ABSTRACT
Objective@#To construct influenza B virus Vero cell adapted strain by genetic recombination technology by using the influenza B virus Vero cell adapted strain as the parent strain.@*Methods@#The chick embryo and Vero cell were co-infected with influenza virus Vero cell adapted strain B/Malaysia/2506/2004 Va (Bv) and the vaccine strain B/massachusetts/2/2012 (BX-51B) recommended by WHO. The reassortants were screened with the anti-Bv serum. Plaque-purified reassortants were used to screen for Vero cell-adapted influenza B virus strains containing the surface antigen of the epidemic strain.@*Results@#A Vero cell-adapted influenza B virus strain was obtained with successive passage in Vero cells. The hemagglutination inhibition test and the one-way immunogold agar diffusion test both showed that the reassortant virus was homologous to NYMC BX-51B, and sequence analysis result showed that the reassortment virus has the same HA and NA gene with the vaccine strain.@*Conclusion@#B/Malaysia/2506/2004Va (Bv) can be used as a parent strain to prepare Vero cell vaccine against influenza B virus.
ABSTRACT
Objective: To analyze the recombination of full-length genomic sequences of novel influenza virus A/H1N1 in 2009 pandemic. Methods: The full-length sequences of the novel A/H1N1 and reference sequences were downloaded from NCBI database. MEGA4.0 software was used to connect, align sequences, and analyze the similarity between the full-length sequences of the novel virus and each of the reference strains. Recombination was analyzed by Simplot software (version 3.5.1). Results: Simplot analysis indicated that the PB1 genes (polymerase B1, PB1) of the novel A/H1N1 viruses might evolve from human H3N2 virus (identity: 93.7%); the PB2 genes (polymerase B2, PB2) and the PA genes (polymerase A, PA) might evolve from avian H5N1 viruses (identity: 89.0%, 89.9%, respectively); the HA genes (hemagglutinin, HA), the NP genes (nucleoprotein, NP) and the NS genes (non-structural protein, NS) showed high similarities with those of swine H1N1 viruses isolated in North America (identity: 91.7%, 93.1%, and 93.1%, respectively); and the NA genes (neuraminidase, NA) and the MP genes (matrix protein, MP) might evolve from European swine H1N1 viruses (identity: 90.5%, 95.5%, respectively). The full-length sequence of the novel A/H1N1 viruses had a highest similarities with swine H1N1 viruses isolated in North America (identity: 83.9%). Conclusion: The novel influenza virus A/H1N1 is a recombinant virus evolving from human H3N2 viruses, swine H1N1 from North America, swine H1N1 from Europe, and swine H5N1 from Asia.