Background H3N2 subtype influenza A viruses have been identified in humans worldwide, raising concerns about their pandemic potential and prompting the development of candidate vaccines to protect humans against this ...Background H3N2 subtype influenza A viruses have been identified in humans worldwide, raising concerns about their pandemic potential and prompting the development of candidate vaccines to protect humans against this subtype of influenza A virus. The aim of this study was to establish a system for rescuing of a cold-adapted high-yielding H3N2 subtype human influenza virus by reverse genetics, Methods In order to generate better and safer vaccine candidate viruses, a cold-adapted high yielding reassortant H3N2 influenza A virus was genetically constructed by reverse genetics and was designated as rgAA-H3N2. The rgAA-H3N2 virus contained HA and NA genes from an epidemic strain A/Wisconsin/67/2005 （H3N2） in a background of internal genes derived from the master donor viruses （MDV）, cold-adapted （ca）, temperature sensitive （ts）, live attenuated influenza virus strain A/Ann Arbor/6/60 （MDV-A）. Results In this presentation, the virus HA titer of rgAA-H3N2 in the allantoic fluid from infected embryonated eggs was as high as 1：1024. A fluorescent focus assay （FFU） was performed 24-36 hours post-infection using a specific antibody and bright staining was used for determining the virus titer. The allantoic fluid containing the recovered influenza virus was analyzed in a hemagglutination inhibition （HI） test and the specific inhibition was found. Conclusion The results mentioned above demonstrated that cold-adapted, attenuated reassortant H3N2 subtype influenza A virus was successfully generated, which laid a good foundation for the further related research.展开更多
Background PB1-F2 protein has been proven to increase the pathogenicity of influenza A virus （IAV） strains in primary infection and in secondary bacterial infection. It can also regulate the activity of viral polyme...Background PB1-F2 protein has been proven to increase the pathogenicity of influenza A virus （IAV） strains in primary infection and in secondary bacterial infection. It can also regulate the activity of viral polymerase. However, it was shown in another retrospective study that a portion of IAVs do not express full-length PB1-F2 protein during virus development; different kinds of stop codons cause exits in the open reading frames and form PB1-F2 gene products with the corresponding genotypes. Truncated PB1-F2 in human H3N2 IAVs has long been detected in North America but its evolution in China is still unclear. Methods Influenza-like illnesses （ILls） from the whole of Jiangsu Province were collected and inspected to determine the type and subtype of the viruses. A portion of isolates collected in the epidemic period were selected as samples for later whole-genome sequencing, and the exact sequences were determined and analyzed. Results H3N2 influenza virus was one of the epidemical strains which had been prevalent during 2009-2010, in Jiangsu. Five H3N2 isolates with truncated PB1-F2 protein （25aa） were detected in influenza samples from Nanjing and Xuzhou, while seven similar H3N2 isolates were also reported in Niigata, Japan. Conclusion This emergence indicates the possibility that there has been transmission of the H3N2 virus between the two countries.展开更多
Dear Editor,Influenza A viruses cause pandemics at an interval of approximately 10-40 years,and pigs are regarded as a＂mixing vessel＂because they are easily infected with avian and human influenza viruses（Ito et al...Dear Editor,Influenza A viruses cause pandemics at an interval of approximately 10-40 years,and pigs are regarded as a＂mixing vessel＂because they are easily infected with avian and human influenza viruses（Ito et al.,1998）.According to previous studies,H3N2,H1N2,and H1N1 subtypes o（swine influenza viruses have been detected in Korean pigs （Pascua et al., 2013; Kim et al., 2014; Song et al., 2007）. Moreover, a novel H3N2 influenza virus containing the matrix （34） gene from a 2009 pandemic influenza virus was detected in Korean pigs in 2013 （Pascua et al., 2013）, an H1N2 influenza virus con- taining the internal genes from a 2009 pandemic influ- enza virus was found in Korean pigs in 2014 （Kim et al., 2014）, and an H1N1 influenza virus containing all genes from the classical swine influenza viruses was isolated from Korean pigs in 2007 （Song et al., 2007）.展开更多
目的了解海南省2019—2020年H3N2亚型流感病毒血凝素基因遗传进化规律与氨基酸变异情况。方法选取2019—2020监测年度海南省5家流感监测网络实验室分离的16株H3N2亚型流感毒株进行一代全基因组测序,利用MEGA 10.1.8构建血凝素基因系统...目的了解海南省2019—2020年H3N2亚型流感病毒血凝素基因遗传进化规律与氨基酸变异情况。方法选取2019—2020监测年度海南省5家流感监测网络实验室分离的16株H3N2亚型流感毒株进行一代全基因组测序,利用MEGA 10.1.8构建血凝素基因系统进化树,并分析氨基酸位点替换情况,应用DNA Star 7.0.1软件进行血凝素基因同源性分析。结果系统进化树显示,相比于疫苗株A/Kansas/14/2017(2019—2020),16株H3N2亚型流感病毒分离株血凝素基因在进化树上与疫苗株A/Singapore/INFIMH-16-0019/2016(2018—2019)亲缘关系更近,属于3C.2a1分支,核苷酸与氨基酸同源性范围分别为98.5%~98.9%、97.9%~98.4%。16株分离株在抗原性位点发生8处氨基酸位点替换,涉及5个抗原决定簇;15株分离株在糖基化位点发生2处缺失。结论2019—2020年监测年度海南省H3N2亚型流感病毒与2018—2019年疫苗株亲缘关系较近,血凝素蛋白抗原性位点在5个决定簇均有变异,易造成较大流行,WHO推荐的2019—2020年疫苗株保护效果可能不理想。应密切关注H3N2亚型流感病毒的流行与基因变异情况,为流感病毒疫苗株推荐及防控提供科学依据。展开更多
文摘Background H3N2 subtype influenza A viruses have been identified in humans worldwide, raising concerns about their pandemic potential and prompting the development of candidate vaccines to protect humans against this subtype of influenza A virus. The aim of this study was to establish a system for rescuing of a cold-adapted high-yielding H3N2 subtype human influenza virus by reverse genetics, Methods In order to generate better and safer vaccine candidate viruses, a cold-adapted high yielding reassortant H3N2 influenza A virus was genetically constructed by reverse genetics and was designated as rgAA-H3N2. The rgAA-H3N2 virus contained HA and NA genes from an epidemic strain A/Wisconsin/67/2005 （H3N2） in a background of internal genes derived from the master donor viruses （MDV）, cold-adapted （ca）, temperature sensitive （ts）, live attenuated influenza virus strain A/Ann Arbor/6/60 （MDV-A）. Results In this presentation, the virus HA titer of rgAA-H3N2 in the allantoic fluid from infected embryonated eggs was as high as 1：1024. A fluorescent focus assay （FFU） was performed 24-36 hours post-infection using a specific antibody and bright staining was used for determining the virus titer. The allantoic fluid containing the recovered influenza virus was analyzed in a hemagglutination inhibition （HI） test and the specific inhibition was found. Conclusion The results mentioned above demonstrated that cold-adapted, attenuated reassortant H3N2 subtype influenza A virus was successfully generated, which laid a good foundation for the further related research.
基金This work was supported by grants from the Natural Science Foundation of Jiangsu Province （No. BK20131450）, Jiangsu Province Key Medical Talent Foundation （No. RC2011084） and National Natural Science Foundation of China （No. 81273143）.
文摘Background PB1-F2 protein has been proven to increase the pathogenicity of influenza A virus （IAV） strains in primary infection and in secondary bacterial infection. It can also regulate the activity of viral polymerase. However, it was shown in another retrospective study that a portion of IAVs do not express full-length PB1-F2 protein during virus development; different kinds of stop codons cause exits in the open reading frames and form PB1-F2 gene products with the corresponding genotypes. Truncated PB1-F2 in human H3N2 IAVs has long been detected in North America but its evolution in China is still unclear. Methods Influenza-like illnesses （ILls） from the whole of Jiangsu Province were collected and inspected to determine the type and subtype of the viruses. A portion of isolates collected in the epidemic period were selected as samples for later whole-genome sequencing, and the exact sequences were determined and analyzed. Results H3N2 influenza virus was one of the epidemical strains which had been prevalent during 2009-2010, in Jiangsu. Five H3N2 isolates with truncated PB1-F2 protein （25aa） were detected in influenza samples from Nanjing and Xuzhou, while seven similar H3N2 isolates were also reported in Niigata, Japan. Conclusion This emergence indicates the possibility that there has been transmission of the H3N2 virus between the two countries.
基金in part funded by a 2015 research fund from Chungnam National University
文摘Dear Editor,Influenza A viruses cause pandemics at an interval of approximately 10-40 years,and pigs are regarded as a＂mixing vessel＂because they are easily infected with avian and human influenza viruses（Ito et al.,1998）.According to previous studies,H3N2,H1N2,and H1N1 subtypes o（swine influenza viruses have been detected in Korean pigs （Pascua et al., 2013; Kim et al., 2014; Song et al., 2007）. Moreover, a novel H3N2 influenza virus containing the matrix （34） gene from a 2009 pandemic influenza virus was detected in Korean pigs in 2013 （Pascua et al., 2013）, an H1N2 influenza virus con- taining the internal genes from a 2009 pandemic influ- enza virus was found in Korean pigs in 2014 （Kim et al., 2014）, and an H1N1 influenza virus containing all genes from the classical swine influenza viruses was isolated from Korean pigs in 2007 （Song et al., 2007）.
文摘目的了解海南省2019—2020年H3N2亚型流感病毒血凝素基因遗传进化规律与氨基酸变异情况。方法选取2019—2020监测年度海南省5家流感监测网络实验室分离的16株H3N2亚型流感毒株进行一代全基因组测序,利用MEGA 10.1.8构建血凝素基因系统进化树,并分析氨基酸位点替换情况,应用DNA Star 7.0.1软件进行血凝素基因同源性分析。结果系统进化树显示,相比于疫苗株A/Kansas/14/2017(2019—2020),16株H3N2亚型流感病毒分离株血凝素基因在进化树上与疫苗株A/Singapore/INFIMH-16-0019/2016(2018—2019)亲缘关系更近,属于3C.2a1分支,核苷酸与氨基酸同源性范围分别为98.5%~98.9%、97.9%~98.4%。16株分离株在抗原性位点发生8处氨基酸位点替换,涉及5个抗原决定簇;15株分离株在糖基化位点发生2处缺失。结论2019—2020年监测年度海南省H3N2亚型流感病毒与2018—2019年疫苗株亲缘关系较近,血凝素蛋白抗原性位点在5个决定簇均有变异,易造成较大流行,WHO推荐的2019—2020年疫苗株保护效果可能不理想。应密切关注H3N2亚型流感病毒的流行与基因变异情况,为流感病毒疫苗株推荐及防控提供科学依据。
