我国首例iVDPV病例Ⅱ型脊髓灰质炎病毒分离株的基因特征  

The Genetic Characterization of Type Ⅱ Immunodeficient Vaccine-derived Polioviruses Firstly Isolated in China

作　　者：张勇[1] 严冬梅[1] 王东艳[1] 朱贞[1] 刘中华[1] 赵月萍[2] 陈晓琴[2] 祝双利[1] 李崇山[1] 安洪秋[1] 许文波[1] 

机构地区：[1]中国疾病预防控制中心病毒病预防控制所,北京100050 [2]安徽省疾病预防控制中心,合肥230061

出　　处：《病毒学报》2007年第3期188-194,共7页Chinese Journal of Virology

基　　金：卫生部2005疾控和计免专项基金

摘　　要：对分离于我国首例iVDPV病例的Ⅱ型脊髓灰质炎病毒分离株的基因特征进行了研究。随机选择CHN9230-F3-Ⅱ株为研究对象,将其VP1区RT-PCR产物连接到T载体上进行克隆,随机挑选45个阳性克隆进行序列测定后获得45条VP1区核苷酸序列,这45条序列的VP1基因与昆明Ⅱ型疫苗株VP1基因差异13-24个核苷酸,变异率为1.44%-2.66%。45条序列在同源进化树图上分为3组,但都来源于CHN9230-F3-Ⅱ株,组成以优势株为主的相关突变株的病毒群,是典型的居群样存在形式。经RT-PCR后直接进行序列测定,并根据序列图中优势峰判读结果得到的CHN9230-F3-Ⅱ株核苷酸序列位于序列数量最多的第2组中,然而没有任何一条序列与之完全相同,说明它可能并不能代表具体的某一种序列,而只能是代表主序列具有的一般特征。3个组中的核苷酸序列与Ⅱ型疫苗株相比平均变异率分别为97.50%、97.93%和98.31%,根据脊灰病毒的进化率和3个组VP1区核苷酸序列的变异率推测,患者共5次服脊灰减毒活疫苗（OPV）史中的前3次OPV中的Ⅱ型疫苗病毒存活下来,依照疫苗接种顺序,分别形成了第1组、第2组和第3组的病毒居群样存在形式。我国Ⅱ型iVDPV以复杂的居群样形式存在,由于其进化速率较快并且感染了免疫缺陷患者,使其在该患者体内形成了持续性感染,它已经并可能将在更长的时间内在患者体内持续存在,一旦将来我国停止使用OPV后,iVDPV病例长期持续向外环境中排毒将对我国“维持无脊灰”带来严峻的挑战。To study the genetic characterization of type Ⅱ immunodeficient vaccine-derived polioviruses （iVDPVs） isolated from an immunodeficient patient in China, viral isolate CHN9230-F3-Ⅱ strain was randomly selected for analyzing. RT-PCR product of VP1 gene of CHN9230-F3-Ⅱ was ligated to T vector and cloned into E. coli-DH5a. 45 VP1 gene sequences were gained from 45 positive randomly selected clones. There were 13-24 nucleotide substitutions in VP1 gene as compared with that of type Ⅱ polio vaccine, the mutation rate ranged from 1.44% to 2.66%. 45 nucleotide sequences of the clones derived from CHN9230- F3-Ⅱ could be divided into 3 groups in the phylogenetic tree base on VP1 gene homology, forming a viral mutant population with a few preponderant sequences, and this was the so called typical quasispecies. The sequence of. CHN9230-F3-Ⅱ obtained by direct sequencing after RT-PCR belonged to Group 2 where involved the most of the cloned sequences, as the fact that there was no other sequences in Group 2 completely identifying to this sequence, so this sequence may not be the delegate of any of the concrete sequence but the common characterization of the master sequence. The average mutation rates of these 3 groups when compared with that of type II polio vaccine were 97.50%, 97.93% and 98.31% respectively, indicating that only type Ⅱ polio vaccine viruses during the first three OPV immunizations could survive according to the evolution rate of poliovirus and the mutation rate of the 3 groups. And the first three of the five OPV immunizations formed Group 1, Group 2 and Group 3 quasispecies successively. Type Ⅱ iVDPVs found in China in 2005 existed as complicated quasispecies with high mutation rate and the infection of immunodeficient patient lead a persistent infection, it has already long survived to now and seem will survive for a longer time hereafter, and when time of cessation of OPV occurs in the future, it will be a big challenge to ＂polio free＂ status in China, in fearing that the iVDPV pa

关 键 词：疫苗衍生脊髓灰质炎病毒(VDPV) 免疫缺陷 居群样 

分 类 号：R373.2[医药卫生—病原生物学]