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. 2023 Jan-Dec;15(1):2281763.
doi: 10.1080/19420862.2023.2281763. Epub 2023 Nov 29.

Anti-citrullinated histone monoclonal antibody CIT-013, a dual action therapeutic for neutrophil extracellular trap-associated autoimmune diseases

Maarten van der Linden  1 , Sangeeta Kumari  1 , Daphne Montizaan  1 , Stephanie van Dalen  1 , Annemarie Kip  1 , Martyn Foster  2 , Inge Reinieren-Beeren  1 , Elsa Neubert  3   4 , Luise Erpenbeck  3   5 , Kelsy Waaijenberg  1 , Tirza Bruurmijn  1 , Rezie Te Poele  1 , Peter van Zandvoort  1 , Paul Vink  1 , Eric Meldrum  1 , Helmuth van Es  1 , Renato G S Chirivi  1
Affiliations

Anti-citrullinated histone monoclonal antibody CIT-013, a dual action therapeutic for neutrophil extracellular trap-associated autoimmune diseases

Maarten van der Linden et al. MAbs. 2023 Jan-Dec.

Abstract

Neutrophil extracellular traps (NETs) contribute to the pathophysiology of multiple inflammatory and autoimmune diseases. Targeting the NETosis pathway has demonstrated significant therapeutic potency in various disease models. Here, we describe a first-in-class monoclonal antibody (CIT-013) with high affinity for citrullinated histones H2A and H4, which inhibits NETosis and reduces tissue NET burden in vivo with significant anti-inflammatory consequences. We provide a detailed understanding of the epitope selectivity of CIT-013. Detection of CIT-013 epitopes in rheumatoid arthritis (RA) synovium provides evidence that RA is an autoimmune disease with excessive citrullinated NETs that can be targeted by CIT-013. We show that CIT-013 acts upon the final stage of NETosis, binding to its chromatin epitopes when plasma membrane integrity is compromised to prevent NET release. Bivalency of CIT-013 is necessary for NETosis inhibition. In addition, we show that CIT-013 binding to NETs and netting neutrophils enhance their phagocytosis by macrophages in an Fc-dependent manner. This is confirmed using a murine neutrophilic airway inflammation model where a mouse variant of CIT-013 reduced tissue NET burden with significant anti-inflammatory consequences. CIT-013's therapeutic activity provides new insights for the development of NET antagonists and indicates the importance of a new emerging therapy for NET-driven diseases with unmet therapeutic needs.

Keywords: Citrullinated histones; mechanism of neutrophil extracellular trap inhibition; neutrophil extracellular trap phagocytosis; rheumatoid arthritis; therapeutic monoclonal antibody.

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Conflict of interest statement

Citryll employees have financial interest.

Figures

Figure 1.
Figure 1.
Elevated CIT-013 epitope in RA synovial tissue with moderate to marked active synovitis.
Figure 2.
Figure 2.
CIT-013 does not bind blood cells and does not affect neutrophil anti-microbial activity other than NETosis.
Figure 3.
Figure 3.
CIT-013 specifically inhibits the release of citrullination rich NETs.
Figure 4.
Figure 4.
Bivalency is necessary for the NET-inhibitory capacity of CIT-013.
Figure 5.
Figure 5.
CIT-013 blocks chromatin release from netting neutrophils.
Figure 6.
Figure 6.
Phagocytosis of CIT-013-opsonized NETs and netting neutrophils by macrophages.
Figure 7.
Figure 7.
Reduced inflammatory infiltrate and enhanced phagocytosis induced by m-ACHA in a neutrophilic airway inflammation mouse model.
See this image and copyright information in PMC

References

    1. Brinkmann V, Reichard U, Goosmann C, Fauler B, Uhlemann Y, Weiss DS, Weinrauch Y, Zychlinsky A.. Neutrophil Extracellular Traps Kill Bacteria. Sci. 2004;303(5663):1532–22. doi: 10.1126/science.1092385. - DOI - PubMed
    1. Li P, Li M, Lindberg MR, Kennett MJ, Xiong N, Wang Y.. PAD4 is essential for antibacterial innate immunity mediated by neutrophil extracellular traps. J Exp Med. 2010;207(9):1853–62. doi: 10.1084/jem.20100239. - DOI - PMC - PubMed
    1. Tambralli A, Gockman K, Knight JS. NETs in APS: Current knowledge and future perspectives. Curr Rheumatol Rep. 2020;22(10):67. doi: 10.1007/s11926-020-00936-1. - DOI - PubMed
    1. Li RHL, Tablin F. A comparative review of neutrophil extracellular traps in sepsis. Front Vet Sci. 2018;5:291. doi: 10.3389/fvets.2018.00291. - DOI - PMC - PubMed
    1. Papayannopoulos V. Neutrophil extracellular traps in immunity and disease. Nat Rev Immunol. 2018;18(2):134–47. doi: 10.1038/nri.2017.105. - DOI - PubMed

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