Quantitation of haemagglutinin in H5N1 influenza viruses reveals low haemagglutinin content of vaccine virus NIBRG-14 (H5N1)

The assessment of potential candidate influenza vaccine viruses includes a number of factors. Growth properties of the virus and yield of antigen, specifically the haemagglutinin (HA), are of key importance. The recently developed H5N1 candidate vaccine virus NIBRG-14 (with HA and NA genes derived from the clade 1 virus A/Viet Nam/1194/2004 in an A/Puerto Rico/8/34 background) has been suggested to yield low amounts of antigen. While investigating the antigen yield of H5N1 vaccine viruses, we found that accurate quantitation of the HA content of some H5N1 viruses was difficult due to the migration characteristics of the proteins on SDS-PAGE gels. The HA1 and HA2 bands co-migrated with nucleoprotein (NP) and matrix protein (M1) respectively, preventing accurate analysis. We have developed an accurate way of quantitating HA from these H5N1 viruses by introducing a deglycosylation step to the standard protocol. Using this method, we showed reproducibly that the low yield of NIBRG-14 is, at least in part, due to a lower than usual content of HA in virus preparations. This was also found to be the case for the parent wild type A/Viet Nam/1194/2004 virus.     

安徽省甲型H1N1流感抗体水平调查

目的了解安徽省不同人群甲型H1N1流感抗体水平,为防控措施的制定提供依据。方法 2010年1月10～25日期间,采取分层随机抽样的方法抽取4 567名调查对象,进行问卷调查,并运用血清抗凝实验方法检测甲型H1N1流感抗体水平。结果全人群抗体阳性率为29.41%,未接种疫苗人群抗体阳性率为23.94%;全人群中,省会城市抗体阳性率高于中小城市,中小城市高于农村;在全人群和未接种疫苗的人群中,6～岁和16～岁年龄组抗体阳性率较高,60岁及以上组抗体阳性率最低,中小学生抗体阳性率最高,其次是幼托儿童和医护人员。结论人群中甲型H1N1流感免疫屏障尚未建立,目前仍需加强疫苗接种和疫情监测。     

长沙市甲型Ｈ１Ｎ１流感抗体水平趋势数学模型模拟研究

摘要：目的　采用常微分方程（ｏｒｄｉｎａｒｙｄｉｆｆｅｒｅｎｔｉａｌｅｑｕａｔｉｏｎ,ＯＤＥ）模型模拟长沙市甲型Ｈ１Ｎ１流感抗体
水平。方法　根据甲型Ｈ１Ｎ１流感在人群中的传播及抗体消长特点,建立全人群及各年龄组人群抗体水平
变化趋势的ＯＤＥ 模型,利用长沙市人口学资料、以及长沙市人群血清学横断面调查资料拟合模型参数,并
模拟长沙市人群的抗体水平变化趋势、以及抗体水平低于人群最低免疫屏障的具体时间。结果　大流行结
束后疫苗接种者抗体水平高于未接种者,但前者的抗体消失速度高于后者,两者抗体水平分别在２０１０ 年
１２月和２０１３年１月开始接近人群最低免疫屏障。在疫苗接种人群中,抗体消失速度最快的是“≥６０ 岁”
年龄组,最慢的是“０～５岁”年龄组,而“６～１５岁”、“１６～２４岁”、“２５～５９岁”３个年龄组人群抗体水
平消失速度较为接近。在未接种疫苗人群中,抗体消失速度最快的是“６～１５ 岁” 年龄组,其次是“１６～
２４岁”、“０～５岁”、“≥６０岁”年龄组,最慢的是“２５～５９岁” 年龄组。长沙市流感监测数据显示,２０１３
年１月开始甲型Ｈ１Ｎ１流感成为优势毒株,并在１～４月份发生４起甲型Ｈ１Ｎ１流感暴发疫情和１起流感样
病例暴发疫情,这与模型预测结果相似。结论　本研究建立的ＯＤＥ 模型可以较好地模拟长沙市甲型Ｈ１Ｎ１
流感抗体水平变化特点。疫苗接种获得的免疫屏障维持时间比自然感染短。不同年龄组获得免疫屏障水平
不同、消减速度亦不同。
关键词：甲型Ｈ１Ｎ１流感;抗体;常微分方程模型;模拟
中图分类号：Ｒ１８１．２　　文献标识码：Ａ　　文章编号：１００９ ６６３９ （２０１４）０３ ０１７３ ０８     

甲型H1N1流感流行病学研究进展

自2009年3月18日以来,墨西哥、美国等国家相继发生甲型H1N1流感暴发疫情[1],成为国际关注的公共卫生事件.此后,疫情向各国蔓延,短短数月疫情就已肆虐全球,世界卫生组织将流感大流行预警级别提升到最高级别6级,并宣称全球已处于2009年流感大流行的中期.为有效应对甲型H1N1流感疫情,我国已于2009年4月30日将其列入<中华人民共和国传染病防治法>乙类传染病,并采取甲类传染病的预防控制措施.为防控甲型H1N1流感赢得时间,作者通过介绍甲型H1N1流感的流行病学研究进展,为科学、有效地防控甲型H1N1流感提供参考依据.     

Infection with influenza A H1N1. 1. Production and persistence of antibody

Three outbreaks of influenza caused by influenza A H1N1 occurred in a boys' boarding school in 1978, 1979 and 1983. The serological response to infection with variants of the H1N1 virus was studied by radial haemolysis and haemagglutination inhibition after primary infection and reinfection. The persistence of this antibody was also studied. Infection in 1978 resulted in the production of persistent antibody to both the haemagglutinin and neuraminidase of the homotypic strain. Antibody which cross-reacted with later variants of the virus was less frequently produced, the peak response was delayed and such antibody persisted less well. Infection in 1979 resulted in a similar response to that observed in 1978 after primary infection. Reinfection resulted in a broad response in all cases. In 1983 all infected boys produced antibody which reacted with the homotypic strain but only approximately one-third of primary infections produced antibody which reacted with the A/USSR/92/77 strain. The neuraminidase of the A/USSR strain failed to detect one third of the primary infections. Reinfection again resulted in a broad response.     

Infection with influenza A H1N1. 1. Production and persistence of antibody.

Three outbreaks of influenza caused by influenza A H1N1 occurred in a boys'' boarding school in 1978, 1979 and 1983. The serological response to infection with variants of the H1N1 virus was studied by radial haemolysis and haemagglutination inhibition after primary infection and reinfection. The persistence of this antibody was also studied. Infection in 1978 resulted in the production of persistent antibody to both the haemagglutinin and neuraminidase of the homotypic strain. Antibody which cross-reacted with later variants of the virus was less frequently produced, the peak response was delayed and such antibody persisted less well. Infection in 1979 resulted in a similar response to that observed in 1978 after primary infection. Reinfection resulted in a broad response in all cases. In 1983 all infected boys produced antibody which reacted with the homotypic strain but only approximately one-third of primary infections produced antibody which reacted with the A/USSR/92/77 strain. The neuraminidase of the A/USSR strain failed to detect one third of the primary infections. Reinfection again resulted in a broad response.     

2010年云南省部分人群甲型H1N1流感抗体监测分析

目的 了解云南省普通人群甲型H1N1流感抗体水平,分析和预测其流行趋势,为预防和控制疫情提供依据.方法 2010年1-3月,对云南省不同年龄组部分人群开展了4次调查,用血凝抑制试验进行抗体检测.结果 云南省普通人群甲型H1N1流感抗体阳性率为28.300(452/1 600),3月的抗体阳性率和GMT高于1,2月.结论...     

从鸟类中分离到的H1N1流感病毒株的鉴定

目的:对采集新鲜鸟粪便中甲型流感病毒进行检测、分离和鉴定.方法:采用鸡胚进行病毒分离,采用血凝试验初步确定病毒效价,用逆转录聚合酶链反应法(RT-PCR)扩增分离株的部分片段后进行克隆和测序.然后进行进化树分析.结果:从采集的80份新鲜鸟粪便中分离到一株低致病性流感病毒,其编号为WH-1,测出的部分NP基因序列经Blast比较,与A/Canterbury/106/20041H1NI的同源性最高,核苷酸为99%.氨基酸为100%,与GenBank中收录的AIV其它病毒株NP基因相应片段的同源性在96%以上.结论:分离得到WH-1为一株新的甲型流感分离毒株,该分离株可以用RT-PCR方法进行检测.     

2018-2019年宁夏甲型H1N1流感病毒血凝素基因组序列分析

目的了解宁夏2018-2019流感监测年度流感病毒病原学检测情况,分析甲型H1N1流感病毒血凝素(HA)基因特征。方法采用real time RT-PCR方法对流感监测哨点医院采集的流感样病例(ILI)标本进行核酸检测;对阳性标本进行毒株分离;提取甲型H1N1毒株的RNA,采用RT-PCR方法扩增HA片段并测序,利用生物信息软件对测序结果进行比对分析。结果宁夏流感网络实验室检测咽拭子标本共5 214份,核酸检测阳性数为760份,其中甲型H1N1阳性数为485份,占总阳性数的63.82%,分离出甲型H1N1毒株161株。宁夏分离毒株与疫苗株A/Califaoria/07/2009不在同一进化分支,同源性为92.6%～96.3%;与疫苗株A/Michigan/45/2015(H1N1)为同一进化分支,同源性为96.6%～98.1%。与疫苗株A/Califaoria/07/2009比较,抗原位点、受体结合位点及其他位点均有变异,除毒株A/Ningxia_Xixia/SWL1176/2019(H1N1)第222位氨基酸发生D222G变异外,其他甲型H1N1流感毒株均未发生D...     

青海省西宁地区甲型H1N1流感抗体水平的调查

目的 了解西宁地区普通人群甲型H1N1流感病毒抗体水平,为科学评估和防控疫情提供参考依据.方法 2009年12月～2010年4月连续5个月,随机选择在医院就诊和血站献血的人员2132人,采集静脉血进行甲型H1H1流感血清抗体水平检测和分析.结果 调查期间人群总体阳性率为38.18％,GMT水平为1∶24.35.疫苗接种人群的阳性率和GMT水平为89.71％和1∶51.75,明显高于未接种疫苗人群的33.57％和1∶22.76.非疫苗免疫人群中,6～24岁年龄组抗体阳性率和GMT水平最高(45.29％～50.25％,1∶27.8～1∶31.86),3岁以下、60岁及以上年龄组最低(21.62％～22.45％,1∶18.31～1∶19.84).随着时间的推移未接种疫苗人群抗体的阳性率和GMT水平呈逐步上升的趋势.结论 普通人群总体阳性率水平为41.02％,但幼儿和老年人保护性抗体比例仍然较低,提示该人群是今后甲型H1N1流感重点保护的对象.     

H1N1流感病毒的遗传进化研究

2009年3月底,墨西哥流感样疾病（ILI）病例异常增加,2009年4月17～28日期间,共报道1551例严重肺炎流感疑似病例（其中7例确诊死亡病例）,随后与之毗邻的美国也相继出现类似病例。2009年4月25日,世界卫生组织（WHO）宣布本次疫情为国际关注的突发公共卫生事件（PHEIC）,并于4月30日将流感大流行警戒级别从4级提高到5级,     

Efficacy of inactivated swine influenza virus vaccines against the 2009 A/H1N1 influenza virus in pigs

The gene constellation of the 2009 pandemic A/H1N1 virus is a unique combination from swine influenza A viruses (SIV) of North American and Eurasian lineages, but prior to April 2009 had never before been identified in swine or other species. Although its hemagglutinin gene is related to North American H1 SIV, it is unknown if vaccines currently used in U.S. swine would cross-protect against infection with the pandemic A/H1N1. The objective of this study was to evaluate the efficacy of inactivated vaccines prepared with North American swine influenza viruses as well as an experimental homologous A/H1N1 vaccine to prevent infection and disease from 2009 pandemic A/H1N1. All vaccines tested provided partial protection ranging from reduction of pneumonia lesions to significant reduction in virus replication in the lung and nose. The multivalent vaccines demonstrated partial protection; however, none was able to prevent all nasal shedding or clinical disease. An experimental homologous 2009 A/H1N1 monovalent vaccine provided optimal protection with no virus detected from nose or lung at any time point in addition to amelioration of clinical disease. Based on cross-protection demonstrated with the vaccines evaluated in this study, the U.S. swine herd likely has significant immunity to the 2009 A/H1N1 from prior vaccination or natural exposure. However, consideration should be given for development of monovalent homologous vaccines to best protect the swine population thus limiting shedding and the potential transmission of 2009 A/H1N1 from pigs to people.     

A live attenuated H5N2 prime- inactivated H5N1 boost vaccination induces influenza virus hemagglutinin stalk specific antibody responses

BackgroundThe emergence and spread of highly pathogenic avian influenza (H5N1) viruses have raised global concerns of a possible human pandemic, spurring efforts towards H5N1 influenza vaccine development and improvements in vaccine administration methods. We previously showed that a prime-boost vaccination strategy induces robust and broadly cross-reactive antibody responses against the hemagglutinin globular head domain. Here, we specifically measure antibodies against the conserved hemagglutinin stem region in serum samples obtained from the prior study to determine whether stalk-reactive antibodies can also be induced by the prime-boost regimen.MethodSerum samples collected from 60 participants before vaccination and on days 7, 28 and 90 following boosting vaccination were used in this study. 40 participants received two doses of live attenuated H5N2 vaccine (LAIV H5N2) followed by one dose of inactivated H5N1 vaccine a year later, while 20 participants received only the inactivated H5N1 vaccine. We tested these serum samples for stalk-reactive antibodies via enzyme-linked immunosorbent (ELISA) and microneutralization assays.ResultsStalk-specific antibody levels measured by both assays were found to be significantly higher in primed individuals than the unprimed group. ELISA results showed that 22.5, 70.5 and 57.5% of primed participants had a four-fold or more increase in stalk antibody titers on days 7, 28 and 90 following boosting vaccination, respectively; whereas the unprimed group had no increase. Peak geometric mean titers (GMT) for stalk antibodies in the LAIV H5N2 experienced group (24,675 [95% CI; 19,531–31,174]) were significantly higher than those who received only the inactivated H5N1 vaccine (8877 [7140–11,035]; p < 0·0001). Moreover, stalk antibodies displaying neutralizing activity also increased in primed participants, but not in the unprimed group.ConclusionOur finding emphasizes the importance of prime-boost vaccination for effectively inducing stalk antibodies, which is an attractive target for developing vaccines that induce stalk reactive antibodies.     

Antigenic analysis of H2 influenza virus haemagglutinin with monoclonal antibodies

Antigenic analysis of human and avian H2 influenza virus was carried out with monoclonal antibodies to the HA molecules of H2 influenza viruses isolated in the early stage of an H2 pandemic. The study revealed antigenic differences between inhibitor sensitive (Japan⁺/57, RI⁺57) and inhibitor resistant strains (Japan^?/57, Ri^?/57). This indicates that the receptor-binding specificity of the haemagglutinin can markedly influence the antigenic analysis obtained with monoclonal antibodies in HI test. Minor antigenic differences (microheterogeneity) could be detected between different H2 influenza viruses isolated in 1957. Minor antigenic variation continued in the H2 viruses until 1961, but significant antigenic drift occurred in 1962 so that viruses isolated after that date reacted with few monoclonal antibodies. Analysis of avian H2 influenza viruses suggested antigenic differences between the different avian H2 haemagglutinin but no correlation between the year of isolation and the progressive antigenic drift similar to that seen in the human strains was found.     

全球甲型H1N1流感血清学研究现况

1 前言 2009年4月中下旬,美国、墨西哥相继发现甲型H1N1流感病毒引起的急性呼吸道感染性疾病暴发,随后疫情迅速跨国、跨州进行传播,世界卫生组织(WHO)于6月15日宣布全球进入甲型H1N1流感(简称甲流)大流行阶段[1,2].     

2005年广西H1N1亚型流感病毒基因特性研究

目的阐明2005年广西流行的H1N1亚型流感病毒血凝素基因变异情况。方法挑选3株2005年广西流感病毒分离株,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,然后使用DNA—STAR分析软件进行进化特性分析。结果HA1区核苷酸序列和氨基酸序列分析表明,与2005年的国际疫苗推荐株A／New Caledonia／20／1999（H1N1）比较,三株分离株的HA1蛋白均含有7个糖基化位点。分离株A／Gx／566／2005发生以下氨基酸位点替换：82T〉K、94Y〉R、145R〉K、165V〉A,208R〉K、251W〉R、266T〉N,其中165位点位于HA1的抗原决定簇上。分离株A／GX／8／2005及分离株A／GX／13／2005发生了以下位点变异：165V〉A、194E〉G、251W〉R、252Y〉F、314V〉A,其中165及194位于HA1抗原决定簇上。结论2005年在广西同时流行着三系不同的H1N1病毒。一系接近国际疫苗推荐株A／New Caledonia／20／1999（H1N1）东部江苏的2000—2002年毒株,一系接近江苏2005—2006年毒株。尤其需要密切关注与疫苗株HA1蛋白发生较大变异一系H1N1,避免此系H1N1病毒的流行和暴发。     

北京市甲型H1N1流感病毒病原学监测分析

目的 分析北京市2009年5-12月甲型H1N1流感病毒检测结果,探讨流感大流行时期甲型H1N1流感病原流行病学特征.方法 2009年5月1日至2009年12月27日,共采集101 852份咽拭子样本,北京市传染病网络实验室利用荧光定量PCR方法检测,并做统计分析.结果 101 852份检测样本中,甲型H1N1流感病毒核酸阳性9843份,总阳性率为9.66%,其中5-6月阳性率为2.85%,7-8月阳性率为3.32%,9-10月阳性率为8.35%,11月阳性率为29.67%,12月阳性率为24.33%.可疑病例排查阳性率为8.40%,病例密切接触者阳性率为4.75%,门诊流感样病例(ILI)阳性率为11.46%,聚集性发热病例及其他病例阳性率为7.33%.年龄分布以5～14岁和15～24岁年龄段为主,男女性别构成比为1.5:1.结论 北京市2009年5-11月甲型H1N1流感病毒感染呈持续上升,12月呈下降趋势,具有一定的流行病学特征.     

淄博市甲型H1N1流感感染状况的调查

目的了解淄博市不同人群甲型H1N1流感实际感染水平和动态变化趋势,为应对流感大流行,完善防控措施提供可靠依据。方法 2010年1月～9月期间,采取多阶段随机抽样方法抽取4500名调查对象,进行问卷调查,并采集血清利用血凝抑制方法检测甲型H1N1流感抗体水平。结果该市甲型H1N1流感病毒抗体阳性率为25.60%,自然感染率为21.09%,显性感染和隐性感染比例为1.97︰1;抗体阳性率以16～24和6～15岁年龄组最高,60岁以上年龄组最低;教师和学生阳性率最高,医务人员阳性率相对较低;第1次调查抗体阳性率最高,第3次调查最低,接种甲型H1N1流感疫苗半年后抗体阳性率为11.36%。结论甲型H1N1流感大流行期间,该市实际感染人数远远超过确诊病例数,学龄人群和年轻人是最大的感染群体,人群中存在无症状感染者,自然感染或接种疫苗后抗体水平随时间推移逐步下降。