疫苗是预防和控制恙虫病的最佳途径，目前尚无理想的恙虫病疫苗可供使用，急需研制新型有效的恙虫病疫苗。基于恙虫病东方体外膜蛋白的融合亚单位疫苗是目前研究的主要方向之一，东方体Sta56、Sta47、Sta22基因编码的蛋白可作为研发恙虫病疫苗的理想靶抗原。转基因植物作为生物反应器生产口服疫苗为医用疫苗的生产提供了新途径。本项目在克隆恙虫病东方体Karp株Sta56、Sta47和Sta22基因主要抗原表位编码片段的基础上，获得Sta56-Sta47-Sta22-CTB融合编码基因；通过植物载体介导其在叶用莴苣叶绿体中进行生物封装表达，获得稳定遗传的转基因莴苣株系、特异融合抗原蛋白以及叶片组织冻干胶囊并鉴定；观察评价所得到的纯化抗原蛋白、转基因莴苣叶片胶囊的小鼠免疫原性及保护、治疗效果，阐明各种抗原物质的动物免疫应答机制。本项目研究将为研制和开发新型的恙虫病疫苗提供新思路、新材料并奠定其理论基础。

Vaccine is the best way for prevention and control tsutsugamushi disease (TD). New more effective and safe TD vaccines are urgently needed to manufacture since there is no ideal vaccines for using all over the world. The strategy based on fusion antigen proteins outside membrane of orientia tsutsugamushi(Ot) for developing novel subunit vaccines could promote efficient protection. The 56kD, 47kD and 22kD proteins encode by Sta56, Sta47 and Sta22 genes of Ot can be used as the desirable target antigens for TD vaccine research. Transgenic plants as bioreactors provide a new way for medical production of oral vaccine. We will clone Sta56, Sta47 and Sta22 gene segments of Ot strain Karp encoded major antigenic epitopes and obtain Sta56-Sta47-Sta22-CTB fusion antigen gene in this research, then express them in lettuce chloroplasts by means of bioencapsulation and nuclear genetic expression mode mediated by plant vector,gain genetic stability transgenic lettuce strains, specific fusion antigen proteins and capsules from lyophilized lettuce leaves, evaluate immunogenicity of all kinds of antigen materies after identification, protection and treatment effects, elucidate animal immune response mechanism of various antigens.This research will provide new materials and theoretical foundation for study and development new TD vaccines.