FIG. 2.

Flow cytometry analysis of WHV-naive PBMC exposed to either WHV virions or cloned recombinant WHV (rWHV) DNA and subjected or not to stepwise DNase/trypsin/DNase digestion and WHV DNA-specific PCR amplification. PBMC isolated from a healthy woodchuck were incubated with either 3 × 10⁸ WHV virions (approximately 300 virions/cell) (upper panel) or 1 ng of recombinant WHV DNA (approximately 300 virus genome equivalents/cell) (lower panel), washed, and treated or not with DNase/trypsin/DNase before PCR and flow cytometric examination. Adsorption of virions or protein-free WHV DNA to PBMC is evident in the absence of enzyme treatment, whereas following treatment, no positive cell signal was observed, indicating successful elimination of the attached WHV particles or nucleic acid sequences.