Changes in IL-12 and INF-γ levels over time in IL-12-treated mice. BALB/c mice were administered with either tIL-12 or rIL-12 as described in the methods section and sacrificed 2, 4, 8, 16 and 24 h after treatment and their lungs removed. Whole lung homogenates were prepared and IL-12 (A) and INF-γ (B) assayed by ELISA. Mice treated with extracts from a non-transgenic wild type tomato (wt) were included as controls. Results are given as mean ± SEM (n = 4 for each group). * P < 0.05 vs control.