螯虾甘露糖受体抗白斑综合征病毒研究

White spot syndrome virus (WSSV) is the most devastating pathogen in crustacean aquaculture and causes giant economic loss. Endocytosis is the host cell’s main immune response to WSSV infection, but the molecular mechanism underlying how crustacean immune cells recognize WSSV and initiate endocytosis remains elusive. Therefore, studying on cell surface receptor-mediated endocytosis is crucial for elucidating the counteraction between WSSV and the host, as well as for developing strategy against WSSV infection. Here we obtained a novel mannose receptor involved in WSSV endocytosis, which is a transmembrane protein containing 14 C-type lectin domains. Our preliminary results showed the expression of this mannose receptor is constantly up-regulated after WSSV challenge. RNAi-mediated knockdown of mannose receptor significantly impaired the phagocytosis of hemocytes against WSSV, suggesting its anti-viral activity. Moreover, we found that the recombinant mannose receptor protein can bind to WSSV. This project is designed to further investigate the mechanism of mannose-receptor-mediated endocytosis against WSSV. First, the mechanism of binding between mannose receptor and WSSV will be investigated; second, the impact of mannose receptor on endocytosis against WSSV and on WSSV infection rate will be determined; third, the components involved in mannose-receptor-mediated endocytosis will be identified and the endocytosis mechanism will be studied. This project can provide us more information on the role of endocytosis during WSSV infection and elucidate the mechanism of this specific receptor-mediated endocytosis. Moreover, this study can provide guidance on application studies to prevent white spot disease.

白斑综合征病毒（WSSV）是危害虾类养殖业最大的病原之一。内吞作用是宿主清除病毒感染的重要免疫反应，但虾类免疫细胞是如何识别WSSV并启动内吞作用尚不明确，研究细胞表面受体介导的内吞作用对阐明宿主和病毒互作机制及防治病毒感染具有重要意义。我们在克氏原螯虾中发现一种可能参与WSSV内吞的甘露糖受体，该受体是包含14个C-型凝集素结构域的跨膜蛋白。初步研究显示：该受体在WSSV感染后上调表达；干扰该受体后，血细胞对WSSV吞噬率降低，并促使体内病毒拷贝数上升；重组表达的甘露糖受体能够结合WSSV。本课题将对甘露糖受体介导的WSSV内吞作用进行进一步研究。内容包括：明确甘露糖受体结合WSSV的方式及其关键结构域；探明甘露糖受体对细胞吞噬WSSV及病毒感染率的影响；阐明参与该内吞途径的重要组分和具体作用机制。通过本课题实施，将加深我们对于病毒感染和吞噬机制的理解，为甲壳动物白斑病的防治提供指导。

白斑综合征病毒（WSSV）是危害虾类养殖业最大的病原之一。内吞作用是宿主清除病毒感染的重要免疫反应，但虾类免疫细胞是如何识别WSSV并启动内吞作用尚不明确。我们在克氏原螯虾中发现首个参与WSSV内吞的甘露糖受体（PcMR），该受体是包含14个C-型凝集素结构域的跨膜蛋白。研究显示，该分子主要在螯虾的肝胰腺和血细胞中表达，在WSSV感染后上调表达；将PcMR分段重组表达后，发现其中11-14CTLD能够通过VP28结合WSSV。干扰该受体后，血细胞对WSSV吞噬率降低，体内病毒拷贝数上升，感染了WSSV的螯虾死亡率上升。进一步研究发现，PcMR分布在血细胞膜表面，在WSSV感染后发生内化，并且该内化是由arrestin和clathrin介导的。综上所述，我们发现PcMR可通过识别WSSV的囊膜蛋白，介导arresitn和clathrin参与的病毒内吞作用，最终杀灭病毒。通过本课题实施，加深了我们对于病毒感染和吞噬机制的理解，为甲壳动物白斑病的防治提供指导。