Figure 5.

15d-PGJ₂ induces regulatory T cell markers in conventional T cells. (a) FOXP3 mRNA expression was quantified by real-time PCR in draining lymph nodes from naïve mice (white bar) or collagen-immunized and challenged DBA/1 mice treated with vehicle (black bar) or 15d-PGJ₂ (hatched bar) after 7 days of treatment. Results are presented as the mean ± SEM, N = 6; ^∗ P < 0.05 compared with PBS-treated group. Total cells (2 × 10⁶ cells/mL) from the draining lymph nodes from naïve or arthritic animals were in vitro incubated with 15d-PGJ₂ (5 μM) (black bars) or vehicle (DMSO) (white bars) for 96 hours on plates coated with α-CD3. The nonadherent cells were phenotyped by flow cytometry using specific antibodies: anti-CD3 conjugated with FITC, anti-CD4 conjugated with PerCP, and anti-CD25 conjugated with APC-Cy7 (b) and anti-FOXP3 (c), anti-GITR (d), and anti-CTLA-4 (e) conjugated with PE. Lymphocytes were gated on CD4⁺CD25⁺ or CD4⁺CD25⁻, and the population expressing the markers described above was subsequently analyzed. In (f), representative histograms of FOXP3, CTLA-4, and GITR are shown in each box. The values above are expressed as the mean ± SEM, which are representative of quadruplicate samples from two independent experiments (N = 4). ^# P < 0.05 compared with CD4⁺CD25⁻ group control (vehicle).