B effector cells in rheumatoid arthritis and experimental arthritis

Abstract

Rheumatoid arthritis is a chronic autoimmune immune disease affecting approximately 1% of the population. There has been a renewed interest in the role of B cells in rheumatoid arthritis based on the evidence that B cell depletion therapy is effective in the treatment of disease. This review summarizes the current knowledge of the mechanisms by which B cells contribute to autoimmune arthritis including roles as autoantibody producing cells, antigen-presenting cells, cytokine producing cells, and regulatory cells.

Figure 1

B cell-exclusive expression of CD80/86 was not sufficient to induce arthritis. SCID and SCID^{CD80/86−/−} were repopulated with purified B cell (1 × 10⁷) and T-cells (B cell-depleted splenocytes) (1 × 10⁷) from WT and CD80/86^−/− mice (B^WTT^WT)→ SCID, (B^WTT^WT)→SCID^{CD80/86−/−}, B^{CD80/86−/−}T^{CD80/86−/−}→ SCID^{CD80/86−/−} and B^WT T^{CD80/86−/−}→ SCID^{CD80/86−/−} One wk after repopulation, mice were immunized with PG in adjuvant i.p. 3 times at 3 wk intervals. (A) Arthritis score was based on the degree of erythema and swelling. Paws were scored on a scale of 1 to 4. (B) Arthritis Incidence denotes percentage of mice that develop arthritis. Data represent the mean and SEM (n=7). All groups are statistically significantly different p<0.05 than the control group (B^WTT^WT)→ SCID.

Figure 2

Donor cell sufficiently repopulated the recipients; however, CD86 was reduced on donor cells. At the termination of the experiment (A & C) percentage and (B & D) number of presence of B cell, T cells, and macrophages (A & B) along with their expression CD86 (C & D) were determined by flow cytometry of spleen cells. Data represent the mean and SEM (n=7). * represents statistically significantly different p<0.05 than the control group (B^WTT^WT)→ SCID.

Figure 3

Decrease in T cell and antibody in SCID^{CD80/86−/−} recipient mice. (A) T cell proliferation was measured by ³H-thymine incorporation in PG activated spleen cell cultures, (B) cytokine levels in supernatants from PG activated spleen cells, (C) serum human PG-specific antibody response, (D) serum mouse PG-specific. Data represents the mean and SEM (n=7). Data represent the mean and SEM (n=7). ^* represents statistically significantly differents p<0.05 from the control group (B^WTT^WT)→ SCID.