Figure 1

RA treatment of bone marrow myeloid cells produces a regulatory myeloid cell population. Bone marrow cells were differentiated in the presence of GM-CSF with or without 100 nM of either estriol or retinoic acid over 6–7 days of differentiation to generate MCs, E3 MC_regs or RA MC_regs. A portion of these cells were also challenged with LPS in the last 24 hours of differentiation. BM-MCs (A) and LPS-stimulated BM-MCs (B) were co-cultured with responder immune cells containing T cell receptor transgenic CD4⁺ T cells specific for peptide for 96 hours with media, antigen or anti-CD3 stimulation and then pulsed with H³ thymidine in the final 18 hours of culture. In MCs, E3 MC_regs and RA MC_regs, (C) the relative percentage of IL-10⁺ cells was determined and (D) the ability of these cells (after a 5 day co-culture) to induce FoxP3⁺ cells from naïve FoxP3-EGFP reporter immune cells was determined by flow cytometry. Data are representative of at least three separate experiments * = p < 0.05.