Binding of the virus is required for the inhibition of DC development.

(A) The effect of the virus was abolished by adsorption on EBV receptor–positive cell lines and was enhanced by concentration. EBV was concentrated from B95.8 supernatant by ultracentrifugation, and EBV-depleted supernatant was obtained by adsorption on EBV receptor–positive Raji cells. Purified CD14⁺ monocytes were infected with untreated, absorbed, or concentrated B95.8 supernatant for 2 hours at 37°C and then were cultured in the presence of GM-CSF and IL-4. Results are from 1 of 3 to 5 representative experiments performed with each type of virus preparation. Mean ± SD of triplicates. (B) Virus absorption was performed using magnetic beads conjugated with 2L10 mAb. Beads conjugated with OKT3 mAb were used as control. Results are from 1 of 3 representative experiments. (C) Effect of the virus was neutralized by preincubation with EBV antibody–positive sera. B95.8 supernatant was preincubated for 30 minutes at room temperature with 1:20 dilution of sera from EBV antibody-negative (EBV−) or -positive (EBV+) healthy donors or from patients with nasopharyngeal carcinoma before it was used for infection of purified monocytes. The percentage recovery relative to uninfected controls is shown. Mean ± SD of 4 experiments.