血吸虫病是严重危害人类健康的感染性疾病，研究其免疫机制十分必要。科学家们已揭示了易感宿主如人和小鼠T细胞在血吸虫病中的重要作用，但对非适应性宿主如东方田鼠和SD大鼠抗血吸虫病是否依赖T细胞还缺乏研究。明确这一问题需要在遗传模型上取得突破。本项目利用CRISPR/Cas9技术敲除东方田鼠和SD大鼠T细胞发育所必需的Lck基因，获得T细胞缺陷遗传模型。申请人已完成SD大鼠Lck基因敲除，并在前期实验中成功将东方田鼠胸腺移植到NOG小鼠肾被膜，后者能发育东方田鼠T细胞且获得对血吸虫病的保护作用。本项目将获得T细胞缺陷东方田鼠，验证其与SD大鼠对血吸虫病抗性是否依赖T细胞，比较T细胞缺陷动物与野生型对照感染血吸虫后虫体发育、宿主肝脏病理变化。进一步分选感染后不同宿主的脾脏T细胞，用荧光定量PCR分析其辅助T细胞分化的差异。本项目旨在阐明T细胞对非适宜宿主抗血吸虫病的作用，为血吸虫病防治提供新思路。

Schistosomiasis is a major infectious disease in which the immunopathological mechanisms still need to be elucidated. Previous studies have revealed the critical roles of T cells in the occurrence of schistosomiasis in susceptible hosts such as humans and mice. However very little is known about the T cell role in resistance of non-permissive hosts such as the vole termed Microtus Fortis and SD rat to schistosomiasis. To unmask whether and how T cells are involved in such an infectious disorder, it is essential to perform genetic engineering and develop genetic models. In this study, we will use the CRISPR/Cas9 genome editing technology to inactivate in vivo the Lck gene which is required for T cell development in thymus, to obtain T cell deficient animals. The applicant has succeeded in generating the Lck deleted SD rats and also found that transplant of thymus tissue of Microtus Fortis into the renal capsule of NOG recipient mice allowed for development of xenografted T cells, which resulted in a protective function against schistosomiasis in the host mice. In this study, we will further obtain the Lck disrupted T cell deficient Microtus Fortis, and verify the resistance to schistosomiasis of the genetically engineered animals. In the T cell deficient animals and T cell sufficient controls, the parasitic worm development will be compared and so the histopathological changes in the host livers. Using mice as control, we will sort T cells from the non-permissive hosts and analyze the T helper cell differentiation by real-time quantitative PCR. This project is set to determine the role of T cells in resistance of non-permissive hosts to schistosomiasis, which may provide a new perspective for prevention and treatment of schistosomiasis.