弓形虫是一种呈世界性分布的顶复门原虫，在猫和经亚油酸处理的小鼠肠上皮细胞内可完成配子发育。阐明弓形虫在终末宿主肠上皮细胞内的发育过程是研究弓形虫致病机制重中之重。我们前期将弓形虫PRU株经口感染猫，发现TgCDPK4A蛋白上调表达时间与弓形虫从A型裂殖体发育为配子体的过程相吻合。但目前尚无对TgCDPK4A蛋白参与调控弓形虫在终末宿主小肠内发育过程的研究。本项目利用TgPRU构建的cdkp4A基因和部分基因缺失株，通过体外感染猫小肠上皮细胞和体内经亚油酸处理的小鼠的实验，研究该蛋白在弓形虫裂殖生殖、配子发育及卵囊形成过程中的调控作用。研究结果将揭示TgCDPK4A参与弓形虫在终末宿主肠上皮细胞内发育的分子机制，为下一步猫弓形虫病的防治提供新的思路。

Toxoplasma gondii is a worldwide apicomplexan protozoan. Oocysts could be found in the intestinal monolayer culture medium of mouse as well as in felids in vitro after added excess linoleic acid. The development of T. gondii in the intestinal of definitive host is one of the crucial issues in the parasite study. In our previous study, the TgCDPK4A protein was detected in up-regulated expression after T. gondii cyst infection in cats, of which the period was coincide with the development of T. gondii from Type A schizonts to gamonts. However, whether the TgCDPK4A protein participated in the development of T. gondii in the definitive host was not available. Here, the cdpk4a-deficient strains and partial cdpk4a-deficient strains of T. gondii PRU will be constructed to infect cat intestinal monolayer culture medium in vitro and live mice which supplement the inhibition of delta-6-desaturase and linoleic acid in food. Then, the developments of asexual enteroepithelial stages, gametogenesis and oocyst formation will be detected. Expected results will provide “foundation-data” for investigation of molecular mechanism of T. gondii development in the intestinal of definitive host, and also will provide new ideas for prevention and control of cat toxoplasmosis.