| 摘要 |
PURPOSE: A recombinant PR8 virus is provided to ensure high productivity in chicken embryos, high immunogenicity in mammals, and non-pathogenicity in birds and mammals, and to be used as a killed vaccine or a live vaccine. CONSTITUTION: An amino acid has one or more mutation selected from a group consisting of substitutions: at 119th amino acid, H to Y(H119Y); at 177th amino acid, K to E(K177E); at 333th amino acid, L to P(L333P); and at 393th amino acid, R to K(R393K). A composition for enhancing proliferation of influenza virus in chicken embryos contains the amino acid molecule. The composition contains an amino acid molecule with an amino acid sequence among sequence numbers 2-16, and an amino acid molecule with an amino acid sequence of sequence number 18. An expression vector contains a gene encoding the amino acid molecule. A low pathogenicity influenza virus mutant strain has substituted NA amino acid sequence at 369th amino acid, S to N(S369N). A vaccine composition for influenza virus contains the strain. |
