HCMV-induced suppression of monocyte oxidative activity occurs in PBMCs from seropositive as well as seronegative donors. Inactivated cell-free HCMV, To/pso 0.002 MOI equivalent, was incubated as described previously with three PBMCs from seronegative donors and three PBMCs from seropositive donors. The monocyte oxidative activity was measured after 4 days. Results are presented as the mean ± SD of the 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.