The optimal immunization procedure of DNA vaccine pcDNA-TA4-IL-2 of Eimeria tenella and its cross-immunity to Eimeria necatrix and Eimeria acervulina

The immunization procedure of DNA vaccine pcDNA-TA4-IL-2 of Eimeria tenella, including route, dose, time of immunization and age of primary immunization of chicken, was optimized. The stability and the cross-species protection of the vaccine were also analyzed. Efficacy of immunization was evaluated on the basis of oocyst decrease ratio, lesion Score, body-weight gain and the anti-coccidial index (ACI). Chinese Yellow chickens were randomly distributed into corresponding groups (30/group). The challenged, unchallenged and vector control groups were designed. The results illustrated that 25 mu g was the optimal dose and intramuscular injection was the most effective route to induce protective immunity. There were no significant differences of ACIs between boosting and non-boosting groups. Storage time and temperature had little effect on the immunizing efficacy of the vaccine. The vaccine Could provide partial cross-protection against the challenge with E. necatrix and E acervulina, but not with E. maxima. (c) 2008 Elsevier B.V. All rights reserved.