Optimising genomic RNA RNA interactions for development of flexible influenza virus vector backbones for co vaccination

由阿斯利康公司以FluMist/Fluenz销售的减毒流感活疫苗（LAIV）是联合王国儿童流感疫苗接种计划的支柱，每年以鼻喷雾剂的形式向所有2-12岁的儿童提供。与灭活疫苗不同，LAIV在产生显著的粘膜免疫方面是独特的（Barria等人，在2013-14和2015-16流感季节，在美国观察到流感喷雾的H1N1组分的低疫苗有效性，这归因于人鼻上皮细胞中LAIV复制的减少（霍克斯沃思等人，Vaccine，2020），而不是降低HA抗原稳定性（帕克等人，疫苗2019）。这种适应性降低的一个潜在因素是携带所有八个基因组片段的感染性病毒颗粒的产生减少。观察结果还表明，历史上MDV基因组整合来自不同当代甲型流感病毒的HA和NA基因的能力可能不同，该项目旨在了解LAIV的基因组片段是如何组装的，以便生物工程改造下一代LAIV，适合作为所有季节性或大流行性流感病毒株的灵活载体，针对SARS-CoV-2等病毒的疫苗接种--我们还没有能够赋予粘膜免疫力的疫苗。该项目旨在（1）绘制驱动LAIV毒株组装的RNA：RNA相互作用的图谱;（2）利用这一知识设计灵活的MDV骨架，从而能够有效地产生季节性或大流行性LAIV，（3）还可以作为流感沿着其他呼吸道病原体共同接种的灵活平台。

The Live Attenuated Influenza Vaccine (LAIV), marketed as FluMist/Fluenz by AstraZeneca forms the backbone of the United Kingdom's childhood influenza vaccination programme and is given as a nasal spray annually to all 2-12 year-olds. Unlike inactivated vaccines, LAIVs are unique in generating significant mucosal immunity (Barria et al., J Infect Dis, 2013), offering the possibility of pre-empting virus spread from the upper to lower respiratory tract and consequent risk of severe disease.In the 2013-14 and 2015-16 influenza seasons, low vaccine effectiveness was observed for the H1N1 component of FluMist in the USA, attributed to decreased LAIV replication in human nasal epithelial cells (Hawksworth et al., Vaccine, 2020), rather than decreased HA antigen stability (Parker et al., Vaccine 2019). One potential contributing factor to this reduced fitness was a decrease in the production of infectious virus particles carrying all eight genome segments. Observations also suggest that the ability of the historic MDV genome to incorporate HA and NA genes from different, contemporary influenza A viruses can vary, resulting in LAIV strains with unexpected replicative differences.This project aims to understand how the genome segments of LAIVs are assembled in order to bioengineer a next-generation of LAIVs suitable as flexible vectors for all seasonal or pandemic influenza strains and co-vaccination against viruses such as SARS-CoV-2 - to which we have no vaccine that confers mucosal immunity. Such a vaccine would be invaluable, since existing vaccines are largely ineffective at halting transmission.This project aims to (1) map RNA:RNA interactions that drive assembly of LAIV strains and (2) to use this knowledge to engineer a flexible MDV backbone enabling efficient generation of either seasonal or pandemic LAIV, that (3) can also act as a flexible platform for co-vaccination of influenza along with other respiratory pathogens.