{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,3]],"date-time":"2026-02-03T22:00:47Z","timestamp":1770156047289,"version":"3.49.0"},"reference-count":20,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2025,6,25]],"date-time":"2025-06-25T00:00:00Z","timestamp":1750809600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"research contract with CSL Behring AG"},{"name":"Canadian Blood Services\u2019 Graduate Fellowship Program (GFP) award"},{"name":"Canadian Blood Services\u2019 Postdoctoral Fellowship award"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background\/Objectives: Recombinant Fc proteins have been produced that have a protective effect in mouse models of arthritis, such as the K\/BxN rheumatoid arthritis model. We have previously shown that a recombinant human IgG1 Fc with a point mutation at position 309, replacing a leucine with a cysteine, fused to the human IgM tailpiece to form a human IgG1 Fc hexamer, rFc-\u00b5TP-L309C, effectively prevents neutrophil infiltration into the joints and ameliorates arthritis in the K\/BxN serum transfer model and in the endogenous chronic arthritis K\/BxN model. We have now investigated the effect of rFc-\u00b5TP-L309C on T-cells in the K\/BxN chronic arthritis mouse model. Methods: PBMCs were isolated from the spleen, lymph nodes and joint synovial fluid from K\/BxN mice having severe chronic arthritis that had been treated with 200 mg\/kg rFc-\u00b5TP-L309C or human serum albumin (HSA). Flow cytometry was used to isolate the activated CD4+CD44+ T-cells and T-regulatory cells (Tregs). Intracellular staining was used to identify Th1 and Th17 T-cell subsets, and CD4+CD25+FoxP3+ Tregs. ELISA was used to measure levels of IL-10 and TGF-\u03b2 in synovial fluid. Results: We find that amelioration of the arthritis occurs after treatment with rFc-\u00b5TP-L309C and results in a decrease in Th1 cells\u2019 production of IFN\u03b3 and Th17 cells\u2019 production of IL-17. Amelioration also results in decreased production of GM-CSF. Moreover, amelioration results in increased Tregs and IL-10 production in the synovial fluid. Conclusions: rFc-\u00b5TP-L309C reduces the inflammatory T-cells and increases the regulatory anti-inflammatory T-cells in the chronic arthritis K\/BxN mouse model. This effect explains, in part, the ability of rFc-\u00b5TP-L309C to ameliorate the arthritis and reduce damage on the articular cartilage of K\/BxN mice.<\/jats:p>","DOI":"10.3390\/jcm14134509","type":"journal-article","created":{"date-parts":[[2025,6,26]],"date-time":"2025-06-26T05:53:13Z","timestamp":1750917193000},"page":"4509","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Recombinant IgG1 Fc-\u03bcTP-L309C Ameliorates Endogenous Rheumatoid Arthritis in the K\/BxN Mouse Model by Decreasing Th1 and Th17 Cells in the Spleen, Lymph Nodes and Joint and Increasing T Regulatory Cells and IL-10 in the Joint"],"prefix":"10.3390","volume":"14","author":[{"given":"Bonnie J. B.","family":"Lewis","sequence":"first","affiliation":[{"name":"Department of Laboratory Medicine and Pathobiology, University of Toronto, 30 Bond St., Toronto, ON M5B 1W8, Canada"},{"name":"Centre for Innovation, Canadian Blood Services, 30 Bond St., Toronto, ON M5B 1W8, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Selena","family":"Cen","sequence":"additional","affiliation":[{"name":"Centre for Innovation, Canadian Blood Services, 30 Bond St., Toronto, ON M5B 1W8, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ruqayyah J.","family":"Almizraq","sequence":"additional","affiliation":[{"name":"Bluerock Therapeutics, 101 College St., Toronto, ON M5G 0A3, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Beth","family":"Binnington","sequence":"additional","affiliation":[{"name":"Centre for Innovation, Canadian Blood Services, 30 Bond St., Toronto, ON M5B 1W8, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rolf","family":"Spirig","sequence":"additional","affiliation":[{"name":"CSL Behring Biologics Research Center, 200031 Bern, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4255-9350","authenticated-orcid":false,"given":"Fabian","family":"K\u00e4sermann","sequence":"additional","affiliation":[{"name":"CSL Behring Biologics Research Center, 200031 Bern, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8974-2451","authenticated-orcid":false,"given":"Donald R.","family":"Branch","sequence":"additional","affiliation":[{"name":"Department of Laboratory Medicine and Pathobiology, University of Toronto, 30 Bond St., Toronto, ON M5B 1W8, Canada"},{"name":"Centre for Innovation, Canadian Blood Services, 30 Bond St., Toronto, ON M5B 1W8, Canada"},{"name":"Department of Medicine, University of Toronto, 30 Bond St., Toronto, ON M5B 1W8, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,6,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"373","DOI":"10.1126\/science.1154315","article-title":"Recapitulation of IVIG anti-inflammatory activity with a recombinant IgG Fc","volume":"320","author":"Anthony","year":"2008","journal-title":"Science"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"19571","DOI":"10.1073\/pnas.0810163105","article-title":"Identification of a receptor required for the anti-inflammatory activity of IVIG","volume":"105","author":"Anthony","year":"2008","journal-title":"Proc. Nat. Acad. Sci. USA"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"110","DOI":"10.1038\/nature10134","article-title":"Intravenous gammaglobulin suppresses inflammation through a novel TH2 pathway","volume":"475","author":"Anthony","year":"2011","journal-title":"Nature"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"2542","DOI":"10.4049\/jimmunol.1701171","article-title":"rIgG1 Fc hexamer inhibits antibody-mediated autoimmune disease via effects on complement and Fc\u03b3Rs","volume":"200","author":"Spirig","year":"2018","journal-title":"J. Immunol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"670","DOI":"10.1126\/science.1129594","article-title":"Anti-inflammatory activity of immunoglobulin G resulting from Fc sialylation","volume":"313","author":"Kaneko","year":"2006","journal-title":"Science"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Lewis, B.J.B., Ville, J., Blacquiere, M., Cen, S., Spirig, R., Zuercher, A.W., Fasermann, F., and Branch, D.R. (2019). Using the K\/BxN mouse model of endogenous, chronic, rheumatoid arthritis for the evaluation of potential immunoglobulin-based therapeutic agents, including IVIg and Fc-\u03bcTP-L309C, a recombinant IgG1 Fc hexamer. BMC Immunol., 20.","DOI":"10.1186\/s12865-019-0328-6"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Mott, P.J., and Lazarus, A.H. (2013). CD44 antibodies and immune thrombocytopenia in amelioration of murine inflammatory arthritis. PLoS ONE, 8.","DOI":"10.1371\/journal.pone.0065805"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"212","DOI":"10.1186\/s13075-024-03424-4","article-title":"R\u00f4le of TLR4 activation and signaling in bone remodeling, and afferent sprouting in serum transfer arthritis","volume":"26","author":"Cardenas","year":"2024","journal-title":"Arthritis Res. Ther."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1172\/JCI200522753","article-title":"Can antibodies with specificity for soluble antigens mimic the therapeutic effects of intravenous IgG in the treatment of autoimmune disease?","volume":"115","author":"Siragam","year":"2005","journal-title":"J. Clin. Investig."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"176","DOI":"10.1159\/000528780","article-title":"Modulation of neutrophil function by recombinant human IgG1 Fc hexamer in the endogenous K\/BxN mouse model of rheumatoid arthritis","volume":"108","author":"Almizraq","year":"2023","journal-title":"Pharmacology"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"811","DOI":"10.1016\/S0092-8674(00)81989-3","article-title":"Organ-specific disease provoked by systemic autoimmunity","volume":"87","author":"Kouskoff","year":"1996","journal-title":"Cell"},{"key":"ref_12","first-page":"15.22.1","article-title":"The K\/BxN arthritis model","volume":"15","author":"Monach","year":"2008","journal-title":"Curr. Protoc. Immunol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"4392","DOI":"10.4049\/jimmunol.1600121","article-title":"Therapeutic targeting of the G-CSF receptor reduces neutrophil trafficking and joint inflammation in antibody-mediated inflammatory arthritis","volume":"197","author":"Campbell","year":"2016","journal-title":"J. Immunol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"509","DOI":"10.1002\/art.22272","article-title":"Where FoxP3-edpendent regulatory T cells impinge on the development of inflammatory arthritis","volume":"56","author":"Nguyen","year":"2007","journal-title":"Arthritis Rheum."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"683","DOI":"10.1146\/annurev.immunol.19.1.683","article-title":"Interleukin-10 and the interleukin-10 receptor","volume":"19","author":"Moore","year":"2001","journal-title":"Ann. Rev. Immunol."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Fujio, K., Okamura, T., Sumitomo, S., and Yamamoto, K. (2012). Regulatory T cell-mediated control of autoantibody-induced inflammation. Front. Immunol., 3.","DOI":"10.3389\/fimmu.2012.00028"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1084\/jem.20021345","article-title":"CD4+CD25+ TR cells suppress innate immune pathology through cytokine-dependent mechanisms","volume":"197","author":"Maloy","year":"2003","journal-title":"J. Exp. Med."},{"key":"ref_18","first-page":"174","article-title":"Role of transforming growth factor-beta (TGF) beta in the physiopathology of rheumatoid arthritis","volume":"10","year":"2014","journal-title":"Reumatol. Clin."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"2918","DOI":"10.1073\/pnas.88.7.2918","article-title":"Protective effect of transforming growth factor beta 1 on experimental autoimmune diseases in mice","volume":"88","author":"Kuruvilla","year":"1991","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"580","DOI":"10.1038\/nri856","article-title":"Roles of Fc receptors in autoimmunity","volume":"2","author":"Takai","year":"2002","journal-title":"Nat. Rev. Immunol."}],"container-title":["Journal of Clinical Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2077-0383\/14\/13\/4509\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T17:58:41Z","timestamp":1760032721000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2077-0383\/14\/13\/4509"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,6,25]]},"references-count":20,"journal-issue":{"issue":"13","published-online":{"date-parts":[[2025,7]]}},"alternative-id":["jcm14134509"],"URL":"https:\/\/doi.org\/10.3390\/jcm14134509","relation":{},"ISSN":["2077-0383"],"issn-type":[{"value":"2077-0383","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,6,25]]}}}