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为揭示广东地区2007～2010年甲型H3N2毒株血凝素(HA)基因特征和变异,采用时空抽样方法抽样,检测广东2007～2010年甲型H3N2毒株HA基因核苷酸序列,同时检索全球HA基因序列作为对照,采用Lasergene7.1和Mega 5.05软件对HA基因核苷酸序列进行比对和分析;并结合流行病学资料,对变异毒株进行进化速度分析;同时进行抗原分析。结果发现,广东2007～2010年H3N2毒株HA基因同义进化(Ks)和错义进化(Ka)速度分别为2.06×10-3～2.23×10-3核苷酸/年和1.05×10-3～1.21×10-3核苷酸/年,HA1较HA2的错义突变速率要高3.13倍。与疫苗株A/Perth/16/2009的HA基因比较,2009年广东毒株同源性达到98.8%～99.7%、2010年同源性达到98.0%～98.4%。在广东2007～2010年毒株中,HA1五个抗原表位均有氨基酸位点变异,尤其是2010年毒株B区(N160K)和D区(K174R/N)的变异;此外,广东2010年毒株受体结合部位(RBS)还发生K189E/N/Q和T228A置换变异;两个糖基化位点变异影响到抗原性;目前使用的H3N2疫苗株与目前流行毒株的抗原性有差异。广东地区2007～2010年的毒株中,血凝抑制抗体的抗原分析结果有差异。结果提示,目前广东乃至全球甲型H3N2毒株HA1B区和D区均有氨基酸位点变异,RBS的两个位点发生置换,糖基化位点变异影响到表位A区和B区抗原性;与WHO推荐2011年流感H3N2毒株疫苗株比较,目前流行毒株HA基因有抗原位点变异。
To reveal the genetic characteristics and variation of hemagglutinin (HA) gene of H3N2 strain in Guangdong from 2007 to 2010, the nucleotide sequence of HA gene of H3N2 strain in Guangdong from 2007 to 2010 was detected by sampling by time-space sampling method. Global HA gene sequence as a control, using Lasergene7.1 and Mega 5.05 software to align and analyze the HA gene nucleotide sequence; combined with epidemiological data, evolutionary analysis of the evolution of the mutant strains; simultaneous antigen analysis. The results showed that the HA gene evolutionary evolution (Ks) and missense evolution (Ka) velocities of H3N2 strains in Guangdong from 2007 to 2010 were 2.06 × 10-3 ~ 2.23 × 10-3 nucleotides / year and 1.05 × 10 ~ 3 ~ 1.21 × 10-3 nucleotides / year, the mutation rate of HA1 was 3.13 times higher than that of HA2. Compared with the HA gene of the vaccine strain A / Perth / 16/2009, the homology of Guangdong strains reached 98.8% -99.7% in 2009 and reached 98.0% -98.4% in 2010. In Guangdong province from 2007 to 2010, all the five epitopes of HA1 had amino acid site variation, especially the variation of strain B (N160K) and D (K174R / N) in 2010; in addition, Guangdong 2010 Mutations in K189E / N / Q and T228A also occur at the RBS binding site; variations in the two glycosylation sites affect antigenicity; the antigenicity of the currently used H3N2 vaccine strain is different from that of currently available strains . Among the isolates in Guangdong Province from 2007 to 2010, there were differences in the antigen analysis results of the hemagglutination inhibition antibody. The results suggest that at present there are amino acid site variations in HA1B and D regions of H3N2 strain in Guangdong and even in the world. The two sites of RBS are replaced, and the variation of glycosylation sites affects the antigenicity of epitopes A and B ; Compared with the WHO recommended influenza H3N2 vaccine strain in 2011, there are antigenic site variation in HA gene of the currently prevailing strains.