Anti-4-1BB pre-activated PDCA-1⁺ B cells inhibit in vitro Ig class switching.

A PDCA-1⁺ B cells were sort-purified from spleens of naïve B6 mice and stained as indicated, and flow cytometry was performed. One of four independent experiments is shown (n = 4). B Purified splenic PDCA-1⁺ B cells were stimulated with the indicated agonists, after which in vitro Ig class switching was analyzed by flow cytometry. One of four independent experiments is shown (n = 4). C Purified splenic PDCA-1⁺ B cells were stimulated with soluble anti-4-1BB (5 µg/ml) and/or IL-7 (100 ng/ml) for 3d then re-stimulated with LPS/IL-4 for 4d, after which in vitro Ig class switching was analyzed by flow cytometry. One of four independent experiments is shown (n = 4).