1
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So EC, Zhou H, Greenwell A, Burch EE, Ji Y, Mérigeon EY, Olsen HS, Bentzen SM, Block DS, Zhang X, Strome SE. Complement component C1q is an immunological rheostat that regulates Fc:Fc[Formula: see text]R interactions. Immunogenetics 2023:10.1007/s00251-023-01311-x. [PMID: 37322230 DOI: 10.1007/s00251-023-01311-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 06/01/2023] [Indexed: 06/17/2023]
Abstract
Though binding sites for the complement factor C1q and the canonical fragment crystallizable (Fc) gamma receptors (Fc[Formula: see text]Rs) on immunoglobulin G (IgG) molecules overlap, how C1q decoration of immune complexes (ICs) influences their ability to engage Fc[Formula: see text]Rs remains unknown. In this report, we use recombinant human Fc multimers as stable IC mimics to show that C1q engagement of ICs directly and transiently inhibits their interactions with Fc[Formula: see text]RIII (CD16) on human natural killer (NK) cells. This inhibition occurs by C1q engagement alone as well as in concert with other serum factors. Furthermore, the inhibition of Fc[Formula: see text]RIII engagement mediated by avid binding of C1q to ICs is directly associated with IC size and dependent on the concentrations of both C1q and Fc multimers present. Functionally, C1q-mediated Fc blockade limits the ability of NK cells to induce the upregulation of the cosignaling molecule, 4-1BB (CD137), and to mediate antibody-dependent cell-mediated cytotoxicity (ADCC). Although C1q is traditionally viewed as a soluble effector molecule, we demonstrate that C1q may also take on the role of an "immunologic rheostat," buffering Fc[Formula: see text]R-mediated activation of immune cells by circulating ICs. These data define a novel role for C1q as a regulator of immune homeostasis and add to our growing understanding that complement factors mediate pleiotropic effects.
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Affiliation(s)
- Edward C So
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Hua Zhou
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Ariana Greenwell
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Erin E Burch
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Yaping Ji
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | | | | | - Søren M Bentzen
- Department of Epidemiology and Public Health, Division of Biostatistics and Bioinformatics, University of Maryland School of Medicine, Baltimore, MD, USA
| | | | - Xiaoyu Zhang
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Scott E Strome
- Department of Microbiology, Immunology, and Biochemistry, College of Medicine, University of Tennessee Health Science Center (UTHSC), 910 Madison Avenue, 10th floor Suite 1002, Memphis, TN, 38163, USA.
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2
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Ning Y, Huang Y, Wang M, Cheng A, Yang Q, Wu Y, Tian B, Ou X, Huang J, Mao S, Sun D, Zhao X, Zhang S, Gao Q, Chen S, Liu M, Zhu D, Jia R. Alphaherpesvirus glycoprotein E: A review of its interactions with other proteins of the virus and its application in vaccinology. Front Microbiol 2022; 13:970545. [PMID: 35992696 PMCID: PMC9386159 DOI: 10.3389/fmicb.2022.970545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 07/15/2022] [Indexed: 11/13/2022] Open
Abstract
The viral envelope glycoprotein E (gE) is required for cell-to-cell transmission, anterograde and retrograde neurotransmission, and immune evasion of alphaherpesviruses. gE can also interact with other proteins of the virus and perform various functions in the virus life cycle. In addition, the gE gene is often the target gene for the construction of gene-deleted attenuated marker vaccines. In recent years, new progress has been made in the research and vaccine application of gE with other proteins of the virus. This article reviews the structure of gE, the relationship between gE and other proteins of the virus, and the application of gE in vaccinology, which provides useful information for further research on gE.
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Affiliation(s)
- Yaru Ning
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
| | - Yalin Huang
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
| | - Mingshu Wang
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
| | - Anchun Cheng
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
- *Correspondence: Anchun Cheng,
| | - Qiao Yang
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
| | - Ying Wu
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
| | - Bin Tian
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
| | - Xumin Ou
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
| | - Juan Huang
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
| | - Sai Mao
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
| | - Di Sun
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
| | - Xinxin Zhao
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
| | - Shaqiu Zhang
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
| | - Qun Gao
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
| | - Shun Chen
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
| | - Mafeng Liu
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
| | - Dekang Zhu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
| | - Renyong Jia
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China
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3
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Ning Y, Huang Y, Wang M, Cheng A, Jia R, Liu M, Zhu D, Chen S, Zhao X, Zhang S, Yang Q, Wu Y, Huang J, Tian B, Ou X, Mao S, Gao Q, Sun D, Yu Y, Zhang L. Evaluation of the Safety and Immunogenicity of Duck-Plague Virus gE Mutants. Front Immunol 2022; 13:882796. [PMID: 35515004 PMCID: PMC9067127 DOI: 10.3389/fimmu.2022.882796] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 03/28/2022] [Indexed: 11/13/2022] Open
Abstract
Duck plague (DP) is an acute infectious disease in the duck industry. The duck plague virus (DPV) is the pathogen, a subfamily of alphaherpesvirinae. gE is a type I membrane protein that contains three parts: an extracellular domain, a transmembrane domain, and a cytoplasmic domain. gE is the major virulence determinant of α-herpesvirus. However, the functions of the gE extracellular and cytoplasmic domains have not been reported in DPV. In this study, a gE extracellular domain deletion mutant and a gE cytoplasmic domain deletion mutant were constructed from DPV. Virus replication kinetics showed that the growth titers of both the gE ectodomain-deleted mutant virus and the gE cytoplasmic domain-deleted virus in DEFs were lower than that of the parental virus CHv-50. DPV CHv-gEΔET and DPV CHv-gEΔCT were continuously passed to the 20th passage in DEFs and the 10th in ducklings. The mutant virus DNA after passage was extracted for identification. The results showed that the gE ectodomain and gE cytoplasmic domain deletion mutant viruses have good genetic stability. The ducklings in each group (n=10) were inoculated with the same titers of DPV CHv-gEΔET, DPV CHv-gEΔCT, DPV CHv-ΔgE, and parental CHv-50, respectively. Clinical symptoms and serum antibody levels were detected after inoculation. The results showed that the virulence of DPV CHv-gEΔCT to ducklings was reduced compared with parental CHv-50, while the virulence of DPV CHv-gEΔET to ducklings was significantly reduced. 105 TCID50 DPV CHv-gEΔET or DPV CHv-ΔgE can induce ducklings to produce DPV-specific antibodies, protect the ducklings from virulent CHv challenge. Therefore, DPV CHv-gEΔET may serve as a promising vaccine candidate to prevent and control duck plague.
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Affiliation(s)
- Yaru Ning
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yalin Huang
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Mingshu Wang
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Anchun Cheng
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Renyong Jia
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Mafeng Liu
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Dekang Zhu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Shun Chen
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Xinxin Zhao
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Shaqiu Zhang
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Qiao Yang
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Ying Wu
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Juan Huang
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Bin Tian
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Xumin Ou
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Sai Mao
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Qun Gao
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Di Sun
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yanlin Yu
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Ling Zhang
- Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
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4
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Xia L, Liu Y, Zhang Z, Gong Y, Yu T, Zhao D, Qiu W, Wang Y, Zhang J. Modulation of IL-6 Expression by KLF4-Mediated Transactivation and PCAF-Mediated Acetylation in Sublytic C5b-9-Induced Rat Glomerular Mesangial Cells. Front Immunol 2022; 12:779667. [PMID: 35046941 PMCID: PMC8761757 DOI: 10.3389/fimmu.2021.779667] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/06/2021] [Indexed: 12/17/2022] Open
Abstract
Interleukin-6 (IL-6) overproduction has been considered to contribute to inflammatory damage of glomerular mesangial cells (GMCs) in human mesangial proliferative glomerulonephritis (MsPGN) and its rat model called Thy-1 nephritis (Thy-1N). However, the regulatory mechanisms of IL-6 expression in GMCs upon sublytic C5b-9 timulation remain poorly understood. We found that Krüppel-like factor 4 (KLF4) bound to the IL-6 promoter (−618 to −126 nt) and activated IL-6 gene transcription. Furthermore, lysine residue 224 of KLF4 was acetylated by p300/CBP-associated factor (PCAF), which was important for KLF4-mediated transactivation. Moreover, lysine residue 5 on histone H2B and lysine residue 9 on histone H3 at the IL-6 promoter were also acetylated by PCAF, which resulted in an increase in IL-6 transcription. Besides, NF-κB activation promoted IL-6 expression by elevating the expression of PCAF. Overall, these findings suggest that sublytic C5b-9-induced the expression of IL-6 involves KLF4-mediated transactivation, PCAF-mediated acetylation of KLF4 and histones, and NF-κB activation in GMCs.
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Affiliation(s)
- Lu Xia
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Yu Liu
- Department of Microbiology and Immunology, Jiangsu Health Vocational College, Nanjing, China
| | - Zhiwei Zhang
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Yajuan Gong
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Tianyi Yu
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Dan Zhao
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Wen Qiu
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Yingwei Wang
- Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Jing Zhang
- Department of Immunology, Nanjing Medical University, Nanjing, China.,Key Laboratory of Immunological Environment and Disease, Nanjing Medical University, Nanjing, China.,Key Laboratory of Antibody Technology of Ministry of Health, Nanjing Medical University, Nanjing, China
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5
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New insights into IVIg mechanisms and alternatives in autoimmune and inflammatory diseases. Curr Opin Hematol 2021; 27:392-398. [PMID: 32868670 DOI: 10.1097/moh.0000000000000609] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE OF REVIEW Intravenous immunoglobulin (IVIg) is an effective treatment for an increasing number of autoimmune and inflammatory conditions. However, IVIg continues to be limited by problems of potential shortages and cost. A number of mechanisms have been described for IVIg, which have been captured in newly emergent IVIg mimetic and IVIg alternative therapies. This review discusses the recent developments in IVIg mimetics and alternatives. RECENT FINDINGS Newly emergent IVIg mimetics and alternatives capture major proposed mechanisms of IVIg, including FcγR blockade, FcRn inhibition, complement inhibition, immune complex mimetics and sialylated IgG. Many of these emergent therapies have promising preclinical and clinical trial results. SUMMARY Significant research has been undertaken into the mechanism of IVIg in the treatment of autoimmune and inflammatory disease. Understanding the major IVIg mechanisms has allowed for rational development of IVIg mimetics and alternatives for several IVIg-treatable diseases.
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6
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Fc-Receptor Targeted Therapies for the Treatment of Myasthenia gravis. Int J Mol Sci 2021; 22:ijms22115755. [PMID: 34071155 PMCID: PMC8198115 DOI: 10.3390/ijms22115755] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 12/16/2022] Open
Abstract
Myasthenia gravis (MG) is an autoimmune disease in which immunoglobulin G (IgG) antibodies (Abs) bind to acetylcholine receptors (AChR) or to functionally related molecules in the postsynaptic membrane at the neuromuscular junction. IgG crystallizable fragment (Fc)-mediated effector functions, such as antibody-dependent complement deposition, contribute to disease development and progression. Despite progress in understanding Ab-mediated disease mechanisms, immunotherapy of MG remained rather unspecific with corticosteroids and maintenance with immunosuppressants as first choice drugs for most patients. More specific therapeutic IgG Fc-based platforms that reduce serum half-life or effector functions of pathogenic MG-related Abs are currently being developed, tested in clinical trials or have recently been successfully translated into the clinic. In this review, we illustrate mechanisms of action and clinical efficacies of emerging Fc-mediated therapeutics such as neonatal Fc receptor (FcRn)-targeting agents. Furthermore, we evaluate prospects of therapies targeting classical Fc receptors that have shown promising therapeutic efficacy in other antibody-mediated conditions. Increased availability of Fc- and Fc receptor-targeting biologics might foster the development of personalized immunotherapies with the potential to induce sustained disease remission in patients with MG.
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7
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Hu S, Han R, Chen L, Qin W, Xu X, Shi J, Zhu X, Zhang M, Zeng C, Tang Z, Bao H, Liu Z. Upregulated LRRC55 promotes BK channel activation and aggravates cell injury in podocytes. J Exp Med 2021; 218:e20192373. [PMID: 33346797 PMCID: PMC7756252 DOI: 10.1084/jem.20192373] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 07/27/2020] [Accepted: 09/16/2020] [Indexed: 12/15/2022] Open
Abstract
Podocyte injury is a common hallmark in various glomerular diseases. The level of LRRC55 was increased in podocytes of patients with focal segmental glomerulosclerosis (FSGS), diabetic nephropathy (DN), and membranous nephropathy (MN). Upregulated LRRC55 and increased intracellular Ca2+ led to BK channel activation and the loss of intracellular potassium, resulting in apoptosome formation and caspase-3 activation in angiotensin II (Ang II)-treated podocytes. Knockout of Lrrc55 or the BK channel prevented the BK current and ameliorated podocyte injury in Ang II-treated mice. Upstream, NFATc3 regulated the expression of LRRC55. Increased LRRC55 expression in podocytes was also evident in animal models of FSGS, DN, and MN. Treatment with losartan or LRRC55 siRNA suppressed LRRC55 expression, prevented BK channel activation, and attenuated podocyte injury in animal models of FSGS, DN, and MN. In conclusion, upregulated LRRC55 promotes BK channel activation and aggravates cell injury in podocytes in FSGS, DN, and MN. LRRC55 inhibition may represent a new therapeutic approach for podocyte injury.
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Affiliation(s)
- Shuai Hu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Runhong Han
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Long Chen
- National Standard Laboratory of Pharmacology for Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China
| | - Weisong Qin
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Xiaodong Xu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Jingsong Shi
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Xiaodong Zhu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Mingchao Zhang
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Caihong Zeng
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Zheng Tang
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Hao Bao
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Zhihong Liu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
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8
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Shock A, Humphreys D, Nimmerjahn F. Dissecting the mechanism of action of intravenous immunoglobulin in human autoimmune disease: Lessons from therapeutic modalities targeting Fcγ receptors. J Allergy Clin Immunol 2020; 146:492-500. [PMID: 32721416 DOI: 10.1016/j.jaci.2020.06.036] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 06/25/2020] [Accepted: 06/29/2020] [Indexed: 12/18/2022]
Abstract
Since the first description of the administration of high doses of pooled serum IgG, also referred to as intravenous IgG (IVIg) therapy, as being able to ameliorate various autoimmune diseases, researchers have been investigating which molecular and cellular pathways underlie IVIg activity. Apart from trying to understand the obvious conundrum that IgG can trigger both autoimmune pathology and resolution of inflammation, the rapidly expanding use of IVIg has led to a lack of availability of this primary blood product, providing a strong rationale for developing recombinant alternatives. During the last decade, a tremendous number of novel insights into IVIg activity brought the goal of replacing IVIg within reach, at least in select indications, and has led to the initiation of several clinical trials. At the forefront of this effort is the modulation of autoantibody half-life and blocking access of autoantibodies to fragment cystallizable γ receptors (Fcγ receptors). In this rostrum article, we will briefly discuss current models of IVIg activity, followed by a more specific focus on novel therapeutic avenues that are entering the clinic and may replace IVIg in the future.
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Affiliation(s)
| | | | - Falk Nimmerjahn
- Institute of Genetics, Department of Biology, Friedrich Alexander University of Erlangen-Nuremberg, Erlangen, Germany; Medical Immunology Campus Erlangen, Erlangen, Germany.
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9
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Lewis BJ, Branch DR. Mouse Models of Rheumatoid Arthritis for Studies on Immunopathogenesis and Preclinical Testing of Fc Receptor-Targeting Biologics. Pharmacology 2020; 105:618-629. [DOI: 10.1159/000508239] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 04/27/2020] [Indexed: 11/19/2022]
Abstract
<b><i>Background:</i></b> Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes inflammation, swelling, and pain in the joints and involves systemic complications. Mouse models of RA have been extensively used to model the pathogenesis of RA and to develop effective therapies. Although many components of the immune system have been studied in these models, the role of crystallizable fragment (Fc) gamma receptors (FcγRs) in RA has been sorely neglected. The aim of this review was to introduce the different mouse models of RA and to describe the different drug development strategies that have been tested in these models to target FcγR function, with the focus being on drugs that have been made from the Fc of immunoglobulin G (IgG). <b><i>Summary:</i></b> Evidence suggests that FcγRs play a major role in immune complex-induced inflammation in autoimmune diseases, such as RA. However, there is limited knowledge on the importance of FcγRs in the human disease even though there has been extensive work in mouse models of RA. Numerous mouse models of RA are available, with each model depicting certain aspects of the disease. Induced models of RA have nonspecific immune activation with cartilage-directed autoimmunity, whereas spontaneous models of RA develop without immunization, which results in a more chronic form of arthritis. These models have been used to test FcγR-targeting monoclonal antibodies, intravenous immunoglobulin (IVIg), subcutaneously administered IVIg, and recombinant Fcs for their ability to interact with and modify FcγR function. Recombinant Fcs avidly bind FcγRs and exhibit enhanced therapeutic efficacy in mouse models of RA. <b><i>Key Message:</i></b> The therapeutic utility of targeting FcγRs with recombinant Fcs is great and should be explored in human clinical trials for autoimmune diseases, such as RA.
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10
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Fitzpatrick EA, Wang J, Strome SE. Engineering of Fc Multimers as a Protein Therapy for Autoimmune Disease. Front Immunol 2020; 11:496. [PMID: 32269572 PMCID: PMC7109252 DOI: 10.3389/fimmu.2020.00496] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 03/04/2020] [Indexed: 02/06/2023] Open
Abstract
The success of Intravenous Immunoglobulin in treating autoimmune and inflammatory processes such as immune thrombocytopenia purpura and Kawasaki disease has led to renewed interest in developing recombinant molecules capable of recapitulating these therapeutic effects. The anti-inflammatory properties of IVIG are, in part, due to the Fc region of the IgG molecule, which interacts with activating or inhibitory Fcγ receptors (FcγRs), the neonatal Fc Receptor, non-canonical FcRs expressed by immune cells and complement proteins. In most cases, Fc interactions with these cognate receptors are dependent upon avidity—avidity which naturally occurs when polyclonal antibodies recognize unique antigens on a given target. The functional consequences of these avid interactions include antibody dependent cell-mediated cytotoxicity, antibody dependent cell phagocytosis, degranulation, direct killing, and/or complement activation—all of which are associated with long-term immunomodulatory effects. Many of these immunologic effects can be recapitulated using recombinant or non-recombinant approaches to induce Fc multimerization, affording the potential to develop a new class of therapeutics. In this review, we discuss the history of tolerance induction by immune complexes that has led to the therapeutic development of artificial Fc bearing immune aggregates and recombinant Fc multimers. The contribution of structure, aggregation and N-glycosylation to human IgG: FcγR interactions and the functional effect(s) of these interactions are reviewed. Understanding the mechanisms by which Fc multimers induce tolerance and attempts to engineer Fc multimers to target specific FcγRs and/or specific effector functions in autoimmune disorders is explored in detail.
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Affiliation(s)
- Elizabeth A Fitzpatrick
- Department of Microbiology, Immunology and Biochemistry, College of Medicine, University of Tennessee Health Science Center (UTHSC), Memphis, TN, United States
| | - Jin Wang
- College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN, United States
| | - S E Strome
- Department of Microbiology, Immunology and Biochemistry, College of Medicine, University of Tennessee Health Science Center (UTHSC), Memphis, TN, United States
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11
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Wabnitz H, Khan R, Lazarus AH. The use of IVIg in fetal and neonatal alloimmune thrombocytopenia- Principles and mechanisms. Transfus Apher Sci 2019; 59:102710. [PMID: 31926738 DOI: 10.1016/j.transci.2019.102710] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a rare neonatal disorder that is caused by alloimmunization against platelet antigens during pregnancy. Although rare, affecting only 1 in 1000 live births, it can cause intracranial hemorrhage and other bleeding complications that can lead to miscarriage, stillbirth and life-long neurological complications. One of the gold-standard therapies for at risk pregnancies is the administration of IVIg. Although IVIg has been used in a variety of different disorders for over 40 years, its exact mechanism of action is still unknown. In FNAIT, the majority of its therapeutic effect is thought the be mediated through the neonatal Fc receptor, however other mechanisms cannot be excluded. Due to safety, supply and other concerns that are associated with IVIg use, alternative therapies that could replace IVIg are additionally being investigated. This includes the possibility of a prophylaxis regimen for FNAIT, similarly to what has been successfully used in hemolytic disease of the fetus and newborn for over 50 years.
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Affiliation(s)
- Hanna Wabnitz
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5S 1A8, Canada; Keenan Research Centre, Department of Laboratory Medicine, St. Michael's Hospital, Toronto, ON, M5B 1W8, Canada; Toronto Platelet Immunobiology Group (TPIG), Toronto, ON, M5B 1T8, Canada
| | - Ramsha Khan
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5S 1A8, Canada; Keenan Research Centre, Department of Laboratory Medicine, St. Michael's Hospital, Toronto, ON, M5B 1W8, Canada; Toronto Platelet Immunobiology Group (TPIG), Toronto, ON, M5B 1T8, Canada; Canadian Blood Services, Centre for Innovation, Ottawa, ON, K1G 4J5, Canada
| | - Alan H Lazarus
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5S 1A8, Canada; Keenan Research Centre, Department of Laboratory Medicine, St. Michael's Hospital, Toronto, ON, M5B 1W8, Canada; Toronto Platelet Immunobiology Group (TPIG), Toronto, ON, M5B 1T8, Canada; Canadian Blood Services, Centre for Innovation, Ottawa, ON, K1G 4J5, Canada; Department of Medicine, St. Michael's Hospital, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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12
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Next-generation Fc receptor–targeting biologics for autoimmune diseases. Autoimmun Rev 2019; 18:102366. [DOI: 10.1016/j.autrev.2019.102366] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 04/11/2019] [Indexed: 01/04/2023]
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13
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Hoffmann JHO, Enk AH. High-Dose Intravenous Immunoglobulin in Skin Autoimmune Disease. Front Immunol 2019; 10:1090. [PMID: 31244821 PMCID: PMC6579842 DOI: 10.3389/fimmu.2019.01090] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 04/29/2019] [Indexed: 11/26/2022] Open
Abstract
The immunomodulatory potential and low incidence of severe side effects of high-dose intravenous immunoglobulin (IVIg) treatment led to its successful application in a variety of dermatological autoimmune diseases over the last two decades. IVIg is usually administered at a dose of 2 g per kg body weight distributed over 2–5 days every 4 weeks. They are most commonly used as a second- or third-line treatment in dermatological autoimmune disease (pemphigus vulgaris, pemphigus foliaceus, bullous pemphigoid, mucous membrane pemphigoid, epidermolysis bullosa acquisita, dermatomyositis, systemic vasculitis, and systemic lupus erythematosus). However, first-line treatment may be warranted in special circumstances like concomitant malignancy, a foudroyant clinical course, and contraindications against alternative treatments. Furthermore, IVIg can be considered first line in scleromyxedema. Production of IVIg for medical use is strictly regulated to ensure a low risk of pathogen transmission and comparable quality of individual batches. More common side effects include nausea, headache, fatigue, and febrile infusion reactions. Serious side effects are rare and include thrombosis and embolism, pulmonary edema, renal failure, aseptic meningitis, and severe anaphylactic reactions. Regarding the mechanism of action, one can discriminate between functions of the Fcγ region and the F(ab)2 region and their effects on a cellular level. These functions are not mutually exclusive, and more than one pathway may contribute to the beneficial effects. Here, we present a historical background, details on manufacturing, hypotheses on the mechanisms of action, information on the clinical application in the abovementioned conditions, and a brief outlook on future directions of IVIg treatment in dermatology.
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Affiliation(s)
| | - Alexander H Enk
- Department of Dermatology, University of Heidelberg, Heidelberg, Germany
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14
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NK cell expression of Tim-3: First impressions matter. Immunobiology 2019; 224:362-370. [DOI: 10.1016/j.imbio.2019.03.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 02/04/2019] [Accepted: 03/01/2019] [Indexed: 12/17/2022]
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15
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Zhang X, Owens J, Olsen HS, So E, Burch E, McCroskey MC, Li X, Weber GL, Bennett D, Rybin D, Zhou H, Hao H, Mérigeon EY, Block DS, LaRosa G, Strome SE. A recombinant human IgG1 Fc multimer designed to mimic the active fraction of IVIG in autoimmunity. JCI Insight 2019; 4:121905. [PMID: 30674715 DOI: 10.1172/jci.insight.121905] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 12/11/2018] [Indexed: 12/30/2022] Open
Abstract
The antiinflammatory effects of i.v. Ig (IVIG) in the treatment of autoimmune disease are due, in part, to the Fc fragments of Ig aggregates. In order to capitalize on the known antiinflammatory and tolerogenic properties of Ig Fc aggregates, we created a recombinant human IgG1 Fc multimer, GL-2045. In vitro, GL-2045 demonstrated high-avidity binding to Fc receptors, blocked the binding of circulating immune complexes from patients with rheumatoid arthritis to human Fcγ receptors (FcγRs), and inhibited antibody-mediated phagocytosis at log order-lower concentrations than IVIG. In vivo, administration of GL-2045 conferred partial protection against antibody-mediated platelet loss in a murine immune thrombocytopenic purpura (ITP) model. GL-2045 also suppressed disease activity in a therapeutic model of murine collagen-induced arthritis (CIA), which was associated with reduced circulating levels of IL-6. Furthermore, GL-2045 administration to nonhuman primates (NHPs) transiently increased systemic levels of the antiinflammatory cytokines IL-10 and IL-1RA, reduced the proinflammatory cytokine IL-8, and decreased surface expression of CD14 and HLA-DR on monocytes. These findings demonstrate the immunomodulatory properties of GL-2045 and suggest that it has potential as a treatment for autoimmune and inflammatory diseases, as a recombinant alternative to IVIG.
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Affiliation(s)
- Xiaoyu Zhang
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Jane Owens
- Pfizer Inc., Cambridge, Massachusetts, USA
| | | | - Edward So
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Erin Burch
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | | | | | | | | | | | - Hua Zhou
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Haiping Hao
- Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | | | | | | | - Scott E Strome
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
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16
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Strome AL, Zhang X, Strome SE. The evolving role of immuno-oncology for the treatment of head and neck cancer. Laryngoscope Investig Otolaryngol 2019; 4:62-69. [PMID: 30828620 PMCID: PMC6383301 DOI: 10.1002/lio2.235] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 10/08/2018] [Accepted: 11/08/2018] [Indexed: 12/13/2022] Open
Abstract
Monoclonal antibodies (mAbs) that target immune co‐signaling pathways have the potential to enable immune mediated tumor eradication. While early adoption of these agents for the treatment of advanced squamous cell carcinoma of the head and neck (SCCHN) has produced some astounding clinical successes, the majority of patients fail to respond to therapy. The purpose of this review is to first provide a broad overview of the immuno‐oncology (I‐O) landscape and to then focus on the current status of mAb‐based I‐O (mAb:I‐O) for the treatment of SCCHN, with particular attention to the development of strategies for improving treatment responses.
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Affiliation(s)
| | - Xiaoyu Zhang
- Department of Otorhinolaryngology-Head and Neck Surgery University of Maryland School of Medicine Baltimore Maryland
| | - Scott E Strome
- Department of Otorhinolaryngology-Head and Neck Surgery University of Maryland School of Medicine Baltimore Maryland.,College of Medicine University of Tennessee Health Science Center Memphis Tennessee
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17
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Spirig R, Campbell IK, Koernig S, Chen CG, Lewis BJB, Butcher R, Muir I, Taylor S, Chia J, Leong D, Simmonds J, Scotney P, Schmidt P, Fabri L, Hofmann A, Jordi M, Spycher MO, Cattepoel S, Brasseit J, Panousis C, Rowe T, Branch DR, Baz Morelli A, Käsermann F, Zuercher AW. rIgG1 Fc Hexamer Inhibits Antibody-Mediated Autoimmune Disease via Effects on Complement and FcγRs. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2018; 200:2542-2553. [PMID: 29531170 PMCID: PMC5890536 DOI: 10.4049/jimmunol.1701171] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 02/13/2018] [Indexed: 12/27/2022]
Abstract
Activation of Fc receptors and complement by immune complexes is a common important pathogenic trigger in many autoimmune diseases and so blockade of these innate immune pathways may be an attractive target for treatment of immune complex-mediated pathomechanisms. High-dose IVIG is used to treat autoimmune and inflammatory diseases, and several studies demonstrate that the therapeutic effects of IVIG can be recapitulated with the Fc portion. Further, recent data indicate that recombinant multimerized Fc molecules exhibit potent anti-inflammatory properties. In this study, we investigated the biochemical and biological properties of an rFc hexamer (termed Fc-μTP-L309C) generated by fusion of the IgM μ-tailpiece to the C terminus of human IgG1 Fc. Fc-μTP-L309C bound FcγRs with high avidity and inhibited FcγR-mediated effector functions (Ab-dependent cell-mediated cytotoxicity, phagocytosis, respiratory burst) in vitro. In addition, Fc-μTP-L309C prevented full activation of the classical complement pathway by blocking C2 cleavage, avoiding generation of inflammatory downstream products (C5a or sC5b-9). In vivo, Fc-μTP-L309C suppressed inflammatory arthritis in mice when given therapeutically at approximately a 10-fold lower dose than IVIG, which was associated with reduced inflammatory cytokine production and complement activation. Likewise, administration of Fc-μTP-L309C restored platelet counts in a mouse model of immune thrombocytopenia. Our data demonstrate a potent anti-inflammatory effect of Fc-μTP-L309C in vitro and in vivo, likely mediated by blockade of FcγRs and its unique inhibition of complement activation.
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Affiliation(s)
| | - Ian K Campbell
- CSL Ltd., Bio21 Institute, Parkville, Victoria 3010, Australia
| | - Sandra Koernig
- CSL Ltd., Bio21 Institute, Parkville, Victoria 3010, Australia
| | - Chao-Guang Chen
- CSL Ltd., Bio21 Institute, Parkville, Victoria 3010, Australia
| | - Bonnie J B Lewis
- Centre for Innovation Canadian Blood Services, Toronto, Ontario K1G 4J5, Canada; and
- Department of Medicine, University of Toronto, Toronto, Ontario M5G 2M1, Canada
| | - Rebecca Butcher
- CSL Ltd., Bio21 Institute, Parkville, Victoria 3010, Australia
| | - Ineke Muir
- CSL Ltd., Bio21 Institute, Parkville, Victoria 3010, Australia
| | - Shirley Taylor
- CSL Ltd., Bio21 Institute, Parkville, Victoria 3010, Australia
| | - Jenny Chia
- CSL Ltd., Bio21 Institute, Parkville, Victoria 3010, Australia
| | - David Leong
- CSL Ltd., Bio21 Institute, Parkville, Victoria 3010, Australia
| | - Jason Simmonds
- CSL Ltd., Bio21 Institute, Parkville, Victoria 3010, Australia
| | - Pierre Scotney
- CSL Ltd., Bio21 Institute, Parkville, Victoria 3010, Australia
| | - Peter Schmidt
- CSL Ltd., Bio21 Institute, Parkville, Victoria 3010, Australia
| | - Louis Fabri
- CSL Ltd., Bio21 Institute, Parkville, Victoria 3010, Australia
| | | | | | | | | | | | - Con Panousis
- CSL Ltd., Bio21 Institute, Parkville, Victoria 3010, Australia
| | - Tony Rowe
- CSL Ltd., Bio21 Institute, Parkville, Victoria 3010, Australia
| | - Donald R Branch
- Centre for Innovation Canadian Blood Services, Toronto, Ontario K1G 4J5, Canada; and
- Department of Medicine, University of Toronto, Toronto, Ontario M5G 2M1, Canada
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