Correlation of DNA, RNA, and protein content by flow cytometry in normal and Coxiella burnetii-infected L929 cells.

L929 cell populations persistently infected for more than 600 days exhibited cell cycle distributions and generation times similar to those of uninfected cells. The RNA and protein contents of these long-term-infected cells, as determined by flow cytometry and correlated with the cell cycle, were likewise approximately the same as those in normal uninfected cells. Also, the ratios of RNA to DNA and RNA to protein of infected cells were not significantly different from those of normal cells. Collectively, these data indicate that the long-term-infected cells remained in a state of balanced growth and maintained normal cycle progression and division capacity, allowing for growth and proliferation of host cells and thus ensuring the propagation and persistence of the parasite.