Antibody blockade of IL-27 has differential effects on IL-10 production in CD4⁺ and CD8⁺ conventional T cells vs Tregs. (A-B) Anti-CD3/28 antibody activated CD4⁺ or CD8⁺ conventional T cells (Tconv) (A) or Tregs (B) from B6 IL-10 10Bit.Foxp3^EGFP reporter mice cultured in IL-2 (30 U/mL) in the absence or presence of graded doses of IL-27 (1-200 ng/mL) for 3 days. The percentage of IL-10–producing conventional or regulatory CD4⁺ and CD8⁺ T cells is depicted. (C) IL-10 levels in the culture supernatants of CD4⁺ and CD8⁺ T cells stimulated as in panel A as determined by Bioplex assay. Data are derived from 3 experiments. (D-F) Balb/c mice were transplanted with BM and spleen cells from 10Bit.Foxp3^EGFP reporter mice and treated with an isotype or p28 antibody on days 0 and 6. Representative dot plots showing the percentage of CD4⁺ or CD8⁺ T cells that expressed Foxp3 and IL-10 in the spleen, liver, lung, and colon 10 days posttransplantation (D). The frequency and absolute number of conventional (E) and regulatory (F) CD4⁺ and CD8⁺ T cells expressing IL-10 in the spleen, liver, lung, and colon on day 10 are depicted. *P < .05, **P < .01, ***P < .001.