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 100microg intramuscularly. At 28 days of age, all chickens except the non-vaccinated non-challenged control group were inoculated orally with 5x10(4) 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.