抗旋毛虫病Ts87DNA疫苗滴鼻初免-蛋白疫苗加强免疫策略增强免疫保护应答

ENHANCED PROTECTIVE EFFECT AGAINST TRICHINELLOSIS OF A TS87 DNA VACCINE PRIME INTRANASALLY- PROTEIN BOOST STRATEGY

为优化抗旋毛虫病核酸疫苗免疫策略，本文探讨了Ts87DNA疫苗滴鼻初免与蛋白疫苗皮下注射加强免疫诱导产生的保护效果及免疫应答特征。分别在第0d以旋毛虫Ts87DNA疫苗sL7207／pVAx1-Ts87滴鼻初免，第14／28d以蛋白疫苗rTs87皮下注射加强免疫小鼠，在第35d攻击感染旋毛虫肌幼虫，第84d剖杀小鼠，计算减虫率观察免疫保护效果；进行小鼠血清中特异性IgG抗体效价、抗体亚型分析及肠道盥洗液sIgA水平分析，检测脾淋巴细胞增殖反应、脾及颈部淋巴结细胞分泌细胞因子水平。结果显示，DNA疫苗滴鼻初免一重组蛋白加强的联合免疫组的保护作用优于单独DNA疫苗滴鼻及单独重组蛋白免疫组，显著提高了减虫率（46．1％）；DNA疫苗滴鼻初免和蛋白疫苗加强免疫方式不仅诱导小鼠产生了粘膜免疫应答，同时也诱导了有效的细胞和体液免疫应答，其免疫应答类型是以Th2型为主的混合型Th1／Th2免疫反应。该研究为新型抗旋毛虫病疫苗接种策略的优化提供了实验依据。

To optimize DNA vaccination strategy against trichinellosis, the protective effect induced by a Ts87 DNA vaccine prime intranasally/Ts87 protein boost hypodermically was evaluated and the mechanism was discussed. Mice were immunized intranasally with Ts87 DNA vaccine SL7207/pVAX1-Ts87 at 0 d and boosted hypodermically twice with Ts87 protein at 14 d and 28 d. At 35 d, the mice were challenged with muscle larvae of Trichinella spiralis and sacrificed at 84 d. The larvae burden reduction was calculated and the protective effect was evaluated. The levels of antigen-specific total IgG and subtype IgG1 and IgG2a antibodies in the sera of immunized mice were determined. Total slgA in intestinal washes was also measured. T cell proliferation assay of splenocytes was performed and cytokines secreted by the splenocytes and cervical lymph nodes of immunized mice were detected. The results showed that mice with DNA-prime/protein boost vaccination induced better protective effect than those immunized with DNA prime-boost or protein prime-boost individually and the muscle larval reduction was increased significantly to 46. 1%. The results also revealed that DNA-prime/protein-boost vaccination with Ts87 induced not only higher levels of mucosal immune responses, but also humoral and cellular immune responses as well. The results demonstrated that mice vaccinated with Ts87 in a DNA-prime/protein-boost strategy effectively elicited a local mucosal IgA response and a mixed Thl/Th2 immune response, with Th2 predominant. The present study provided an experimental evidence for optimizing vaccination strategy against trichinellosis.