III型干扰素介导的抗汉坦病毒天然免疫机制研究

抗汉坦病毒（HV）天然免疫机制尚不清楚。新型λ干扰素（IFN-λ）具有抗病毒作用，如HBV、HCV等。在国家基金资助下我们研究发现IFN-λ通过上调CC-趋化因子、Ⅰ型干扰素、APOBEC3G/3F抑制HIV-1在人巨噬细胞中的感染。我们还发现，IFN-λ能抑制HV在Vero E6中的复制，且呈剂量和时间效应，据此推测IFN-λ可能介导了抗HV的天然免疫。本项目通过应用实时定量RT-PCR、免疫荧光等技术进一步验证IFN-λ抑制HV对靶细胞（HUVEC或A549）的感染，确定IFN-λ抗HV作用；并探讨IFN-λ对靶细胞上β3整合素受体、Toll样受体（TLR）、干扰素激活因子（IRF）以及STAT信号转导途径的影响，同时明确IFN-λ激活了靶细胞内Ⅰ型干扰素介导的抗HV病毒因子，如IFN-α、IFN-β、microRNA等，阐明IFN-λ介导的抗HV天然免疫作用机制。

The mechanism of Hantavirus (HV) in innate immune is unclear. The newly identified type III interferon (IFN-λ) has antiviral activity against a broad spectrum of viruses, including HBV and HCV. Supported by National Nature Science Foundation, we found that IFN-λ inhibited HIV-1 infection of macrophages. Invesigation of the mechanism(s) responsible for IFN-λ action showed that INF-λ induced the expression of CC-chemokines, the ligands for CCR5, and upregulated intracellular expression of type I IFNs and APOBEC3G/3F, the newly identified anti-HIV-1 cellular factors. More importantly, we showed that IFN-λ could inhibit HV replication in vero E6 cells. This inhibitory effect on HV by IFN-λ was dose and time dependent. These data provide direct and compelling evidence that IFN-λ has a critical role in innate immunity against HV infection. So this project through the real-time quantitative RT-PCR, immunofluorescence technique will further prove that IFN-λ could suppress replication of HV in target cells (HUVEC or A549) in order to determine the activity of IFN-λ against HV infection. We will also examine the mechanism(s) of involved in IFN-λ action on HV. We are particularly interested in the role of IFN-λ in the modulation of β3 integrin receptor and Toll-like receptor (TLR) for HV entry into target cells. At both mRNA and protein level in target cells, we will explore the expression of interferon regulatory factors (IRFs) and signal transducer and activator of transcription (STAT). Type I IFNs (IFN-α/β) are well known for their ability to inhibit a wide range of viruses, including HV. Thus, the induction of intracellular IFN-α/β expression by IFN-λ provides an additional mechanism for the anti-HV action of IFN-λ in target cells. Several cellular factors, such as microRNAs, OAS1, ISG15, have recently been identified as type I IFN-inducible anti-HV elements in HV-infected target cells. Therefore, it is important to determine whether IFN-λ has the ability to enhance the expression of these newly identified innate anti-HV factors in target cells. In conclusion, these studies provide the first experimental evidence at cellular and molecular levels that IFN-λ has the ability to suppress HV infection in target cells, which would be of importance not only for our understanding of HV immunopathogenesis but also for the design and development of IFN-λ-based intervention strategies for treating HV infected patients.