Host Genetic Factors to Combat Lassa Hemorrhagic Fever

描述(由申请者提供)：这笔赠款重点研究病毒的发病机制(病毒如何致病)，以及为什么在感染期间，一些宿主病情严重并死亡，而另一些宿主相对毫发无损。从淋巴细胞性脉络膜脑膜炎病毒(LCMV)学到的经验教训适用于拉沙热病毒(LASV)。LASV每年感染30多万人，导致20,000多人死亡。LASV曾被从西非的旅行者运送到美国。它作为生物武器的潜力引起了全国的关注。LASV被列入A类微生物制剂名单。本实验室鉴定α-Dystroglan(？-DG)是LCMV和LASV的宿主细胞受体，并证明？-DG优先定位于树突状细胞(DC)。然后我们证明了糖基转移酶大的翻译后修饰对于？-DG作为LASV和LCMV结合、进入和复制的受体的功能成熟是绝对关键的。P.Sabeti和他的同事发现，大突变在西非的尼日利亚和塞拉利昂人群中很常见，在那里LASV感染是地方性的，但在那些LASV不是地方性的西非人群中却没有。在LASV流行的人群中，约35%的人存在大等位基因的多态性，其中约45%的个体为杂合子，16%的个体为纯合子。在LASV幸存者中发现了大量突变。由于高病毒血症(&gt；9个空斑形成单位[pfu/ml血清])通常与严重LASV感染和死亡的迹象有关，而较低的病毒血症(&lt；8个pfu/ml或更低)与恢复有关，并且？-DG/大复合体控制着LASV的进入和随后的复制，很可能是大型突变通过有利于宿主对该病毒的生存而进化。限制产生的病毒数量为宿主的免疫系统提供了一个机会之窗，以建立有效的抗LASV免疫反应，从而防止严重疾病和促进病毒清除。这笔赠款的目的是确定大型突变是否对LASV感染的存活率负责。我们将在功能性大酶分析中检测允许LASV感染的细胞(DC/单核细胞)，并使用LASV GP/LCMV重组病毒进行病毒结合、进入和复制。重组病毒可用于BSL/2实验室，并已被证明可在允许的人和鼠细胞中结合、进入和复制。此后，将在疾病预防控制中心用wtLASV对具有大突变并显示LASV结合、进入或复制或酶活性改变的个体的DC和单核细胞进行检测。这些研究的成果提供了识别影响人类进化的力量的机会，因为拥有大的突变等位基因的个体很可能被选择为对LASV的抗性。此外，这些研究还可能确定替代标记，以对这种病毒感染的易感或耐药个体进行分类。

DESCRIPTION (provided by applicant): This grant focuses on arenavirus pathogenesis (how viruses cause disease) and why during infection some hosts become severely ill and die while others remain relatively unscathed. Lessons learned from lymphocytic choriomeningitis virus (LCMV) are applied to Lassa fever virus (LASV). LASV infects over 300,000 individuals per year resulting in over 20,000 deaths. LASV has been transported by travelers from Western Africa to the USA. Its potential as a weapon of biowarfare is a source of national concern. LASV is placed on the Category A list of microbial agents. My laboratory identified alpha-dystroglycan (¿-DG) as the host cell receptor for LCMV and LASV and demonstrated preferential localization of ¿-DG on dendritic cells (DCs). We then showed that post- translational modification of ¿-DG by the glycosyltransferase LARGE is absolutely critical for the functional maturation of ¿-DG as a receptor for LASV and LCMV binding, entry and replication. P. Sabeti and colleagues found that mutations in LARGE were common in West African populations of Nigeria and Sierra Leone where LASV infection is endemic, but absent in those populations in West Africa where LASV is not endemic. Polymorphisms of the LARGE allele are present in about 35% of the population where LASV is endemic with about 45% of individuals heterozygous and 16% homozygous for it. Mutations in LARGE are found in LASV survivors. Since high viremia (> 9 logs of plaque forming units [PFU/ml of sera]) is routinely associated with signs of severe LASV infection and death, whereas lower viremia (< 8 logs of PFU/ml or less) with recovery, and the ¿-DG/LARGE complex controls LASV entry and subsequent replication, it is likely that mutations in LARGE shape evolution by favoring survival of the host against this virus. Limiting the amount of virus made provides the host's immune system a window of opportunity to mount an effective anti-LASV immune response thereby preventing severe disease and promoting virus clearance. This grant's purpose is to determine if LARGE mutations are responsible for survival to LASV infection. We will assay cells permissive to LASV infection (DCs/monocytes) that contain LARGE mutations in a functional LARGE enzyme assay, and for virus binding, entry and replication using a LASV Gp/LCMV recombinant virus. The recombinant virus can be used in BSL/2 laboratory and has been shown to bind, enter and replicate in permissive human and mouse cells. Thereafter those DCs and monocytes from individuals having LARGE mutations and displaying altered LASV binding, entry or replication or enzymatic activity will be tested at CDC with wtLASV. The fruits of these studies provide the opportunity to identify forces shaping human evolution in that individuals possessing LARGE mutant alleles are likely selected for resistance to LASV. Further, these studies may also identify surrogate markers to classify susceptible or resistant individuals to this viral infection.