Exposure to TGF-β during antigen uptake reduces the capacity of BMDCs to present antigen efficiently to T cells. C57BL/6 BMDCs
were pulsed with whole OVA in the presence or absence of 5 ng/mL recombinant TGF-β. After washing, they were cultured together
with CFSE-labeled OT-II OVA-specific CD4+ T cells (A) or OT-I OVA-specific CD8+ T cells (B) and proliferation was assessed. Filled squares, proliferation without DC; filled circles, proliferation with control BMDC;
open circles, proliferation with TGF-β–exposed BMDC. To determine antigen uptake, APC-labeled microbeads were added to the
BMDCs in the presence or absence of 5 ng/mL recombinant TGF-β at 37°C. Control BMDCs were incubated with beads at 4°C. Filled
squares, bead uptake at 4°C; filled circles, bead uptake in control BMDC; open circles, bead uptake in TGF-β–exposed BMDC
(C). Differences between groups were assessed using the Mann-Whitney test. Results show four cultures from each condition with
DCs and T cells originating from the same source and are representative of at least three independent experiments. **P ≤ 0.01, ***P ≤ 0.001.