Recombinant equine influenza virus strain, preparation method thereof and vaccine prepared from recombinant equine influenza virus strain

The invention discloses a recombinant equine influenza virus strain, a preparation method thereof and a vaccine prepared from the recombinant equine influenza virus strain. The recombinant influenza virus strain contains genes HA and NA of an equine influenza virus A/equine/xinjiang/3/07 (H3N8) strain and six internal genes PB2, PB1, PA, NP, M and NS of an influenza virus A/Puerto Rico/8/34/Mount Sinai (H1N1) or A/PR/8/34 (H1N1 short for PR8 virus). The recombinant equine influenza virus strain disclosed by the invention is named as rH3N8-PR and is preserved with the number of CGMCC NO.8161. The invention also discloses a preparation method of the recombinant equine influenza virus strain and a vaccine prepared from the recombinant equine influenza virus strain. Compared with a parental strain, the recombinant equine influenza virus strain disclosed by the invention can generate very high virus titer and blood clotting titer on both chick embryos and MDCK (Madin Darby Canine Kidney) cells, and the pathogenicity of the recombinant equine influenza virus strain to mice is remarkably reduced; experiments prove that the vaccine prepared from the recombinant equine influenza virus strain disclosed by the invention has favorable immunogenicity and protective effect.