Figure 3. Cytokine levels in the organs of mice after R. equi infection.

BALB/c mice were orally immunized on days 0 and 14 with S. enterica Typhimurium χ3987-pYA3137vapA (closed triangles/dashed line), or inoculated with either S. enterica Typhimurium χ3987-pYA3137 (closed squares) or PBS (open circles). All mice were intravenously challenged with 4×10⁶ CFU of R. equi ATCC33701 14 days after the last immunization. The lung (A–E), liver (F–J), and spleen (K–O) were harvested 2, 4, 8, and 10 days post-infection and homogenized for IL-12 (A, F, and K), IFN-γ (B, G, and L), TNF-α (C, H, and M), IL-10 (D, I, and N), and IL-4 (E, J, and O) detection. Results are expressed as means of five mice per group ± SD and are representative of three experiments. *p<0.05, **p<0.01, and ***p<0.001 compared to the two control groups; and ⁺p<0.05, ⁺⁺p<0.01, and ⁺⁺⁺p<0.001 compared to the PBS control group.