Positive charge of Arg-201 on #hemagglutinin is required for the #binding of #H6N1 #avian #influenza virus to its target through a two-step process (Virus Res., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Virus Res. 2019 May;265:132-137. doi: 10.1016/j.virusres.2019.03.018. Epub 2019 Mar 26.

Positive charge of Arg-201 on hemagglutinin is required for the binding of H6N1 avian influenza virus to its target through a two-step process.

Hsieh MS1, Chang YC2, He JL3, Juang RH4.

Author information: 1 Institute of Biotechnology, National Taiwan University, Taipei, 10617, Taiwan. 2 Institute of Cellular and Organismic Biology, Academia Sinica, No. 128, Section 2 Academia Road, Nankang, Taipei, 115, Taiwan. 3 Department of Post-Baccalaureate Veterinary Medicine, Asia University, Taichung, 413, Taiwan. 4 Institute of Biotechnology, National Taiwan University, Taipei, 10617, Taiwan; Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10617, Taiwan. Electronic address: juang@ntu.edu.tw.

 

Abstract

In our previous study, we produced a monoclonal antibody EB2 that recognized an epitope in the HA1 domain on the hemagglutinin (HA) of H6N1 influenza virus (A/chicken/Taiwan/2838 V/00). The residue Arg-201 (R201) on this epitope was protected by the glycan at Asn-167 (N167) from tryptic digestion; therefore, the infectivity of the virus was retained. R201 was extremely conserved in various subtypes of the influenza virus. To explore the role of R201 and the protecting glycan, we developed a bi-cistronic baculovirus expression system for the production of H6HA1 and H6HA0 (nearly full-length HA), which were glycosylated in insect cells. The expressed H6HA1 was mostly found in the trimeric form, and the H6HA0 protein was only found in the monomeric form. The trimeric H6HA1 was resistant to tryptic digestion; however, it could not bind to fetuin, a glycoprotein containing sialylated N-linked and O-linked glycans. By contrast, the monomeric H6HA0 could bind to fetuin but was sensitive to tryptic digestion. We found that the positive charge on R201 was critical for binding HA to the negatively charged surface of host cells because the mutant R201A of H6HA0 lost its binding capacity substantially. Moreover, this binding capacity was dependent on the pH value and inhibited by free electrically charged amino acids. We propose a two-step model for binding the influenza virus with a host cell. The first step involved the specific recognition of the receptor binding site on HA to the sialylated glycan on the host cell. After the virus is engulfed by the acidic endosome, R201 could bind to the cell surface with stronger interactions and trigger the fusion process.

Copyright © 2019 Elsevier B.V. All rights reserved.

KEYWORDS: Avian influenza virus; Charged amino acid; H6N1 subtype; Hemagglutinin; Receptor binding site; Two-step binding process

PMID: 30926385 DOI: 10.1016/j.virusres.2019.03.018 [Indexed for MEDLINE]

Keywords: Avian Influenza; H6N1.

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Development of #American-Lineage #Influenza #H5N2 #Reassortant #Vaccine Viruses for #Pandemic #Preparedness (Viruses, abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Viruses. 2019 Jun 11;11(6). pii: E543. doi: 10.3390/v11060543.

Development of American-Lineage Influenza H5N2 Reassortant Vaccine Viruses for Pandemic Preparedness.

Chen PL1,2, Hu AY3, Lin CY4, Weng TC5, Lai CC6,7, Tseng YF8, Cheng MC9,10, Chia MY11,12, Lin WC13, Yeh CT14, Su IJ15, Lee MS16.

Author information: 1 National Institution of Infectious Diseases and Vaccinology, National Health Research Institutes (NHRI), Zhunan, Miaoli 35053, Taiwan. letitia@nhri.org.tw. 2 Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu 30013, Taiwan. letitia@nhri.org.tw. 3 National Institution of Infectious Diseases and Vaccinology, National Health Research Institutes (NHRI), Zhunan, Miaoli 35053, Taiwan. alanhu@nhri.org.tw. 4 National Institution of Infectious Diseases and Vaccinology, National Health Research Institutes (NHRI), Zhunan, Miaoli 35053, Taiwan. grayingaries@outlook.com. 5 National Institution of Infectious Diseases and Vaccinology, National Health Research Institutes (NHRI), Zhunan, Miaoli 35053, Taiwan. wtc@nhri.org.tw. 6 National Institution of Infectious Diseases and Vaccinology, National Health Research Institutes (NHRI), Zhunan, Miaoli 35053, Taiwan. laicc2@nhri.org.tw. 7 College of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan. laicc2@nhri.org.tw. 8 National Institution of Infectious Diseases and Vaccinology, National Health Research Institutes (NHRI), Zhunan, Miaoli 35053, Taiwan. yufents@gmail.com. 9 Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan. mccheng@mail.npust.edu.tw. 10 Animal Health Research Institutes, Danshui, New Taipei City 25158, Taiwan. mccheng@mail.npust.edu.tw. 11 National Institution of Infectious Diseases and Vaccinology, National Health Research Institutes (NHRI), Zhunan, Miaoli 35053, Taiwan. chiaminyuan@dragon.nchu.edu.tw. 12 Department of Veterinary Medicine, National Chung Hsing University, Taichung 40227, Taiwan. chiaminyuan@dragon.nchu.edu.tw. 13 Institute of Preventive Medicine, National Defence Medical Centre, Taipei 23742, Taiwan. spps057@gmail.com. 14 Institute of Preventive Medicine, National Defence Medical Centre, Taipei 23742, Taiwan. yyhome@mail.ndmctsgh.edu.tw. 15 National Institution of Infectious Diseases and Vaccinology, National Health Research Institutes (NHRI), Zhunan, Miaoli 35053, Taiwan. suihjen0704@stust.edu.tw. 16 National Institution of Infectious Diseases and Vaccinology, National Health Research Institutes (NHRI), Zhunan, Miaoli 35053, Taiwan. minshi@nhri.org.tw.

 

Abstract

Novel low-pathogenic avian influenza (LPAI) H5N2 viruses hit poultry farms in Taiwan in 2003, and evolved into highly pathogenic avian influenza (HPAI) viruses in 2010. These viruses are reassortant viruses containing HA and NA genes from American-lineage H5N2 and six internal genes from local H6N1 viruses. According to a serological survey, the Taiwan H5N2 viruses can cause asymptomatic infections in poultry workers. Therefore, a development of influenza H5N2 vaccines is desirable for pandemic preparation. In this study, we employed reverse genetics to generate a vaccine virus having HA and NA genes from A/Chicken/CY/A2628/2012 (E7, LPAI) and six internal genes from a Vero cell-adapted high-growth H5N1 vaccine virus (Vero-15). The reassortant H5N2 vaccine virus, E7-V15, presented high-growth efficiency in Vero cells (512 HAU, 107.6 TCID50/mL), and passed all tests for qualification of candidate vaccine viruses. In ferret immunization, two doses of inactivated whole virus antigens (3 μg of HA protein) adjuvanted with alum could induce robust antibody response (HI titre 113.14). In conclusion, we have established reverse genetics to generate a qualified reassortant H5N2 vaccine virus for further development.

KEYWORDS: American-lineage H5N2 vaccine; American-lineage reassortant influenza viruses; Pandemic preparedness

PMID: 31212631 DOI: 10.3390/v11060543

Keywords: Avian Influenza; H5N1; H5N2; H6N1; Reassortant Strain; Vaccines.

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An #avian #influenza virus #H6N1 #outbreak in commercial #layers: case report and reproduction of the disease (Avian Pathol., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Avian Pathol. 2019 Apr;48(2):98-110. doi: 10.1080/03079457.2018.1551612. Epub 2018 Dec 20.

An avian influenza virus H6N1 outbreak in commercial layers: case report and reproduction of the disease.

Landman WJM1, Germeraad EA2, Kense MJ1.

Author information: 1a GD – Animal Health , Deventer , Netherlands. 2b Department of Virology , Wageningen Bioveterinary Research Lelystad , Netherlands.

 

Abstract

An outbreak of low pathogenic avian influenza (LPAI) subtype H6N1 (intravenous pathogenicity index = 0.11) infection occurred in four productive brown layer flocks on three farms in the Netherlands within a period of two months. The farms were located at a maximum distance of 4.6 km from each other. The infections were associated with egg production drops up to 74%, pale eggshells and persisting high mortality up to 3.2% per week. Three flocks were slaughtered prematurely as they were not profitable anymore. Newcastle disease, infectious bronchitis, egg drop syndrome and Mycoplasma gallisepticum infections could very likely be excluded as cause of or contributor to the condition in the field. Also, the anticoccidial drug nicarbazin, which can cause egg production drops and eggshell decolouration, was not detected in eggs from affected flocks. Furthermore, post mortem examinations revealed no lesions indicative of bacterial infection. Moreover, bacteriological analysis of hens was negative. The condition was reproduced in commercial brown layers after intratracheal inoculation with virus isolates from affected flocks. It is concluded that the LPAI H6N1 virus is very likely the only cause of the disease. An overview of main manuscripts published since 1976 describing non-H5 and non-H7 avian influenza (AI) virus infections in chickens and their biological significance is included in the present study, in which once more is shown that not only high pathogenic AI virus subtypes H5 and H7 can be detrimental to flocks of productive layers, but also non-H5 and non-H7 LPAI viruses (H6N1 virus).

 

ESEARCH HIGHLIGHTS

  • LPAI H6N1 can be detrimental to productive layers
  • Detrimental effects are severe egg drop and persistent high mortality
  • LPAI H6N1 virus outbreak seems to be self-limiting.

KEYWORDS: Avian influenza virus; H6N1; LPAI; egg production; layers; mortality

PMID: 30484684 DOI: 10.1080/03079457.2018.1551612 [Indexed for MEDLINE]

Keywords: Avian Influenza; H6N1; Poultry.

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#Aerosol #exposure enhanced #infection of low pathogenic #avian #influenza viruses in #chickens (Transbound Emerg Dis., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Transbound Emerg Dis. 2019 Jan;66(1):435-444. doi: 10.1111/tbed.13039. Epub 2018 Nov 2.

Aerosol exposure enhanced infection of low pathogenic avian influenza viruses in chickens.

Jegede A1, Fu Q1, Lin M1,2, Kumar A2, Guan J1.

Author information: 1 Ottawa Laboratory (Fallowfield), Canadian Food Inspection Agency, Ottawa, Ontario, Canada. 2 Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada.

 

Abstract

To assess the impact of different routes of inoculation on experimental infection of avian influenza (AI) viruses in chickens, this study compared virus replication and cytokine gene expression in respiratory and gastrointestinal organ tissues of chickens, which were inoculated with four low pathogenic subtypes, H6N1, H10N7, H10N8, and H13N6 AI viruses via the aerosol, intranasal, and oral routes respectively. Aerosol inoculation with the H6N1, H10N7, and H10N8 viruses significantly increased viral titres and upregulated the interferon (IFN)-γ, interleukin (IL)-6, and IL-1β genes in the trachea and lung tissues compared to intranasal or oral inoculation. Furthermore, one or two out of six chickens died following exposure to aerosolized H6N1 or H10N8 virus respectively. The H13N6 virus reached the lung via aerosol inoculation although failed to establish infection. Collectively, chickens were more susceptible to aerosolized AI viruses compared to intranasal or oral inoculation, and virus aerosols might post a significant threat to poultry health.

© 2018 Blackwell Verlag GmbH.

KEYWORDS: aerosols; and chickens; avian influenza viruses; cytokine gene expression; virus replication

PMID: 30307712 DOI: 10.1111/tbed.13039 [Indexed for MEDLINE]

Keywords: Avian Influenza; Animal models; Poultry; H6N1; H10N7; H10N8; H13N6.

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Continued #reassortment of #avian #H6 #influenza viruses from Southern #China, 2014-2016 (Transbound Emerg Dis., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Transbound Emerg Dis. 2019 Jan;66(1):592-598. doi: 10.1111/tbed.13037. Epub 2018 Oct 26.

Continued reassortment of avian H6 influenza viruses from Southern China, 2014-2016.

Li J1, Quan C2,3, Xie Y4, Ke C5, Nie Y6, Chen Q7, Hu T1, Chen J7, Wong G8,9, Wang Q3, Feng L10, Yu H10, Liu Y8, Liu W2, Gao GF2,3,8,10, Liu WJ3, Shi W1, Bi Y2,8.

Author information: 1 Key Laboratory of Etiology and Epidemiology of Emerging Infectious Diseases in Shandong Universities, Taishan Medical College, Taian, Shandong, China. 2 CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Center for Influenza Research and Early-warning (CASCIRE), Chinese Academy of Sciences, Beijing, China. 3 National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China. 4 Jiangxi Provincial Center for Disease Control and Prevention, Nanchang, China. 5 Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, China. 6 Henan Provincial Center for Disease Control and Prevention, Zhengzhou, China. 7 CAS Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Hubei, China. 8 Shenzhen Key Laboratory of Pathogen and Immunity, State Key Discipline of Infectious Disease, Shenzhen Third People’s Hospital, Second Hospital Affiliated to Southern University of Science and Technology, Shenzhen, China. 9 Département de microbiologie-infectiologie et d’immunologie, Université Laval, Québec, Québec, Canada. 10 Chinese Center for Disease Control and Prevention, Beijing, China.

 

Abstract

H6 subtype avian influenza virus (AIV) was prevalent in poultry and could sporadically infect humans. Here, a total of 196 novel H6 AIVs isolated from poultry in eight provinces of China from 2014 to 2016 were phylogenetically characterized. Our analysis revealed that they could be divided into two clades in the Asian H6 HA lineage, A/wild duck/Shantou/2853/2003(H6N2) (ST2853-like) (85.7%) and A/duck/Shantou/339/2000(H6N2) (ST339-like) (14.3%), in which ST2853-like strains predominate. These novel strains belonged to the H6N6 (n = 165, 84.2%), H6N2 (n = 30, 15.3%), and H6N3 (n = 1, 0.51%) subtypes, which could be classified into 36 genotypes including 12 novel genotypes described in this study. In particular, several strains possessed the V190 and S228 mutations in HA (H3 numbering), which is critical for human receptor binding and identical to the human-derived strain A/Taiwan/2/2013(H6N1). Furthermore, 10.3% of the H6N6 isolates possessed the N6-∆11b (59-69) deletion. In summary, we describe phylogenetic and molecular characterizations of H6 AIVs in southern China and highlight the constant prevalence of H6 AIVs in poultry as well as adaptation to mammalian hosts.

© 2018 Blackwell Verlag GmbH.

KEYWORDS: H6 subtype; evolution; low pathogenic avian influenza; molecular characterization; reassortment

PMID: 30300968 DOI: 10.1111/tbed.13037 [Indexed for MEDLINE]

Keywords: Avian Influenza; Poultry; China; Reassortant Strain; H6N1; H6N2; H6N3; H6N6.

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Isolation and characterization of novel #reassortant #H6N1 #avian #influenza viruses from #chickens in Eastern #China (Virol J., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Virol J. 2018 Oct 24;15(1):164. doi: 10.1186/s12985-018-1063-y.

Isolation and characterization of novel reassortant H6N1 avian influenza viruses from chickens in Eastern China.

Wu H1, Yang F1, Liu F1, Lu R2, Peng X1, Chen B1, Yao H1, Wu N3.

Author information: 1 State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, School of Medicine, Zhejiang University, 79 Qingchun Road, Zhejiang, 310003, Hangzhou, China. 2 Department of Emergency, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China. 3 State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, School of Medicine, Zhejiang University, 79 Qingchun Road, Zhejiang, 310003, Hangzhou, China. flwnp@zju.edu.cn.

 

Abstract

BACKGROUND:

The H6N1 subtype of avian influenza viruses (AIVs) can infect people with an influenza-like illness; the H6N1 viruses possess the ability for zoonotic transmission from avians into mammals, and possibly pose a threat to human health.

METHODS:

In 2017, live poultry markets (LPMs) in Zhejiang Province were surveyed for AIVs. To better understand the genetic relationships between these strains from Eastern China and other AIVs, all gene segments of these strains were sequenced and compared with sequences available in GenBank. In this study, we analyzed the receptor-binding specificity, antigenic characteristics, and pathogenicity of these two H6N1 viruses.

RESULTS:

In 2017, two H6N1 AIVs were isolated from chickens during surveillance for AIVs in LPMs in Eastern China. Phylogenetic analysis showed that these strains shared genetic characteristics from H6, H10, H1, and H4 AIVs found in ducks and wild birds in East Asia. These AIV strains were able to replicate in mice without prior adaptation.

CONCLUSIONS:

In this study, we report the discovery of new strains of H6N1 viruses from chickens with novel gene reassortments. Our results suggest that these chickens play an important role generating novel reassortments in AIVs, and emphasize the need for continued surveillance of AIV strains circulating in poultry.

KEYWORDS: Avian influenza viruses; Chickens; Eastern China; Reassortant; Subtype H6N1

PMID: 30355336 DOI: 10.1186/s12985-018-1063-y

Keywords: Avian Influenza; H6N1; Reassortant Strain; Poultry; China.

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#Heterosubtypic #Protections against #Human-Infecting #Avian #Influenza Viruses Correlate to Biased Cross-T-Cell Responses (mBio, abstract)

[Source: mBio, full page: (LINK). Abstract, edited.]

Heterosubtypic Protections against Human-Infecting Avian Influenza Viruses Correlate to Biased Cross-T-Cell Responses

Min Zhao a,b, Kefang Liu c,d, Jiejian Luo e,f,g, Shuguang Tan a, Chuansong Quan d, Shuijun Zhang a, Yan Chai a, Jianxun Qi a, Yan Li a, Yuhai Bi a,h,i, Haixia Xiao j, Gary Wong a,h,i, Jianfang Zhou d, Taijiao Jiang e,f,g, Wenjun Liu a, Hongjie Yu k, Jinghua Yan a, Yingxia Liu i, Yuelong Shu d, Guizhen Wu d, Aiping Wu e,f, George F. Gao a,b,c,d,h,i, William J. Liu c,d,i

a CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing, China; b Research Network of Immunity and Health (RNIH), Beijing Institutes of Life Science, University of Chinese Academy of Sciences, Beijing, China; c College of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China; d Key Laboratory of Medical Virology, Ministry of Health, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention (China CDC), Beijing, China; e Center for Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China; f Suzhou Institute of Systems Medicine, Suzhou, China; g CAS Key Laboratory of Protein and Peptide Pharmaceuticals, Institute of Biophysics, Chinese Academy of Sciences (CAS), Beijing, China; h Center for Influenza Research and Early-Warning (CASCIRE), Chinese Academy of Sciences, Beijing, China; i Shenzhen Key Laboratory of Pathogen and Immunity, State Key Discipline of Infectious Disease, Shenzhen Third People’s Hospital, Shenzhen, China; j Laboratory of Protein Engineering and Vaccine, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; k Key Laboratory of Surveillance and Early Warning on Infectious Disease, Division of Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China

Stefan H. E. Kaufmann, Editor

Author Affiliations: Max Planck Institute for Infection Biology

Address correspondence to Aiping Wu, wap@ism.cams.cn, George F. Gao, gaof@im.ac.cn, or William J. Liu, liujun@ivdc.chinacdc.cn.

M.Z., K.L., and J.L. contributed equally to this article.

 

ABSTRACT

Against a backdrop of seasonal influenza virus epidemics, emerging avian influenza viruses (AIVs) occasionally jump from birds to humans, posing a public health risk, especially with the recent sharp increase in H7N9 infections. Evaluations of cross-reactive T-cell immunity to seasonal influenza viruses and human-infecting AIVs have been reported previously. However, the roles of influenza A virus-derived epitopes in the cross-reactive T-cell responses and heterosubtypic protections are not well understood; understanding those roles is important for preventing and controlling new emerging AIVs. Here, among the members of a healthy population presumed to have previously been infected by pandemic H1N1 (pH1N1), we found that pH1N1-specific T cells showed cross- but biased reactivity to human-infecting AIVs, i.e., H5N1, H6N1, H7N9, and H9N2, which correlates with distinct protections. Through a T-cell epitope-based phylogenetic analysis, the cellular immunogenic clustering expanded the relevant conclusions to a broader range of virus strains. We defined the potential key conserved epitopes required for cross-protection and revealed the molecular basis for the immunogenic variations. Our study elucidated an overall profile of cross-reactivity to AIVs and provided useful recommendations for broad-spectrum vaccine development.

 

IMPORTANCE

We revealed preexisting but biased T-cell reactivity of pH1N1 influenza virus to human-infecting AIVs, which provided distinct protections. The cross-reactive T-cell recognition had a regular pattern that depended on the T-cell epitope matrix revealed via bioinformatics analysis. Our study elucidated an overall profile of cross-reactivity to AIVs and provided useful recommendations for broad-spectrum vaccine development.

KEYWORDS: T-cell responses –  avian influenza viruses –  cross-reactivity –  heterosubtypic protection

 

FOOTNOTES

Citation Zhao M, Liu K, Luo J, Tan S, Quan C, Zhang S, Chai Y, Qi J, Li Y, Bi Y, Xiao H, Wong G, Zhou J, Jiang T, Liu W, Yu H, Yan J, Liu Y, Shu Y, Wu G, Wu A, Gao GF, Liu WJ. 2018. Heterosubtypic protections against human-infecting avian influenza viruses correlate to biased cross-T-cell responses. mBio 9:e01408-18. https://doi.org/10.1128/mBio.01408-18.

This article is a direct contribution from a Fellow of the American Academy of Microbiology.

Solicited external reviewers: Kwok Yung Yuen, University of Hong Kong; Xiaoning Xu, Chelsea and Westminster Hospital.

Received 29 June 2018  – Accepted 3 July 2018  – Published 7 August 2018

Copyright © 2018 Zhao et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.

Keywords: Avian Influenza; H5N1; H7N9; H6N1; H9N2; H1N1pdm09; Seasonal Influenza; Human.

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