Turco J, Winkler H H
Infect Immun. 1982 Mar;35(3):783-91. doi: 10.1128/iai.35.3.783-791.1982.
The growth of avirulent (E) and virulent (Breinl) strains of Rickettsia prowazekii was compared in four mouse macrophage-like cell lines (RAW264.7, J774.1, P388D1, and PU5), one human macrophage-like cell line (U937-1), and the mouse fibroblast line L929. The E and Breinl strains grew equally well in L929 cells. However, all of the mouse macrophage-like cell lines clearly differentiated between the two strains by restricting the growth of the E strain relative to that of the Breinl strain. A nonuniform response to infection was sometimes observed in which E strain rickettsiae were cleared from the majority of the infected cells, but multiplied in some of the remaining infected cells. The human line U937-1 was not very effective at differentiating the E and Breinl strains. Addition of rabbit antirickettsial antiserum to the Breinl or E strains of R. prowazekii immediately before infection of L929 cells caused a marked decrease in the initial infection but had no effect on the subsequent growth of the rickettsiae in the L929 cells. In contrast, addition of antiserum to Breinl or E strain rickettsiae immediately before infection of macrophage-like cell lines caused either no change or an increase in the initial infection. Most of the rickettsiae that infected the mouse macrophage-like cell lines in the presence of antiserum were destroyed in these cell lines. Thus, when the infection took place in the presence of antiserum, the mouse macrophage-like cell lines no longer differentiated between the E and Breinl strains. These data indicate that mouse macrophage-like cell lines should be a useful model system for defining the differences between the E and Breinl strains of Rickettsia prowazekii, differences which should lead to an understanding of the biochemical basis of virulence in this organism.
在四种小鼠巨噬细胞样细胞系（RAW264.7、J774.1、P388D1和PU5）、一种人巨噬细胞样细胞系（U937-1）以及小鼠成纤维细胞系L929中，比较了无毒力的普氏立克次体（E株）和有毒力的普氏立克次体（布雷因尔株）的生长情况。E株和布雷因尔株在L929细胞中的生长情况相同。然而，所有小鼠巨噬细胞样细胞系都能通过限制E株相对于布雷因尔株的生长，明显区分这两种菌株。有时会观察到对感染的反应不一致，即E株立克次体在大多数感染细胞中被清除，但在一些剩余的感染细胞中繁殖。人源细胞系U937-1在区分E株和布雷因尔株方面效果不佳。在感染L929细胞之前，立即向普氏立克次体的布雷因尔株或E株中加入兔抗立克次体抗血清，会使初始感染显著减少，但对L929细胞中立克次体的后续生长没有影响。相比之下，在感染巨噬细胞样细胞系之前，立即向布雷因尔株或E株立克次体中加入抗血清，初始感染要么没有变化，要么有所增加。在抗血清存在的情况下感染小鼠巨噬细胞样细胞系的大多数立克次体在这些细胞系中被破坏。因此，当在抗血清存在的情况下发生感染时，小鼠巨噬细胞样细胞系不再区分E株和布雷因尔株。这些数据表明，小鼠巨噬细胞样细胞系应该是一个有用的模型系统，用于确定普氏立克次体E株和布雷因尔株之间的差异，这些差异应该有助于理解该生物体毒力的生化基础。
