Cytokine expressions inT. spiralis-infected pigs. The levels of IL-2 (A), IL-4 (B), IL-10 (C), TGF-β1 (D) and IL-17A (E) in serum of pigs inoculated with 100, 1000, and 10 000 muscle larvae of T. spiralis were determined by ELISA. The results shown are the means ± SEMs of three independent pigs per group. *P < 0.05, **P < 0.01, and ***P < 0.001 indicate statistically significant differences compared to the control group.