• Title, Summary, Keyword: Influenza A virus

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Structure and Function of the Influenza A Virus Non-Structural Protein 1

  • Han, Chang Woo;Jeong, Mi Suk;Jang, Se Bok
    • Journal of Microbiology and Biotechnology
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    • v.29 no.8
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    • pp.1184-1192
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    • 2019
  • The influenza A virus is a highly infectious respiratory pathogen that sickens many people with respiratory disease annually. To prevent outbreaks of this viral infection, an understanding of the characteristics of virus-host interaction and development of an anti-viral agent is urgently needed. The influenza A virus can infect mammalian species including humans, pigs, horses and seals. Furthermore, this virus can switch hosts and form a novel lineage. This so-called zoonotic infection provides an opportunity for virus adaptation to the new host and leads to pandemics. Most influenza A viruses express proteins that antagonize the antiviral defense of the host cell. The non-structural protein 1 (NS1) of the influenza A virus is the most important viral regulatory factor controlling cellular processes to modulate host cell gene expression and double-stranded RNA (dsRNA)-mediated antiviral response. This review focuses on the influenza A virus NS1 protein and outlines current issues including the life cycle of the influenza A virus, structural characterization of the influenza A virus NS1, interaction between NS1 and host immune response factor, and design of inhibitors resistant to the influenza A virus.

Interpretation and Prospection of Influenza Virus through Swine-origin Influenza Virus (신종플루 바이러스를 통한 인플루엔자 바이러스의 해석 및 전망)

  • Chang, Kyung-Soo
    • Korean Journal of Clinical Laboratory Science
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    • v.42 no.1
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    • pp.1-15
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    • 2010
  • Swine influenza virus (SIV) or swine-origin influenza virus (S-OIV) is endemic in swine, and classified into influenza A and influenza C but not influenza B. Swine influenza A includes H1N1, H1N2, H3N1, H3N2 and H2N3 subtypes. Infection of SIV occurs in only swine and that of S-OIV is rare in human. What human can be infected with S-OIV is called as zoonotic swine flu. Pandemic 2009 swine influenza H1N1 virus (2009 H1N1) was emerged in Mexico, America and Canada and spread worldwide. The triple-reassortant H1N1 resulting from antigenic drift was contained with HA, NA and PB1 of human or swine influenza virus, PB2 and PA polymerase of avian influenza virus, and M, NP and NS of swine influenza virus, The 2009 H1N1 enables to transmit to human and swine. The symptoms and signs in human infected with 2009 H1N1 virus are fever, cough and sore throat, pneumonia as well as diarrhea and vomiting. Co-infection with other viruses and bacteria such as Streptococcus pneumoniae can occur high mortality in high-risk population. 2009 H1N1 virus was easily differentiated from seasonal flu by real time RT-PCR which contributed rapid and confirmed diagnosis. The 2009 H1N1 virus was treated with NA inhibitors such as oseltamivir (Tamiflu) and zanamivir (Relenza) but not with adamantanes such as amantadine and rimantadine. Evolution of influenza virus has continued in various hosts. Development of a more effective vaccine against influenza prototypes is needed to protect new influenza infection such as H5 and H7 subtypes to infect to multi-organ and cause high pathogenicity.

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Chemical Constituents of Essential Oils Possessing Anti-Influenza A/WS/33 Virus Activity

  • Choi, Hwa-Jung
    • Osong Public Health and Research Perspectives
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    • v.9 no.6
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    • pp.348-353
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    • 2018
  • Objectives: This study was conducted to determine whether essential oils had anti-influenza A/WS/33 virus activity and whether there were specific compounds associated with this activity. Methods: There were 63 essential oils evaluated for anti-influenza (A/WS/33 virus) activity using a cytopathic effect reduction method. The chemical composition of the anti-influenza essential oils was phytochemically analyzed by gas chromatography-mass spectrometry. Results: The antiviral assays demonstrated that 11 of the 62 essential oils ($100{\mu}g/mL$) possessed anti-influenza activity, reducing visible cytopathic effects of influenza A/WS/33 virus activity by > 30%. Furthermore, marjoram, clary sage and anise oils exhibited anti-influenza A/WS/33 virus activity of > 52.8%. However, oseltamivir (the anti-influenza A and B drug), showed cytotoxicity at the same concentration ($100{\mu}g/mL$) as the essential oils. The chemical composition detected by GC-MS analysis, differed amongst the 3 most potent anti-viral essential oils (marjoram, clary sage and anise oils) except for linalool, which was detected in all 3 essential oils. Conclusion: This study demonstrated anti-influenza activity in 11 essential oils tested, with marjoram, clary sage and anise essential oils being the most effective at reducing visible cytopathic effects of the A/WS/33 virus. All 3 oils contained linalool, suggesting that this may have anti-influenza activity. Further investigation is needed to characterize the antiviral activity of linalool against influenza A/WS/33 virus.

Effect of Oral Administration of Korean Red Ginseng on Influenza A (H1N1) Virus Infection

  • Kim, Jin-Young;Kim, Hyoung-Jin;Kim, Hong-Jin
    • Journal of Ginseng Research
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    • v.35 no.1
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    • pp.104-110
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    • 2011
  • Korean red ginseng (RG), which is a ginseng treated by heating and steaming, has biological activity similar to Panax ginseng. The effect of ginseng on influenza infection has not been studied although it is known to have a broad range of biological activities. The aim of the study is to investigate the effect of RG extract on influenza A (H1N1) virus infection. We investigated the inhibitory effect of RG extract on plaque formation by influenza A virus in a cell-based plaque assay, and the effect of orally administered RG on influenza A virus infection in mice. RG extract, which was applied at a non-cytotoxic concentration, inhibited plaque formation by influenza A virus in the cell-based plaque assay. The orally administered RG extract ameliorated body weight loss and significantly increased survival in mice infected with influenza A virus. Our results suggest that RG extract has components that reduce the severity of infection by influenza A virus and could potentially be used as a complement to treatment of influenza A virus infections.

Isolation of Influenza Virus from Patients with Respiratory Disease in Pusan in 1997 (1997년도 부산지역 호흡기환자로부터 인플로엔자 바이러스의 분리)

  • 조경순;차인호;정구영
    • Journal of Life Science
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    • v.8 no.6
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    • pp.667-672
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    • 1998
  • This study was done to detect the causative agent of patient with respiratory disease in Pusan, 1997. Male and female patients with respiratory disease in Pusan, 1997, were 31.9% and 68.1 %, respectively. In the aspect of out-break by month, patients with respiratory disease were mostly concentrated at February, March, April, October, November and December. Fifteen strains of influenza virus were isolated from 1,268 swabbed samples of throat, and thirteen strains and 2 strains among 15 isolates were classified with influenza A and B virus, respectively. One of 13 influenza A virus was confirmed as A/Johannesburg/33/94- like strain, and the other isolates of influenza A virus were confirmed as A/sydney/05/97-like strains. Two isolates of influenza B virus were confirmed as B/Bei-jing/08/93-like strains.

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Mucosal Immunization with Recombinant Adenovirus Encoding Soluble Globular Head of Hemagglutinin Protects Mice Against Lethal Influenza Virus Infection

  • Kim, Joo Young;Choi, Youngjoo;Nguyen, Huan H.;Song, Man Ki;Chang, Jun
    • IMMUNE NETWORK
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    • v.13 no.6
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    • pp.275-282
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    • 2013
  • Influenza virus is one of the major sources of respiratory tract infection. Due to antigenic drift in surface glycoproteins the virus causes annual epidemics with severe morbidity and mortality. Although hemagglutinin (HA) is one of the highly variable surface glycoproteins of the influenza virus, it remains the most attractive target for vaccine development against seasonal influenza infection because antibodies generated against HA provide virus neutralization and subsequent protection against the virus infection. Combination of recombinant adenovirus (rAd) vector-based vaccine and mucosal administration is a promising regimen for safe and effective vaccination against influenza. In this study, we constructed rAd encoding the globular head region of HA from A/Puerto Rico/8/34 virus as vaccine candidate. The rAd vaccine was engineered to express high level of the protein in secreted form. Intranasal or sublingual immunization of mice with the rAd-based vaccine candidates induced significant levels of sustained HA-specific mucosal IgA and IgG. When challenged with lethal dose of homologous virus, the vaccinated mice were completely protected from the infection. The results demonstrate that intranasal or sublingual vaccination with HA-encoding rAd elicits protective immunity against infection with homologous influenza virus. This finding underlines the potential of our recombinant adenovirus-based influenza vaccine candidate for both efficacy and rapid production.

Post-pandemic influenza A (H1N1) virus detection by real-time PCR and virus isolation

  • Zaki, Ali Mohamed;Taha, Shereen El-Sayed;Shady, Nancy Mohamed Abu;Abdel-Rehim, Asmaa Saber;Mohammed, Hedya Said
    • Korean Journal of Microbiology
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    • v.55 no.1
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    • pp.25-32
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    • 2019
  • Influenza A (H1N1) virus caused a worldwide pandemic in 2009-2010 and still remains in seasonal circulation. Continuous surveillance activities are encouraged in the post pandemic phase to watch over the trend of occurrence every year, this is better to be done by a rapid and sensitive method for its detection. This study was conducted to detect proportions of occurrence of influenza A virus (H1N1) in patients with influenza-like illness. Samples from 500 patients with influenza or influenza-like clinical presentation were tested by real-time reverse transcription polymerase chain reaction (RT-PCR) and virus tissue culture. Among the total 500 participants, 193 (38.6%) were females and 307 (61.4%) males. Seventy-one patients (14.2%) were positive for H1N1 virus infection with real-time RT-PCR while 52 (10.4%) were positive by tissue culture. Non-statistically significant relation was found between age and gender with the positivity of H1N1. Sensitivity and specificity of real-time RT-PCR was 98.08% and 95.54%, respectively, in comparison to virus isolation with accuracy 95.8%. This study showed that H1N1 virus was responsible for a good proportion of influenza during the post-pandemic period. Real-time RT-PCR provides rapidity and sensitivity for the detection of influenza A virus (H1N1) compared with virus isolation and thus it is recommended as a diagnostic tool.

Immunogenicity and Protective Efficacy of a Dual Subunit Vaccine Against Respiratory Syncytial Virus and Influenza Virus

  • Park, Min-Hee;Chang, Jun
    • IMMUNE NETWORK
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    • v.12 no.6
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    • pp.261-268
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    • 2012
  • Respiratory syncytial virus (RSV) and influenza virus are the most significant pathogens causing respiratory tract diseases. Composite vaccines are useful in reducing the number of vaccination and confer protection against multiple infectious agents. In this study, we generated fusion of RSV G protein core fragment (amino acid residues 131 to 230) and influenza HA1 globular head domain (amino acid residues 62 to 284) as a dual vaccine candidate. This fusion protein, Gcf-HA1, was bacterially expressed, purified by metal resin affinity chromatography, and refolded in PBS. BALB/c mice were intranasally immunized with Gcf-HA1 in combination with a mucosal adjuvant, cholera toxin (CT). Both serum IgG and mucosal IgA responses specific to Gcf and HA1 were significantly increased in Gcf-HA1/CT-vaccinated mice. To determine the protective efficacy of Gcf-HA1/CT vaccine, immunized mice were challenged with RSV (A2 strain) or influenza virus (A/PR/8/34). Neither detectable viral replication nor pathology was observed in the lungs of the immune mice. These results demonstrate that immunity induced by intranasal Gcf-HA1/CT immunization confers complete protection against both RSV and homologous influenza virus infection, suggesting our Gcf-HA1 vaccine candidate could be further developed as a dual subunit vaccine against RSV and influenza virus.

Detection of influenza A viruses by RT-PCR with single primer of nonstructural gene (비구조 단백질 유전자 primer를 사용한 RT-PCR에 의한 인플루엔자 A형 바이러스의 검출)

  • Moon, Hyeong-Sun;Bae, Yoon-Yeong;Jin, Ji-Dong;Kang, Zheng-Wu;Hahn, Tae-Wook
    • Korean Journal of Veterinary Service
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    • v.32 no.2
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    • pp.103-109
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    • 2009
  • Influeza type A virus have been worldwide problematic in animals as well as in humans. In this study, the use of reverse-transcriptase polymerase chain reaction (RT-PCR) was described for detecting influenza virus type A. The primer of RT-PCR was designed from an nonstructural (NS) gene of Influenza A virus. By RT-PCR, a product with the size of 189 bp was detected only when influenza virus type A was used as template. No products could be detected with Influenza virus type B as well as other respiratory pathogens. The detection limit of the RT-PCR was up to $10^{0.3}TCID_{50}$ which is comparable to the sensitivity of cell culture method. The RT-PCR could detect the influenza A virus from nasal turbinates of the ferrets infected with influenza virus type A not type B.

Intake of Korean Red Ginseng Extract and Saponin Enhances the Protection Conferred by Vaccination with Inactivated Influenza A Virus

  • Xu, Mei Ling;Kim, Hyoung-Jin;Choi, Yoo-Ri;Kim, Hong-Jin
    • Journal of Ginseng Research
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    • v.36 no.4
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    • pp.396-402
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    • 2012
  • Vaccination is the main strategy for preventing influenza infection. However, vaccine efficacy is influenced by several factors, including age and health status. The efficacy of the influenza vaccine is much lower (17% to 53%) in individuals over 65 yr of age compared with young adults (70% to 90%). Therefore, increasing vaccine efficacy remains a challenge for the influenza vaccine field. In this study, we investigated the impact of supplementing vaccination with the dietary intake of Korean red ginseng (RG) extract and RG saponin. Mice were immunized two times intranasally with inactivated influenza A (H1N1) virus. Mice received RG extract or RG saponin orally for 14 d prior to the primary immunization. After the primary immunization, mice continued to receive RG extract or RG saponin until the secondary immunization. Mice vaccinated in combination with dietary intake of RG extract and RG saponin showed elevated serum anti-influenza A virus IgG titers and improved survival rates in lethal influenza A virus infection: 56% and 63% of mice receiving RG extract or RG saponin survived, respectively, while 38% of mice that only received the vaccine survived. Moreover, mice receiving RG extract supplementation recovered their body weight more quickly than those not receiving RG extract supplementation. We propose that the dietary intake of RG extract and RG saponin enhances the vaccine-induced immune response and aids in providing protection against influenza virus infection.