Fig. 2.

T cell–derived IL-10 is elevated, whereas Tfh and anti-commensal antibodies are reduced in the colons of ICOSL-deficient mice. (A) Representative flow cytometry plots showing CD4⁺Thy1.1⁺ cells from the lamina propria of the proximal, middle, and distal colon of 10BiT.Icosl^+/+ and 10BiT.Icosl^−/− mice. Graphs show (B) frequencies and (C) numbers of cells per mouse analyzed as in A. (D) Representative flow cytometry plots showing Tfh cells in the lymph nodes draining the proximal, middle, and distal colon of 10BiT.Icosl^+/+ and 10BiT.Icosl^−/− mice. Graphs show (E) frequencies and (F) numbers of cells per mouse analyzed as in D. Plots in A and D are gated on CD4⁺TCRβ⁺ cells, and numbers represent the percentage of cells in the gate shown. 10BiT.Icosl^+/+ n = 7, 10BiT.Icosl^−/− n = 6. Data from one of two independent experiments are shown. (G) Representative flow cytometric analysis of IgA and IgG expression by B220^lo cells from the colonic lamina propria of WT, Icosl^−/−, or Tcrbd^−/− mice. (H) Frequency of B220^lo cells expressing IgA or IgG as depicted in A. WT, n = 8; Icosl^−/−, n = 7; Tcrbd^−/−, n = 6. Data are compiled from two independent experiments. (I) ELISA of total IgA and IgG in colonic mucus from WT, Icosl^−/−, or Tcrbd^−/− mice. WT, n = 9; Icosl^−/−, n = 11; Tcrbd^−/−, n = 8. (J) ELISA of IgG1, IgG2b, IgG2c, and IgG3 in colonic mucus from WT, Icosl^−/−, or Tcrbd^−/− mice. WT, n = 9; Icosl^−/−, n = 10; Tcrbd^−/−, n = 9. Data are compiled from three independent experiments. In all graphs, each symbol represents an individual mouse; error bars represent mean ± SD. P values were calculated by ANOVA followed by Tukey’s multiple comparisons test. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.