vBcl-2 is required for transitional B cell latency.

<p>B6 mice were infected i.n. with 10⁴ PFU wild-type MHV68, MHV68.vBcl-2stop or MHV68.vCycD.LacZ, and spleens were harvested at 16 days post-inoculation. (<b>A</b>) Flow cytometric cell sorting was performed to isolate purified transitional B (CD19⁺AA4⁺) cells (post-sort purity analyses of transitional B cell (CD19⁺AA4⁺) populations were performed for each sort and are listed in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003916#ppat.1003916.s008" target="_blank">Table S3</a>). (<b>B</b>) Limiting dilution nested PCR for viral genome was utilized to determine the frequency of cells that harbored MHV68 DNA. The frequency of cells positive for viral genome was calculated by Poisson distribution analysis of mean data (n = 3 experiments, 5 mice pooled per group per experiment), as indicated by the dashed line at 63.2%, which is the point at which one viral genome-positive cell per reaction is predicted to occur. <i>X</i>-axis is the numbers of cells per reaction, <i>Y</i>-axis is the percentage of 12 reactions positive for viral genome.