Abstract: To effectively control coccidiosis with a subunit vaccine, the refractile body antigen SO7 adjuvanted with Chicken Interferon-gamma (ChIFN-gamma) was administered to chickens and its ability to protect against virulent challenge by E. tenella was evaluated. About 5 days old chickens were subcutaneously immunized with SO7 antigen (100 μg per chick) mixed with various doses of ChIFN-gamma or without adjuvant. A boost of the same dose was given at 12 and 19 days of age. The specific antibody response and lymphocyte proliferation response to SO7 antigen were measured at 5, 12, 19 and 26 days of age. Chickens in all groups were orally challenged with 1x105 homologous sporulated oocysts of E. tenella at 26 days of age and killed at 8 days postchallenge. Results showed that when immunized by antigen adjuvanted with ChIFN-gamma, specific lymphocyte proliferation in chichens was obviously observed at 19 and 26 days of age and specific antibody response was obviously observed at 12, 19 and 26 days of age. All groups administered with antigen mixed in adjuvant showed higher protective immunity compared to PBS control, non-adjuvanted antigen control in which the group given adjuvanted antigen with 5,000 units ChIFN-gamma showed significantly stronger adjuvant effects in terms of lower mortality, oocyst output, lesion score and higher weight gain (p<0.05). Protective immunity was affected by dose of the adjuvant, no linear dose relationship was observed. These results suggest that ChIFN-gamma has a strong adjuvant effect at a appropriate dose and may potentially serve as a vaccine adjuvant against avian coccidiosis.
Jinjun Xu, Jinbiao Peng and Jianping Tao, 2012. Interferon-Gamma Enhance Immune Response and Efficacy of Recombinant Subunit Vaccine Against Eimeria tenella in Chickens. Journal of Animal and Veterinary Advances, 11: 4394-4400.