HCMV DNA copy number determination by QC-PCR across a time course of infection of myeloid progenitor cells. (A) Lysates of 1.0 × 103 cells from HCMV-infected myeloid progenitor cell cultures harvested on days 1, 2, 3, 5, and 11 after infection were each analyzed by PCR in the presence of between 1.0 and 1.0 × 106 copies of competitor template, an HCMV ie1/ie2 cDNA plasmid pON2347. The number of copies of competitor template added to each reaction is indicated at the top of lanes. The position of the 387-bp product derived from HCMV genomic DNA and the 217-bp product derived from the cDNA competitor template are indicated by arrows. Samples from either mock-infected myeloid progenitor cell cultures (Mock), productively infected HFs (Pos), or samples without any added DNA template (Neg) were included as controls. Marker was GeneRuler DNA ladder mix (Fermentas). (B) To determine whether the PCR data were affected by virus particles stuck to the outer cell-surface membranes of myeloid progenitors, QC-PCR was repeated using an acid-stripping protocol to remove surface-bound material from infected myeloid progenitors (day 3 after infection, MOI = 3). Non–acid-stripped cells were examined in parallel.
