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目的研究中国(未包括香港、澳门特别行政区和台湾地区,下同)2011年急性弛缓性麻痹(Acute Flaccid Paralysis,AFP)病例粪便标本中分离到的Ⅲ型(Type 3)脊髓灰质炎(脊灰)病毒(Poliovirus,PV)(PV_Ⅲ)分子生物学特征,为中国维持无脊灰提供实验室依据。方法采用逆转录-聚合酶链反应(Reverse Transcription-Pogymerase Chain Reaction,RT-PCR)对PV_Ⅲ的衣壳蛋白VP_1编码区基因进行扩增,并对PCR产物进行核苷酸序列测定和分析,对VP_1编码区的核苷酸神经毒力位点和突变热点进行分析,并建立亲缘关系进化树,分析毒株间的进化关系。结果中国2011年从AFP病例粪便标本中,共分离到159株PV_Ⅲ,包括149株疫苗类似株PV和10株免疫缺陷相关的疫苗衍生(Immunodeficiency-associated Vaccine-derived)PV(i_VDPV),未发现Ⅲ型野生型(Wild Type)PV(WPV_Ⅲ)。15株PV_Ⅲ均在VP_1编码区基因已知的神经毒力位点核苷酸2493发生突变。结论突变热点的存在说明PV_Ⅲ的VP_1编码区的核苷酸变异并不是随机分布的,PV_Ⅲ的VP_1编码区基因突变热点可能与PV_Ⅲ的生物学特性有一定的关系。从宁夏回族自治区发现的10株i_VDPVs与以往发现的i_VDPV基因进化上无相关性,证明是新发现的i_VDPV。对VP1编码区的检测为继续维持中国无脊灰状态,为及时发现VDPCs传播和WPV的输入性爆发提供实验室依据。
Objective To study the effects of poliovirus type 3 (Type 3) polio isolated from stool samples of Acute Flaccid Paralysis (AFP) cases in 2011 in China (excluding Hong Kong SAR, Macao SAR and Taiwan) ) Poliovirus (PV) (PV_III) molecular biology characteristics, providing laboratory basis for maintaining poliovirus in China. Methods The capsid protein VP_1 coding region of PV_III was amplified by reverse transcription-polymerase chain reaction (RT-PCR). The PCR products were sequenced and analyzed. The VP_1 Nucleotide nucleotide virulence sites and mutation hot spots in the coding region were analyzed, and the phylogenetic tree was constructed to analyze the evolutionary relationships among the strains. Results A total of 159 PV_III strains were isolated from the stool specimens of AFP in China in 2011, including 149 vaccine-like PVs and 10 immunodeficiency-associated Vaccine-derived PVs (i_VDPV). No Ⅲ Wild Type PV (WPV_III). Fifteen PV_Ⅲ mutants were found in nucleotides 2493 at the known neurovirulence site of VP_1 coding region. Conclusion The existence of mutated hot spots indicates that the nucleotide variations of VP_1 coding region in PV_III are not randomly distributed. The hot spots in the PV_1 coding region of PV_Ⅲ may have some relations with the biological characteristics of PV_III. The 10 i_VDPVs found in Ningxia Hui Autonomous Region were not related to the i_VDPV gene previously found, which proved to be a newly discovered i_VDPV. The VP1 coding region was detected in order to maintain polio-free status in China, providing a laboratory basis for discovering the spread of VDPCs and WPV input in time.