Studies on the mechamism of latency and reactivation of beta-herpesviruses

疱疹病毒（CMV、HHV-6和HHV-7）属于β-疱疹病毒亚科，在初次感染后潜伏感染体内。然而，潜伏期及其再激活的机制尚不清楚。Minamishima等报道了日本孕妇中CMV的血清阳性率，提示日本CMV感染率仍然很高，与欧洲和美国不同。Hirai等报道了CMV的UL 112/113基因产物是DNA复制所必需的，属于早期基因，pp 34抗体的出现与肾移植后的临床症状相关。Nishiyama等报道，在CMV感染的细胞中，I类MHC的H链合成正常，但在感染的细胞中，MHC从RES向高尔基体的转运受到抑制。因此，MHC不能到达细胞膜。Tsutsui等通过去除小鼠CMV的立即早期基因开发了转基因小鼠，并试图将其用作人类模型。Ihara等已经开发了中和HCMV的人源化单克隆抗体，并打算将其用于治疗器官移植后的CMV感染。Shiraki等在药用植物提取物中发现了抗CMV剂. Kurata等开发了HHV-6A在视网膜色素上皮细胞系中的潜伏系统. Nii等发现HHV-7在SupT 1细胞中持续感染。Yamanishi等按年龄比较了健康儿童唾液中HHV-6和HHV-7的检出率，提示HHV-7即使在成人中也高度分泌。此外，他们分析了一个可能在HHV-6基因表达调控中起重要作用的即刻早期基因。

Herpesviruses (CMV,HHV-6 and HHV-7), which belong to beta-herpesvirus subfamily, infect latently in vivo after the primary infection. However the mechanism of latency and its reactivation is not clear yet. Minamishima et al.reported the seroprevalence of CMV in pregnant women in Japan, suggesting the CMV infection in Japan is still high and different from that in Europe and USA.Hirai et al.reported that the gene products of UL112/113 of CMV,which belong to early gene, are essential for DNA replication, and the appearance of antibody to pp34 correlated with the clinical symptoms after the renal transplantation. Nishiyama et al reported that the H strand of MHC class I was synthesized normally in CMV-infected cells but the transport if MHC from RES to Golgi apparatus was inhibited in infected cells. Therefore, MHC can not reach the cell membrane. Tsutsui et al.have been developing the transgenic mice by transfecting a immediate early gene of mouse CMV and trying to use it as a human model. Ihara et al.have developed humanized monoclonal antibodies which neutrakize HCMV and are going to use them for treatment of CMV infection after the organ transplantation. Shiraki et al.found anti-CMV agents in the extract of medicinal plants. Kurata et al.developed the latent system of HHV-6A in a retinal pigment epithelial cell line. Nii et al.found that HHV-7 infects persistenly in SupT1 cells. Yamanishi et al.compared the detection rate of HHV-6 and HHV-7 in saliva of healthy children by age, suggesting that HHV-7 was highly secreted even in adults. Furthemore, they analyzed an immediate early gene which may an important role for the regulation of HHV-6 gene expression.