Genetic Characterization of H1N1 Influenza A Virus Obtained from Shenzhen in 2009

Objective To compare the susceptivity of novel H1N1 influenza virus on MDCK cell and chick embryos,and to identify the characteristics of influenza isolates for influenza vaccine developing.Methods The influenza virus was isolated from both MDCK cell and chick embryos,and reverse transcriptase polymerase chain reaction(RT-PCR)was conducted to identify the subtype of influenza virus.The sequences of novel H1N1 influenza virus were compared to NCBI database by using Clustal and MEGA4.1 software.Results Of 334 respiratory specimens,134 strains of novel H1N1 were isolated through MDCK cell culture,with the positive rate of 40.12%,and 150 strains were isolated through embryonated chicken's egg culture,with the positive rate of 44.91%.The sequences of 344 amino acids in 10 strains of novel H1N1 were obtained and then compared with international representative strain A/California/07/2009,only a few of sites were changed.After virus infection,it would take 9 days to produce protective antibodies.Conclusions The susceptivity of novel H1N1 influenza virus on MDCD cell and embryonated chicken's eggs is similar.Antigenic change is not found among the novel H1N1 strains.