Activation upregulates 4-1BB expression in PDCA-1⁺ cells.

A Total BM-derived cells were stimulated with the indicated soluble agonists for 3d, stained with fluorochrome- tagged Abs to 4-1BB, PDCA-1, and IgD, then analysed by flow cytometry. The percentages of 4-1BB⁺ cells in gated PDCA-1⁺IgD⁺ and PDCA-1⁺IgD⁻ fractions are presented as bar graphs (mean ± SD). The results of three pooled independent experiments are shown (n = 3). B Purified splenic PDCA-1⁺ B cells from naïve B6 mice were stimulated with anti-4-1BB (5 µg/ml) for 3d, stained as indicated, and flow cytometry was performed. The frequencies of cells expressing the indicated activation markers were evaluated and are presented as bar graphs (mean ± SD). The results of three pooled independent experiments are shown (n = 3). * p<0.05.