Flow cytometry was performed on uninfected cells, cells infected with CMV, and cells incubated with UV-irradiated CMV. The background fluorescence of the uninfected cells was subtracted from the respective samples to give a final quantity of CMV positive cells. 'CMV' indicates BJAB-B1 cells infected with viable CMV and 'uvCMV' indicates cells incubated with UV-irradiated virus. Time points are as indicated. Quantitative values are per 10,000 cells.