FIG. 4.

EBNA3 proteins are expressed by latently infected naive but not IgD⁻ B cells in the tonsil. IgD⁺ (naive) and IgD⁻ B cells were isolated from tonsils using biotinylated antibodies and MACS columns as described in the legend to Fig. 1. cDNA was prepared from 5 × 10⁶ cells of each population and divided for DNA PCR detection of EBNA2, EBNA3a, EBNA3b, and EBNA3c. The PCR products were fractionated on agarose gels, Southern blotted, and probed with sequence-specific probes. For details, see the text. The expected positions of the PCR products are indicated by the arrows. (A) Representative example of tonsils that express EBNA2 and all of the EBNA3 family. (B) Representative example of tonsils that express EBNA2 but lack detectable EBNA3s.