Hodgkin P D, Scalzo A A, Swaminathan N, Price P, Shellam G R
Department of Microbiology, University of Western Australia, Nedlands, Perth.
J Virol Methods. 1988 Dec;22(2-3):215-30. doi: 10.1016/0166-0934(88)90104-8.
In a study of the infection of mouse embryo fibroblasts with murine cytomegalovirus (MCMV), we found that plaque number is directly related to virus concentration and not to the total amount of virus contained in the inoculum. These results suggested that virus binding was reversible and that during infection a binding equilibrium is established which limits the amount of bound virus. Further analysis revealed three categories of plaque based on reversibility after virus adsorption. One group was removed simply by washing cell monolayers after virus removal. A second group of plaques was lost gradually with time, giving complete reversal after 5 min at 37 degrees C. The rate of reversal was temperature dependent, and probably represented true virus dissociation. The final group was irreversible plaques, the number of which increased with increasing infection time. The number of reversible plaques remained constant with time of infection, and represented about 70% of the total plaques after 1 h of virus adsorption. Centrifugation of the virus inoculum onto the fibroblast monolayer at 1000 X g increased plaque numbers up to 100-fold, but had little effect on plaque number when carried out after the virus inoculum was removed. In contrast centrifugation increased the number of reversible plaques, suggesting an increase in the number of virus particles attached to the cell monolayers. We suggest that centrifugation enhances MCMV infection by three mechanisms related to reversibility of binding: (1), it increases the rate of virus association; (2), it decreases the rate of dissociation; (3), by increasing the length of time each virus particle is bound it increases the probability of virus being taken into the cell.
在一项关于小鼠胚胎成纤维细胞感染鼠巨细胞病毒（MCMV）的研究中，我们发现蚀斑数量与病毒浓度直接相关，而与接种物中所含病毒的总量无关。这些结果表明病毒结合是可逆的，并且在感染过程中会建立一个结合平衡，该平衡限制了结合病毒的量。进一步分析显示，根据病毒吸附后的可逆性可将蚀斑分为三类。一类在去除病毒后只需通过洗涤细胞单层即可去除。第二类蚀斑会随时间逐渐消失，在37℃下5分钟后完全逆转。逆转速率取决于温度，可能代表真正的病毒解离。最后一类是不可逆蚀斑，其数量随着感染时间的增加而增加。可逆蚀斑的数量随感染时间保持恒定，在病毒吸附1小时后约占总蚀斑的70%。以1000×g的速度将病毒接种物离心到成纤维细胞单层上，蚀斑数量可增加多达100倍，但在去除病毒接种物后进行离心对蚀斑数量影响很小。相比之下，离心增加了可逆蚀斑的数量，表明附着在细胞单层上的病毒颗粒数量增加。我们认为离心通过与结合可逆性相关的三种机制增强MCMV感染：（1），它增加了病毒结合的速率；（2），它降低了解离的速率；（3），通过增加每个病毒颗粒的结合时间，它增加了病毒进入细胞的概率。
