间日疟原虫输出蛋白TRAgs与人脾脏相关细胞互作及其在虫体免疫逃避中的作用机制

疟原虫输出蛋白在疟疾的免疫逃避中起重要作用，而间日疟原虫相关研究匮乏。我们前期发现，间日疟原虫色氨酸富集抗原（PvTRAgs）在虫体侵入红细胞后大量输出到红细胞膜表面。此蛋白可与人体脾脏成纤维细胞(HSF)发生互作。但互作的具体分子机制以及是否影响免疫细胞应答尚不清楚。本课题以PvTRAgs与HSF的互作为切入点，通过蛋白体外结合、蛋白芯片筛选、表面等离子共振等方法，明确PvTRAgs可特异性结合HSF，及二者的互作模式；通过siRNA干扰、RNA水平检测、体外抑制剂调控，明确PvTRAgs-HSF互作对HSF迁移的经典途径激活的影响；通过B淋巴细胞分泌抗体、巨噬细胞迁移及释放活性无助检测，明确PvTRAgs对免疫细胞功能的影响；通过小鼠模型，验证PvTRAgs与脾脏相关细胞的互作；最后综合评价PvTRAgs在人脾脏中对虫体免疫逃避及致病机制。

Export proteins play an important role in immune evasion of Plasmodium parasite, while we know little about it in Plasmodium vivax. Previously, we found that P. vivax tryptophan rich antigens (PvTRAgs) exported to infected erythrocyte membrane at trophozoite stage. PvTRAgs induce human splenic fibroblasts (HSF) migration. Additionally, PvTRAgs interact with HSF. However the detail of this interaction and effects of immune response are not clear. In present study, we aim to know the function of PvTRAgs in immune evasion and malaria pathogen. Firstly, identify the receptor(s) to PvTRAgs from HSF membrane proteins, and confirm the specific interaction of PvTRAgs-HSF receptor(s) through pull-down assay, protein array, surface plasmon resonance, and passive transfer assay. Secondly, show effect of PvTRAgs on the functions of immune cells by testing IgM or IgG produced by B cell, chemotaxis of macrophages and ROI and RNI produced by macrophages. Furthermore, we try to understand how PvTRAgs-HSF interaction stimulates HSF migration signaling pathway. Finally, the function of PvTRAgs will be confirmed in mouse model using transfection in P. yoelii 17XNL strain. This study will help in understanding the role of PvTRAgs in P. vivax immune evasion.