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In this study, the swabs were collected among patients with an influenza-like illness (ILI) admitted to 2 sentinel surveillance hospitals of Yantai from April 2014 to August 2017. All specimen were cultured and identified by hemagglutination inhibition assay. Complete sequences of Hemagglutinin (HA) of influenza A were amplified, sequenced and analyzed using molecular and phylogenetic methods. The potential vaccine efficacy were calculated using Pepitope model. The results showed that the antigenicity of A (H3N2) had changed greatly. 8 strains of influenza A (H1N1) pdm09 belonged to subclade 6B.1 and 14 strains clustered in 6B.2. 12 strains of influenza A (H3N2) fell into subgroup 3C.3a and 33 strains clustered in 3C.2a. Several residues at antigen sites and potential glycosylation sites had changed in influenza A strains. Vaccine efficacy of influenza A (H1N1) pdm09 in 2015/2016 and 2016/2017 seasons were 77.29% and 79.11% of that of a perfect match with vaccine strain, meanwhile vaccine efficacy of influenza A (H3N2) in 2014/2015, 2015/2016 and 2016/2017 were-5.18%, 16.97% and 42.05% separately. In conclusion, the influenza A virus circulated in Yantai from 2014 to 2017 presented continual genetic variation. The recommended vaccine strains still afforded protection against influenza A (H1N1) pdm09 strains and provided suboptimal protection against influenza A (H3N2) strains.
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Objective To investigate the preparation of influenza virus vaccine without thimerosal for children dose and its sta-bility .Methods H1N1 ,H3N2 ,B-type influenza virus were inoculated into allantoic fluid to prepare three batches of influenza virus vaccine without thimerosal for children dose and the vaccine stability test was performed .Single radial immunodiffusion(SRID) and enzyme-linked immunosorbent assay(ELISA) were used to detect the concentration of hemagglutinin and egg albumin .Total protein concentration ,appearance ,sterility test ,endotoxin ,free formaldehyde and the pH value of vaccine were also measured .Results The pH value of vaccine was 7 .2 ,with total protein concentration of 182-189 mg/mL .Hemagglutinin concentrations of H1N1 ,H3N2 and B-type influenza virus decreased when they had been placed in 2-8 ℃ for 3 ,6 ,9 ,12 ,18 months or (37 .0 ± 2 .0) ℃ for 7 ,14 days ,however ,they maintained at 6 .0 μg/0 .25 mL or more at last .Conclusion Influenza virus vaccine without thimerosal for chil-dren dose shows improved safty and is accord with the standard of Chinese Pharmacopoeia(2010 edition) .
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ObjectiveTo understand the detections of influenza A (H1N1) in 2009,and haemagglutinin (HA) gene mutations and the comparisons with standard strains.MethodsThe nasopharyngeal swabs from patients with influenza-like illness (ILI) in National Influenza Sentinel Surveillance Hospital and the outbreak epidemic area were collected.The virus typing and A (H1N1) viruses were tested by real time-polymerase chain reaction (RT-PCR).Then the pathogens were isolated with MDCK cells,the virus titer was determined with hemagglutination test and the virus typing was identified with hemagglutination inhibition test (HA1).The RT-PCR products of HA1 gene of virulent strains were sequenced and then analyzed through bioinformatics.Results A total of 996 pharyngeal swab specimens were tested,and nucleic acid positive cases included 337 A (H1N1) subtype,1 seasonal A (H1N1) subtype,67 A (H3N2) subtype,and 12 B type.The positive rate of nucleic acid detection of influenza was 41.87％ and that of A (H1N1) was 33.84％.Thirty-six influenza A (H1N1) virus strains were isolated,and 10 of them were successfully sequenced and several amino acid mutations were identified.There were 6 amino acid mutations found compared with vaccine strain A/California/07/2009 (H1N1),and 1 site was in area B of epitope.Conclusions A (H1N1) is absolute predominant among isolated strains in 2009.HA gene of virulent strains is mutated compared with vaccine strain provided by World Health Organization,which shows that the area B of epitope changes,while the key amino acid position 222 doesn't change.
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Objectives To explore the type and subtype distribution of influenza viruses in influenza-like patients and the hemagglutinin(HA)genetic variation of influenza A viruses in Shang- hai and Wuxi during the influenza prevalent season from 2004 to 2006.Methods Throat swabs were collected from the influenza-like patients in the sentinel hospitals and during the outbreaks,and then inoculated into MDCK cells to isolate influenza viruses,which were subsequently identified by direct immunofluorescence(DIF)and reverse transcription-polymerase chain reaction(RT-PCR).HA seg- ments of influenza A viruses were sequenced to analyze the genetic variation of HA.Results One hundred and twenty-six strains of influenza viruses,including 53 H3N2,43 H1N1 and 30 influenza B viruses were isolated from August 2004 to September 2006,and 7 outbreaks.All these outbreaks oc- curred in February or March The pathogens were identified as H1N1 in one outbreak,H3N2 in two outbreaks,B in two outbreaks and mix infections in two outbreaks(1 H1N1 and B,1 H3N2 and B, respectively).By sequencing the HA segment,the H3 and H1 segments were all homologous to the isolates from different countries in the same period.Conclusion H3N2 and H1N1 are the major strains prevalent in Shanghai and Wuxi,which reach the peak from January to March No HA and NA recom- binant strains and new HA and NA subtypes are found in these areas.The variations of H1 and H3 are similar to those found in other countries.
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Objective: To construct an eukaryotic expression plasmid containing gene coding for the hemagglutinin neuraminidase(HN) of Newcastle disease virus (NDV), and to study its mechanism and value in antitumor therapy. Methods: The HN cDNA was abtained from NDV with RT PCR and an eukaryotic expression vector of HN gene ( pcDNA3 HN ) was constructed. The antitumor effect was evaluated after injecting pcDNA3 HN into mice bearing B16 melanoma. Results: The HN cDNA of NDV was successfully cloned and pcDNA3 HN had a good expression in COS 7 cells. Animal experiments suggested that the pcDNA3 HN could significantly increase CTL and NK activity of tumor bearing mice. Conclusion:The eukaryotic expression plasmid containing the gene coding for the (HN) has the function of increasing CTL and NK activity of tumor bearing mice.