Antigenic characteristics of influenza B virus strains isolated in an orphanage during an influenza outbreak in Moscow in the winter of 1988

Examinations of ARD patients in an orphanage for defective children in Moscow during an influenza outbreak in the winter of 1988 yielded 12 influenza virus strains, including 6 influenza B strains and 6 influenza A (H3N2) strains. The antigenic analysis of hemagglutinin of influenza B virus isolates showed that with respect to the B/Leningrad/179/86 strain (an antigenic analogue of B/Ann Arbor/1/86 strain recommended for inclusion into the influenza vaccine for 1987-1988) they could be divided into 2 groups: antigenically close to the B/Leningrad/86 strain (isolate B/712) and markedly differing from it (the remaining isolates). As compared with reference strains of the previous years, all the new virus isolates fell into 4 groups: isolate B/712 antigenically related to B/Hong Kong/73 and B/Leningrad/86 strains; B/722 antigenically close to B/Singapore/222/79 and B/USSR/100/83 strains; B/724, an antigenic analogue to B/USSR/100/83; and the remaining isolates, to some or other extent, differing from various reference strains. This attests to simultaneous circulation of various antigenic variants of influenza B virus during the 1988 winter outbreak of influenza in Moscow. An interesting feature of the B/712/88 isolate consists in its antigenic specificity of hemagglutinin being indistinguishable from that of B/Hong Kong/8/73 strains.     

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.     

Demonstration and study of the internal proteins of the influenza B virus using solid-phase radioimmunological analysis

Internal proteins of influenza B/USSR/14/80 virus retaining their antigenic and immunogenic activities were obtained by electrophoresis in 1% agarose. Antisera to eluted NP and M polypeptides were prepared. Study of influenza B viruses isolated in 1940-1984, performed by solid-phase radioimmunoassay, revealed no differences in the antigenic properties of nucleoprotein and matrix protein, except in the B/Yamagata/73 virus.     

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.     

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.     

Rapid detection and identification of two lineages of influenza B strains with monoclonal antibodies.

Monoclonal antibodies (Mabs) against influenza B virus were obtained by immunizing mice with B/Nagasaki/1/87, one of the strains of the B/Victoria group. Immunoprecipitation analysis revealed that individual Mabs precipitated the nucleoprotein (NP), the matrix protein (M) or the hemagglutinin protein (HA). By using these Mabs by the peroxidase-antiperoxidase (PAP) staining method, a rapid detection and identification method for influenza B virus was established. Monolayers of Madin-Darby canine kidney cells in microplates were infected with each-strain and incubated for about 24 h, and then were subjected to the PAP staining method using the Mabs as the first antibody. Influenza B virus strains are classified into two major phylogenetic trees, the B/Victoria group and the B/Yamagata group. When anti-NP and anti-M antibodies were used in the PAP staining method, all 13 influenza B virus strains isolated from clinical specimens between 1940 and 1994 were detected regardless of the antigenic drift of the influenza virus. On the other hand, several anti-HA Mabs which reacted specifically with the strains of the B/Victoria group, did not react with any strain of the B/Yamagata group. In the 1996/97 influenza season in Osaka Prefecture in Japan, two antigenically distinct groups of influenza B virus strains were isolated. They belonged to different phylogenetic trees and were clearly distinguishable by the PAP staining method with anti-HA Mabs.     

Antigenic determinant study of the hemagglutinin in the composition of influenza viruses A subtype H1N1 by an indirect solid-phase radioimmunological analytical method

A comparative study of antigenic determinants of influenza A virus, subtype H1N1, hemagglutinins isolated in 1947-1953 and in 1977-1979 was carried out. The competitive capacity of 8 virus strains for antibody of 4 hyperimmune antisera to A/Fm/1/47, A/Moscow/Pan/52, A/USSR/090/77, and A/Brazil/11/78 viruses was studied by solid-phase radioimmunoassay (SPRIA) in two modifications: in the homologous and heterologous systems. The analysis of competition in the heterologous system permits one to study isolated subpopulations of antibody homologous to viruses fixed on the solid phase. The combination of both modifications allows investigations of a wider spectrum of antibodies than those possible in the homologous system alone. The results of the study showed the antigenic determinants of hemagglutinin exposed on the surface of particles of different influenza A virus strains to differ in their capacity to stimulate antibody synthesis. The analysis of the time course of changes in the antigenic properties of hemagglutinin regions of similar structure in various viral strains may facilitate prognosing of evolution of virus strains of the same subtype.     

Influenza viruses which preconditioned the epidemic rise in Russia in 2002-2003. A resumed circulation of influenza viruses similar to V/Victoria/2/87

According to research, the epidemic rise of influenza was preconditioned, during 2002-2003, in Russia by the circulation of influenza A(H1N1), A(H3N2) and B viruses. The Center of Influenza Ecology and Epidemiology undertook a study of 178 epidemic strains: 41 strains A(H1N1), 116 strains A(H3N2) and 21 strains of influenza B were among them. All strains were isolated in the MDCK cell culture. A simultaneous isolation in embryonated eggs as well as changing of the isolation system from MDCK to embryonated eggs were found to be effective only for influenza A(H1N1) viruses. According to the antigenic analysis, all A(H1N1) viruses were variants of the etalon A/New Caledonia/20/99. The A(H3N2) viral strains' population was heterogeneous by its antigenic properties: among its isolates, there were variants similar to the etalons of A/Moscow/10/99 and of A/Panama/200/99 as well as strains, which weakly reacted with sera of both above etalons; possibly the latter were close to the etalon of A/Fujian/411/02. All epidemic strains of influenza B virus belonged, according to the antigenic properties of hemagglutinin, to the virus group of B/Victoria/2/87-like and were antigenic variants of the etalon of B/Hong Kong/22/01. This confirmed that influenza B viruses with the antigenic hemagglutinin structure of the virus group of B/Victoria/2/87-like, which were not present in Russia for more than 10 years, re-entered the active circulation. An analysis of antigenic properties of neuraminidases (NA) of the mentioned epidemic strains showed their different degrees of relationship with the NA etalons of both evolutionary groups, i.e. B/Victoria/2/87 and B/Yamagata/16/88-like. A study of paired sera obtained from patients showed a growth of antibodies to the etalons of influenza A(H1N1), A(H3N2) and B viruses of the season in question, which confirmed the virology data.     

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.     

Antigenic and biological characteristics of influenza virus A strains isolated in 1985

The antigenic structure of hemagglutinin of influenza A virus (H3N2) strains isolated in 1985 was studied using a series of monoclonal antibody to A/Dunedin/4/73/A (H3N2) and A/Bangkok/1/79/A (H3N2), and biological and physico-chemical properties of these strains were compared with those of influenza A (H3N2) virus of 1983 and reference A (H3N2) of 1979-1984 (the rate of adsorption on chick erythrocytes and eluting activity, thermostability of hemagglutinin and neuraminidase, sensitivity to nonionic detergents, sensitivity to remantadine, analysis of virion polypeptide composition). A high degree of heterogeneity of the 1985 strain population of influenza A (H3N2) virus was revealed both in the antigenic structure of hemagglutinin and in all the biological and physico-chemical parameters tested. It was suggested that the A/Caen/1/84 strain originated not from A/Philippines/2/82 but directly from A/Texas/1/77.     

Characteristics of the biological and antigenic properties of reference strains of the influenza B virus at various periods of isolation

The results of a comparative analysis of biological and antigenic properties of reference influenza B virus strains, B/Lee/40, B/Singapore/222/79, and B/USSR/100/83, are presented. The most marked changes were found in the antigenic properties of hemagglutinin and neuraminidase. Hemagglutinins of the strains under study were found to have both common antigens and qualitatively different strain-specific determinants. The degree of intensity of immunity to the challenge B/Singapore/222/79 Pm+ virus corresponded to the intensity of antigenic relationship in the strains under study.     

The characteristics of the evolutionary variability of influenza A (H1N1) viruses]

Studies of the antigenic structure of hemagglutinins of influenza A (H1N1) viruses isolated in 1978-1988 using monospecific and monoclonal antibodies demonstrated the strains of the H1N1 subtype to be highly apt to antigenic drift. The evolutional variability of that period was peculiar and characterized by antigenic drift in various directions. In those years, the variants were regularly isolated which had retained the determinants of viruses of 1933-1957 circulation period in their hemagglutinin structure. The variants containing in their hemagglutinin 2 antigenic sites common with A/USSR/090/77 virus and antigenic groupings characterizing the strain specificity of each isolate, were epidemically active. At the same time, epidemically important variants were dominant whose properties were markedly different from those of previously known viruses. Their hemagglutinin contained 2 basically new antigenic determinants. This direction of evolutional development of influenza A (H1N1) virus is the most prospective epidemically.     

Genetic characterization of the hemagglutinin of two strains of influenza B virus co-circulated in Taiwan.

Two isolates of influenza B virus were obtained in the spring of 1997. One strain, B/Taiwan/21706/97, was isolated from a patient who had acute tonsillitis. The other, B/Taiwan/3143/97, was isolated from a patient who was diagnosed with meningoencephalitis. This implies that the influenza B viruses not only cause respiratory symptoms but may also cause inflammation of the nervous system. Sequence analysis of the hemagglutinin (HA) gene, HA1 domain, indicated that there were remarkable amino acid changes in the strain B/Taiwan/3143/97 compared to B/Victoria/2/87, B/Yamagata/16/88, and B/Taiwan/7/88. The changes in the positions 116, 200, 238, 242, and 271 were correlated with receptor binding. Furthermore, a potential glycosylation site at position 233 was lost. In total, 30 amino acid changes were noted at positions ranging from 116 to 295. These changes may affect the antigenicity of the virus. Phylogenetic analyses also showed that the B/Taiwan/3143/97 was located in an independent lineage, when compared to the reference strains belonging to B/Victoria/2/87 and B/Yamagata/16/88 lineages. This supports the hypothesis that influenza B viruses with distinct genetic characteristic were co-circulated in Taiwan.     

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.     

Antigenic and genetic analyses of influenza B viruses\\ isolated in Lusaka, Zambia in 1999

Summary.  Previous studies of the hemagglutinin (HA) genes of various influenza B virus isolates demonstrated the existence of two antigenically distinct virus lineages represented by B/Victoria/2/87 and B/Yamagata/16/88, respectively. Here, we investigated the antigenic and genetic characteristics of influenza B viruses isolated from children living in Lusaka, Zambia between January and May 1999. Antigenic analysis with chicken antiviral sera showed that all the Zambian isolates had the HA protein belonging to B/Yamagata/16/88-related lineage. Furthermore, phylogenetic analyses of the eight RNA segments performed by using the total or partial nucleotide sequences of the two representative Zambian strains (B/Lusaka/270/99 and B/Lusaka/432/99) as well as the previously reported sequences suggested that the Zambian viruses are closely related to the recently circulating reassortants represented by B/Shiga/T30/98 and B/Yamanashi/166/98 which acquired the genes coding for three polymerase proteins (PB2, PB1, and PA), HA, nucleoprotein, and matrix protein from a B/Yamagata/16/88-like parent and the gene encoding nonstructural proteins (NS1 and NS2) from a B/Guandong/8/93-like parent. Accepted June 15, 2001 Received April 17, 2001     

Cross-reactive antibodies induced by a monovalent influenza B virus vaccine.

Influenza viruses related to the markedly antigenically divergent strains B/Yamagata/16/88 and B/Victoria/2/87 are circulating in human populations. Adults develop cross-reacting antibodies against recent and earlier influenza B virus strains after vaccination with B/Yamagata/16/88, probably because of previous influenza B virus infections or immunizations. Vaccines containing B/Yamagata/16/88 should adequately protect adults against B/Victoria/2/87 infections.     

Genetic analysis of an influenza B virus isolated from a patient with encephalopathy in Japan

An influenza B virus, B/Saga/S172/99 (SAG99), was isolated from the nasopharynx of a patient with encephalopathy/encephalitis in Japan in 1999. To clarify the molecular characteristics of this virus, detailed analysis of the gene segments coding for the hemagglutinin (HA), neuraminidase (NA), nucleoprotein (NP), matrix protein (M) and non-structural protein (NS) was undertaken. All five genes of SAG99 showed high nucleotide and predicted amino acid similarities with those of recent non-encephalopathic strains isolated in the same epidemic season. Subsequent phylogenetic analysis revealed that all five gene segments of SAG99 analyzed in the present study were most similar to those of the recent Yamagata/16/88-like viruses. The hemagglutinin and neuraminidase proteins of SAG99 were each distinguished from those of recent epidemic strains by one characteristic amino acid substitution. These substitutions were not found in the previously reported encephalopathy/encephalitis-derived influenza B viruses, and we could not find any common characteristic amino acid changes in SAG99 and these viruses. Similarly, among the internal proteins studied, only the M2 protein of SAG99 was found to contain a single novel amino acid change when compared with other recent isolates. Thus, it was apparent that SAG99 contained very few amino acid differences when compared with other epidemic viruses. The association of recent B/Yamagata/16/88-like viruses with encephalitis/encephalopathy observed in the present study and previously suggest that these viruses may have a higher potential for causing neurological complications in certain individuals.     

北京市门头沟区2015—2016年Victoria系乙型流感病毒HA1基因特征分析

目的 了解北京市门头沟区2015—2016年分离的Victoria系乙型流感病毒血凝素HA1基因变异特征,分析流行株与我国疫苗株的匹配情况,为乙型流感防控提供依据.方法 对狗肾传代细胞(MDCK)培养分离得到的14株Victoria系乙型流感病毒进行核酸提取,采用逆转录-聚合酶链反应(RT-PCR)扩增病毒HA1基因后进行核苷酸序列测定,采用邻接法进行遗传进化树分析.结果 2015—2016年北京市门头沟区流行的乙型流感病毒以Victoria系为主.分离并测序的14株Victoria系乙型流感病毒HA1基因与WHO推荐的2016—2017年流感疫苗株B/Brisbane/60/2008(FJ766842)和国内代表株B/JilinNanguan/1223/2016(EPI768805)亲缘性更近.与B/Brisbane/60/2008和B/JilinNanguan/1223/2016(EPI768805)的HA1区的氨基酸相比,所有毒株都在2个位点发生氨基酸替换,个别毒株也会在其他个别位点发生点突变,变异涉及1个抗原决定簇.而与WHO推荐的2015—2016年Yamagata系疫苗株B/Phuket/3073/2013(EPI608074)亲缘关系稍远一些.结论 在2015—2016年流感监测季中,北京市门头沟区乙型流感病毒以Victoria系为优势流行株.而WHO推荐的乙型流感疫苗株为Yamagata系,可见疫苗株与本区流行株匹配性不佳.     

甘肃省2000-2007年度流感监测结果分析

目的 掌握我省流感流行情况,为流感防治提供依据.方法 按照国家流感监测方案,在6所国家级哨点医院门诊内、儿科开展流感样病例的监测和在全省开展流感暴发疫情的监测,采集流感样患者的鼻咽拭子标本,用MDCK细胞或鸡胚进行流感病毒分离与鉴定.结果 2000-2007年,哨点医院流感样病例占门诊就诊人数的5.16%,从国家级监测哨点医院及暴发疫情共采集标本6383份,分离出流感病毒943份,分离率14.77%,其中H1N1亚型218株,H3N2亚型352株,B型(Victoria系)312株,B型(Yamagata系)61株;全省发生的61起疑似流感疫情暴发,经实验室检测44起确定为流感暴发,其中38起为B(victoria)亚型流感病毒,3起为H3N2亚型、2起为B型(Yamagata系)、1起为H1N1亚型.结论 流感每年均会在人群中活动,冬季以甲型流感为主;2005-2007年,每年3-6月份B型(Victoria系)是造成学校、幼儿园等集体单位暴发的主要病毒.     

Detection of the determinants of influenza virus H3 hemagglutinin by the technic of radioimmunologic analysis

The interrelations between H3/73 hemagglutinin of human influenza virus and the other 16 mammalian and avian hemagglutinin subtypes (a total of 50 strains) were studied by the method of radioimmunologic analysis (RIA). The antigenic relations of H3, Hav7 and Heq2 were confirmed, certain common determinants were also found in H3/73 hemagglutinin and avian viral Hav6 and Hav9 hemagglutinins. No interrelations were revealed with previously circulating human influenza viruses H0, H1, H2 as well as with swine influenza virus and avian viruses Hav1-Hav5, Hav8. It has been shown that the H3/73 determinant in some avian viruses evolves similarly to drift-variants of human influenza virus. The method can be recommended for fine analysis of influenza virus antigenic structure as it allows detecting small antigenic quantities.