(A) Detection of EBV genome in human neutrophils. Cells were incubated for increasing time periods before DNA isolation and Southern blot analysis. EBV DNA was detected by hybridization with aBamHI W probe. Raji cell line was used as positive control. Neutrophils were either cultured in absence (control) or in presence of EBV (15 minutes and 2, 5, 10, and 24 hours). The experiment is representative of two other experiments. (B) Densitometric analysis of viral DNA levels in EBV-infected neutrophils. Results are the mean of three experiments. (C) Detection of EBV genome in isolated nuclei. Neutrophils from two healthy donors were preincubated with the phagocytosis inhibitor cytochalasin B (10 μmol/L) for 15 minutes and then treated with EBV or culture medium (mock) for 10 hours. Cells were obtained and genomic DNA was extracted from purified nuclei. EBV genomic DNA was detected by PCR as described in Materials and Methods. B95-8 cells were used as positive control. M represents a 100-bp molecular weight marker.