FIG. 5.
Different latent ΔM33BT2 DNA loads in the spleen and lungs following i.n. inoculation leads to reduced reactivation from the spleen but not the lungs. Five-week-old BALB/c mice were inoculated i.n. with 1 × 106 PFU of K181 (K-Perth) or ΔM33BT2 (ΔM33). At 92 dpi, spleens and lungs were collected and analyzed for reactivation from latency or detection of latent viral DNA. (A) Spleens and lungs were minced and cultured for 6 weeks in explant reactivation assays. Detection of virus in the cultures was determined weekly by plaque assay. (B) Tissue DNA was isolated as described in Materials and Methods and screened for the presence of MCMV ie1 by PCR using primers CH16 and CH17. Ethidium bromide-stained agarose gel of amplified PCR products are shown: 100-bp DNA ladder, DNA samples from K181 (KP) and ΔM33, and negative PCR control (−). Amplification of β-actin is shown below to control for DNA isolation. Results shown are from one study (four mice/group).