江苏省2011年乙型流感病毒血凝素和神经氨酸酶分子流行特征

目的 分析2011年江苏省乙型流感病毒的血凝素(HA)和神经氨酸酶(NA)的分子流行特征.方法 选择13株2011年江苏省不同地区、不同流行时间的乙型流感毒株进行全基因组测序,通过生物信息学方法对HA、NA分子流行特征进行分析.结果 13株乙型流感毒株中,10株属于Victoria系,3株属于Yamagata系.10株Victoria系毒株的NA基因来源于Yamagata系病毒,是基因重配流行株.与疫苗株相比,10株Victoria系毒株和3株Yamagata系毒株的HA蛋白分别在197和196位增加一个糖基化位点.结论 2011年江苏省乙型流感Victoria系和Yamagata系病毒同时流行,其中重配的Victoria系病毒占优势.     

2015年北京市房山区乙型Yamagata系流感病毒HA基因特性分析

目的 了解北京市房山区2015年乙型Yamagata系流感病毒HA1基因变异情况.方法 选取2015年流感病原学监测中分离到的乙型Yamagata系毒株共13株,采用RT-PCR法扩增病毒HA基因片段后进行序列测定,与WHO推荐的疫苗株进行比对并构建进化树.采用MEGA6软件对测序结果进行分析.结果 2015年房山区乙型Yamagata系流感病毒HA1基因片段序列测定拼接后核苷酸长度为1059bp,编码氨基酸为353个,与2014-2015年的疫苗株B/Massachusetts/02/2012比较,13株毒株的氨基酸均在第123、131、165、180、187、196、211、217、244、313、327位点有变异;与2012-2013年的疫苗株B/Wisconsin/01/2010比较,13株毒株的氨基酸在第187、313、327均有变异.做进化树分析,房山区2015年分离到的乙型Yamagata系流感病毒与疫苗株B/Wisconsin/1/2010在同一个分支上,距离较近,与B/Massachusctts/2/2012不在一个分支上,距离较远.结论 2015年北京市房山区乙型Yamagata系流感病毒HA1基因在抗原决定簇区已发生变异,但疫苗株B/Wisconsin/01/2010有保护作用,应继续关注氨基酸的替换.     

北京市2021—2022年流行季首起乙型流感疫情的血凝素基因分析

目的:分析2021—2022年流行季北京市首起乙型流感Victoria系（BV）疫情的病毒血凝素（HA）的基因变异和进化特征以及与流感疫苗株的匹配性。方法:采集北京市朝阳区某小学乙型流感疫情流感样病例的咽拭子标本,提取核酸后利用二代测序技术进行测序分析。应用BioEdit分析HA基因的核苷酸和氨基酸变异位点,采用Meg...     

2021—2022年流感监测季北京市乙型Victoria系流感病毒血凝素基因特性和抗原性分析

目的分析2021—2022年流感监测季北京市乙型Victoria系流感病毒(BV)的血凝素(hemagglutinin, HA)基因特性、抗原性及与流感疫苗组分株的匹配性。方法采集2021—2022年流感监测季流感样病例(influenza like-illness, ILI)咽拭子样本经MDCK和鸡胚培养分离流感病毒, 提取病毒核酸后测序。应用MEGA5.0进行病毒HA基因的核苷酸和氨基酸变异, 采用maximum likelihood方法构建HA基因的遗传进化树, 在线预测N-糖基化位点。SWISS-MODEL同源建模, 建立BV毒株HA的蛋白质三维空间模拟图。通过血凝抑制(hemagglutination inhibition, HI)试验, 进行毒株的抗原性分析。结果共收集402株BV毒株, 选取58株测序获得HA基因全长序列, 与本年度的疫苗组分BV株(B/Washington/02/2019)HA基因相比较显示, 有27个氨基酸位点发生变异, 其中11个变异位点位于4个不同的抗原决定簇。遗传进化树分析显示:3个进化分支的毒株共同流行, 其中54株(54/58, 93.10%...     

江苏省2019—2022年乙型流感病毒Victoria系HA基因特征分析

目的分析江苏省2019—2022年乙型流感病毒Victoria系流行特征, 了解其基因变异情况, 监测江苏省流感活动水平和流行趋势。方法通过"中国流感监测信息系统"收集的江苏省2019—2022年流感样病例监测数据, 选取16株乙型流感病毒Victoria系毒株进行全基因组测序, 利用MEGA 7软件构建进化树并进行HA基因序列特征分析。结果江苏省2019—2022年监测到的流感病毒中乙型流感病毒Victoria系占绝对优势。16株标本株中2019—2020年度的毒株在V1A.3早期分支, 而2021—2022年度的毒株则聚类在3a.2亚型分支。与疫苗株相比, 2019—2020及2020—2021年度的毒株发生了1个氨基酸位点的改变并增加了1个糖基化位点, 而2021—2022年度的毒株则存在多个位点变异, 其中H122Q、A127T、R133G、P144L、N150K、S194D及K200R位于抗原决定簇上。结论江苏省乙型流感病毒Victoria系在多处基因位点发生了变异, 提示对该亚型变异的持续监测至关重要, 可为疫苗的更新提供重要依据。     

1994-2006年深圳市分离的B型流感病毒分子进化研究

目的 通过对深圳市分离的B型流感病毒HA1分子系统进化分析,初步了解深圳市B型流感病毒的流行变异规律.方法 选取深圳市1994-2006共13年间分离的50株B型流感毒株,通过RT-PCR将其HA1基因片段扩增后进行序列解析,然后,通过MEGA等软件对序列进行分子进化分析.结果 1994-2006年间深圳市流行的B型流感病毒分为Yamagata和Victoria两个亚系,两系的毒株分别是不同年份的主要流行株.两个亚系的HA1分子具有1个糖基化位点的差异,在4个抗原决定簇区域也分布有多个氨基酸位点的变异.结论 1994-2006年间深圳市B型流感病毒的两个亚系分别在不同年份主导流行,但变异均比较缓慢.

Abstract：

Objective To study the prevalence and variation of influenza B viruses of Shenzhen. Methods Fifty strains influenza B viruses in Shenzhen from 1994 to 2006 were selected. HA1 gene were amplified by RT-PCR and sequenced. Phylogenetic analysis of HA1 was conducted by MEGA program. Results The influenza B viruses of Shenzhen were divided into Yamagata and Victoria lineage. The two lineages prevailed respectively in different years from 1994 to 2006. The variance of glycosylation site and some mutations of antigenic determinants were detected in the two lineages. Conclusion The viruses of Yamagata and Victoria lineage prevailed respectively in different years in Shenzhen but the mutation rates of the two lineages were slowly.     

2004-2005年中国B型流感病毒抗原性及基因特性研究

目的 阐明2004-2005年中国流行的B型流感病毒血凝素抗原性及其基因变异情况.方法 对2004-2005年分离的B型毒株先进行单向血凝抑制试验;在此基础上选取不同时间、地点的B型流感毒株进行血凝素基因HA1区核苷酸序列测定并推导出其氨基酸序列,然后进行基因进化特性分析.结果 2004-2005年我国人群中同时流行着B型Yamagata系和Victoria系毒株.Yamagata系毒株与B/Shanghai/361/02比较,2004年有3.7%病毒单向血凝抑制效价有4倍以上差异,2005年有4.5%病毒单向血凝抑制效价有4倍以上差异,并且在血凝素基因HA1区发生9个氨基酸替换,在196为增加一个糖基化位点.Victoria系毒株与B/Hong kong/330/01比较,2004年有8.5%病毒单向血凝抑制效价有4倍以上差异,2005年有20.6%病毒单向血凝抑制效价有4倍以上差异,并且在HA1区发生9个氨基酸替换,在197位增加一个糖基化位点.结论 2004-2005年我国人群中流行的B型流感病毒的抗原性与B/Shanghai/361/02、B/Hong kong/330/01相比抗原性已经发生了变化.     

1990～2000年间我国乙型流感病毒HA1基因演变的特征

目的 了解1990—2000年间我国乙型流感病毒HA1基因的演变特征。方法 提取病毒RNA，经逆转录和聚合酶链式反应扩增后测序，测定的序列和Gen bank中已有的相关序列进行比较。结果 ①我国乙型流感病毒在此期间一直存在两个差别较大的谱系，除1994年和1997年Victoria谱系为主外，其余各年均以Yamagata谱系为主；②1992年以后Yamagata谱系又分化出两个组，彼此间氨基酸序列差异达6％；③1990—2000年间非回复突变的、大的变异株引导乙型流感的流行；④除了个别毒株之外，同一年份我国不同地区流行的属于同一谱系的乙型毒株HA1基因序列差别不大。结论 我国乙型流感病毒1990—2000年间一直存在两个差别较大的谱系，其中Yamagata谱系在此期间又分化出两个组，谱系的更换和同一谱系内出现大的变异株具有重要的流行病学意义。     

B型流感病毒Yamagata系和Victoria系双重荧光PCR诊断方法的建立与应用

目的 建立一种新型的双重荧光PCR诊断方法,用于B型流感病毒By (B/Yamagata)和Bv(B/Victoria)亚系的准确分子分型.方法 从GenBank随机下载By和By HA(hemagglutinin)基因各50条序列,通过MEGA分析,利用Primer Primer软件设计亚系特异性引物和通用探针,建立双重荧光PCR诊断方法.用HAI(hemagglutination inhibition)实验确认的B型流感病毒亚系分离毒株和A型流感病毒进行特异性验证,用体外转录核酸拷贝数进行灵敏度实验.结果 2006-2010流感监测年份,对17 765份流感样病例咽拭标本中分离到B型流感病毒793株,本方法鉴定有152株By和641株Bv病毒,与HAI鉴定结果一致.本诊断方法的检测特异性达100％,灵敏度达102拷贝/μl,重复性变异系数＜3.5％.结论 本研究所建立的荧光PCR方法为流感实时监测提供了有力的技术支撑,适合于流感监测实验室对流感病毒的快速分子诊断.     

广东省深圳市流感流行特征分析

目的 掌握深圳市流感流行规律,了解甲流大流行以后流感的流行趋势.方法 对深圳市流感样病例监测数据、病原学检测结果和暴发疫情资料进行分析.结果 深圳市的流感样病例百分比(ILI％)为4.67％,呈逐年下降趋势,ILI年龄构成以0-4岁为主(占54.2％).流感病毒分离平均阳性率为10.6％,按月分析流感病毒分离阳性率与ILI％变化趋势呈正相关(r=0.447,P =0.001).全市报告了482起ILI暴发疫情,以乙型流感为主(占63.9％).2010年深圳市季节性流感出现了春季和夏季流行高峰,分别以乙型Victoria系和甲型H1N1亚型为优势株;2011年为冬春季和秋季高峰,以甲型H1N1和季节性H3亚型为优势株;2012年出现了冬春季和夏季高峰,以乙型(Victoria系和Yamagata系)和季节性H3亚型为优势株;2013年出现了春、秋、冬季三个流行高峰,分别以甲型H1N1、季节性H3和乙型Yamagata系为优势株.结论 深圳市季节性流感每年均出现2-3个流行高峰,分别在冬春季和夏秋季,每年流行高峰出现的时间不同,每年流行的型别不同.     

Increasing appearance of reassortant influenza B virus in Taiwan from 2002 to 2005

Genetic and antigenic analyses of influenza B virus field strains isolated in Taiwan from 1998 to 2005 were performed. To investigate the molecular evolution of influenza B viruses, sequence analysis of the hemagglutinin (HA1 subunit) and neuraminidase genes was performed. All influenza B viruses isolated between 1998 and 2000 belonged to the B/Yamagata/16/88 lineage. The B/Victoria/2/87 lineage, which was cocirculating with the Yamagata lineage, was identified in Taiwan in March 2001. Concurrently, there was an increasing prevalence of this lineage in many parts of the world, including North America and Europe, during the 2001-2002 season. Since 2002, genetic reassortants of influenza B virus with the Victoria lineage of hemagglutinin and the Yamagata lineage of neuraminidase have been found at a rate of 46%. Therefore, in 2002, at least three sublineages of influenza B virus strains, the B/Shanghai/361/2002-like strain (Yamagata lineage), the B/Hong Kong/330/01-like strain (Victoria lineage), and the B/Hong Kong/1351/02-like strain (B reassortant lineage), were identified in Taiwan. The results showed that genetically distinct lineages can cocirculate in the population and that the reassortment among these strains plays a role in generating the genetic diversity of influenza B viruses. Interestingly, from January to April 2005, B reassortant viruses became dominant (73%) in Taiwan, which indicated that a mismatch had occurred between the influenza B vaccine strain recommended for the 2004-2005 season in the Northern hemisphere by the World Health Organization and the epidemic strain.     

Phylogenetic analysis of influenza B virus in Taiwan, 1997 to 2001.

Seventeen strains of influenza B virus were isolated and identified from 1997 to 2001. Throat swabs were collected in children who presented in medical centers in both central and northern parts of Taiwan. To clarify the molecular characteristics of these isolates, both partial hemagglutinin (HA) gene and nonstructural (NS) gene nucleotide sequences were cloned and subjected to nucleotide sequence analysis. The phylogenetic analysis of the HA gene revealed that 16 out of 17 strains were similar to B/Yamagata/16/88-like virus, but grouped together to form an independent cluster. Only one strain, B/Taiwan/21706/97, was similar to the B/Victoria/2/87-like lineage. In addition, all isolates, except for B/Taiwan/21706/97, were similar to B/Beijing/184/93 and B/Yamanashi/166/98, which were chosen as the recommended vaccine strains in 1999 and 2001. In contrast, the NS gene of these isolates was evolved from B/Guangdong/8/93. Based on the accumulation of antigenic drift in our isolates, we conclude that influenza B virus is still prevalent in Taiwan and the accumulation of nucleotide mutations indicated that our isolates form a new cluster that evolved from the YA88 lineage.     

Genetic diversity of influenza B virus: the frequent reassortment and cocirculation of the genetically distinct reassortant viruses in a community

To characterize the genetic diversity of influenza B viruses isolated during one influenza season, the antigenic and genetic relationships among 20 strains of influenza B virus isolated in February and March 2001 at one pediatric clinic in Yamagata City, Japan, were investigated. The HA gene and seven other gene segments were phylogenetically divided into three distinct sublineages (Harbin/7/94-, Tokyo/6/98-, and Shiga/T30/98-related lineage) of the Yamagata/16/88-like lineage. The NS genes of the viruses belonging to the Harbin/7/94-related lineage have additional three nucleotides at positions 439-447, and were phylogenetically distinguishable from those of the currently circulating Yamagata/16/88- and Victoria/2/87-like lineages, but were closely related to that of the Yamagata/16/88-like lineage isolated before 1994. Moreover, four strains of influenza B virus isolated in the same community between 2002 and 2003 were further examined. Phylogenetic analysis revealed that a virus of Victoria/2/87-like lineage isolated in 2003 had acquired the NA, NS, M, and PA gene segments from a Shiga/T30/98-like virus, and two strains of Harbin/7/94-related lineage had acquired the various gene segments from Shiga/T30/98-like virus through a reassortment event. These results indicate that genetically distinct multiple viruses can combine to cause an influenza B epidemic in a community and that the frequent reassortment among these viruses plays a role in generating the genetic diversity of influenza B viruses.     

Reassortment and evolution of current human influenza A and B viruses

During the 2001-2002 influenza season, human influenza A (H1N2) reassortant viruses were detected globally. The hemagglutinin (HA) of these H1N2 viruses was similar to that of the A/New Caledonia/20/99 (H1N1) vaccine strain both antigenically and genetically, while their neuraminidase (NA) was antigenically and genetically related to that of recent human influenza H3N2 reference viruses such as A/Moscow/10/99. All six internal genes of the H1N2 reassortants originated from an H3N2 virus. After being detected only in eastern Asia during the past 10 years, Influenza B/Victoria/2/87 lineage viruses reappeared in many countries outside of Asia in 2001. Additionally, reassortant influenza B viruses possessing an HA similar to that of B/Shandong/7/97, a recent B/Victoria/2/87 lineage reference strain, and an NA closely related to that of B/Sichuan/379/99, a recent B/Yamagata/16/88 lineage reference strain, were isolated globally and became the predominant influenza B epidemic strain. The current influenza vaccine is expected to provide good protection against H1N2 viruses because it contains A/New Caledonia/20/99 (H1N1) and A/Panama/2007/99 (H3N2) like viruses whose H1 HA or N2 NA are antigenically similar to those of recent circulating H1N2 viruses. On the other hand, widespread circulation of influenza B Victoria lineage viruses required inclusion of a strain from this lineage in influenza vaccines for the 2002-2003 season.     

Evaluation of Influenza Virus A/H3N2 and B Vaccines on the Basis of Cross-Reactivity of Postvaccination Human Serum Antibodies against Influenza Viruses A/H3N2 and B Isolated in MDCK Cells and Embryonated Hen Eggs

The vaccine strains against influenza virus A/H3N2 for the 2010-2011 season and influenza virus B for the 2009-2010 and 2010-2011 seasons in Japan are a high-growth reassortant A/Victoria/210/2009 (X-187) strain and an egg-adapted B/Brisbane/60/2008 (Victoria lineage) strain, respectively. Hemagglutination inhibition (HI) tests with postinfection ferret antisera indicated that the antisera raised against the X-187 and egg-adapted B/Brisbane/60/2008 vaccine production strains poorly inhibited recent epidemic isolates of MDCK-grown A/H3N2 and B/Victoria lineage viruses, respectively. The low reactivity of the ferret antisera may be attributable to changes in the hemagglutinin (HA) protein of production strains during egg adaptation. To evaluate the efficacy of A/H3N2 and B vaccines, the cross-reactivities of postvaccination human serum antibodies against A/H3N2 and B/Victoria lineage epidemic isolates were assessed by a comparison of the geometric mean titers (GMTs) of HI and neutralization (NT) tests. Serum antibodies elicited by the X-187 vaccine had low cross-reactivity to both MDCK- and egg-grown A/H3N2 isolates by HI test and narrow cross-reactivity by NT test in all age groups. On the other hand, the GMTs to B viruses detected by HI test were below the marginal level, so the cross-reactivity was assessed by NT test. The serum neutralizing antibodies elicited by the B/Brisbane/60/2008 vaccine reacted well with egg-grown B viruses but exhibited remarkably low reactivity to MDCK-grown B viruses. The results of these human serological studies suggest that the influenza A/H3N2 vaccine for the 2010-2011 season and B vaccine for the 2009-2010 and 2010-2011 seasons may possess insufficient efficacy and low efficacy, respectively.     

Exploration of the emergence of the Victoria lineage of influenza B virus

Summary. The Victoria lineage represented by B/Victoria/2/87 is one of the two major distinctive haemagglutinin (HA) lineages of influenza B virus, and its recent re-emergence has aroused great concerns. However, it remains unknown when, where, and how this HA lineage emerged in the world. In this study, the HA1 domain of the HA gene of fourteen influenza B viruses isolated in China in 1972–1984 was sequenced. The sequences were phylogenetically analyzed with the HA1 sequences of 41 other important influenza B isolates. The results unveiled some earlier footprints of the Victoria lineage in China, and the epidemic history of the Victoria lineage could be traced back from the year 1985 to 1975. Moreover, phylogenetic analysis, the history of China, and the epidemiology of influenza B virus indicated that the Victoria lineage possibly emerged in China in the 1970s through gradual evolution from a minor lineage.     

唐山市甲型H1N1流感病毒血凝素基因序列分析

目的 分析2010—2016年唐山市甲型H1N1流感病毒血凝素(hemagglutinin,HA)基因序列进化特征.方法 选取唐山市3家哨点医院流感样病例分离到的24株甲型H1N1病毒,通过RT-PCR和测序方法获得HA基因的全长序列,运用分子生物学软件和统计学软件对序列进行拼接、比对和分析.结果 同源进化分析显示,24株甲型H1N1流感病毒HA基因与疫苗株A/California/7/2009的核苷酸和氨基酸的同源性分别为97.0%~99.0%和97.0%~98.5%.进化分析显示,2010—2016年唐山地区流行的甲型H1N1流感病毒属于1、7、6三个基因分支,其中6分支毒株分为6C、6B、6B.1和6B.2亚支.氨基酸位点分析显示,不同毒株与疫苗株比较存在8~16处氨基酸位点改变,其中7个变异涉及3个抗原表位:H138Q/Y和S203T突变位于Ca区,N125S、K153E、S162N、K163T/Q突变位于Sa区,S185T突变位于Sb区同时也位于受体结合部位;2015—2016流行季6B.1分支毒株抗原位点S162N突变增加了新的潜在糖基化位点.结论 与疫苗株比较,随着时间推移唐山地区甲型H1N1流感病毒发生了抗原漂变,未来仍应关注6B分支流行株的变化.     

Molecular analysis of isolates from influenza B outbreaks in the U.S. and Nepal, 2005

Summary. Currently circulating influenza B viruses can be divided into two antigenically and genetically distinct lineages referred to by their respective prototype strains, B/Yamagata/16/88 and B/Victoria/2/87, based on amino acid differences in the hemagglutinin surface glycoprotein. During May and July 2005, clinical specimens from two early season influenza B outbreaks in Arizona and southeastern Nepal were subjected to antigenic (hemagglutinin inhibition) and nucleotide sequence analysis of hemagglutinin (HA1), neuraminidase (NA), and NB genes. All isolates exhibited little reactivity with the B/Shanghai/361/2002 (B/Yamagata-like) vaccine strain and significantly reduced reactivity with the previous 2003/04 B/Hong Kong/330/2001 (B/Victoria-like) vaccine strain. The majority of isolates were antigenically similar to B/Hawaii/33/2004, a B/Victoria-like reference strain. Sequence analysis indicated that 33 of 34 isolates contained B/Victoria-like HA and B/Yamagata-like NA and NB proteins. Thus, these outbreak isolates are both antigenically and genetically distinct from the current Northern Hemisphere vaccine virus strain as well as the previous 2003–04 B/Hong Kong/330/2001 (B/Victoria lineage) vaccine virus strain but are genetically similar to B/Malaysia/2506/2004, the vaccine strain proposed for the coming seasons in the Northern and Southern Hemispheres. Since these influenza B outbreaks occurred in two very distant geographical locations, these viruses may continue to circulate during the 2006 season, underscoring the importance of rapid molecular monitoring of HA, NA and NB for drift and reassortment.