南京市部分幼儿TT病毒DNA检测及基因序列分析

Detection of TT virus DNA and sequence analysis of TTV gene in sera from young children in Nanjing

目的 了解幼儿人群中TT病毒的流行率及基因型别。方法 设计、合成引物 ,采用半套式聚合酶链反应 (hemi nestedPCR)方法检测幼儿血清标本并进行序列分析。结果 在 110份幼儿血清中 ,TTVDNA总检出率为 12 73 %。在 10 7名ALT正常 ,抗HAV IgM、HBsAg、抗HCV阴性的幼儿血清中 ,TTVDNA检出率为 11 2 % (12 / 10 7) ;从 1名ALT升高幼儿血清中检出TTVDNA ,从 2名HBsAg阳性幼儿血清中检出TTVDNA阳性血清 1份。对 2株TTVDNA阳性株序列分析结果显示 ,它们与日本分离株N2 2、TA2 78(G1a)、TX0 11(G1b)、TS0 0 3(G2a)、NA0 0 4(G2b)和中国株CHN1相应位置核苷酸序列的同源性分别为 83 3 % / 86 9%、84 2 % / 87 8%、93 7% / 98 6 %、6 7 6 % /6 7 1%、6 4 9% / 6 4 4%、83 8% / 88 3 % ,经系统发育分析它们同属于G1b型。结论 幼儿人群中存在TTV感染 ,TTV流行率为 12 73%。TTV感染可能存在血源传播途径外的其他传播途径 。

Objective To investigate the prevalence of TTV genomes in young children from Nanjing and establish the PCR method for detecting TTV DNA. Methods A hemi nested polymerase chain reaction (PCR) assay was established to detect TTV DNA in 110 young children and two PCR amplified products were sequenced and the data were analyzed with the computer programs. Results TTV DNA was detected in 14 out of 110 children,and 222 bp sequences of 2 isolates from the children were analyzed. Compared with representative of published isolates,they have the nucleotide identity of 93.7%-98.6% with TX011. Conclusions The infection rate of TTV in children is 12.73%,and 2 isolates from children belong to subgroup G1b. Our results indicates that TTV could be transmitted via other pathway besides hematogenous one,and TTV could be carried by healthy population.