HCMV-associated suppression of monocyte oxidative activity. PBMCs from two HCMV seronegative donors were incubated for 2, 4, and 6 days with infectious cell-free HCMV, To/inf (A) or psoralen/UV-inactivated cell-free HCMV, To/pso (B). Infectious or inactivated cell-free HCMV, 0.002 MOI equivalent, and the respective mock preparations, used at the same dilutions, were added concurrently to the cells and maintained in culture. The monocyte oxidative activity, was measured using the MTS/PMS assay. Assays were performed in triplicate and results are presented as the mean ± SD of the optical density (OD) values. The boxes contain the percentage of oxidative activity inhibition (mean ± SD) corresponding to the ratio between the OD value obtained with HCMV and the mock preparation multiplied by 100.