To assess cytokine production, mesenteric single cell suspensions from young (n = 6) and old (n = 8) mice were activated in vitro. Cells were then stained for CD45 (total leukocytes), CD3 (pan T cells), CD4, CD8, interferon (IFN)-γ and tumor necrosis factor (TNF)-α. (A) Sample IFN-γ flow cytometry plots. (B) Proportion and (C) number of IFN-γ producing T cells. (D) Sample TNF-α flow cytometry plots. (E) Proportion and (F) number of TNF-α producing T cells. Group differences were assessed with an independent samples T test. p values are included on the panel with a horizontal line indicating the group comparison. Data are shown as mean ± standard deviation, n represents the number of independent animals in each group.