Effect of HCMV on the colony formation by CD34⁺ BM cells. Purified CD34⁺ cells were either mock-infected or infected with 95(2) or Towne/lox2 at a multiplicity of infection (MOI) of 100 PFU/cell. A total of 7 × 10³ cells were plated per well of 6-well plate in methylcellulose. The cultures were supplemented with 50 ng/mL SCF, 50 ng/mL IL-3, 50 ng/mL GM-CSF, 5 U/mL Epo, and 50 ng/mL M-CSF. Colonies were counted after 14 days in culture. Results represent the mean colony number ± SEM of the total amount of colonies (CFU-Mix), erythroid colonies (BFU-E), and myeloid colonies (CFU-GM) of four experiments performed.