Generation and Characterization of Anti–Citrullinated Protein Antibody–Producing B Cell Clones From Rheumatoid Arthritis Patients. Issue 3 (2nd February 2019)

• Record Type: Journal Article
• Authors: Germar, Kristine; Fehres, Cynthia M.; Scherer, Hans U.; van Uden, Nathalie; Pollastro, Sabrina; Yeremenko, Nataliya; Hansson, Monika; Kerkman, Priscilla F.; van der Voort, Ellen I. H.; Reed, Evan; Maassen, Hanna; Kwakkenbos, Mark J.; Bakker, Arjen Q.; Klareskog, Lars; Malmström, Vivianne; de Vries, Niek; Toes, René E. M.; Lundberg, Karin; Spits, Hergen; Baeten, Dominique L.
• Is Part Of: Arthritis & rheumatology. Volume 71:Issue 3(2019)
• Page Start: 340
• Page End: 350
• Publication Date: 2019-02-02
• Subjects: Arthritis -- Periodicals; Rheumatism -- Periodicals; 616.72
• DOI: 10.1002/art.40739
• Languages: English
• ISSNs: 2326-5191

Abstract

Abstract : Objective: Anti–citrullinated protein antibodies (ACPAs) are a hallmark of rheumatoid arthritis (RA). Aside from autoantibody production, the function of autoantigen‐specific B cells remains poorly understood in the context of this disease. This study set out to elucidate autoantigen‐specific B cell functions through the isolation and immortalization of unique citrullinated protein/peptide (CP)–reactive B cell clones from RA patients. Methods: B cell clones from either the blood or synovial fluid of cyclic citrullinated peptide 2 (CCP2) antibody–positive RA patients were immortalized by genetic reprogramming with Bcl‐6 and Bcl‐xL. Enzyme‐linked immunosorbent assay and flow cytometry were used to identify CCP2‐reactive clones and to further characterize surface marker and cytokine expression as well as B cell receptor signaling competence. Global gene expression profiles were interrogated by RNA sequencing. Results: Three unique CP‐reactive memory B cell clones were generated from the blood or synovial fluid of 2 RA patients. CP‐reactive memory B cells did not appear to be broadly cross‐reactive, but rather had a fairly restricted epitope recognition profile. These clones were able to secrete both pro‐ and antiinflammatory cytokines and had a unique surface profile of costimulatory molecules and receptors, including CD40 and C5a receptor type 1, when compared to non‐CP–reactive clones from the same patient. In addition, CP‐reactive clones bound citrullinated protein, but not native protein, and could mobilize calcium in response to antigen binding. Conclusion: CP‐reactive memory B cells comprise a rare, seemingly oligoclonal population with restricted epitope specificity and distinct phenotypic and molecular characteristics suggestive of antigen‐presenting cells. Cloning by genetic reprogramming opens new avenues to study the function of autoreactive memory B cells, especially in terms of antigen processing, presentation, and subsequent T cell polarization.