FIG. 1.

Quantitation of viral load in cells fractionated on the basis of CD19 expression. Viral load is restricted to the CD19⁺ fraction of peripheral blood lymphocytes. (A) Flow cytometric profile of CD19 fluorescence in a typical lymphocyte preparation from a chronic viral load carrier. The CD19⁺ fraction is composed of a CD19^hi and a CD19^lo peak of fluorescence. (B) Ethidium bromide-stained DNA products of QC-PCRs using 10⁴ CD19⁺ or 10⁵ CD19⁻ cells and 8, 40, 200, or 1,000 copies of an identical competitor target sequence (lower of the two PCR product bands) were analyzed by agarose gel electrophoresis. Results for patient 8 (a low-load carrier) and patient 16 (a high-load carrier) are shown. The interpolated DNA concentration in copy numbers of EBV genomes detected is shown below each panel.