Morey A L, Ferguson D J, Fleming K A
University of Oxford, Nuffield Department of Pathology and Bacteriology, John Radcliffe Hospital, U.K.
J Pathol. 1993 Feb;169(2):213-20. doi: 10.1002/path.1711690207.
Human parvovirus B19 cannot be cultured in standard cell lines and relatively little is known about the intracellular life-cycle of the virus. In this study, ultrastructural features of B19 infection were examined using haemopoietic cell suspension cultures derived from human fetal liver. Erythroblasts from infected cultures frequently contained crystalline arrays of both full and empty virus-like particles. The number and size of these arrays increased with the duration of culture, and their location changed from exclusively nuclear at 24 h post-infection to both nuclear and cytoplasmic at 3 days post-infection. Arrays were occasionally found in cytoplasmic protuberances which appeared to be pinching off from the cell. The location of the arrays corresponded to the distribution of viral capsid protein determined by immunolabelling at the light microscope level. Cells containing viral crystalline arrays also exhibited nucleolar degeneration, extreme margination of the nuclear heterochromatin, and cytoplasmic vacuolation. These features are typical of cells undergoing individual programmed cell death or 'apoptosis'. The triggering of apoptosis in erythroid precursors by parvovirus B19 may help to explain the apparent lack of a strong inflammatory response to fetal B19 infection and may have implications for understanding the mechanisms of viral spread throughout the host.
人细小病毒B19无法在标准细胞系中培养，人们对该病毒的细胞内生命周期了解相对较少。在本研究中，利用源自人胎儿肝脏的造血细胞悬浮培养物检测了B19感染的超微结构特征。受感染培养物中的成红细胞经常含有完整和空的病毒样颗粒的晶体阵列。这些阵列的数量和大小随培养时间的延长而增加，其位置从感染后24小时的仅细胞核内，变为感染后3天的细胞核和细胞质内均有。在似乎从细胞上掐断的细胞质突起中偶尔发现阵列。阵列的位置与在光学显微镜水平通过免疫标记确定的病毒衣壳蛋白分布相对应。含有病毒晶体阵列的细胞还表现出核仁变性、核异染色质极度边缘化和细胞质空泡化。这些特征是经历个体程序性细胞死亡或“凋亡”的细胞所特有的。细小病毒B19触发红系前体细胞凋亡可能有助于解释对胎儿B19感染明显缺乏强烈炎症反应的现象，并且可能对理解病毒在整个宿主体内传播的机制具有启示意义。
