Experimental studies of latency and persistence in vitro by human cytomegalovirus

人巨细胞病毒(HCMV)可在体内建立持续感染和潜伏感染。为了研究人巨细胞病毒在体内潜伏感染和持续感染的机制，本研究利用人细胞培养技术建立了人巨细胞病毒潜伏感染和持续感染的体外模型，并对其进行了表征。人甲状腺乳头状癌细胞株(TPC-1)感染人巨细胞病毒后，在37℃和40.5℃培养，可分别建立持续感染和潜伏感染的细胞系。通过改变孵育温度，病毒潜伏状态和持续状态是可逆的。虽然在潜伏期内可以检测到HCMV特异性的即刻早期蛋白和抗原，但没有诱导出可检测到的病毒特异性DNA聚合酶水平，这表明在潜伏感染的培养物中，HCMV复制的阻断发生在HCMV复制周期的早期阶段。潜伏感染的细胞对HCMV同源和异种毒株的重叠感染敏感，对补体介导的免疫细胞溶解具有抵抗力。将孵育温度从40.5℃降至37℃，可使潜伏的HCMV重新激活。然而，当潜伏感染的培养物在转变到37后立即用前列腺素合成的抑制剂(吲哚美辛和四环素)处理时，没有观察到潜伏病毒的重新激活。

Human cytomegalovirus (HCMV) is capable of establishing both persistent and latent infections after a primary infection in vivo. For study of the mechanisms of HCMV latent and persistent infections in vivo, I have attempted to establish and characterize an in vitro HCMV latency and persistence model system using human cell cultures. When a human thyroid papillary carcinoma cell line (TPC-1) was infected with HCMV and incubated at 37 or 40.5 , persistently or latently infected cultures could be established, respectively. The virus latent and persistent states were reversible by shifting the incubation temperature. Although HCMV-specific immediate early proteins and antigens were detectable during the latent period, a detectable level of virus-specified DNA polymerase was not induced, suggesting that the blockage of HCMV replication in the latently infected cultures occurs at the early stages of the HCMV replicatin cycle. The latently infected cells were shown to be susceptible to superinfection with homologous and heterologous strains of HCMV and to be resistance to complement-mediated immune cytolysis. The latent HCMV was reactivated by reducing the incubation temperature from 40.5 to 37 . However, when the latently infected cultures were treated with inhibitors of prostaglandin synthesis (indomethacin and tetracatine) immediately after being shifted to 37 , reactivation of the latent virus was not observed.