RESUMO
Forty-two H9N2 subtype AIV strains were isolated from vaccinated commercial chickens in China from 2012 to 2015. Their HA genes had nucleotide sequence homology from 86.7% to 99.7%, and similarity to the classic vaccine strain was 88.6%-92.6%. A comparison was carried out with published HA genes (410 H9 strains) and whole genomes (306 strains) isolated in China during 2012-2015. Interestingly, 99.1% (448/452) of Chinese H9N2 AIV belonged to lineage h9.4.2, and 98.5% (445/452) of the viruses belonged to h9.4.2.5. Meanwhile, 99.6% (443/445) of lineage 9.4.2.5 viruses had PSRSSR↓GLF instead of PARSSR↓GLF motifs in the HA cleavage sites; 98.2% (444/452) of HA genes showed human receptor binding associated mutation Q226L. A total of 96.8% (337/348) of the viruses had three amino-acid deletions at 63-65 in the NA stalk, associated with enhanced virulence in chickens and mice; 97.1% (338/348) of M2 proteins had the S31N mutation associated with adamantane resistance in humans. Two H9 viruses isolated in this study were highly homologous to the human-origin H9N2 virus reported in 2013. The isolates were divided into four different genotypes (U, S, V, and W). Genotype S was the major one, accounting for 94.8% (330/348). Genotypes V and W were new reassortment genotypes, with genotype W recombined with the PB2 gene originating from the new wild waterfowl-like lineage. According to the cross-HI antibody titer data, HA gene evolution, and isolation history, the isolates were divided into A, B, and C antigenic groups successively. All the antigenic group viruses were found to circulate throughout China. This study emphasizes the importance of updated vaccine and strengthened veterinary biosecurity on poultry farms and trade markets.
Assuntos
Variação Genética , Vírus da Influenza A Subtipo H9N2/genética , Influenza Aviária/virologia , Doenças das Aves Domésticas/virologia , Animais , Antígenos Virais/genética , Antígenos Virais/imunologia , Galinhas , China/epidemiologia , Evolução Molecular , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Vírus da Influenza A Subtipo H9N2/classificação , Vírus da Influenza A Subtipo H9N2/isolamento & purificação , Influenza Aviária/epidemiologia , Filogenia , Doenças das Aves Domésticas/epidemiologiaRESUMO
AIM: To investigate the anti-tumor effect of newcastle disease virus (NDV). METHODS: Plaque formation test was used to investigate the effect of NDV on chicken embryofibroblasts(CEF). Cell suppression test, agarose gel electrophoresis, cytoskeleton staining, fluorescence staining, TUNEL staining, and sialic acid content determination were used to observe the influence of NDV on several human tumor cells. RESULTS: The Plaque formation was observed in chicken embryo fibroblasts.NDV could lead to the apparent cytopathy of BHK, Hela and Hep-2 tumor cells, but has no apparent effect on Wish cells. The strong suppressive effect of NDV on the growth of these tumor cells was found without dose dependence. The optimal dose of NDV could induce the death of tumor cells which was mainly apoptosis, as showed by the classical DNA ladder in DNA gel electrophoresis. NDV also resulted in the changes of cytoskeleton and decreased the level of sialic acid contents on tumor cells. CONCLUSION: NDV may be a potential anti-tumor agent.
