鸡柔嫩艾美球虫DNA疫苗pcDNA4．0(C)-pEtK2-IL-2对其他球虫的交叉保护力

Cross-protection of Eimeria tenella DNA vaccine pcDNA4.0(c)-pEtK2-IL-2 against other Eimeria species

将柔嫩艾美球虫DNA疫苗pcDNA4.0(c)-pEtK2-IL-2以50μg分别对14日龄和21日龄雏鸡进行胸部肌肉注射免疫,28日龄对各未免疫组与免疫组鸡分别口服接种柔嫩艾美球虫、巨型艾美球虫、堆形艾美球虫和毒害艾美球虫孢子化卵囊,36日龄剖杀,分析比较免疫保护效果。结果显示,柔嫩艾美球虫攻毒免疫试验组与柔嫩艾美球虫攻毒未免疫对照组比较,增重、盲肠病变记分、OPG值差异显著(P<0.05),免疫保护效果明显,抗球虫指数(ACI)达186.50;而巨型艾美球虫、堆形艾美球虫和毒害艾美球虫攻毒免疫试验组的ACI分别为147.85、142.71和153.82,增重、盲肠病变记分、OPG值和ACI与相应的攻毒未免疫对照组比较,均有不同程度改善,免疫保护效果不明显。表明,该DNA疫苗对柔嫩艾美球虫的攻击具有完全免疫保护作用,而对巨型艾美球虫、堆形艾美球虫、毒害艾美球虫的攻击具有部分交叉保护力。

To evaluate the cross-protection of E. tenella DNA vaccine pcDNA4. 0 （c）-pEtK2-IL-2 against E. maxima, E. acervulina and E. necatrix, the 50 p.g DNA vaccine was injected intramuscularly into chest of chickens on day old 14 and 21, respectively. Both chickens in the challenged and unimmunized group and in the challenged and immunized group were orally challenged separately with the 4 species of homologous sporulated oocysts （5）〈 104 oocysts per bird） on day old 28, and killed on day old 36. Mortality, weight gains, cecal lesion scores, oocyst output per gram feces（OPG） and anticoccidial index（ACI） were examined and compared with those in the control group. Immune effects of challenge with E. tenella and immunized group on weight gains, lesion scores and OPG were significantly better than those in the unimmunized positive control group（P〈0.05）,and its ACI reached 186.50. The ACIs of challenge separately with E. maxima,E, acervulina, and E. necatrix and immunized groups were 147. 85,142. 71 and 153.82,and the other 4 indexes were improved to some extent. The results revealed that the DNA vaccine had complete protection for chickens challenged with E. tenella, and partial cross-protection for chickens respectively challenged with E. maxima, E. acervulina and E. necatrix.