霍乱毒素A、B亚单位增强DNA疫苗免疫效果的佐剂活性和机制研究

霍乱毒素A、B亚单位通常被用作蛋白类疫苗佐剂，而我们在前期工作中发现：在与目标免疫原融合表达时，霍乱毒素A、B亚单位同样可以显著增强DNA疫苗免疫原性，并且未发现明显的细胞毒性作用。为进一步阐明其佐剂作用特征和机制，本研究将首先以BALB/c鼠为模型，运用多色流式技术观察霍乱毒素A、B亚单位对DNA疫苗所活化的特异性CD8+ T细胞功能和疫苗保护效果的影响。 然后，采用表达谱芯片和多重细胞因子检测技术，在细胞模型和小鼠模型上观察霍乱毒素A、B亚单位对抗原提呈细胞基因转录和细胞因子分泌的影响，并探讨其分子机制。最后，运用基因敲除鼠或体内RNA干扰技术，解析差异基因或细胞因子对霍乱毒素A、B亚单位发挥佐剂效应的影响。本研究的开展不仅有助于补充、深化对CTA、CTB佐剂效应特征及机制的认识，亦可为DNA疫苗寻找到一类新的有效佐剂。

Both cholera toxin subunit A and B were widely used as adjuvants for protein based vaccines. However,in a pilot experiment,we found that cholera toxin subunit A and B also showed potent adjuvant activity towards DNA vaccine, when their genes were fused with antigen coding gene. And the fusion gene vaccine showed no obvious cytotoxicity. To elucidate the underlying mechanisms, in this study, we will first investigate the influences of cholera toxin subunit A and B on the efficacy of DNA vaccine and fucntion of specific CD8+ T cells elicited by DNA vaccine.Then, by using the methods of RNA chip and mouse cytokine Th1/Th2/Th17 cytometric beads array, we will investigate the gene transciption and cytokine secretion profile of antigen presenting cells after being stimulated both in vitro and in vivo with DNA vaccines encoding fusion immunogens containing CTA or CTB. Finally, by using gene knockout mice or in vivo RNAi technique, we shall clarify the relationship between key differential genes or cytokines and the adjuvant activities of CTA and CTB. This study will not only help to indentify new adjuvant mechanisms of CTA and CTB,but also will provide a new kind of adjuvant for DNA vaccine.