The use of antiviral drugs such as influenza neuraminidase (NA) inhibitors is a critical strategy to prevent and control flu pandemic, but this strategy faces the challenge of emerging drug-resistant strains. For a highly pathogenic avian influenza (HPAI) H5N1 virus, biosafety restrictions have significantly limited the efforts to monitor its drug responses and mechanisms involved. In this study, a rapid and biosafe assay based on NA pseudovirus was developed to study the resistance of HPAI H5N1 virus to NA inhibitor drugs. The H5N1 NA pseudovirus was comprehensively tested using oseltamivir-sensitive strains and their resistant mutants. Results were consistent with those in previous studies, in which live H5N1 viruses were used. Several oseltamivir-resistant mutations reported in human H1N1 were also identified to cause decreased oseltamivir sensitivity in H5N1 NA by using the H5N1 NA pseudovirus. Thus, H5N1 NA pseudoviruses could be used to monitor HPAI H5N1 drug resistance rapidly and safely.
Animals ; Birds ; Drug Resistance, Viral ; genetics ; Enzyme Inhibitors ; therapeutic use ; HEK293 Cells ; Humans ; Influenza A Virus, H1N1 Subtype ; drug effects ; genetics ; pathogenicity ; Influenza A Virus, H5N1 Subtype ; drug effects ; genetics ; pathogenicity ; Influenza in Birds ; drug therapy ; genetics ; virology ; Influenza, Human ; drug therapy ; genetics ; virology ; Mutagenesis, Site-Directed ; Neuraminidase ; antagonists & inhibitors ; genetics ; Oseltamivir ; administration & dosage

This study is to establish a cell-based model targeting to neuraminidase (NA) of the 2009 H1N1 influenza A virus. NA is an influenza virus structural protein with enzymatic activity of the cleavage of HA-sialic acid interaction to release new viral particles from cells. A model of HIV-1 (pNL4-3.Luc.R(-)E(-)) based pseudovirions packed with HA [hemagglutinin, A/VietNam/1203/2004 (H5N1)] and NA [A/California/04/2009 (H1N1)] was established to evaluate compounds activities on NA function. The viral release can be blocked by neuraminidase inhibitors, oseltamivir and oseltamivir carboxylate, with IC50 of (61 +/- 31) nmol L(-1) and (5.5 +/- 2.9) nmol L(-1) respectively. A point mutation of H275Y on NA leads oseltamivir-resistance. This corresponding mutation was introduced into the system which was also confirmed by oseltamivir and oseltamivir carboxylate.
Cell Line, Tumor ; Drug Resistance, Viral ; genetics ; Enzyme Inhibitors ; pharmacology ; HEK293 Cells ; HIV-1 ; genetics ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; metabolism ; Humans ; Influenza A Virus, H1N1 Subtype ; drug effects ; genetics ; metabolism ; Influenza A Virus, H5N1 Subtype ; drug effects ; genetics ; metabolism ; Mutation ; Neuraminidase ; antagonists & inhibitors ; genetics ; metabolism ; Oseltamivir ; analogs & derivatives ; pharmacology ; Plasmids ; Transfection ; Virus Internalization

To study the effect of Yinghua Pinggan granule (YHPG) against influenza A/H1N1 virus in vivo and on the immunologic function of infected mice. The intranasal influenza virus infection was adopted in ICR mouse to establish the influenza virus pneumonia model. At the 3rd and 7th day after the infection, the lung index and pathologic changes in lung tissues of mice were detected. Realtime PCR and flow cytometry were employed to observe the virus load in lung tissues and the levels of CD4+, CD8+, and CD4+/CD8+ in peripheral blood. The result showed that at the 3rd and 7th day after the infection, YHPG (15, 30 g x kg(-1)) can significant decrease in the lung index and virus load in lung tissues of mice infected with influenza virus, alleviate the pathologic changes in lung tissues, significantly increase the levels of CD4+ and CD4+/CD8+ ratio and reduce the levels of CD8+ in whole blood. This indicated that YHPG can inhibit the influenza virus replication, alleviate pulmonary damage and adjust the weak immunologic function of infected mice, with a certain therapeutic effect on mice infected by H1N1 virus in vivo.
Animals ; Antiviral Agents ; administration & dosage ; Humans ; Influenza A Virus, H1N1 Subtype ; drug effects ; genetics ; physiology ; Influenza, Human ; drug therapy ; pathology ; virology ; Lung ; pathology ; virology ; Male ; Mice ; Mice, Inbred ICR ; Virus Replication ; drug effects

This study aims to investigate the characteristics of genomic variation of pandemic A/H1N1/2009 influenza virus isolated in Fujian Province, China. Complete genome sequence analysis was performed on 14 strains of pandemic A/H1N1/2009 influenza virus isolated from Fujian during 2009-2012. All virus strains were typical low-pathogenic influenza viruses, with resistance to amantadine and sensitivity to neuraminidase inhibitors. Eight genome fragments of all strains were closely related to those of A/California/07/2009 (H1N1) vaccine strain, with > or = 98.2% homology. Compared with the vaccine strain, the influenza strains from Fujian had relatively large variation, and variation was identified at 11 amino acid sites of the HA gene of A/Fujiangulou/SWL1155/2012 strain, including 4 sites (H138R, L161I, S185T, and S203T) involved inthree antigen determinants (Ca, Sa, and Sb). In conclusion, the influenza vaccine has a satisfactory protective effect on Fujian population, but the influenza strains from Fujian in 2012 has antigenic drift compared with the vaccine strain, more attention should therefore be paid to the surveillance of mutations of pandemic A/H1N1/2009 influenza virus.
Antiviral Agents ; pharmacology ; China ; epidemiology ; Drug Resistance, Viral ; genetics ; Genome, Viral ; genetics ; Genomics ; Humans ; Influenza A Virus, H1N1 Subtype ; drug effects ; genetics ; immunology ; physiology ; Influenza, Human ; epidemiology ; prevention & control ; Pandemics ; prevention & control ; Viral Vaccines ; immunology

In 2009, pandemic influenza A (H1N1) virus (H1N1 09) started to spread quickly in many countries. It causes respiratory infection with signs and symptoms of common infectious agents. Thus, clinicians sometimes may miss the H1N1 patient. Clinical laboratory tests are important for the diagnosis of the H1N1 infection. There are several tests available, however, the rapid test and direct fluorescence antigen test are unable to rule out the influenza virus infection and viral culture test is time consuming. Therefore, nucleic acid amplification techniques based on reverse transcription polymerase chain reaction assays are regarded as a specific diagnosis to confirm the influenza virus infection. Although the nucleic acid-based techniques are highly sensitive and specific, the high mutation rate of the influenza RNA-dependent RNA polymerase could limit the utility of the techniques. In addition, their use depends on the availability, cost and throughput of the diagnostic techniques. To overcome these drawbacks, evaluation and development of the techniques should be continued. This review provides an overview of various techniques for specific diagnosis of influenza infection.
Disease Outbreaks/prevention & control ; Drug Resistance, Viral ; Fluorescent Antibody Technique, Direct/methods ; Humans ; Influenza A Virus, H1N1 Subtype/drug effects/*genetics ; Influenza, Human/*diagnosis/drug therapy ; Polymerase Chain Reaction/methods ; Sensitivity and Specificity ; Time Factors

OBJECTIVETo identify antiviral activity of Toddalia asiatica against influenza virus type A in vitro.

METHODMore than two hundred Chinese medicinal herb extracts were screened for antiviral activities against influenza A/PR/8/34 (H1N1) virus using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay for virus induced cytopathic effect (CPE) in a primary screening. Positive samples were picked up and were subjected to quantitative real-time polymerase chain reaction (PCR) to quantify reduction of H1N1 virus genomic RNA.

RESULTToddalia asiatica showed potent antiviral activities against H1N1 virus, with 50% effective concentration (EC50) value of 4.7 mg x L(-1) in MTS assay and 0.9 mg x L(-1) in quantitative PCR assay respectively. The cytotoxicity test of Toddalia asiatica generated a CC50 value of 187.2 mg x L(-1) and a selective index (SI) larger than 206 in quantitative PCR. Although the best antiviral activity of Toddalia asiatica was observed with co-treatment of influenza virus infection, it remained effective even when administrated 24 h before and after the initiation of infection.

CONCLUSIONThe results suggested that Toddalia asiatica compound extract could be a candidate for anti-H1N1 virus agent in the treatment of influenza.

Animals ; Antiviral Agents ; isolation & purification ; pharmacology ; Cells, Cultured ; Dogs ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; toxicity ; Influenza A Virus, H1N1 Subtype ; drug effects ; genetics ; Kidney ; cytology ; Plants, Medicinal ; chemistry ; RNA, Viral ; drug effects ; Rutaceae ; chemistry ; Time Factors

OBJECTIVETo observe the effect of volatile oil of Schizonepetae Herba (VOSH), and its essential components-menthone and pulegone against anti-influenza virus A/PR/8/34 (H1N1) in vivo and in vitro, as well as the signaling mechanism of its toll-like receptor/interferon (TLR/IFN).

METHODThe lung-adapted PR-8 virus model was prepared in mice. They were administered with preventive and therapeutic drugs, and the hemagglutination titer of model animals was determined to evaluate in vivo effect against H1N1. ELISA test was conducted to observe the effect on IFN-alpha, IFN-beta, IL-2, IL-6 and TNF-alpha in serum, as well as IFN-beta secretion in H1N1 infected MDCK supernatant. Real-time RT-PCR was employed to observe the expression levels of IRAK4 and TLR3 mRNA.

RESULTThe in vivo experiment shows that the hemagglutination titer was significantly decreased when the mice were treated with VOSH (0.266 mg x kg(-1)), menthone(0.5 mg x kg(-1)) and pulegone (0.19 mg x kg(-1)) in therapeutic way; VOSH (0.226 mg x kg(-1)) had a significant effect on increasing serum levels of IFN-alpha, IL-2; Methone (0.5 mg x kg(-1)) had a significant effect on increasing serum levels of IFN-beta; Methone (0.5 mg x kg(-1)) and pulegone (0.19 mg x kg(-1)) had a significant effect on decreasing serum levels of IL-6; VOSH (0.452, 0.226 mg x kg(-1)) and pulegone (0.19 mg x kg(-1)) had a significant effect on decreasing serum levels TNF-alpha. The in vitro experiment showed that the expression levels of IRAK4 mRNA and IFN-beta were significantly increased in VOHS (0.1 g x L(-1)) and pulegone (0.1 g x L(-1)) groups; and the menthone (0.25 g x L(-1)) group showed a significant rise in the expression levels of IRAK4 mRNA, but a notable decline in TLR3 mRNA.

CONCLUSIONThe administration with VOSH, methone and pulegone in therapeutic way can significantly decrease the hemagglutination titer, which demonstrates the anti-virus effect of the administration in therapeutic way, but no notable efficacy of the administration in preventive way. The in vivo anti-virus mechanism is related to regulation of IFN-alpha, IFN-beta and IL-2.

Animals ; Drugs, Chinese Herbal ; pharmacology ; Female ; Humans ; Influenza A Virus, H1N1 Subtype ; drug effects ; physiology ; Influenza, Human ; drug therapy ; genetics ; immunology ; virology ; Interferon-alpha ; genetics ; immunology ; Interleukin-1 Receptor-Associated Kinases ; Interleukin-2 ; genetics ; immunology ; Interleukin-6 ; genetics ; immunology ; Lamiaceae ; chemistry ; Male ; Mice ; Oils, Volatile ; pharmacology ; Tumor Necrosis Factor-alpha ; genetics ; immunology

BACKGROUNDThe first case of pandemic influenza A (H1N1) virus infection in Macau Special Administrative Region (SAR) of the People's Republic of China was documented on June 18, 2009. Subsequently, persons with suspected infection or of contact with suspected cases received screening. All the confirmed cases were hospitalized and treated with oseltamivir. Their clinical features were observed. This may help for better management for later patients and be of benefit to the government of Macau SAR to adjust its strategy to combat the pandemic influenza A (H1N1) virus infection more efficiently.

METHODSFrom June to July 2009, the initial 72 cases of influenza A (H1N1) in Macau were hospitalized in Common Hospital Centre S. Januario (CHCSJ). The infection was confirmed by real-time reverse-transcriptase polymerase chain reaction (RT-PCR). The clinical features of the disease were closely observed and documented. Oseltamivir was given to all patients within 48 hours after the onset of disease and maintained for 5 days.

RESULTSThe mean age of the 72 patients was 21 years old. Forty of them were men and 32 were women. The median incubation of the virus was 2 days (1 to 7 days). The most common symptoms were fever (97.2%) and cough (77.8%). The rate of gastrointestinal symptoms including nausea, vomiting, and diarrhea was 2.8%. Fever typically lasted for 3 days (1 to 9 days). The median time from the onset to positive results of real-time RT-PCR was 6 days (3 to 13 days). After treatment with oseltamivir, most patients became afebrile within 48 hours. Only one aged patient with a history of glaucoma and hypothyroidism was found to have lung infiltration on chest X-ray.

CONCLUSIONSThe initial cases of pandemic influenza A (H1N1) virus infection in Macau SAR showed that most of the infected persons had a mild course. The virus could be detected by real-time RT-PCR within a median of 6 days from the onset. Oseltamivir was effective.

Adolescent ; Adult ; Aged ; Antiviral Agents ; therapeutic use ; Child ; Child, Preschool ; China ; Female ; Humans ; Influenza A Virus, H1N1 Subtype ; drug effects ; genetics ; pathogenicity ; Influenza, Human ; diagnosis ; drug therapy ; pathology ; Macau ; Male ; Middle Aged ; Oseltamivir ; therapeutic use ; Reverse Transcriptase Polymerase Chain Reaction ; Young Adult

Influenza A/H1N1 virus-encoded nonstructural, or NS1, protein inhibits the 3'-end processing of cellular pre-mRNAs by binding the cellular protein: the 30-kDa subunit of CPSF (cleavage and polyadenylation specificity factor, CPSF30). CPSF30 binding site of the NS1 protein is a potential target for the development of drugs against influenza A/H1N1 virus. A yeast two-hybrid screening system was constructed and used for screening Chinese medicines that inhibit the interaction of the A/H1N1 flu NS1 protein and human CPSF30 protein. The NS1 gene of A/H1N1 virus was amplified by consecutive polymerase chain reaction (PCR), and the human CPSF30 gene of HeLa cell cloned by reverse transcriptase-polymerase chain reaction (RT-PCR). Then the two gene fragments confirmed by sequencing were subcloned into the yeast expression vectors pGBKT7 and pGADT7, respectively. The two constructs, bait vector pGBKNS1 and prey vector pGADCPSF, were co-transformed into yeast AH109. The eight individual yeast colonies were picked and subjected to verification by PCR/gel electrophoresis. The inhibition of the NS1-CPSF30 interaction was allowed the identification of selective inhibitors. The four of more than thirty identified Chinese medicines, including 'Shuanghuanglian oral liquid', showed the strong inhibition of the NS1-CPSF30 interaction.
Base Sequence ; Binding Sites ; Cleavage And Polyadenylation Specificity Factor ; genetics ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Gene Amplification ; HeLa Cells ; Humans ; Influenza A Virus, H1N1 Subtype ; genetics ; Peptide Fragments ; genetics ; Plasmids ; Protein Binding ; drug effects ; Transformation, Genetic ; Two-Hybrid System Techniques ; Viral Nonstructural Proteins ; genetics ; metabolism

OBJECTIVETo observe the anti-virus effects of andrographolide (AD) on the retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs) signaling pathway when immunological cells were infected with H1N1.

METHODSLeukomonocyte was obtained from umbilical cord blood by Ficoll density gradient centrifugation, and immunological cells were harvested after cytokines stimulation. Virus infected cell model was established by H1N1 co-cultured with normal human bronchial epithelial cell line (16HBE). The optimal concentration of AD was defined by methyl-thiazolyl-tetrazolium (MTT) assay. After the virus infected cell model was established, AD was added into the medium as a treatment intervention. After 24-h co-culture, cell supernatant was collected for interferon gamma (IFN-γ) and interleukin-4 (IL-4) enzyme-linked immunosorbent assay (ELISA) detection while immunological cells for real-time polymerase chain reaction (RT-PCR).

RESULTSThe optimal concentration of AD for anti-virus effect was 250 μg/mL. IL-4 and IFN-γ in the supernatant and mRNA levels in RLRs pathway increased when cells was infected by virus, RIG-I, IFN-β promoter stimulator-1 (IPS-1), interferon regulatory factor (IRF)-7, IRF-3 and nuclear transcription factor κB (NF-κB) mRNA levels increased significantly (P<0.05). When AD was added into co-culture medium, the levels of IL-4 and IFN-γ were lower than those in the non-interference groups and the mRNA expression levels decreased, RIG-I, IPS-1, IRF-7, IRF-3 and NF-κB decreased significantly in each group with significant statistic differences (P<0.05).

CONCLUSIONSThe RLRs mediated viral recognition provided a potential molecular target for acute viral infections and andrographolide could ameliorate H1N1 virus-induced cell mortality. And the antiviral effects might be related to its inhibition of viral-induced activation of the RLRs signaling pathway.

Adaptor Proteins, Signal Transducing ; genetics ; metabolism ; Antiviral Agents ; pharmacology ; Cells, Cultured ; Coculture Techniques ; DEAD Box Protein 58 ; DEAD-box RNA Helicases ; genetics ; metabolism ; Dendritic Cells ; drug effects ; immunology ; virology ; Diterpenes ; pharmacology ; Fetal Blood ; cytology ; Humans ; Influenza A Virus, H1N1 Subtype ; drug effects ; immunology ; Influenza, Human ; drug therapy ; immunology ; virology ; Interferon-beta ; genetics ; metabolism ; Interferon-gamma ; metabolism ; Interleukin-4 ; metabolism ; Leukocytes, Mononuclear ; drug effects ; immunology ; virology ; Macrophages ; drug effects ; virology ; NF-kappa B ; genetics ; metabolism ; Promoter Regions, Genetic ; drug effects ; immunology ; RNA, Messenger ; metabolism ; Signal Transduction ; drug effects ; genetics ; immunology