FIG. 4.

Viral replicative fitness in quiescent fibroblasts in cell culture. MEF were growth arrested in low-serum starvation medium and were centrifugally infected at an MOI of 0.4 (0.02 PFU/cell × 20; centrifugal enhancement of infectivity) with the viruses indicated. (A) Quantitation of viral genomes in infected cells as determined by gene M55(gB)-specific real-time PCR with normalization to the cellular gene pthrp. (B) Quantitation of infectious virus released into the cell culture supernatant as determined by virus plaque assay. The data refer to 10⁶ cells. Shown are the multistep growth curves for a period of 72 h postinfection (p.i.) corresponding to three viral growth cycles. Time zero is defined as the end of the 30-min period of centrifugal infection revealing the inoculum viral genomes and infectivity. The dots represent data from three six-well cultures for each of the time points indicated. The median values are marked by horizontal lines. The productivity after the first viral growth cycle is highlighted by gray shading, indicating the onset of viral-DNA replication after 16 h and virus release after 24 h, which is in perfect accordance with previous findings (39).