Figure 3.

Suppression of Arthritis by Butyrate Supplementation Depends upon AhR Activation and IL-10 Expression in B Cells

(A) Bar chart shows expression of Cyp1a1 relative to β-actin in splenic B cells isolated from control or butyrate-supplemented mice (cumulative n = 5, one representative experiment of two experiments is shown).

(B) Mean clinical score of control and butyrate-supplemented Mb1^cre/+ mice or Ahr^fl/−Mb1^cre/+ mice; y axis shows percentage swelling in antigen-injected knee compared to control knee (cumulative n = 15 per group, one representative experiment of five experiments is shown).

(C) IL-10 production by splenic B cells isolated from control Mb1^cre/+ mice, butyrate-supplemented Mb1^cre/+ mice, control Ahr^fl/−Mb1^cre/+ mice, and butyrate-supplemented Ahr^fl/−Mb1^cre/+ mice at day 7 post-disease onset as measured by ELISA (cumulative n = 3 per group).

(D) Representative flow cytometry plots and bar charts showing the frequency and number of CD19⁺CD21^hiCD24^hiB cells in control Mb1^cre/+ mice (cumulative n = 8), butyrate-supplemented Mb1^cre/+ mice (cumulative n = 5), control Ahr^fl/−Mb1^cre/+ mice (n = 7), and butyrate-supplemented Ahr^fl/−Mb1^cre/+ mice (cumulative n = 6) at day 7 post-disease onset (cumulative data are shown).

(E) Representative flow cytometry plots and bar charts showing the frequency and number of CD19⁺CD138⁺Blimp-1⁺B cells in control Mb1^cre/+ mice (cumulative n = 8), butyrate-supplemented Mb1^cre/+ mice (cumulative n = 5), control Ahr^fl/−Mb1^cre/+ mice (cumulative n = 7), and butyrate-supplemented Ahr^fl/−Mb1^cre/+ mice (cumulative n = 6) (cumulative data are shown).

(F) Representative flow cytometry plots and bar charts showing the frequency and number of CD19⁺CD95⁺GL7⁺B cells in control Mb1^cre/+ mice (cumulative n = 8), butyrate-supplemented Mb1^cre/+ mice (cumulative n = 5), control Ahr^fl/−Mb1^cre/+ mice (cumulative n = 7), and butyrate-supplemented Ahr^fl/−Mb1^cre/+ mice (cumulative n = 6) (cumulative data are shown).

Cells were isolated at day 7 post-disease onset. Data represent mean ± SE (A, Student’s t test; C, E, and F, one-way ANOVA; B, two-way ANOVA). See also Figures S5 and S6.