Development of genotyping method for TT virus (TTV) and its application to elucidation of pathogenesis.

1997年，我们从一名输血后急性肝炎患者的血清中分离到一种新的DNA病毒，并将其命名为TT病毒（TTV）。的索引患者。最近，国际病毒分类委员会（ICTV）的TTV研究小组提出了TTV的分类命名法：该项目的首席研究员（H.O.）是研究小组的成员它被命名为Torque Teno病毒（TTV）：这个名字来自“Torque”，意思是项链，“Tenuis”意思是薄，与其DNA基因组的环状单链性质有关。TTV被归类为一个新的漂浮属，即Anelovirus属，该属尚未被分配到一个科。该属的名称Anellovirus来自“anello”，意思是环，与DNA基因组的环状性质有关。TTV作为DNA病毒具有广泛的序列差异，已经鉴定了大约40种基因型。在本研究中，我们进一步将它们分为5个远缘遗传组（组1-5），并开发了一种选择性PCR方法，使用特异性寡核苷酸引物的TTV的5个遗传组的每个TTV分类到5个遗传组。使用这种PCR方法，我们研究了TTV的五个遗传组的患病率与年龄的关系。第4组TTV流行于幼儿期，在五个已知的遗传组中，最常在成年期检测到。第1组TTV在> 6个月的婴儿中检出。其发生率随年龄增长而增加，成年期为10-15%。第3组TTV基因型最多（包括SENV基因型A ~ H在内的15种基因型），成年后与第1组TTV和/或第4组TTV共感染。目前，我们已经建立了一种实时定量检测第1、2、3、4、5组TTV的方法，并尝试将其应用于临床调查。

In 1997, we isolated a novel DNA virus from the serum of a patient with posttransfusion acute hepatitis of unknown etiology and named it TT virus (TTV) after the initials (T.T.) of the index patient. Recently, taxonomic nomenclature for TTV has been proposed by the TTV study group of the International Committee on Taxonomy of Viruses (ICTV) : head investigator of this project (H.O.) was a member of the study group. It was designated as Torque Teno virus (TTV): this name was derived from "Torque" which means the necklace, and "Tenuis" means thin, and relates to circular, single-stranded nature of its DNA genome. TTV was classified into a novel floating genus, the Anellovirus genus, which has not yet been assigned to a family. The name of the genus, Anellovirus, was derived from "anello," which means the ring, and relates to the circular nature of the DNA genome. TTV has a wide range of sequence divergence for a DNA virus, and approximately 40 genotypes have been identified. In the present study, we classified them further into five distantly related genetic groups (Groups 1-5), and developed a selective PCR method using oligonulceotide primers specific for TTVs of each of the five genetic groups to classify TTVs into the five genetic groups. Using this PCR method, we examined the prevalence of five genetic groups of TTV in relation to age. TTVs of group 4 were prevalent in early childhood, and detected most frequently in adulthood among the five known genetic groups. TTVs of group 1were detectable in infants aged> 6 months. Its frequency increased with age and was 10-15% in adulthood. TTVs of group 3 comprised the greatest number of genotypes (15 genotypes including SENV of genotypes A to H), were coinfected with TTVs of group 1 and/or TTVs of group 4 in adulthood. Presently, we have established a real-time detection method for quantitating TTVs of group 1,2,3,4 or 5 with an attempt to apply it to clinical surveys.