Adjuvant effect of chicken interleukin-18 on the immune responses to coccidiosis vaccine.

3-day-old SPF chickens were inoculated intramuscularly with recombinant plasmid pIL-18,pIL-18 and coccidiosis vaccine or coccidiosis vaccine.Chicken spleen lymphocytes were detected by methyl thiazolyl tetrazolium(MTT)and the sera were collected to examine antibodies of chickens by ELISA on 1 d,4 d,6 d,9 d,14 d,21 d,26 d and 28 d after first immunization.The chickens were challenged on day 14 post the booster.The results showed that chicken IL-18 was able to improve obviously the immunogenicity of coccidiosis vaccine,and enhance the humoral immunity level and cellular immunity level of the vaccinated chickens.Therefore,chickens vaccinated with pIL-18 and coccidiosis vaccine were protected effectively against challenge with eimeria coccidia.