Development of live attenuated influenza virus vaccine

描述(申请人提供)：流感是一种全球公共卫生高度关注的传染性病毒疾病，每年影响数百万人。仅在美国，流感病毒造成的发病率和死亡率就增加了2万-4万人/年，经济损失达100-200亿美元/年。疫苗基本上每年都供不应求。此外，有一种禽流感或禽流感病毒对全球大流行构成威胁，目前还没有有效的疫苗，如果大流行发生，将需要大量疫苗来抗击。随着人口老龄化的增加，这种风险每年都在增加，新一轮大流行的可能性正在迫在眉睫。因此，迫切需要一种高度减毒的活疫苗。我们的初步研究证实，在A/WSN/33(H1N1)病毒中，流感病毒基质蛋白(M1)的保守CCHH基序(可能是锌指基序)可以发生突变，而不会影响病毒在MDCK细胞中的复制。一些CCHH突变病毒在小鼠体内高度减毒，并能保护小鼠免受致死性WT病毒的攻击。在这个项目中，我们想要在制造流感疫苗的A/PR8/34(H1N1)病毒中创造这些突变，并测试这些突变对小鼠的毒力、在细胞培养和胚胎鸡卵中的生长以及对WT致死病毒攻击的保护效果。此外，还将在CCHH突变的基础上增加其他基因的突变，并将确定它们对细胞培养和胚胎培养中的毒力、稳定性、生长和保护效率的影响。一株高度减毒和无毒的PR8病毒可作为生产高度减毒的流感活疫苗的主菌株。以这种方式生产的减毒活疫苗将比目前使用的感冒适应疫苗的耐热性更低。活疫苗可以很容易地在细胞培养或胚胎鸡蛋中培养。活疫苗可以很容易地提供，并且需要较小的剂量来为提供充足疫苗供应的人接种疫苗。活疫苗还将产生针对流行和/或大流行病毒的更广泛和持久的保护性免疫。公共卫生相关性：流感是一种全球公共卫生高度关切的传染性病毒疾病，每年影响数以百万计的人。该项目的目标是创造高度减毒的PR8病毒，可用作生产减毒活流感疫苗的主菌株。减毒活疫苗可以大量生产，易于交付，并将对强毒流感病毒产生更广泛和持久的保护性免疫。

DESCRIPTION (provided by applicant): Influenza is a global infectious viral disease of great public health concern affecting millions of people every year. Influenza viruses cause increased morbidity and mortality in the range of 20,000-40,000 death/yr in USA alone and economic loss of 10-20 billions of dollars/yr. Vaccines are in short supply essentially every year. Furthermore, there is a bird flu or avian flu virus posing a global pandemic threat against which there is no effective vaccine and massive amount of vaccine will be required to combat the pandemic if and when it occurs. With the increasing aging population, this risk is increasing every year and a possibility of a new pandemic looming. Therefore a highly attenuated live vaccine is urgently needed. Our preliminary studies have identified that in A/WSN/33(H1N1) virus, a conserved CCHH motif (the putative zinc finger motif) of influenza virus matrix protein (M1) can be mutated without affecting virus replication in MDCK cells in culture. Some CCHH mutant viruses were highly attenuated in mice and protected mice against lethal WT virus challenge. In this project, we want to create these mutations in A/PR8/34(H1N1) virus which is commonly used for making influenza vaccine and test the effect of these mutations in mice virulence, growth in cell cultures and embryonated chicken eggs and protection efficiency against WT lethal virus challenge. In addition, other mutations in other genes will be added to CCHH mutations and their effect on virulence, stability, growth in cell cultures and embryonated eggs and protection efficiency will be determined. A highly attenuated and avirulent PR8 virus can be used as master strain for generating highly attenuated live influenza vaccine. Live attenuated vaccine produced in this way will be less thermo-labile than the presently used cold adapted vaccine. Live vaccine can be grown easily in cell culture or in embryonated chicken eggs. A live vaccine can be delivered easily and a smaller dose will be required to immunize people providing plenty supply of vaccine. Live vaccine will also produce broader and long lasting protective immunity against epidemic and/or pandemic viruses. PUBLIC HEALTH RELEVANCE: Influenza is a global infectious viral disease of great public health concern affecting millions of people every year. The goal of this project is to create highly attenuated PR8 viruses which can be used as master strains for generating live attenuated influenza vaccine. Live attenuated vaccines can be produced in mass quantity, delivered easily and will produce broader and long lasting protective immunity against virulent influenza viruses.