Figure 6.

Increased steady-state IL-10 production in PD-1^−/− mice is derived from T cells. Splenic leukocytes were harvested from naïve control Vert-X and PD-1^−/− Vert-X mice and IL-10 (eGFP) expression was quantified by flow cytometry. The (A) frequency and (B) total number of IL-10⁺ cells within the spleen were determined by flow cytometry. (C) Serum IL-10 in the same animals as in (A) and (B), was determined by IVCCA. Each symbol represents an individual animal and bar represents the mean. (D) The frequency of IL-10⁺ cells within various the various lymphocyte subsets within the spleen was measured. (E) The total number of IL-10⁺ cells within each subset was determined. (F) Serum IL-10 levels in isotype control, anti-CD4 or anti-CD8-treated Vert-X WT or PD1-deficient mice, as determined by IVCCA are shown. (G) Serum IL-12p70 levels after in vivo depletion as described in (F) were determined. (D–G) Data are shown as mean + SEM of four animals and are from single experiments representative of two independent experiments performed. *p < 0.05, **p < 0.01, two-way ANOVA with Bonferroni posttest.