Enhanced expression of IL-10 in contrast to IL-12B mRNA in poultry with experimental coccidiosis

Interleukin (IL)-12 and IL-10 are immunoregulatory cytokines with an antagonistic effect on the T-helper (Th)1/Th2 cytokine balance and they provide a functional link between innate resistance and the adaptive immune response. This investigation was conducted to determine the expression of IL-10 and IL-12B mRNA levels in chickens' gut mucosa infected with Eimeria tenella and in sulfachlorpyrazine-sodium treated animals after infection. Broiler chickens were randomly allocated in three groups: healthy untreated control; infected untreated animals and infected, treated with sulfachlorpyrazine sodium chickens 6 days after the challenge with an E. tenella. Quantitative real time PCR analysis was performed using specific primer pairs and probes for IL-10 and IL-12B. The expression of IL-10 mRNA was greater in the duodenum then in the caecum and the liver of healthy chickens. E. tenella infection led to significant up-regulation of IL-10 mRNA in the caecum, followed by mRNA in the liver. A significant down regulation was observed mainly in the caecum after the treatment with sulfachlorpyrazine. In contrast, IL-12B expression in all investigated tissues remained insignificantly affected in the studied groups of animals. Distinct up-regulation of IL-10 mRNA, after the challenge with E. tenella, in the caecum can be attributed to the tissue tropism of Eimeria spp. The production of IL-12 is regulated by negative feedback through IL-10 which explains lack of increase in IL-12B mRNA. Sulfonamide treatment resulted in clinical improvement and restoration of IL-10 mRNA to the levels observed in healthy chickens.