Figure 7.

Inducible T-cell co-stimulator (ICOS) is required for optimal function and stability of iTregs in vivo. Lethally irradiated BALB/c mice were transplanted with 5 × 10⁶ BM from Rag1^−/− B6 plus 0.5 × 10⁶ CD25^hiCD4⁺ cells isolated from wild-type (WT) or ICOS^−/− mice (Ly5.1⁻). Three days later, 0.5 × 10⁶ CD25⁻Ly5.1⁺ B6 Teffs were injected into each recipient. Recipients were monitored for survival (A) and body weight loss (B) for 80 days, n = 10 mice/group. In separate experiments, spleens and livers were excised and processed for FACS staining on day 14 after allo-bone marrow transplantation (BMT). Histograms of PD-1, CD39, CD127, CXCR5, and α4β7 expressed on gated H-2K^b+Ly5.1⁻CD4⁺Foxp3⁺ in spleen are shown (C). Representative histograms from individual mice and mean percentage of 7-AAD on gated H-2K^b+Ly5.1⁻CD4⁺Foxp3⁺ are shown (D). Mean percentage of CD4⁺Foxp3⁺ gated on H-2K^b+Ly5.1⁻, and Foxp3⁻IFN-γ⁺ and Foxp3⁻IL-4/5⁺ gated on H-2K^b+Ly5.1⁻CD4⁺ cells from spleens and livers are shown (E). n = 5 mice/group. *p < 0.05, **p < 0.01, and ***p < 0.001.