Virological and molecular biological studies on human herpsvirus 6 (HHV-6).

1.HHV-6滴定系统和中和系统的建立：采用外周血淋巴细胞对病毒进行滴定。最近，我们利用已建立的细胞系MT-4细胞开发了一种新的病毒滴定和中和试验系统。由于该系统既可用于病毒滴定，又可用于抗体检测，故在日本和泰国进行了血清流行病学研究。HHV-6的DNA克隆和序列分析：1989年开始进行HHV-6的DNA克隆和序列分析。由于DNA的大小太大，我们还不能完成，但我们正在识别其中的一些。在此基础上，建立了聚合酶链反应（PCR）检测HHV-6 DNA的系统，并将该系统应用于潜伏系统中HHV-6 DNA的检测，以及淋巴瘤、慢性疲劳综合征等多种临床样本的DNA检测。HHV-6病毒多肽分析：对HHV-6病毒粒子进行纯化和分析。鉴定出29种多肽，包括6种糖蛋白。收集HHV-6糖蛋白单克隆抗体后，对3种糖蛋白的生物活性和在感染细胞中的加工进行了表征。此外，发现HHV-6可诱导病毒特异性DNA聚合酶，但不能诱导胸苷激酶。HHV-6感染动物系统的建立：虽然我们在小型啮齿类动物中没有发现任何动物系统，但我们可以在各种猴子中检测到HHV-6抗体。近年来我们发现食蟹和非洲绿猴可感染HHV-6，该系统将为今后HHV-6的潜伏感染系统和发病机制分析提供依据

1.Establishment of titration system and neutralizing system of HHV-6: We have been using peripheral blood lymphocytes to titrate virus. Recently we could develop a new system by using MT-4 cells, which is a established cell line, for titration of virus and for neutralizing test. Since this system is useful for not only titrate virus but also antibody test, seroepidemiology in Japan and Thailand were attempted.2.Analysis of HHV-6 DNA by cloning and sequence: DNA cloning and its sequences of HHV-6 have been done since 1989. Since size of DNA is so big, we could not complete yet, but we are identifying some of them. On the way of this process, the system of detection of HHV-6 DNA by polymerase chain reaction (PCR) has been developed, and we have used this system for detection of HHV-6 DNA in the latent system and for detection of DNA in various clinical samples such as lymphoma, chronic fatique syndrome.3.Analysis of polypeptide of HHV-6: The virion of HHV-6 were purified and analyzed. More than 29 polypeptide including 6 glycoproteins were identified. After collection of monoclonal antibodies to glycoproteins of HHV-6, 3 glyproteins were characterized by biological activity and processing of them in infected cell. Furthermore, it was found HHV-6 induce virus specific DNA polymerase, but not thymidine kinase.4.Development of animal system for HHV-6 infection: Although we could not find any animal system in small' rodents, we could detect antibodies to HHV-6 in various monkeys. Recently we could find cynomolgus and African green monkeys can be infected with HHV-6, and this system will be useful for the system of latent infection and analysis of pathogenesis of HHV-6 in future