Figure 2. Intercellular transport of cAMP through gap junctions and adenosine-A2A receptor (A2AR) signaling are responsible for the iTreg-mediated inhibitory effects on uveitogenic T cells (UTs) obtained from mice with EAU.

(A-B): Coculture with iTregs led to a cell number-dependent inhibition of UT proliferation. (C-D): Coculture with iTregs inhibited the release of IL-17 and IFN-γ into the culture supernatants. (E-J): The expression of IL-17A and IFN-γ in retinas 21 days after immunization was measured by real-time PCR. (G-L): Coculture with iTregs decreased the number and frequency of CD4+IL-17A+ T cells and CD4+IFN-γ+ T cells in UTs (Gated on CD4). (K): Both the A2AR antagonists (ZM 241385) and the gap junction inhibitor (GAP-27) significantly reversed the iTreg-mediated inhibitory effect on UT proliferation. (L): The combination of the A2AR antagonist and the gap junction inhibitor was more effective than either alone. These results were representative of three independent experiments. The data are presented as the means ± SDs. **: P < 0.01 (between the indicated groups). Abbreviations: TGF-β Ab, TGF-β antibody; CTLA-4 Ab, CTLA-4 antibody. Data were analyzed using one-way ANOVA with Bonferroni correction (B-D, K, and L) or independent unpaired two-tailed Student’s t tests (E-I).