Figure 4. CD8+ T cells from elderly mice show reduced Ca2+ signals after T cell receptor stimulation and are less affected in their cytotoxic function by varying free external Ca2+ concentrations. Fura2-AM based Ca2+ Imaging with 2 μg/ml anti-CD3 antibody as stimulus applied in the presence of 0.5 mM [Ca2+]ext of (A) untouched (black: adult, n = 664 cells; red: elderly, n = 327 cells) and (B) stimulated (black: adult, n = 155 cells; red: elderly, n = 116 cells) CD8+ T cells from adult and elderly mice. (C) The cytotoxic function of CD8+ T cells from elderly mice is less affected by varying free [Ca2+]ext. Changes in end-point lysis with the addition of Ca2+ or the Ca2+ chelating agent EGTA to the medium of a cytotoxicity assay for CD8+ T cells of adult (grey, n = 3 - 5) and elderly (n = 2 - 3) mice. Data obtained are presented as mean ± SEM.