Level of viral DNA in myeloid progenitor cells infected with parental or viral IL-10 deletion viruses. Lysates of myeloid progenitors at day 8 after infection with parental virus (AD169) or viral interleukin-10 (IL-10) deletion virus (RVAdIL10C) were analyzed by (A) cell-dilution PCR using primers IEP3C and IEP4BII⁴  to detect a 387-bp product derived from HCMV genomic DNA, and (B) QC-PCR in the presence of between 1.0 and 1.0 × 10⁶ copies of competitor template, an HCMV ie1/ie2 cDNA plasmid,⁴  to determine the amount of viral genomes present in latently infected myeloid progenitors. The number of copies of competitor template added to each reaction is indicated on top of each lane. Arrows represent the position of the 387-bp product derived from HCMV genomic DNA and the 217-bp product derived from the cDNA competitor template. Controls located in another section of the same gel were samples from either mock-infected myeloid progenitors (Mock), productively infected HFs (Pos), or samples without any added DNA template (Neg). (C) At the indicated time points after infection, cells from HCMV strain AD169- and RVAdIL10C-infected myeloid progenitor cell or HF cultures (MOI = 3) were analyzed by cell-dilution PCR and QC-PCR to determine the number of viral genome copies per infected cell. The average from 6 independent replicate experiments is shown as a line graph with SEM.