Fig. 4. Determination of cytokine secretion in the serum of CD26^+/+ and CD26^–/– mice by ELISA.

Blood was taken at the indicated times before and after allogeneic skin transplantation (day 0 represents the day before transplantation). The levels of IFN-γ (a), IL-2 (b), IL-4 (c), IL-6 (d), IL-13 (e), IL-5 (f) and IL-10 (g) were measured by ELISA. The values represent the means ± SD of at least seven mice at each time point