Figure 5.

B Cell AhR Deficiency Exacerbates Antigen Induced Arthritis

(A) Mean clinical score of Mb1^cre/+ and Ahr^fl/−Mb1^cre/+ mice following induction of arthritis; y axis shows percentage swelling in antigen-injected knee compared with control knee (n = 12 per group).

(B) Representative H&E staining of arthritic joints from Mb1^cre/+ and Ahr^fl/−Mb1^cre/+ mice (n = 3; original magnification of 20×). Arrows indicate hyper-vascularization. Scale bar, 100 μM.

(C–H) Representative flow cytometry plots and bar charts showing respectively the percentage and number of (C and D) IFN-γ⁺CD4⁺ cells, (E and F) IL-17⁺CD4⁺ cells, and (G and H) Foxp3⁺CD4⁺T cells in the spleens and DLNs of Mb1^cre/+ and Ahr^fl/−Mb1^cre/+ mice (n = 7).

(I) IL-17 concentration as measured in the synovial fluid of Mb1^cre/+ and Ahr^fl/−Mb1^cre/+ mice (n = 6).

(J) Schematic showing the experimental design of the adoptive transfer system.

(K) Mean clinical score of C57BL/6 mice following adoptive transfer of CD19⁺CD21^hiCD24^hiB cells purified from Mb1^cre/+ and Ahr^fl/−Mb1^cre/+ mice, administered on the day of disease onset. Control (no transfer) group received PBS (n = 5).

(L) Bar charts showing respectively the percentage of IFN-γ⁺CD4⁺ cells and IL-17⁺CD4⁺ cells in the spleens of WT recipient mice, following an adoptive transfer of Mb1^cre/+ and Ahr^fl/−Mb1^cre/+ CD19⁺CD21^hiCD24^hiB cells or a PBS control (n = 5).

All experiments were performed at day 7 post-IA injection. Data are representative of at least three independent experiments with biological replicates. In (A), (D), (F), (H), (I), (K), and (L), data are expressed as mean ± SEM. ^∗p < 0.05 and ^∗∗p < 0.01, one- and two-way ANOVA and Mann-Whitney test.