Fig 5. Increased frequency of CD4⁺ CD25⁺ FoxP3⁺ cells after co-culture with IDO-expressing fibroblast.

Lymphocytes were isolated from mesenteric lymph nodes of recently diabetic NOD mice and were cultured either alone or co-cultured with control or IDO-expressing fibroblasts as described in Methods. The frequency of CD4⁺ gated CD25⁺ FoxP3⁺lypmocytes were measured using flow cytometry before culturing (Pre-culture) and after 7 days mono- or co-cultures. Panel A shows representative plots for CD25+ FoxP3+ regulatory T cells (gated on CD4+ T cells) and panel B shows frequencies of these cells in different experimental groups. (*) denotes statistically significant increase in the frequency of regulatory T cell after co-culturing with IDO-expressing fibroblasts compared to pre-culture amount (P<0.001, n = 3).