[Antigenic and genetic study of influenza virus (H1N1) circulated in China in 2004-2005].
BACKGROUND
To analyze the genetic and antigenic characteristics of hemagglutinin (HA) gene of human influenza (H1N1) virus isolated from the mainland of China since 2004 to 2005.


METHODS
The single-way hemagglutination inhibition (HI) tests were used to test the antigenic characteristics, and the HA1 gene was sequenced based on the antigenic results.


RESULTS
The single-way HI results showed that no virus isolates had 4-folds greater HI titer compared with A/Shanghai/1/1999 (H1N1) in 2004, but there was 6.3% virus had 4-fold greater difference in 2005. The HA1 sequence data showed that the H1N1 virus had the following amino acid mutations such as 54 K > R, 90 T > K, 101 Y > H, 149 R > K, 169 V > A, 190 D > N, 212 R > K, 219 K > R, 245 W > R, 246 Y > F, 258 T > N, 318 V > A and the 54 and 190 amino acids located in antigenic group of HA1.


CONCLUSIONS
The H1N1 virus was changing in antigenic and genetic characteristics.
Xu
Cui-ling
CL
Chinese Influenza Center, Institute for Viral Disease Control and Prevention, State Key Laboratory for Infectious Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 100052, China.
Xiang
Ni-juan
NJ
Zhang
Ye
Y
Wen
Le-ying
LY
Zhao
Xiang
X
Li
Zi
Z
Guo
Jun-feng
JF
Wang
Min
M
Yu
Hong-jie
HJ
Yang
Wei-zhong
WZ
Guo
Yuan-ji
YJ
Shu
Yue-long
YL
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002460:Cell Line; D002681:China / Q000453:epidemiology; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000145:classification / Q000235:genetics* / Q000276:immunology*; D007251:Influenza, Human / Q000097:blood / Q000453:epidemiology / Q000821:virology*; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
D000914:Antibodies, Viral; D012367:RNA, Viral