Influenza A virus attenuated strains and preparation method and application thereof

The invention relates to a group of influenza A virus attenuated strains as well as a preparation method and application thereof, and belongs to the technical field of virus attenuation. The invention provides a group of influenza A virus attenuated strains, the attenuated strains are obtained by modifying an M2 gene, and the modification comprises termination codon mutation and deletion mutation behind the mutated termination codon. The attenuated strain disclosed by the invention has the advantages of higher stability, no reverse mutation after repeated passage, higher safety and low dependence on a cell line, and has stronger advantages in a vaccine production process. 本发明涉及一组A型流感病毒致弱毒株及其制备方法和应用，属于病毒致弱技术领域。本发明提供了一组A型流感病毒致弱毒株，所述致弱毒株通过对M2基因进行修饰获得，所述修饰包括进行终止密码子突变和在突变的终止密码子后进行缺失突变。本发明所述致弱毒株稳定性更强，多次传代不会发生回复突变，安全性更高，对细胞系的依赖不强，在疫苗生产过程中具有较强的优势。