柔嫩艾美球虫重组质粒pVAX1-Mzp57的免疫保护性试验

目的　用柔嫩艾美球虫 (Eimeriatenella ,E .t)子孢子表面蛋白基因构建的DNA重组质粒免疫海兰小公雏 ,观察其诱导鸡产生的免疫应答反应和对球虫攻击的保护作用。　方法　重组质粒经肌肉和鼻黏膜分别于 7、14、2 8日龄3次接种小公雏 ,用间接ELISA、流式细胞仪检测免疫反应。最后一次免疫后 2周经口接种新鲜的E .t孢子化卵囊 ,确定其保护力的大小。　结果　构建的柔嫩艾美球虫重组质粒免疫雏鸡后能诱导有效的细胞免疫和体液免疫 ,表现为CD4+ /CD8+ T细胞比率、特异性抗体滴度明显高于对照组 (P <0 .0 5 )。可对抗中等剂量球虫的攻击 ,试验组和对照组相比 ,攻虫后卵囊排出量显著减少 ,体重增长快 ,盲肠病变较小 ,保护率达 80 %以上。肌注 10 0 μg重组质粒组综合免疫保护效果最好。　结论　构建的重组质粒对鸡柔嫩艾美球虫的攻击有较好的免疫保护作用。

Immunoprotection Induced by Recombinant Plasmids pVAX1-Mzp5-7 of Eimeria tenella

OBJECTIVE: To observe the immunoprotection of recombinant plasmids of lambda Mzp5-7 to chicken challenged with Eimeria tenella (E. t) oocysts. METHODS: All the chickens were immunized with the recombinant plasmids by different inoculation pathways, three times on d7, d14 and d21, and challenged with E. t oocysts. The response of specific humoral and cell immunity were detected by the immunological methods such as the specific antibody response, the ratio of CD4+/CD8+ T cells. RESULTS: The results showed that the recombinant plasmids can induce immune response. The specific immune responses were strengthened with the increase of immunization times. The difference of the immunity indexes among experiment groups was not significant, while the ratio of CD4+/CD8+ T cells and antibody titer were significantly higher in experiment groups than those in the control groups. The number of oocysts shed in experiment groups decreased and the shedding duration was shorter significantly. The body weight of the chicken in experiment groups increased significantly and the lesion in cecum was slighter than that of control groups. CONCLUSION: The recombinant plasmids of lambda Mzp5-7 show an immunoprotection to chicken challenged with E. t oocysts.