25rhk045 10.3205/25rhk045 urn:nbn:de:0183-25rhk0456 Meeting Abstract Özdemir Özdemir Alper Tunga AT

Institut für Immunologie, Universitätsmedizin Johannes Gutenberg-Universität, Mainz

author Voss Voss Ralf-Holger RH

Institut für Immunologie, Universitätsmedizin Johannes Gutenberg-Universität, Mainz

author Attig Attig Sebastian S

Institut für Immunologie, Universitätsmedizin Johannes Gutenberg-Universität, Mainz

author Perkovic Perkovic Mario M

Gene Transfer Department, Translationale Onkologie an der Universitätsmedizin der Johannes-Gutenberg-Universität, Mainz

author Sahin Sahin Ugur U

Institut für Immunologie, Universitätsmedizin Johannes Gutenberg-Universität, Mainz

author Schwarting Schwarting Andreas A

Johannes Gutenberg-Universität, Universitätsmedizin, Schwerpunkt klinische Immunologie und Rheumatologie, Mainz

author German Medical Science GMS Publishing House

Düsseldorf

610 20250917 engl This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. Dieser Artikel ist ein Open-Access-Artikel und steht unter den Lizenzbedingungen der Creative Commons Attribution 4.0 License (Namensnennung). M0627 045 Deutsche Gesellschaft für Rheumatologie Deutsche Gesellschaft für Orthopädische Rheumatologie 53. Kongress der Deutschen Gesellschaft für Rheumatologie (DGRh), 39. Jahrestagung der Deutschen Gesellschaft für Orthopädische Rheumatologie (DGORh) Deutscher Rheumatologiekongress 2025 Experimentelle & Translationale Rheumatologie Wiesbaden 20250917 20250920 ET.27 TextIntroduction: ACPAs are prominent autoantibodies associated with poor prognosis in the pathogenesis of Rheumatoid Arthritis (RA) . Selectively eliminating ACPA-producing B cells is a popular area of research. This study presents data on a Universal-CAR T (Uni-CAR) cell approach using targeting modules of citrullinated peptides, which are specific epitopes of ACPAs.Methods: ACC22 and E43 ACPA-B cell receptor expressing Raji cells were created as target cell models, and their surface expression characteristics and binding properties for citrullinated peptide epitopes (collagen-II359-369, collagen-II483-498, fibrinogen-β60-74, fibrinogen-β36-52, and α-enolase) were validated using PE-labeled streptavidin tetramers and FACS method. To enable the integration of peptides with Uni-CAR, citrullinated peptides containing a myc-tag (targeting module: TM) were synthesized, and co-culture experiments with varying ratios of cells and peptides were conducted. The activation status of Uni-CAR T cells was determined by changes in IFN-γ levels in the medium supernatants. To evaluate efficacy in real patient cells, B cells were isolated from three patients in the active disease stage with Anti-CCP levels >200 U/mL and co-cultured with Uni-CAR T cells. A Luciferase Assay System was used to assess cytotoxic activity.Results: In co-culture experiments, we observed that the production of IFN-γ by Uni-CAR T cells increased proportionally with TM dosage. In the Luciferase Assay, we noted that the cytotoxic effect observed on ACC2 and E4-BCR Raji cells increased with TM doses. Tetramer binding analysis of B cells isolated from RA patients revealed positive cell rates of 10.1%, 7.05%, and 4.45% for collagen-II359-369, as well as 42.4%, 25.9%, and 30% for fibrinogen-β36-52. In cytotoxicity assays with these cells, we again detected an effect consistent with TM dosage.Conclusion: This study highlights the effectiveness of targeting strategies using Uni-CAR T cells against ACPA-producing B cells. The increased IFN-γ production and enhanced cytotoxic effect correlated with TM dosage demonstrate the potential of ACPA-targeted therapies in treating rheumatoid arthritis. The specific binding rates observed in B cells isolated from RA patients suggest that these approaches could be developed as next-generation immunotherapy strategies. The findings provide a significant foundation for future clinical research. Zhang B Wang Y Yuan Y Sun J Liu L Huang D Hu J Wang M Li S Song W Chen H Zhou D Zhang X In vitro elimination of autoreactive B cells from rheumatoid arthritis patients by universal chimeric antigen receptor T cells 2021 Ann Rheum Dis 176-84 Zhang B, Wang Y, Yuan Y, Sun J, Liu L, Huang D, Hu J, Wang M, Li S, Song W, Chen H, Zhou D, Zhang X. In vitro elimination of autoreactive B cells from rheumatoid arthritis patients by universal chimeric antigen receptor T cells. Ann Rheum Dis. 2021 Feb;80(2):176-84. DOI: 10.1136/annrheumdis-2020-217844 http://dx.doi.org/10.1136/annrheumdis-2020-217844 Uysal H Bockermann R Nandakumar KS Sehnert B Bajtner E Engström A Serre G Burkhardt H Thunnissen MM Holmdahl R Structure and pathogenicity of antibodies specific for citrullinated collagen type II in experimental arthritis 2009 J Exp Med 449-62 Uysal H, Bockermann R, Nandakumar KS, Sehnert B, Bajtner E, Engström A, Serre G, Burkhardt H, Thunnissen MM, Holmdahl R. Structure and pathogenicity of antibodies specific for citrullinated collagen type II in experimental arthritis. J Exp Med. 2009 Feb 16;206(2):449-62. 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