Transplantation with IL-27R^−/− marrow grafts reduces GVHD severity. (A) Representative dot plots depicting CD44 and CD62L expression on CD4⁺ and CD8⁺ T cells from B6 and IL-27R^−/− mice. (B) Percentage of CD4⁺ and CD8⁺ T cells from wild-type or IL-27R^−/− animals (n = 10 per group) with a naive, central memory (CM), or effector memory (EM) phenotype. (C). Representative dot plot showing CD25, CD44, CD62L, CTLA4, CD103, GITR, and CD127 expression on gated CD4⁺ Foxp3⁺ T cells from wild-type or IL-27R^−/− mice. (D). Column-purified T cells (1 × 10⁵) from wild-type or IL-27R^−/− mice were labeled with CFSE and cultured with allogeneic Balb/c CD11c-enriched dendritic cells (DCs) (5 × 10⁴) for 4 days. The percentage of CFSE^lo CD4⁺ and CD8⁺ T cells in the absence or presence of DCs is shown for replicate experiments (n = 3). Data are presented as mean ± SEM. (E). Column-purified T cells (3 × 10⁶) from wild-type or IL-27R^−/− mice were cultured with PMA and ionomycin for 6 hours. Representative dot plots depicting the percentage of CD8⁺ T cells that secreted IFN-γ and scatterplots for replicate experiments (n = 4) are shown. (F). Purified CD4⁺ or CD8⁺ T cells from the spleens of wild-type or IL-27R^−/− mice were cultured under T_H1 polarizing conditions for 5 days. Scatterplots depicting the percentage of CD4⁺ or CD8⁺ IFN-γ⁺ T cells are shown (n = 5-9 per group). (G) Balb/c recipients were transplanted with B6 BM alone (●, n = 9), IL-27R^−/− BM (○, n = 9), B6 BM and B6 spleen cells (▪, n = 15), or IL-27R^−/− BM and IL-27R^−/− spleen cells (□, n = 15) (adjusted to yield an αβ T-cell dose of 0.6 × 10⁶ cells). Overall survival is depicted. Data are from 3 experiments. (H-I) Lethally irradiated Balb/c recipients were transplanted with B6 BM alone (black bars, n = 5), IL-27R^−/− BM (light gray bars, n = 5), B6 BM and B6 spleen cells (medium gray bars, n = 10), or IL-27R^−/− BM and spleen cells (dark gray bars, n = 10). The absolute number of donor-derived CD4⁺ and CD8⁺ T cells (H) and CD4⁺ and CD8⁺ T cells that secreted IFN-γ (I) in the liver, lung, and colon 14 days posttransplantation is depicted. Data are from 2 experiments. *P < .05, **P < .01, ***P < .001.