季节性流感裂解疫苗在小鼠中半数有效剂量ED50a的测定

Objective To evaluate the seasonal influenza spilt vaccine's immunogenicity and the 50% effective dose ( ED50a ) of hemagglutin ( HA ) that can make 50% of the mice hemagglutination inhibition antibody ( HI ) titers to 40. Methods The 2008-2009 seasonal influenza spilt vaccine's two components, with HA from H1N1 and H3N2 influenza virus respectively, were used as a model. Mice were immunized once or twice with different doses, and the HI antibody titers were tested to determine the immunization procedure and to evaluate the immugenicity of seasonal influenza spilt vaccine in mice;Consequently, HI antibody response kinetics of the two components were observed to determine the time point when the HI antibody titer reached the peak point; Finally, mice were immunized with different doses of HA to evaluate the ED50a that can make 50% of mice HI titers reach 40. Results Immunization procedures study showed that one-dose of seasonal influenza vaccine induced the HI antibody titem ranged from 10 to 120, while two-dose of influenza vaccine improved the HI antibody titer 10-100 times as compared with one dose; antibody kinetics study suggested that the time point of HI antibody produced to peak is 28-35 days post one dose immunization ; and the ED50a detection results indicated that one dose of 1.5 μg HA could make 50% of the mice HI antibody titer reach 40. Conclusion Seasonal influenza spilt vaccine is very immunogenic in mouse; the time point of HI antibody produced to peak is 28-35 days post one dose immunization; and the ED50a of HA is 1.5 μg, which can make 50% of the mice HI titer reach 40. The experimental results provided foundation for the establishment of influenza vaccine evaluation system based on seasonal influenza vaccine.     

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.     

Apoptosis and proinflammatory cytokine responses of primary mouse microglia and astrocytes induced by human H1N1 and avian H5N1 influenza viruses

Patients with an influenza virus infection can be complicated by acute encephalopathy and encephalitis. To investigate the immune reactions involved in the neurocomplication, mouse microglia and astrocytes were isolated, infected with human H1N1 and avian H5N1 influenza viruses, and examined for their immune responses. We observed homogeneously distributed viral receptors, sialic acid （SA）-a2,3-Galactose （Gal） and SA-a2,6-Gal, on microglia and astrocytes. Both viruses were replicative and productive in microglia and astrocytes. Virus-induced apoptosis and cytopathy in infected cells were observed at 24 h post-infection （p.i.）. Expression of IL-1β, IL-6 and TNF-a mRNA examined at 6 h and 24 h p.i. was up-regulated, and their expression levels were considerably higher in H5N1 infection. The amounts of secreted proinflammatory IL-1β, IL-6 and TNF-a at 6 h and 24 h p.i. were also induced, with greater induction by H5N1 infection. This study is the first demonstration that both human H1N1 and avian H5N1 influenza viruses can infect mouse microglia and astrocytes and induce apoptosis, cytopathy, and proinflammatory cytokine production in them in vitro. Our results suggest that the direct cellular damage and the consequences of immunopathological injury in the CNS contribute to the influenza viral pathogenesis. Cellular ＆ Molecular Immunology.     

深圳市2008-2009年A型H1N1季节性流感病毒神经氨酸酶抑制剂耐药性监测

目的 对深圳市2008-2009年分离到的H1N1季节性流感病毒神经氨酸酶(NA)抑制剂的耐药性进行监测.方法 根据原始临床样本的采集时间,按周抽取了55株2008-2009年分离到的H1N1季节性流感病毒,对其NA片段进行全长测序,选取WHO推荐的疫苗株和部分国内外分离到的H1N1季节性流感病毒作为参考株,运用Mega3.1软件进行种系发生树的构建、耐药相关位点及糖基化位点的分析.结果 对NA片段的序列分析发现2008年有2株(7.1%)出现了H275Y突变,但是2009年则有25株(92.6%)出现了该突变.提示H275Y达菲耐药突变株成为了2009年深圳市社区传播的优势株.同时还发现了一株Q136K变异株,显示对乐感清出现耐药.分子进化分析结果显示,H275Y变异成为了毒株在系统进化树上分布的主要依据.所有的深圳株NA片段上潜在的糖基化位点序列保守.结论 大量H275Y达菲耐药株的出现提示在今后的工作中应当密切关注流感病毒的耐药进展,进一步加强其耐药机制的研究.

Abstract：

Objective To analyze neuraminidase(NA) inhibitor resistance of seasonal H1N1 influenza A viruses isolated in Shenzhen during 2008 to 2009. Methods The NA gene of these viruses were sequenced. Phylogenetic analysis of the sequences was performed with Mega3. 1 software. Results In 2008, most isolates of the seasonal H1 N1 virus were susceptible to neuraminidase inhibitors, but the H275Y mutation in the neuraminidase gene region associated with high-level oseltamivir resistance had been detected in 92.6% of the strains isolated in 2009. Furthermore, a strain with Q136K was found, which showed the resistance to Zanamivir. Conclusion In the light of emerging resistance, close monitoring and understanding of the nature and dynamics of resistance mutations in influenza virus should be a priority.     

The interaction of influenza H5N1 viral hemagglutinin with sialic acid receptors leads to the activation of human γδT cells

Highly pathogenic avian influenza H5N 1 epidemics are a significant public health hazard. Genetically engineered H5N 1 viruses with mammalian transmission activity highlight the potential risk of a human influenza H5N 1 pandemic. Understanding the underlying principles of the innate immune system in response to influenza H5N 1 viruses will lead to improved prevention and control of these potentially deadly viruses, γδT cells act as the first line of defense against microbial infection and help initiate adaptive immune responses during the early stages of viral infection. In this study, we investigated the molecular mechanisms of γδ T cells in response to influenza H5N1 viral infection, We found that recombinant hemagglutinin （rHA） derived from three different strains of influenza H5N 1 viruses elicited the activation of γδ T cells cultured in peripheral blood mononuclear cells （PBMCs）. Both the cell surface expression of CD69, an early activation marker on γδ T cells, and the production of interferon-y （IFN-y） were significantly increased. Notably, the rHA protein-induced γδ T-cell activation was not mediated by TCRγδ, NKG2D or pattern recognition receptors （PRRs） or NKp46 receptors. The interaction of rHA proteins with sialic acid receptors may play a critical role in γδ T-cell activation. Our data may provide insight into the mechanisms underlyingγδT-cell activation in response to infection with H5N1 viruses.     

Detection of factor Ⅷ intron 1 inversion in severe haemophilia A

Objective Screening the intron 1 inversion of factor Ⅷ (FⅧ) in the population of severe haemophilia A(HA) in China and performing carrier detection and prenatal diagnosis. Methods Using LD-PCR to detect intron 22 inversions and multiple-PCR within two tubes to intron 1 inversions in sereve HA patients. Carrier detection and prenatal diagnosis were performed in affected families. Linkage analysis and DNA sequencing were used to verify these tests. Results One hundred and eighteen patients were seven diagnosed as intron 22 inversions and 7 were intron 1 inversions out of 247 severe HA patients. The prevalence of the intron 1 inversion in Chinese severe haemophilia A patients was 2. 8% (7/247). Six women from family A and 2 from family B were diagnosed as carriers. One fetus from family A was affected fetus. Conclusion Intron 1 inversion could be detected directly by multiple-PCR within two tubes. This method made the strategy more perfective in carrier and prenatal diagnosis of haemophilia A.     

Detection of factor Ⅷ intron 1 inversion in severe haemophilia A

Objective Screening the intron 1 inversion of factor Ⅷ (FⅧ) in the population of severe haemophilia A(HA) in China and performing carrier detection and prenatal diagnosis. Methods Using LD-PCR to detect intron 22 inversions and multiple-PCR within two tubes to intron 1 inversions in sereve HA patients. Carrier detection and prenatal diagnosis were performed in affected families. Linkage analysis and DNA sequencing were used to verify these tests. Results One hundred and eighteen patients were seven diagnosed as intron 22 inversions and 7 were intron 1 inversions out of 247 severe HA patients. The prevalence of the intron 1 inversion in Chinese severe haemophilia A patients was 2. 8% (7/247). Six women from family A and 2 from family B were diagnosed as carriers. One fetus from family A was affected fetus. Conclusion Intron 1 inversion could be detected directly by multiple-PCR within two tubes. This method made the strategy more perfective in carrier and prenatal diagnosis of haemophilia A.     

Detection of factor Ⅷ intron 1 inversion in severe haemophilia A

Objective Screening the intron 1 inversion of factor Ⅷ (FⅧ) in the population of severe haemophilia A(HA) in China and performing carrier detection and prenatal diagnosis. Methods Using LD-PCR to detect intron 22 inversions and multiple-PCR within two tubes to intron 1 inversions in sereve HA patients. Carrier detection and prenatal diagnosis were performed in affected families. Linkage analysis and DNA sequencing were used to verify these tests. Results One hundred and eighteen patients were seven diagnosed as intron 22 inversions and 7 were intron 1 inversions out of 247 severe HA patients. The prevalence of the intron 1 inversion in Chinese severe haemophilia A patients was 2. 8% (7/247). Six women from family A and 2 from family B were diagnosed as carriers. One fetus from family A was affected fetus. Conclusion Intron 1 inversion could be detected directly by multiple-PCR within two tubes. This method made the strategy more perfective in carrier and prenatal diagnosis of haemophilia A.     

Detection of factor Ⅷ intron 1 inversion in severe haemophilia A

Objective Screening the intron 1 inversion of factor Ⅷ (FⅧ) in the population of severe haemophilia A(HA) in China and performing carrier detection and prenatal diagnosis. Methods Using LD-PCR to detect intron 22 inversions and multiple-PCR within two tubes to intron 1 inversions in sereve HA patients. Carrier detection and prenatal diagnosis were performed in affected families. Linkage analysis and DNA sequencing were used to verify these tests. Results One hundred and eighteen patients were seven diagnosed as intron 22 inversions and 7 were intron 1 inversions out of 247 severe HA patients. The prevalence of the intron 1 inversion in Chinese severe haemophilia A patients was 2. 8% (7/247). Six women from family A and 2 from family B were diagnosed as carriers. One fetus from family A was affected fetus. Conclusion Intron 1 inversion could be detected directly by multiple-PCR within two tubes. This method made the strategy more perfective in carrier and prenatal diagnosis of haemophilia A.     

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。     

Genetic analysis and evaluation of the reassortment of influenza B viruses isolated in Taiwan during the 2004-2005 and 2006-2007 epidemics

Influenza B viruses were predominant in Taiwan during the 2004-2005 epidemic and both Victoria and Yamagata lineage viruses co-circulated. A reassortant influenza B virus that contained a Victoria lineage hemagglutinin (HA) gene and Yamagata lineage neuraminidase (NA) gene appeared first in 2002 and became predominant during the 2004-2005 epidemic. During the 2006-2007 epidemic, an influenza B outbreak occurred in Taiwan and only Victoria lineage viruses circulated. We characterized the viruses isolated in the 2006-2007 epidemic and found that the HA genes of influenza B viruses from that epidemic were highly similar to those from the 2004-2005 epidemic. We also analyzed the NA genes of isolates from the 2006-2007 epidemic and found that they all belonged to the Yamagata lineage and formed a new genetic subclade. Comparison of isolates from the 2004-2005 and 2006-2007 epidemics revealed four substitutions, N220K, E320D, K343R and E404K in NA genes. Although the HA sequences from the 2006-2007 epidemic were similar to those from the 2004-2005 epidemic, the NA sequences differed, suggesting distinct patterns of evolution of the HA and NA genes from 2004-2007 in Taiwan. This study emphasizes that the evolution of the NA genes may contribute to reemergence of influenza B viruses.     

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.     

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.     

Clinical and genetic characterization of severe influenza B-associated diseases during an outbreak in Taiwan.

BACKGROUND: Mismatches between circulating and vaccine strains of influenza virus had been observed in Taiwan. A comprehensive clinical and genetic analysis of influenza B viruses-associated important diseases was lacking. OBJECTIVES: Clinical and phylogenetic analysis of influenza B viruses during an outbreak in Taiwan. STUDY DESIGNS: Clinical manifestations of hospitalized, culture-confirmed patients were analyzed from July 2004 to June 2005. Partial genome sequence analysis of hemagglutinin (HA), neuraminidase (NA), and nonstructural (NS) genes were performed in 54 influenza B isolates during the study period, and nine srandomly chosen isolates during 2000 and 2003. RESULTS: Three specific diseases were found in these patients, including 13 of encephalitis/encephalopathy, 28 of influenza-associated myositis (IAM), and one of acute respiratory distress syndrome (ARDS). Three phylogenetic groups were identified, including reassortant strains-group 1 (Victoria lineage of HA, Yamagata lineage of NA, clade A of NS), group 2 (Yamagata lineage of HA, Yamagata lineage of NA, clade A of NS), and group 3 (Yamagata lineage of HA, Yamagata lineage of NA, clade B of NS). CONCLUSIONS: Severe influenza B-associated disease in children was not rare and might be fatal. We offered the evidence of co-circulation of the two HA lineages in the same outbreak.     

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.     

Cocirculation of two distinct evolutionary lineages of influenza type B virus since 1983

During 1988-1989 two highly distinct antigenic variants of influenza type B were recognized in hemagglutination-inhibition tests with postinfection ferret serum. These viruses were antigenically related to either B/Victoria/2/87, the most recent reference strain, or B/Yamagata/16/88, a variant that was isolated in Japan in May 1988. All influenza B viruses isolated in the United States during an epidemic in the winter of 1988-1989 were antigenically related to B/Victoria/2/87. However, in several countries in Asia, both B/Victoria/2/87-like viruses and B/Yamagata/16/88-like viruses were isolated. Sequence analysis of the hemagglutinin (HA) genes of several influenza B isolates from 1987 to 1988 indicated that the HA1 domains of the B/Yamagata/16/88-like viruses and B/VI/87-like viruses isolated in 1988 differed by 27 amino acids. Evolutionary relationships based on this sequence data indicated that the B/Yamagata/16/88-like viruses were more closely related to epidemic viruses from 1983 (B/USSR/100/83-like viruses) than to more recent reference strains such as B/Victoria/2/87. All other Asian strains, as well as selected isolates from the United States in 1988, were confirmed by sequence analysis as being genetically related to B/Victoria/2/87. These data provide clear evidence that two parallel evolutionary pathways of influenza type B have existed since at least 1983 and that viruses from each of the separate lineages were isolated from cases of influenza B in 1988. This finding is similar to earlier observations for type A H1N1 and H3N2 influenza viruses.     

Detection and characterization of new influenza B virus variants in 2002

One-hundred five influenza B-positive specimens obtained from southeast Asia in 2002 were categorized on the basis of DNA sequencing of HA1 gene as well as real-time PCR analysis of the NA gene. Phylogenetic analysis of the HA1 gene sequences showed that the majority of the viruses (96.2%) belonged to the B/Victoria/2/87 lineage, while a smaller percentage of the viruses (3.8%) belonged to the B/Yamagata/16/88 lineage. The B/Yamagata/16/88 viruses displayed significant antigenic drift in the deduced amino acid sequences of the HA1 protein, and the B/Victoria/2/87-like viruses consisted of B/Hong Kong/1351/02-like (72.3%) and B/Hong Kong/330/01-like (27.7%) viruses. The B/Hong Kong/1351/02-like viruses were reassortants with the HA gene belonging to the B/Victoria/2/87 lineage and the NA gene belonging to the B/Yamagata/16/88 lineage, whereas both the HA and NA genes of B/Hong Kong/330/01 virus belonged to the B/Victoria/2/87 lineage. In this study, however, all the B/Hong Kong/330/01-like isolates exhibited the B/Yamagata/16/88-like NA gene, which likely resulted from reassortment of B/Hong Kong/330/01 and B/Hong Kong/1351/02 viruses during coinfection. Additional molecular characterization of the six internal genes showed that the M, NS, PA, and PB2 genes of the new variants were B/Hong Kong/1351/02 in origin, whereas the NP and PA genes retained the B/Hong Kong/330/01 origin. Interestingly, these new variants all appeared late in the year 2002. These results support the notion that influenza B viruses continued to evolve through antigenic drift and shift.     

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.     

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.