Fig. 6.

IL-2/CD40 activated elderly-derived macrophages reverse tumor-induced and age-related elderly T cell dysfunction. Peritoneal macrophages from elderly C57BL/6J mice (a) or elderly Balb/c mice (c) were cultured overnight with AE17 (a) or AB1 (c) tumor cell-conditioned media (AE17 sup or AB1 sup), stimulated overnight with M1 (LPS/IFN-γ) or IL-2/anti-CD40 Ab then co-cultured with CFSE-labelled, elderly Balb/c (a) or C57BL/6J (c) splenic lymphocytes and proliferating CFSE⁺CD4⁺ T cells and CFSE⁺CD8⁺ T cells calculated; only macrophage: T cell ratio of 1:5 shown (a and c). Controls included no stimuli, AE17 sup only, M1 stimuli only, and IL-2/CD40 Ab only. MLR supernatants at the macrophage: T cell ratio of 1:2 were assayed for T cell-derived IFN-γ by CBA, as described above (b and d). Representative histograms for CD44 expression on proliferating Balb/c CD8⁺ T cells are shown in e; grey filled histogram indicates no stimuli, bolded line histogram indicates relevant stimuli