FIG. 5.

Cyclin D3 but not cyclin D2 is expressed in germinal center B cells. (A) GC and non-GC B cells were sorted from spleens pooled from 5 to 10 WT animals at 5 days after immunization with SRBCs, as indicated. Values indicate the gated population as a percentage of total cells and represent at least three experiments. Total protein or RNA was prepared from the sorted cells and subjected to Western blot (B) or semiquantitative RT-PCR (C) analysis for cyclin D2 or cyclin D3, as indicated. BCL-6 levels in GL7⁺ IgD⁻ (solid line) and GL7⁻ IgD⁺ (dashed line) PNA⁺ GC B cells were assessed by intracellular staining and flow cytometric analysis (D). The shaded histogram indicates the PNA⁻ non-GC B-cell gate. The data shown are an average derived from at least three mice.