Small intestines from non-manipulated mice from 2 to 24 months of age were removed, separated into duodenum, proximal jejunum, distal jejunum, ileum and homogenized in extract buffer. Extract supernatant was collected for cytokine assay. IFN-γ(A-D), TGF-β(E-H), IL-4(I-L) and IL-10 levels (M-P) were measured by ELISA. Bars represent the mean ± SEM of 5 mice per group. Letters (a, b) represent differences among groups (p< 0.05).