular} (MFI): ^#, ⁺, ^Y, * p ≤ 0.001; ^X, ^ p ≤ 0.01