FIG. 2.
MCMV-ΔM94 is spread deficient, and replication depends on trans complementation of pM94. (A) Parental NIH 3T3 and NT/M94-7 fibroblasts were infected at 0.1 TCID50/cell with MCMV-wt (w) or MCMV-ΔM94 (ΔM94). At the indicated days, infectious virus in the supernatant was quantified on NT/M94-7 cells by TCID50 endpoint titration. Shown are the means plus SD of titrated duplicates. At day 5 postinfection (p.i.) supernatants were additionally titrated on MEF. No PFU was found in 1 ml supernatant of MCMV-ΔM94-infected NT/M94-7 cells. DL, detection limit. (B) Parental NIH 3T3 and NT/M94-7 fibroblasts were infected with MCMV-Δm157-rec-egfp-ΔM94. At the indicated time points EGFP-expressing cells were monitored. hpi, hours p.i. (C) 129.IFNαβR−/− mice (n = 15 for MCMV-ΔM94, n = 8 for MCMV-wt) were infected with 2.5 × 105 TCID50 i.p., and survival was followed for 30 days p.i.