母婴配对血清中TT病毒的分子鉴定

为了解TT病毒（TTV）在我国母婴间传播的可能及分子病毒学依据，合成引物（引物1：5′－ACAGACAGAGGAGAAGGCAACATG－3′；引物2：5′－CTGGCATTTTACCATTTCCAAAGTT－3′；引物3；5′－GGCAACATGTTATGGATAGACTGG－3′），采用半套式聚合酶链反应（hemi-nested PCR）方法，检测了40对母、婴母对血清中的TTV DNA，并对TTV DNA均阳性的一对母婴配对血清中PCR产物进行测序和序列分析，结果发现：（1）在40例产妇血清中，有5例经半套式PCR检出了TTV DNA，检出率为12.5%；40例脐血中，检出TTV DNA阳性血清1例，阳性率为2.5%，脐血呈阳性的新生儿母亲静脉血中TTV DNA也为阳性。（2）母婴同时检出TTV DNA的血清PCR产物经测序后进行序列比对，二者病毒核苷酸序列的同源性为1005；与日本G2b型代表株核苷酸同源性为98.6%，属于G2b亚型，研究结果表明：TTV存在母婴传播途径，TTV可经胎盘垂直传播。

Molecular Virology Identification of Mother to Infant TTV Transmission

To investigate mother to infant transmission of IT vims. A hemi-nested polymerase chain reaction (PCR) assay was established to detect TTV DNA in 40 pairs of sera from mother and paired cord sera, and the PCR-amplified products from a mother and her infant was sequenced and the sequences were analyzed with the computer programs. TTV DNA was detected in 5 of 40 sera of the mother, and 1 of 40 core sera of infant was TTV DNA positive while his mother was TIV infected. 222bp sequences of the infant and his mother were analyzed, and the DNA sequences showed 100% homology between them. When compared these sequences with representative of published isolates, which show that hey have the nucleotide identity of 98. 6% with NA004 and they belong to G2b subgroup. Tl'V can cross the placenta and that transmission in uterus is an important means of TTV diffusion. There is a possibility of mother to infant transmission of TTV.