Suppression of Proteoglycan-Induced Arthritis by Anti-CD20 B Cell Depletion Therapy Is Mediated by Reduction in Autoantibodies and CD4 + T Cell Reactivity This information is current as of September 27, 2021. Keith Hamel, Paul Doodes, Yanxia Cao, Yumei Wang, Jeffrey Martinson, Robert Dunn, Marilyn R. Kehry, Balint Farkas and Alison Finnegan J Immunol 2008; 180:4994-5003; ; doi: 10.4049/jimmunol.180.7.4994 Downloaded from http://www.jimmunol.org/content/180/7/4994 References This article cites 48 articles, 20 of which you can access for free at: http://www.jimmunol.org/ http://www.jimmunol.org/content/180/7/4994.full#ref-list-1 Why The JI? Submit online. • Rapid Reviews! 30 days* from submission to initial decision • No Triage! Every submission reviewed by practicing scientists by guest on September 27, 2021 • Fast Publication! 4 weeks from acceptance to publication *average Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 Copyright © 2008 by The American Association of Immunologists All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. The Journal of Immunology Suppression of Proteoglycan-Induced Arthritis by Anti-CD20 B Cell Depletion Therapy Is Mediated by Reduction in Autoantibodies and CD4؉ T Cell Reactivity1 Keith Hamel,* Paul Doodes,* Yanxia Cao,† Yumei Wang,† Jeffrey Martinson,* Robert Dunn,§ Marilyn R. Kehry,§ Balint Farkas,‡ and Alison Finnegan2*† B cells have been implicated in the pathogenesis of rheumatoid arthritis (RA) since the discovery of RA as an autoimmune disease. There is renewed interest in B cells in RA based on the clinical efficacy of B cell depletion therapy in RA patients. Although, reduced titers of rheumatoid factor and anti-cyclic citrullinated peptide Abs are recorded, the mechanisms that convey clinical improvement are incompletely understood. In the proteoglycan-induced arthritis (PGIA) mouse model of RA, we reported that Ag-specific B cells have two important functions in the development of arthritis. PG-specific B cells are Downloaded from required as autoantibody-producing cells as well as Ag-specific APCs. Herein we report on the effects of anti-CD20 mAb B cell depletion therapy in PGIA. Mice were sensitized to PG and treated with anti-CD20 Ab at a time when PG-specific autoantibodies and T cell activation were evident but before acute arthritis. In mice treated with anti-CD20 mAb, devel- opment of arthritis was significantly reduced in comparison to control mAb-treated mice. B cell depletion reduced the PG-specific autoantibody response. Furthermore, there was a significant reduction in the PG-specific CD4؉ T cell recall ؉ response as well as significantly fewer PG-specific CD4 T cells producing IFN-␥ and IL-17, but not IL-4. The reduction in http://www.jimmunol.org/ PG-specific T cells was confirmed by the inability of CD4؉ T cells from B cell-depleted mice to adoptively transfer disease into SCID mice. Overall, B cell depletion during PGIA significantly reduced disease and inhibited both autoreactive B cell and T cell function. The Journal of Immunology, 2008, 180: 4994–5003. heumatoid arthritis (RA)3 is a chronic and degenerative CD20 is only expressed after the pro-B cell stage and is not autoimmune disease that affects the synovial joints (1). expressed on plasma cells (9). Although autoantibodies are re- R Inflammation leads to cartilage degradation and bone duced in most RA patients treated with anti-CD20, autoanti- erosion, resulting in debilitating pain, joint deformity, and immo- body reduction does not always correlate with efficacy, suggest- by guest on September 27, 2021 bility (2, 3). Although the precise factors that initiate disease have ing that loss of other B cell functions may contribute to not been identified, several cell types have been implicated as me- suppression of RA (8, 10–12). diators of disease, including neutrophils, macrophages, B cells, Several autoimmune diseases, including systemic lupus ery- and T cells (4). The identification of rheumatoid factor (RF) in thematosus (SLE) and RA, are characterized by the presence of RA as an autoantibody provided the first key indicator that RA autoantibodies (13). In RA, the presence of RF and anti-cyclic is an autoimmune disease (5). However, because RF is not al- citrullinated peptide autoantibodies in the serum are an early ways associated with RA and because RF could be produced in predictor of disease in 50% of RA patients by an average of 7.5 diseases other than RA, interest in B cells waned (6). Recently, years (14). Autoantibodies bind to target epitopes, forming im- the importance of B cells in RA has been resurrected based on mune complexes that activate complement components and Fc the clinical efficacy of B cell depletion therapy (rituximab) in receptor-bearing cells that contribute to RA pathogenesis (15, RA patients (7, 8). Rituximab is a chimeric anti-human CD20 16). In several murine models of RA, autoantibodies are patho- mAb that selectively depletes immature and mature B cells, as genic, particularly the K/BxN and collagen-induced arthritis (CIA) models where disease is initiated by transfer of autoan- *Department of Immunology and Microbiology, †Department of Internal Medicine, tibodies to GPI and collagen respectively (17–20). Unlike these Section of Rheumatology, and ‡Department of Orthopedic Surgery, Rush University models, in proteoglycan (PG)-induced arthritis (PGIA), autoan- Medical Center, Chicago, IL 60612; and §Biogen Idec, San Diego, CA 92122 tibodies are required for initiation of disease but are insufficient Received for publication December 11, 2007. Accepted for publication January 21, 2008. to transfer arthritis (19, 21, 22). In addition to producing Abs, there are several functions of B The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance cells that could contribute to autoimmunity (11). B cells are with 18 U.S.C. Section 1734 solely to indicate this fact. highly competent APCs and present Ag 103-104-fold more ef- 1 This research was supported by National Institutes of Health Grant AR47657 ficiently than do macrophages or dendritic cells (23). Costimu- (to A.F.). latory molecules CD80 and CD86 are up-regulated on activated 2 Address correspondence and reprint requests to Dr. Alison Finnegan, Department of Medicine, Section of Rheumatology, Rush University Medical Center, 1735 West B cells, permitting T–B cell interaction. B cells also express Harrison Avenue, Chicago, IL 60612. E-mail address: [email protected] proinflammatory cytokines that may contribute to inflammation 3 Abbreviations used in this paper: RA, rheumatoid arthritis; CIA, collagen-induced (24–26). PGIA is dependent on Ag-specific B cells, and auto- arthritis; PG, proteoglycan; PGIA, proteoglycan-induced arthritis; RF, rheumatoid reactive T cells are not sufficiently activated to induce arthritis factor; SLE, systemic lupus erythematosus. unless PG is presented by B cells (19). Selective deletion of Copyright © 2008 by The American Association of Immunologists, Inc. 0022-1767/08/$2.00 costimulatory molecules CD80 and CD86 on PG-specific B www.jimmunol.org The Journal of Immunology 4995 cells is essential for autoreactive T cell activation and the de- anti-CD20 mAb were dissected, fixed in formalin, decalcified, and embed- velopment of arthritis (27). The requirement for primed auto- ded in paraffin. The tissue sections were stained with H&E. reactive B and T cells to sustain PGIA suggests a need for Abs, anti-CD20 mAb treatment, and B cell depletion reciprocal interactions that maintain chronic autoreactivity (28). Several studies in animal models of autoimmune disease have In experiments to assess the kinetics of B cell depletion, naive cells from spleen, popliteal lymph nodes, bone marrow, and peritoneal cavity (PE) shed some light on the role of B cell depletion in autoimmunity lavages were collected at days 1, 3, 7, 14, and 21 following i.v. injection (29). In CIA, depletion of B cells with an Ab specific for mouse of 250 ␮g of anti-mouse CD20 mAb (18B12, IgG2a) (31) or control Ab CD20 administered before initiation of CIA delays the onset of anti-human CD20 mAb (2B8), an engineered IgG2a derivative of the 2B8 disease; however, B cell depletion was not therapeutic after IgG1 mouse parent of rituximab that has no cross-reactivity with mouse CD20. 18B12 anti-mouse CD20 was generated by immunization of collagen immunization (30). Recently, anti-CD20 mAb con- Ϫ Ϫ CD20 / mice with CD20-transfected cell lines and CD20-peptide-key- ferred resistance in a murine model of lupus when treatment hole limpet hemocyanin conjugate (36). The 18B12 IgG2a variant was began at an early age and was continued for several weeks (31). generated by cloning and expression of 18B12 variable domain with the The ability of anti-CD20 therapy to ameliorate or delay disease IgG2a constant region in CHO cells. Mouse B cell subsets were charac- in these models may be due to the timing of treatment. Deple- terized by flow cytometry after staining with Abs: anti-IgD FITC, anti- CD21 PE, anti-B220 PerCp, anti-IgM APC, anti-IgM PerCp-Cy5.5, anti- tion of B cells in both models was before any clinical signs of CD5 PE, anti-CD38 FITC, anti-B220 PE, anti-B220 FITC, anti-CD43 PE, Ϫ/Ϫ disease and may mimic the disease course of B cell mice, (BD Biosciences), and anti-CD23 APC (Abcam). Profiling of B cell de- thus suggesting that B cells are important in initiation of auto- pletion in PG-immunized mice was performed at days 7 and 21 after anti- immunity (32, 33).