Figure 2.

Interleukin‐10 (IL‐10) administration increased T regulatory (Treg) cells but decreased their immunosuppression activity in Schistosoma japonicum‐infected mice. (a, b) S. japonicum‐infected mice (n = 6 per group) were injected intraperitoneally with PBS (control) or recombinant mouse IL‐10 (rmIL‐10). At 24 hr after the last injection, single cell suspensions of splenocytes were prepared from mouse spleens and stained with PerCP‐Cy5.5 anti‐CD3, FITC anti‐CD4, APC anti‐CD25, and PE anti‐Foxp3. Flow cytometry dot plots of CD25⁺ Foxp3⁺ Treg cells gated on CD3⁺ CD4⁺ T cells are shown. Scatter plot shows, respectively, the average percentages of CD4⁺ CD25⁺ Foxp3⁺ Treg cells in CD4⁺ T cells (c, d) Histogram profiles of Foxp3 gated on CD3⁺ CD4⁺ CD25⁺ T cells are displayed. Scatter plot shows the average MFI of Foxp3 expression in CD3⁺ CD4⁺ CD25⁺ T cells (n = 6 per group). (e) CD4⁺ CD25⁻ T cells (1 × 10⁵/well) from normal control mice were cultured in triplicate wells at 37° for 72 hr with normal mouse‐derived antigen‐presenting cells (1 × 10⁵/well), 2 μg/ml of soluble anti‐CD3 and CD4⁺ CD25⁺ T cells (1 × 10⁵/well) purified from S. japonicum‐infected mice injected with either PBS or rmIL‐10 (n = 5 per group). Proliferation was determined by [³H]thymidine incorporation. (f, g) CD4⁺ CD25⁻ T cells from EGFP‐Tg mice and CD4⁺ CD25⁺ Treg cells from S. japonicum‐infected mice injected with either PBS or rmIL‐10 were co‐cultured as described in (e) (n = 5 per group). The suppressive activity of Treg cells on CD4⁺ CD25⁻ T cells was measured by analysing the expression of Ki‐67 in EGFP ⁺ cells (CD4⁺ CD25⁻ T cells). Histogram profiles of Ki‐67 gated on EGFP ⁺ cells are shown. Scatter plot shows the average percentages of Ki‐67⁺ cells in EGFP ⁺ cells. Each assay has been performed three times on independent cell samples. Flow cytometry dot plots or histograms are representative of three independent experiments. Data (mean ± SD) are representative of three independent experiments. *P < 0·05, **P < 0·01, ***P < 0·001, n.s., not significant. [Colour figure can be viewed at wileyonlinelibrary.com]