Figure 1.

Outline of the model and verification of the establishment of viral latency in the lungs. (A) Sketch of the experimental model of syngeneic hematopoietic cell transplantation (HCT) with BALB/c mice as hematopoietic cell donors and recipients, and schedule of assays. The flash symbol indicates hematoablative treatment of the recipients by total-body γ-irradiation with a single dose of 6.5 Gy prior to performing HCT and infection with mCMV. (B) Scheme of the lungs in anatomical view with tissue pieces p1-p6 used for quantitation of viral transcripts, p7 and p8 used for quantitation of viral transcripts and latent viral DNA load simultaneously, and the left lung used for cytofluorometric analyses. SL, superior lobe; ML, middle lobe, IL, inferior lobe; PCL, postcaval lobe, LL, left lung. (C) Virus titers expressed as plaque-forming units (PFU) per organ, were determined under conditions of centrifugal enhancement of infectivity. Routinely, 1% aliquots of lung homogenate were tested. Negative results were confirmed by plating the homogenate in total to avoid a sampling error. Symbols represent data from individual mice. Median values are marked. (D) Latent viral DNA load determined for lung tissue pieces p7 and p8 of the PCLs of mice #1-to-#5 (at 4 months), #6-to-#10 (at 6 months), and #11-to-#15 (at 8 months). Each single symbol represents the mean value from triplicate determinations. The shaded areas indicate the 95% confidence intervals for the log-normally distributed data. (*) Data sets are considered as being significantly different if p < 0.05.