Figure 4.

The adoptive transfer of iTregs promoted IDO secretion in splenic DCs and the further suppression of CIA. (a) IDO expression levels in CD11b⁺DCs and CD8α ⁺DCs from iTreg-treated CIA mice were determined using FACS. The corresponding DC subsets from untreated CIA mice were used as controls. (b) The results of RT-PCR and Western blotting showed the expression of IDO in CD11b⁺DCs after blocking with 1-MT. (c) CD11b⁺DCs were pretreated with 1-MT to block IDO expression and were subsequently added to the CD4T proliferation system. Four days after cocultivation, CFSE⁺CD4⁺T cells were stained with propidium iodide (PI) and analyzed using flow cytometry. The error bars indicate SEM. The results of 4 replicated experiments were pooled. (d) Recipient mice subjected to the adoptive transfer of CD11b⁺DCs, with or without 1-MT treatment, were sacrificed 49 days after the first CII immunization. The arthritic scores in each group are shown (n = 5). (e) Histopathological examination of the joints of mice described in (d) after H&E staining to visualize inflammatory cell infiltration. The histopathological inflammation scores are expressed as the means ± SEM of five independent experiments. ^* P < 0.05 compared with the indicated groups using unpaired t-tests.