Construction of Attenuated Influenza Virus Vaccines of Vaccines of-2006-2007 / 生物化学与生物物理进展

ABSTRACT

Six gene segments,PB1,PB2,PA,NP,M and NS,were fully synthesized which derived from the master donor virus (MDV),cold-adapted(ca),temperature sensitive(ts),live attenuated influenza virus strain A/Ann Arbor/6/60(MDV-A).Meanwhile,five amino acid substitutions (PB1-391E,58lG,661T,PB2-265S,NP-34G) were artificially altered by human intervention.HA and NA fragments derived from the 2006-2007 circulating strain A/New Caledonia/20/99 (H1N1).Eight fragments were ligated with modified pAD3000 for rescue plasmid construction.Eiight transcription/expression plasmids were named as pMDV-A-PB2,pMDV-A-PB1,pMDV-A-PA,pMDV-A-NP,pMDV-A-M,pMDV-A-NS,pMDV-A-HA,pMDV-A-NA,respectively.The COS-l cells were co-transfected with eight plasmids representing 6 internal viral backbone of the strain A/AA/6/60 and two plasmids containing the CDNA of the HA and NA segments of the strain A/New Caledonia/20/99 (H1N1),the results showed that cold-adapted,attenuated reassortant influenza A virus Was rescued successfully.Titers of a reassorted influenza A virus in embryonated chicken eggs mnged from 1:29to l:210.The rescue system of six intemal genes used as backbone opens the way for further research on gene function and neotype vaccine candidate of cold-adapted,live attenuated human influenza virus.