Experimental studies of latency and persistence in vitro by human cytomegalovirus

人巨细胞病毒（HCMV）能够在体内原发性感染后建立持久和潜伏感染。为了研究HCMV在体内潜伏和持续感染的机制，我试图利用人类细胞培养物建立并表征体外HCMV潜伏和持续感染模型系统。人甲状腺乳头状癌细胞（TPC-1）感染HCMV后，在37℃和40.5℃孵育，分别建立持续感染和潜伏感染的培养物。通过改变孵育温度，病毒的潜伏和持续状态是可逆的。尽管在潜伏期可以检测到HCMV特异性的早期蛋白和抗原，但没有诱导出可检测水平的病毒特异性DNA聚合酶，这表明在潜伏感染的培养物中，HCMV复制的阻断发生在HCMV复制蛋白周期的早期阶段。潜伏感染的细胞易受同源和异源HCMV毒株的重复感染，并对补体介导的免疫细胞溶解具有抗性。将孵育温度从40.5℃降至37℃，可重新激活潜伏的HCMV。然而，当潜伏感染的培养物在转移到37后立即用前列腺素合成抑制剂（吲哚美辛和丁嘌呤）处理时，未观察到潜伏病毒的再激活。

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.