A recombinant DNA vaccine encoding Eimeria acervulina cSZ-2 induces immunity against experimental E. tenella infection

The study describes vaccination experiments with highly immunogenic sporozoite Eimeria acervulina cSZ-2 to determine its efficacy against E. tenella challenge. Chickens were randomly divided into six groups. The chickens in the vaccinated groups were vaccinated with pVAX1-cSZ2, pVAX1-IL-2 and pVAX1-cSZ2-IL-2 twice ‘at days 14 and 21’ with dose rate of 100 μg intramuscularly. At 28 days of age, all chickens except the non-vaccinated non-challenged control group were inoculated orally with 5 × 104 sporulated oocysts of E. tenella. Seven days later, all chickens were weighed and slaughtered for caecum examination. Our findings make it obvious that cSZ-2 DNA immunisation can induce host immune responses by decreasing intestinal lesions, body weight loss and oocyst ratio, imparting partial protection. It is concluded that co-administration of interleukin 2 can further enhance its immunity, leading towards further research.