[Antigenic and genetic characterizations of Victoria like strain of influenza B viruses isolated in China in 2001].
BACKGROUND
To understand the antigenic and genetic characteristics of Victoria like strain of influenza B virus isolated recently and to provide a scientific evidence for influenza surveillance and monitoring of influenza epidemic in future.


METHODS
Viruses were passed in embryonated hen eggs and virion RNA was extracted from allantoic fluid and reverse transcribed to synthesize cDNA. cDNA was amplified by PCR and the PCR product was purified with a purification kit. Afterwards RNA sequence analysis was performed by dideoxynucleotide chain termination and a cloning method. Finally, phylogenetic analysis of the sequencing data was performed with MegAlign.


RESULTS
B/Sichuan/63/2001 and B/Zhejiang/2/2001 viruses were antigenically different from B/Shandong/7/97 strain. The substitution of nucleotide sequences of HA1genes of them compared with those of B/Shandong/7/97strain resulted in the change of amino acid sequences in antigenic determinants on HA1 protein domain. The phylogenetic analysis also indicated that strains isolated recently were genetically different from B/Shandong/7/97/strain. However, there was neither differences on the antigenicity nor genetic partern between these two isotates.


CONCLUSIONS
The antigenic drift of Victoria-like strain of influenza B virus isolated recently in China has further occurred.
Zhang
Ye
Y
Institute of Virology, Chinese Academy of Preventive Medicine, Beijing 100052, China.
Wen
Le-ying
LY
Wang
Min
M
Guo
Jun-feng
JF
Li
Zi
Z
Guo
Yuan-ji
YJ
D000595:Amino Acid Sequence; D000940:Antigenic Variation; D002681:China; D000939:Epitopes; D014644:Genetic Variation; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics / Q000276:immunology; D006801:Humans; D009981:Influenza B virus / Q000235:genetics / Q000276:immunology; D007251:Influenza, Human / Q000821:virology; D008969:Molecular Sequence Data; D012367:RNA, Viral / Q000032:analysis; D017423:Sequence Analysis, RNA
D000939:Epitopes; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D012367:RNA, Viral