CD137-treated monocytes exert no DC activity.

<p>(A) Monocytes from Balb/C mice were cultured for 7 days on plates with immobilized Fc or CD137-Fc protein and where indicated stimulated by LPS for the last 24 h. The cells were cocultured with T cells from C57/Bl6 mice in an allogeneic MLR at a ratio of 1∶10. The rate of proliferation was determined by ³H-thymidine incorporation three days later. iDC: immature DC: monocytes treated for 7 days with GM-CSF + IL-4. DC: iDC stimulated with LPS for 24 h. (B) Maturation of classical iDCs. Immature DCs were treated as indicated for 3 days. Expression of costimulatory molecules (grey histograms) was determined by flow cytometry. Isotype control (open histograms). Numbers in the graphs indicate the percentages of positive cells. *p<0.05. Data are representative of three independent experiments.