OBJECTIVETo analyse seasonal influenza epidemic situation in 2006, and to analyse the genetic and antigenic characteristics of viral hemagglutinin (HA) gene.

METHODSThe single-way hemagglutination inhibition (HI) tests were used to test the antigenic characteristics of these viruses from influenza surveillance network, and the HA1 genes were sequenced based on the antigenic test results according to different isolation times and sites.

RESULTSThe influenza virus types A and B co-circulated in 2006. influenza A H1N1 subtype and Victoria-like B influenza circulated preponderantly during this epidemic season. The HA1 gene sequence of H1N1 viruses showed that 192, 193, 196, 198 positions (located at antigenic site B) have an amino acid substitute, compared with the last circulating strain A/Hubeihongshan/53/2005(H1N1). Two amino acid changes at 142 and 144 positions compared with A/Yunnan/1145/2005 (H3N2). There was no change in influenza B viruses either Victoria-like B or Yamagata-like B virus, i.e . antigenic characteristics is analogous to B/shenzhen/155/2005 and B/tianjin/144/2005, respectively.

CONCLUSIONThe H1N1 and H3N2 influenza viruses had changing antigenic and genetic characteristics in 2006. Influenza virus types B did not change in 2006.

Amino Acids ; analysis ; China ; Hemagglutination Inhibition Tests ; Hemagglutinin Glycoproteins, Influenza Virus ; chemistry ; genetics ; immunology ; Influenza A Virus, H1N1 Subtype ; immunology ; isolation & purification ; Influenza A Virus, H3N2 Subtype ; immunology ; isolation & purification ; Influenza B virus ; immunology ; isolation & purification ; Time Factors

Since March 2009, pandemic A/H1N1/2009 influenza virus has been spreading throughout many countries including China. The emerged virus caused great harm to human health and social economy. Hemagglutinin (HA) is the most important viral surface glycoprotein, mainly possessing three kinds of functions: (1) binding to host cell receptor, (2) triggering the fusion between viral envelop and target cell membrane, (3) stimulating the body to generate the neutralizing antibody. Advances in the structure, primary function, evolution and antigenicity of pandemic A/H1N1/2009 influenza virus HA protein are reviewed in this paper.
Animals ; Evolution, Molecular ; Hemagglutinin Glycoproteins, Influenza Virus ; chemistry ; genetics ; immunology ; metabolism ; Humans ; Influenza A Virus, H1N1 Subtype ; genetics ; immunology ; pathogenicity ; physiology ; Influenza, Human ; epidemiology ; virology ; Pandemics

Antibodies, Viral ; blood ; Hemagglutinin Glycoproteins, Influenza Virus ; chemistry ; genetics ; Humans ; Immunity, Cellular ; Immunity, Humoral ; Influenza A Virus, H1N1 Subtype ; immunology ; Influenza, Human ; epidemiology ; immunology ; Pandemics ; Time Factors

Influenza virus is the causative agent of the seasonal and occasional pandemic flu. The current H1N1 influenza pandemic, announced by the WHO in June 2009, is highly contagious and responsible for global economic losses and fatalities. Although the H1N1 gene segments have three origins in terms of host species, the virus has been named swine-origin influenza virus (S-OIV) due to a predominant swine origin. 2009 S-OIV has been shown to highly resemble the 1918 pandemic virus in many aspects. Hemagglutinin is responsible for the host range and receptor binding of the virus and is therefore a primary indicator for the potential of infection. Primary sequence analysis of the 2009 S-OIV hemagglutinin (HA) reveals its closest relationship to that of the 1918 pandemic influenza virus, however, analysis at the structural level is necessary to critically assess the functional significance. In this report, we report the crystal structure of soluble hemagglutinin H1 (09H1) at 2.9 Å, illustrating that the 09H1 is very similar to the 1918 pandemic HA (18H1) in overall structure and the structural modules, including the five defined antiboby (Ab)-binding epitopes. Our results provide an explanation as to why sera from the survivors of the 1918 pandemics can neutralize the 2009 S-OIV, and people born around the 1918 are resistant to the current pandemic, yet younger generations are more susceptible to the 2009 pandemic.
Animals ; Cloning, Molecular ; Crystallography, X-Ray ; Hemagglutinin Glycoproteins, Influenza Virus ; chemistry ; genetics ; immunology ; isolation & purification ; Influenza A Virus, H1N1 Subtype ; chemistry ; genetics ; immunology ; Models, Molecular ; Protein Conformation ; Swine ; virology

Preparation of maternal strain A/PR/8/34 HA antiserum for influenza virus classical reassortment. A/PR/8/34 virus was digested by bromelain after inactivation and purification. 5%-20% sucrose continuous density gradient centrifugation method was used to purify HA protein. SIRD method was used to select the target protein. SDS-PAGE method was used to identified HA protein. High Immunogenic A/PR/8/34 HA protein was successfully prepared and HI titer reached 10240. High purity HA antiserum was identified by SIRD method. The key reagent in the classical reassortment of influenza virus was prepared, and the complete set of technical methods were explored, which laid the foundation for the independent research and development of seasonal influenza vaccine strains of China.
Animals ; Antibodies, Viral ; immunology ; Electrophoresis, Polyacrylamide Gel ; Female ; Hemagglutination Inhibition Tests ; Hemagglutinin Glycoproteins, Influenza Virus ; analysis ; immunology ; Humans ; Influenza A Virus, H1N1 Subtype ; genetics ; immunology ; Influenza, Human ; immunology ; virology ; Rabbits ; Reassortant Viruses ; genetics ; immunology

Animals ; History, 20th Century ; Humans ; Influenza A Virus, H1N1 Subtype ; genetics ; immunology ; isolation & purification ; Influenza, Human ; epidemiology ; history ; immunology ; virology ; Russia ; epidemiology

Though the 2009 worldwide influenza A (H1N1) pandemic has been declared to have ended, the influenza virus is expected to continue to circulate from some years as a seasonal influenza. A rapid antigen test (RAT) can aid in rapid diagnosis and allow for early antiviral treatment. We evaluated the clinical usefulness of RAT using SD Bioline Influenza Antigen Test(R) kit to detect the influenza virus, considering various factors. From August 1, 2009 to October 10, 2009, a total of 938 patients who visited the outpatient clinic at Korea University Guro Hospital with influenza-like illnesses were enrolled in the study. Throat or nasopharyngeal swab specimens were obtained from each of the patients. Using these specimens, we evaluated the influenza detection rate by rapid antigen test based on the real-time reverse-transcriptase polymerase chain reaction (rRT-PCR) method. In comparison with rRT-PCR, the sensitivity and specificity of the RAT were 44.0% and 99.9%, respectively. The cyclic threshold values of RAT negative specimens were higher than RAT positive specimens (30.1+/-3.1 vs. 28.3+/-3.9, p=0.031). The sensitivity of the RAT kit was higher in patients who visited clinics within two days of symptom onset (60.4% vs. 11.1%, p=0.026). The results of this study show that the RAT cannot be recommended for general use in all patients with influenza-like illness because of its low sensitivity. The RAT may be used, only in the settings with limited diagnostic resources, for patients who visit a clinic within two days of symptom onset.
Antigens, Viral/genetics ; Humans ; Influenza A Virus, H1N1 Subtype/genetics/immunology/*isolation & purification ; Influenza, Human/*diagnosis/virology ; Reagent Kits, Diagnostic ; Reverse Transcriptase Polymerase Chain Reaction ; Sensitivity and Specificity ; Time Factors

On the basis of successful cloning the full length hemagglulinin (HA) and neuramidinase (NA) gene and sequence analysis of influenza virus H1N1, part of the gene was ligated into pMETA. Expression vectors pMETA/HA (52-1 557 bp) and pMETA/NA (121-1 263 bp) were constructed and expressed in pMAD16 induced by methanol. Recombinant protein was purified through Ni2+ affinity chromatography. Western blotting and ELISA were used to determine the antigenic activity of the recombinant protein. SDS-PAGE showed that the recombinant capsid gene could be overexpressed in Pichia methanolica. ELISA and Western blotting showed that the recombinant protein had antigenicity.
Cloning, Molecular ; Genetic Vectors ; genetics ; Hemagglutinins ; biosynthesis ; genetics ; Influenza A Virus, H1N1 Subtype ; genetics ; Neuraminidase ; biosynthesis ; genetics ; Pichia ; genetics ; metabolism ; Recombinant Proteins ; biosynthesis ; genetics ; immunology

The M1 and HA genes of H1N1 influenza virus were amplified and then cloned into the pFastBac dual donor plasmid. The recombinant pFastBac Dual-M1-HA was identified by restriction enzyme digestion. After the pFastBacdual-M1-HA was transformed into the baculovirus shuttle plasmid (bacmid) in DH10Bac competent cells, the colonies were identified by antibiotics and blue-white selection. The rBac-mid-M1-HA was verified by PCR and transfected into S f9 cells to produce recombinant baculovirus (rBac-M1-HA). Gene insertion of rBac-M1-HA was verified and the expression of M1 and HA genes was analyzed by IFA and Western-blot, demonstrating M1 and HA were co-expressed successfully. This study provides the foundation for researching the formation mechanism of influenza VLP and developing new influenza vaccines.
Animals ; Baculoviridae ; genetics ; metabolism ; Cell Line ; Cloning, Molecular ; Gene Expression ; Genetic Vectors ; genetics ; metabolism ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; immunology ; Influenza A Virus, H1N1 Subtype ; genetics ; immunology ; Spodoptera ; Transfection ; Viral Matrix Proteins ; genetics ; immunology

OBJECTIVETo review the epidemiologic and clinical characteristics of 96 cases with novel H1N1 influenza A, and improve the diagnosis and treatment level of novel H1N1 influenza A.

METHODS96 cases of novel H1N1 influenza A admitted to the isolation wards from Oct 20 to Sep 23, 2009 were studied. Their epidemiologic, clinical, laboratory, and radiologic characteristics were analyzed.

RESULTSThe median age of the 96 patients was 26.52 +/- 10.62 years (range, 5 to 60 years). Sixty-four of the 96 patients had a close contact with novel H1N1 influenza A patients. The main symptoms included fever 100%, cough 86.4% , sore throat 66.6% and myalgia 32.3%.

CONCLUSIONThe clinical presentation of novel H1N1 infection is largely indistinguishable from that of seasonal influenza. Combines both a symptom complex with the epidemiological investigation and laboratory characteristics can improve the accuracy of diagnosis of novel H1N1 influenza A.

Adolescent ; Adult ; Child ; Cough ; etiology ; Disease Outbreaks ; Female ; Fever ; etiology ; Humans ; Influenza A Virus, H1N1 Subtype ; genetics ; isolation & purification ; Influenza A virus ; immunology ; Influenza Vaccines ; immunology ; Influenza, Human ; epidemiology ; physiopathology ; Male ; Middle Aged ; Pharyngitis ; etiology ; Research Design ; Young Adult