CD8⁺ T cells from IL-27^−/− mice have a biased inflammatory phenotype. (A) Representative dot plots depicting CD44 and CD62L expression on CD4⁺ and CD8⁺ T cells from B6 and IL-27^−/− mice. (B) Percentage of CD4⁺ and CD8⁺ T cells from wild-type (WT) or IL-27^−/− animals (n = 9 per group) with a naive, central memory (CM), or effector memory (EM) phenotype. (C) Representative histograms showing CD25, CD44, CD62L, CTLA4, CD103, GITR, and CD127 expression on gated CD4⁺Foxp3⁺ T cells from wild-type or IL-27^−/− mice. (D) Column-purified T cells (1 × 10⁵) from wild-type or IL-27^−/− mice were labeled with carboxyfluorescein diacetate succinimidyl ester (CFSE) and cultured with allogeneic Balb/c CD11c-enriched dendritic cells (DCs) (5 × 10⁴) for 4 days. The percentage of CFSE^loCD4⁺ and CD8⁺ T cells in the absence or presence of DCs is shown for replicate experiments (n = 3). Data are presented as mean ± standard error of the mean (SEM). (E) Splenocytes from wild-type or IL-27^−/− 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 (1 × 10⁵) from the spleens of wild-type or IL-27^−/− mice were cultured under T_H1 polarizing conditions (see “Methods”) for 5 days. Scatterplots depicting the percentage of CD4⁺ or CD8⁺ IFN-γ⁺ T cells are shown (n = 5-9 per group). (G) Lethally irradiated Balb/c mice were transplanted with B6 BM alone (●, n = 6), or together with either B6 CD4⁺ (0.9 × 10⁶) and CD8⁺ (0.5 × 10⁶) T cells (▪, n = 10), B6 CD4⁺ and IL-27^−/− CD8⁺ T cells (△, n = 10), IL-27^−/− CD4⁺ and B6 CD8⁺ T cells (▿, n = 10), or IL-27^−/− CD4⁺ and CD8⁺ T cells (♢, n = 10). Survival is shown. Data are from 2 experiments. *P < .05, **P < .01.