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Si M, Li L, Fang M, Ye Z, Zhang XC, Yang W, Nie L, Yu X. Anomalous kinetics of galactose-deficient IgA incurring nephropathy revealed by cross-scale optical imaging. Kidney Int 2023; 103:320-330. [PMID: 36341730 DOI: 10.1016/j.kint.2022.08.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 08/16/2022] [Accepted: 08/19/2022] [Indexed: 11/06/2022]
Abstract
IgA nephropathy (IgAN) is the most common glomerulonephritis, characterized by the presence of predominant IgA deposits in the mesangium. Deposition of pathogenic IgA in kidney tissue is a fundamental initiating process that has not been fully studied. Here, we employed optical imaging to directly visualize kidney deposition of IgA with optimized spatial and temporal resolution in BALB/c nude mice. Real-time fluorescence imaging revealed that IgA isolated from patients with IgAN preferentially accumulated in the kidneys, compared with IgA purified from healthy individuals. There was no difference in the distribution of either IgA preparation by the liver. Photoacoustic computed tomography dynamically demonstrated and quantified the enhanced retention of pathological IgA in the kidney cortex. Photoacoustic microscopy tracked IgA deposition in the glomeruli with a resolution down to three microns in a mouse model. Notably, longitudinal fluorescent imaging revealed that galactose-deficient IgA (Gd-IgA), which was elevated in the circulation of patients with IgAN, persisted in the kidney for longer than two weeks, and stable deposition of Gd-IgA induced kidney impairment, including albuminuria and mesangial proliferation. Thus, our study highlights that the aberrant kidney depositional kinetics of Gd-IgA is involved in the pathogenesis of IgAN. Hence, cross-scale optical imaging has potential applications in assessing immune-mediated kidney diseases and uncovering underlying mechanisms of disease.
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Affiliation(s)
- Meijun Si
- Department of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China; Guangdong-Hong Kong Joint Laboratory on Immunological and Genetic Kidney Diseases, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Lanqing Li
- Medical Research Center, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Mengting Fang
- Department of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China; Guangdong-Hong Kong Joint Laboratory on Immunological and Genetic Kidney Diseases, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Zhiming Ye
- Department of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China; Guangdong-Hong Kong Joint Laboratory on Immunological and Genetic Kidney Diseases, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Xu-Chao Zhang
- Medical Research Center, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Wei Yang
- Medical Research Center, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Liming Nie
- Medical Research Center, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Xueqing Yu
- Department of Nephrology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China; Guangdong-Hong Kong Joint Laboratory on Immunological and Genetic Kidney Diseases, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
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Ding L, Chen X, Cheng H, Zhang T, Li Z. Advances in IgA glycosylation and its correlation with diseases. Front Chem 2022; 10:974854. [PMID: 36238099 PMCID: PMC9552352 DOI: 10.3389/fchem.2022.974854] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 08/23/2022] [Indexed: 11/29/2022] Open
Abstract
Immunoglobulin A (IgA) is the most abundant immunoglobulin synthesized in the human body. It has the highest concentration in the mucosa and is second only to IgG in serum. IgA plays an important role in mucosal immunity, and is the predominant antibody used to protect the mucosal surface from pathogens invasion and to maintain the homeostasis of intestinal flora. Moreover, The binding IgA to the FcαRI (Fc alpha Receptor I) in soluble or aggregated form can mediate anti- or pro- inflammatory responses, respectively. IgA is also known as one of the most heavily glycosylated antibodies among human immunoglobulins. The glycosylation of IgA has been shown to have a significant effect on its immune function. Variation in the glycoform of IgA is often the main characteration of autoimmune diseases such as IgA nephropathy (IgAN), IgA vasculitis (IgAV), systemic lupus erythematosus (SLE), and rheumatoid arthritis (RA). However, compared with the confirmed glycosylation function of IgG, the pathogenic mechanism of IgA glycosylation involved in related diseases is still unclear. This paper mainly summarizes the recent reports on IgA’s glycan structure, its function, its relationship with the occurrence and development of diseases, and the potential application of glycoengineered IgA in clinical antibody therapeutics, in order to provide a potential reference for future research in this field.
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Manral P, Caza TN, Storey AJ, Beck LH, Borza DB. The Alternative Pathway Is Necessary and Sufficient for Complement Activation by Anti-THSD7A Autoantibodies, Which Are Predominantly IgG4 in Membranous Nephropathy. Front Immunol 2022; 13:952235. [PMID: 35874690 PMCID: PMC9301376 DOI: 10.3389/fimmu.2022.952235] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 06/16/2022] [Indexed: 12/12/2022] Open
Abstract
Membranous nephropathy (MN) is an immune kidney disease characterized by glomerular subepithelial immune complexes (ICs) containing antigen, IgG, and products of complement activation. Whereas proteinuria is caused by complement-mediated podocyte injury, the pathways of complement activation remain controversial due to the predominance of IgG4 in ICs, an IgG subclass considered unable to activate complement. THSD7A, a transmembrane protein expressed on podocytes, is the target autoantigen in ~3% of cases of primary MN. In this study, we analyzed sera from 16 patients with THSD7A-associated MN with regard to the anti-THSD7A IgG subclasses and their ability to fix complement in vitro. The serum concentration of anti-THSD7A IgG varied over two orders of magnitude (1.3-243 μg/mL). As a relative proportion of all IgG anti-THSD7A, IgG4 was by far the most abundant subclass (median 79%), followed by IgG1 (median 11%). IgG4 was the dominant subclass of anti-THSD7A antibodies in 14 sera, while IgG1 was dominant in one and co-dominant in another. One quarter of MN sera additionally contained low levels of anti-THSD7A IgA1. ICs formed by predominantly IgG4 anti-THSD7A autoantibodies with immobilized THSD7A were relatively weak activators of complement in vitro, compared to human IgG1 and IgG3 mAbs used as positive control. Complement deposition on THSD7A ICs was dose-dependent and occurred to a significant extent only at relatively high concentration of anti-THSD7A IgG. C3b fixation by THSD7A ICs was completely abolished in factor B-depleted sera, partially inhibited in C4-depleted sera, unchanged in C1q-depleted sera, and also occurred in Mg-EGTA buffer. These results imply that THSD7A ICs predominantly containing IgG4 activate complement at high IgG4 density, which strictly requires a functional alternative pathway, whereas the classical and lectin pathways are dispensable. These findings advance our understanding of how IgG4 antibodies activate complement.
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Affiliation(s)
- Pallavi Manral
- Department of Microbiology, Immunology and Physiology, Meharry Medical College, Nashville, TN, United States
| | | | - Aaron J. Storey
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Laurence H. Beck
- Department of Medicine (Nephrology), Boston University School of Medicine and Boston Medical Center, Boston, MA, United States
| | - Dorin-Bogdan Borza
- Department of Microbiology, Immunology and Physiology, Meharry Medical College, Nashville, TN, United States
- *Correspondence: Dorin-Bogdan Borza,
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Is complement the main accomplice in IgA nephropathy? From initial observations to potential complement-targeted therapies. Mol Immunol 2021; 140:1-11. [PMID: 34601376 DOI: 10.1016/j.molimm.2021.09.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 09/01/2021] [Accepted: 09/17/2021] [Indexed: 12/22/2022]
Abstract
IgA Nephropathy (IgAN) is the main cause of primary glomerulonephritis, globally. This disease is associated with a wide range of clinical presentations, variable prognosis and a spectrum of histological findings. More than fifty years after its first description, this heterogeneity continues to complicate efforts to understand the pathogenesis. Nevertheless, involvement of the complement system in IgAN was identified early on. Dysfunction of the immunoglobulin A (IgA) system, the principal offender in this disease, including modification of isoforms and glycoforms of IgA1, the nature of immune complexes and autoantibodies to galactose deficient IgA1 might all be responsible for complement activation in IgAN. However, the specific mechanisms engaging complement are still under examination. Research in this domain should allow for identification of patients that may benefit from complement-targeted therapy, in the foreseeable future.
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Hansen AL, Reily C, Novak J, Renfrow MB. Immunoglobulin A Glycosylation and Its Role in Disease. EXPERIENTIA SUPPLEMENTUM (2012) 2021; 112:433-477. [PMID: 34687019 DOI: 10.1007/978-3-030-76912-3_14] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Human IgA is comprised of two subclasses, IgA1 and IgA2. Monomeric IgA (mIgA), polymeric IgA (pIgA), and secretory IgA (SIgA) are the main molecular forms of IgA. The production of IgA rivals all other immunoglobulin isotypes. The large quantities of IgA reflect the fundamental roles it plays in immune defense, protecting vulnerable mucosal surfaces against invading pathogens. SIgA dominates mucosal surfaces, whereas IgA in circulation is predominately monomeric. All forms of IgA are glycosylated, and the glycans significantly influence its various roles, including antigen binding and the antibody effector functions, mediated by the Fab and Fc portions, respectively. In contrast to its protective role, the aberrant glycosylation of IgA1 has been implicated in the pathogenesis of autoimmune diseases, such as IgA nephropathy (IgAN) and IgA vasculitis with nephritis (IgAVN). Furthermore, detailed characterization of IgA glycosylation, including its diverse range of heterogeneity, is of emerging interest. We provide an overview of the glycosylation observed for each subclass and molecular form of IgA as well as the range of heterogeneity for each site of glycosylation. In many ways, the role of IgA glycosylation is in its early stages of being elucidated. This chapter provides an overview of the current knowledge and research directions.
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Affiliation(s)
- Alyssa L Hansen
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Colin Reily
- Departments of Medicine and Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jan Novak
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Matthew B Renfrow
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, USA.
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Medrano AS, Muijsemberg A, Wimbury D, Martin M, Jatem E, González J, Colás-Campás L, García-Carrasco A, Martínez C, Barratt J. Relationship between IgA1 lectin-binding specificities, mesangial C4d deposits and clinical phenotypes in IgA nephropathy. Nephrol Dial Transplant 2020; 37:318-325. [PMID: 33315098 DOI: 10.1093/ndt/gfaa356] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND AND OBJECTIVES The reason why mesangial C4d deposits are detected in only certain biopsies of IgA nephropathy remains unclear. We analyse the association between IgA glycosylation patterns, mesangial C4 deposition and clinical phenotypes in IgA nephropathy.Design, setting, participants and measurements: This cross-sectional study included 145 patients with idiopathic IgA nephropathy. We measured the serum levels of three different IgA1 lectin-binding specificities, using enzyme-linked-immunosorbent assays with and without treatment with neuraminidase, and we analysed the relationship between these glycoforms, C4d mesangial deposits and clinical phenotypes. RESULTS C4d-positive vs Cd4-negative patients had higher proteinuria (median: 3.1 g/g [0.9-4.2] vs. 1.8 g/g [1-2.2]; p = 0.000), hematuria (223 cel/µL [32-278] vs 99 cel/µL [25-186], p = 0.000), and higher levels of IgA binding to neuraminidase untreated Helix Aspersa (HA IgA1 neu-) (150.6 ± 52 U vs 96.2 ± 64.1 U, p = 0.000), neuraminidase untreated Helix Pomatia (HPA IgA1 neu-) (0.34 ± 0.15 vs 0.27 ± 0.13p = 0.04), Triticum vulgaris (TV IgA1) (85.1 ± 31.7 vs42.2 ± 26.9p = 0.000), and Canavalia ensiformis (ConA IgA1) (32.5 ± 18 U vs 16.7 ± 9.38 U, p = 0.000). The levels of HA IgA1 neu-, HPA IgA1 neu-, TV IgA1 and ConA IgA1 were all associated with the mesangial deposition of C4d, extracapillary proliferation and acute kidney injury. In ROC curves, HA IgA1 neu-, HPA IgA1 neu-, TV IgA1 and ConA IgA1 significantly discriminated between C4d positive ad C4d-negative biopsies. In logistic models, TVIgA1 and ConAIgA1 were the only independent predictors of mesangial C4d deposits. CONCLUSIONS In IgA nephropathy, the severity of the disease is associated with the level of IgA exposing N-Acetyl-D-Galactosamine, N-Acetyl-D-Glucosamine or mannose whereas C4d deposits are only associated with elevated levels of IgA1 glycoforms exhibiting glycan residues with specificity for mannose and N-Acetyl-D-Glucosamine binding lectins.
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Affiliation(s)
- Alfons Segarra Medrano
- Servicio de Nefrología. Hospital Arnau de Vilanova, Lleida, Spain.,Institut de Recerca Biomèdica, Lleida, Spain
| | - Andrea Muijsemberg
- Servicio de Nefrología. Hospital Arnau de Vilanova, Lleida, Spain.,Institut de Recerca Biomèdica, Lleida, Spain.,Universitat Autònoma de Barcelona, Spain
| | - David Wimbury
- The Mayer IgA Nephropathy Laboratories, University of Leicester, UK
| | - Marisa Martin
- Servicio de Nefrología. Hospital Arnau de Vilanova, Lleida, Spain.,Institut de Recerca Biomèdica, Lleida, Spain
| | - Elias Jatem
- Servicio de Nefrología. Hospital Arnau de Vilanova, Lleida, Spain.,Institut de Recerca Biomèdica, Lleida, Spain
| | - Jorge González
- Servicio de Nefrología. Hospital Arnau de Vilanova, Lleida, Spain.,Institut de Recerca Biomèdica, Lleida, Spain
| | - Laura Colás-Campás
- Grupo de Neurociencias Clínicas, Institut de Recerca Biomèdica de Lleida (IRBLleida). Universitat de Lleida (UdL), Lleida, Spain
| | - Alicia García-Carrasco
- Vascular and Renal Translational Research Group, Institut de Recerca Biomèdica de Lleida (IRBLleida). Universitat de Lleida (UdL), Lleida, Spain
| | - Cristina Martínez
- Servicio de Nefrología. Hospital Arnau de Vilanova, Lleida, Spain.,Institut de Recerca Biomèdica, Lleida, Spain.,Vascular and Renal Translational Research Group, Institut de Recerca Biomèdica de Lleida (IRBLleida). Universitat de Lleida (UdL), Lleida, Spain
| | - Jonathan Barratt
- The Mayer IgA Nephropathy Laboratories, University of Leicester, UK
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7
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Complement-mediated kidney diseases. Mol Immunol 2020; 128:175-187. [DOI: 10.1016/j.molimm.2020.10.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/16/2020] [Accepted: 10/19/2020] [Indexed: 12/19/2022]
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Abstract
Autoimmunity is a leading cause of chronic kidney disease and loss of native and transplanted kidneys. Conventional immunosuppressive therapies can be effective but are non-specific, noncurative, and risk serious side effects such as life-threatening infection and cancer. Novel therapies and targeted interventions are urgently needed. In this brief review we explore diverse strategies currently in development and under consideration to interrupt underlying disease mechanisms in immune-mediated renal injury. Because autoantibodies are prominent in diagnosis and pathogenesis in multiple human glomerulopathies, we highlight several promising therapies that interfere with functions of early mediators (IgG and complement) of the effector arm and with an epicenter (the germinal center) for induction of humoral immunity.
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Affiliation(s)
- Mary Helen Foster
- a Department of Medicine , Duke University Medical Center , Durham , NC , USA.,b Medical and Research Services , Durham VA Medical Center , Durham , NC , USA
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9
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Interleukin-17 receptor A (IL-17RA) as a central regulator of the protective immune response against Giardia. Sci Rep 2017; 7:8520. [PMID: 28819174 PMCID: PMC5561107 DOI: 10.1038/s41598-017-08590-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/12/2017] [Indexed: 12/16/2022] Open
Abstract
The protozoan parasite Giardia is a highly prevalent intestinal pathogen with a wide host range. Data obtained in mice, cattle and humans revealed the importance of IL-17A in the development of a protective immune response against Giardia. The aim of this study was to further unravel the protective effector mechanisms triggered by IL-17A following G. muris infection in mice, by an RNA-sequencing approach. C57BL/6 WT and C57BL/6 IL-17RA KO mice were orally infected with G. muris cysts. Three weeks post infection, intestinal tissue samples were collected for RNA-sequencing, with samples from uninfected C57BL/6 WT and C57BL/6 IL-17RA KO animals serving as negative controls. Differential expression analysis showed that G. muris infection evoked the transcriptional upregulation of a wide array of genes, mainly in animals with competent IL-17RA signaling. IL-17RA signaling induced the production of various antimicrobial peptides, such as angiogenin 4 and α- and β-defensins and regulated complement activation through mannose-binding lectin 2. The expression of the receptor that regulates the secretion of IgA into the intestinal lumen, the polymeric immunoglobulin receptor, was also dependent on IL-17RA signaling. Interestingly, the transcriptome data showed for the first time the involvement of the circadian clock in the host response following Giardia infection.
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Sugimoto M, Watanabe H, Asano T, Sato S, Takagi T, Kobayashi H, Ohira H. Possible participation of IgG4 in the activation of complement in IgG4-related disease with hypocomplementemia. Mod Rheumatol 2015; 26:251-8. [PMID: 26357950 DOI: 10.3109/14397595.2015.1076924] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To investigate which IgG subclasses contribute to the activation of the complement pathway in IgG4-related disease (IgG4RD) patients with hypocomplementemia. METHODS Sera of IgG4RD patients were analyzed for the binding ability of IgG subclasses to complement component 1q (C1q). Polyethylene glycol (PEG) precipitates containing immune complexes (ICs) in sera of IgG4RD patients were analyzed for IgG subclass composition by Western blotting. PEG precipitates containing ICs (PEG-ICs) in sera of patients were also analyzed for their ability to consume complement in normal human serum (NHS) using a total complement hemolytic (CH50) assay and a commercial kit to measure the complement capacity of all three individual complement pathways. RESULTS The C1q binding assay revealed high serum levels of C1q-binding IgG4 in IgG4RD patients with hypocomplementemia. ICs in PEG precipitates were formed with IgG4 in IgG4RD patients, regardless of the presence or absence of hypocomplementemia. We observed a marked reduction of CH50 and reduced complement activity in the classical complement pathway as well as the mannan-binding lectin complement pathway in NHS incubated with PEG-IC isolated from IgG4RD patients with hypocomplementemia. CONCLUSION Our results suggest that IgG4 may participate in the activation of complement in IgG4RD patients with hypocomplementemia.
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Affiliation(s)
- Mitsuru Sugimoto
- a Department of Gastroenterology and Rheumatology, School of Medicine , Fukushima Medical University , Fukushima , Japan
| | - Hiroshi Watanabe
- a Department of Gastroenterology and Rheumatology, School of Medicine , Fukushima Medical University , Fukushima , Japan
| | - Tomoyuki Asano
- a Department of Gastroenterology and Rheumatology, School of Medicine , Fukushima Medical University , Fukushima , Japan
| | - Shuzo Sato
- a Department of Gastroenterology and Rheumatology, School of Medicine , Fukushima Medical University , Fukushima , Japan
| | - Tadayuki Takagi
- a Department of Gastroenterology and Rheumatology, School of Medicine , Fukushima Medical University , Fukushima , Japan
| | - Hiroko Kobayashi
- a Department of Gastroenterology and Rheumatology, School of Medicine , Fukushima Medical University , Fukushima , Japan
| | - Hiromasa Ohira
- a Department of Gastroenterology and Rheumatology, School of Medicine , Fukushima Medical University , Fukushima , Japan
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11
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Divergent antibody subclass and specificity profiles but not protective HLA-B alleles are associated with variable antibody effector function among HIV-1 controllers. J Virol 2013; 88:2799-809. [PMID: 24352471 DOI: 10.1128/jvi.03130-13] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Understanding the coordination between humoral and cellular immune responses may be the key to developing protective vaccines, and because genetic studies of long-term HIV-1 nonprogressors have associated specific HLA-B alleles with spontaneous control of viral replication, this subject group presents an opportunity to investigate relationships between arms of the adaptive immune system. Given evidence suggesting that cellular immunity may play a role in viral suppression, we sought to determine whether and how the humoral immune response might vary among controllers. Significantly, Fc-mediated antibody effector functions have likewise been associated with durable viral control. In this study, we compared the effector function and biophysical features of HIV-specific antibodies in a cohort of controllers with and without protective HLA-B alleles in order to investigate whether there was evidence for multiple paths to HIV-1 control, or whether cellular and humoral arms of immunity might exhibit coordinated profiles. However, with the exception of IgG2 antibodies to gp41, HLA status was not associated with divergent humoral responses. This finding did not result from uniform antibody responses across subjects, as controllers could be regrouped according to strong differences in their HIV-specific antibody subclass specificity profiles. These divergent antibody profiles were further associated with significant differences in nonneutralizing antibody effector function, with levels of HIV-specific IgG1 acting as the major distinguishing factor. Thus, while HLA background among controllers was associated with minimal differences in humoral function, antibody subclass and specificity profiles were associated with divergent effector function, suggesting that these features could be used to make functional predictions. Because these nonneutralizing antibody activities have been associated with spontaneous viral control, reduced viral load, and nonprogression in infected subjects and protection in vaccinated subjects, understanding the specific features of IgGs with potentiated effector function may be critical to vaccine and therapeutic antibody development. IMPORTANCE In this study, we investigated whether the humoral and cellular arms of adaptive immunity exhibit coordinated or compensatory activity by studying the antibody response among HIV-1 controllers with different genetic backgrounds.
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Mühlbauer M, Perez-Chanona E, Jobin C. Epithelial cell-specific MyD88 signaling mediates ischemia/reperfusion-induced intestinal injury independent of microbial status. Inflamm Bowel Dis 2013; 19:2857-66. [PMID: 24141713 PMCID: PMC4039295 DOI: 10.1097/01.mib.0000435445.96933.37] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The Toll-like receptor/MyD88 signaling pathway has been shown to mediate protective functions during intestinal exposure to various noxious events. The goal of this study was to define the role of bacteria and MyD88 signaling in intestinal response to damage using an ischemia-reperfusion (I/R)-induced injury model. We showed that conventionalized mice displayed a better outcome to I/R-induced injury than germ-free mice (3.8 ± 1.98 vs. 11.8 ± 1.83, P < 0.05). However, mice with intestinal epithelial cell (IEC)-specific deletion of Myd88 (Myd88) were protected from I/R-induced injury compared with Myd88 control mice. Myd88 mice also displayed a significantly reduced bacterial translocation (∼85%) into lymph nodes compared with Myd88 mice. Expression of ccl2 and cxcl1 mRNA was significantly reduced (85% and 62%, respectively) in intestinal tissue of Myd88 mice compared with Myd88 mice, which associated with a reduced number of myeloperoxidase-positive cells in intestinal tissues of I/R-exposed Myd88 mice. Immunohistochemistry analysis showed a reduced IgA deposition and complement staining in ischemic tissue of Myd88 mice compared with Myd88 mice. These findings suggest that I/R-induced intestinal injury involves IEC-derived MyD88 signaling leading to increased IgA deposition/degradation, and complement activation in conjunction with an influx of neutrophils mediated by chemokine production.
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Affiliation(s)
- Marcus Mühlbauer
- Departments of Medicine, Microbiology and Immunology, and Pharmacology, University of North Carolina, Chapel Hill, North Carolina
| | - Ernesto Perez-Chanona
- Departments of Medicine, Microbiology and Immunology, and Pharmacology, University of North Carolina, Chapel Hill, North Carolina
- Department of Medicine and Department of Infectious Diseases & Pathology, University of Florida, Gainesville, Florida
| | - Christian Jobin
- Departments of Medicine, Microbiology and Immunology, and Pharmacology, University of North Carolina, Chapel Hill, North Carolina
- Department of Medicine and Department of Infectious Diseases & Pathology, University of Florida, Gainesville, Florida
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Enhanced phagocytic activity of HIV-specific antibodies correlates with natural production of immunoglobulins with skewed affinity for FcγR2a and FcγR2b. J Virol 2013; 87:5468-76. [PMID: 23468489 DOI: 10.1128/jvi.03403-12] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
While development of an HIV vaccine that can induce neutralizing antibodies remains a priority, decades of research have proven that this is a daunting task. However, accumulating evidence suggests that antibodies with the capacity to harness innate immunity may provide some protection. While significant research has focused on the cytolytic properties of antibodies in acquisition and control, less is known about the role of additional effector functions. In this study, we investigated antibody-dependent phagocytosis of HIV immune complexes, and we observed significant differences in the ability of antibodies from infected subjects to mediate this critical effector function. We observed both quantitative differences in the capacity of antibodies to drive phagocytosis and qualitative differences in their FcγR usage profile. We demonstrate that antibodies from controllers and untreated progressors exhibit increased phagocytic activity, altered Fc domain glycosylation, and skewed interactions with FcγR2a and FcγR2b in both bulk plasma and HIV-specific IgG. While increased phagocytic activity may directly influence immune activation via clearance of inflammatory immune complexes, it is also plausible that Fc receptor usage patterns may regulate the immune response by modulating downstream signals following phagocytosis--driving passive degradation of internalized virus, release of immune modulating cytokines and chemokines, or priming of a more effective adaptive immune response.
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14
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Dall’Olio F, Vanhooren V, Chen CC, Slagboom PE, Wuhrer M, Franceschi C. N-glycomic biomarkers of biological aging and longevity: a link with inflammaging. Ageing Res Rev 2013; 12:685-98. [PMID: 22353383 DOI: 10.1016/j.arr.2012.02.002] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 01/24/2012] [Accepted: 02/06/2012] [Indexed: 01/31/2023]
Abstract
Glycosylation is a frequent co/post-translational modification of proteins which modulates a variety of biological functions. The analysis of N-glycome, i.e. the sugar chains N-linked to asparagine, identified new candidate biomarkers of aging such as N-glycans devoid of galactose residues on their branches, in a variety of human and experimental model systems, such as healthy old people, centenarians and their offspring and caloric restricted mice. These agalactosylated biantennary structures mainly decorate Asn297 of Fc portion of IgG (IgG-G0), and are present also in patients affected by progeroid syndromes and a variety of autoimmune/inflammatory diseases. IgG-G0 exert a pro-inflammatory effect through different mechanisms, including the lectin pathway of complement, binding to Fcγ receptors and formation of autoantibody aggregates. The age-related accumulation of IgG-G0 can contribute to inflammaging, the low-grade pro-inflammatory status that characterizes elderly, by creating a vicious loop in which inflammation is responsible for the production of aberrantly glycosylated IgG which, in turn, would activate the immune system, exacerbating inflammation. Moreover, recent data suggest that the N-glycomic shift observed in aging could be related not only to inflammation but also to alteration of important metabolic pathways. Thus, altered N-glycans are both powerful markers of aging and possible contributors to its pathogenesis.
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Kolka R, Valdimarsson H, Bodvarsson M, Hardarson S, Jonsson T. Defective immunoglobulin A (IgA) glycosylation and IgA deposits in patients with IgA nephropathy. APMIS 2013; 121:890-7. [DOI: 10.1111/apm.12051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 12/14/2012] [Indexed: 11/29/2022]
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Daha NA, Banda NK, Roos A, Beurskens FJ, Bakker JM, Daha MR, Trouw LA. Complement activation by (auto-) antibodies. Mol Immunol 2011; 48:1656-65. [DOI: 10.1016/j.molimm.2011.04.024] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 04/15/2011] [Accepted: 04/20/2011] [Indexed: 12/24/2022]
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Kodar K, Kurtenkov O, Klaamas K. The Thomsen-Friedenreich antigen and alphaGal-specific human IgG glycoforms: concanavalin A reactivity and relation to survival of cancer patients. Immunol Invest 2010; 38:704-17. [PMID: 19860583 DOI: 10.3109/08820130903147193] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Glycan structures of IgG strongly influence the affinity for Fcgamma receptors and antibody effector functions. However, no particular attention has been paid yet to the glycosylation of tumor antigen-specific IgG. The objectives of this study were (i) to investigate the concanavalin A lectin (ConA) reactivity of human anti-Thomsen-Friedenreich (TF) and anti-alphaGal specific IgG in gastric cancer patients and healthy controls and (ii) to evaluate whether the ConA-reactivity of anti-TF and anti-alphaGal specific IgG is associated with the survival rate of patients with cancer. Total IgG was purified from the sera of patients with gastric cancer and healthy blood donors. The anti-TF and anti-alphaGal glycotope specific IgG were detected with ELISA using synthetic saccharide-polyacrylamide conjugates as antigen. In parallel plate, the ConA reactivity of the anti-TF or anti-alphaGal IgG was determined and the ConA index was calculated. Results show that serum anti-TF specific IgG antibodies of patients with cancer contain significantly higher content of ConA positive IgG glycoform compared to IgG of controls. No correlation between the ConA reactivity of anti-TF IgG and anti-alphaGal IgG was observed. High level of anti-TF IgG ConA reactivity was associated with a significantly lower survival rate of patients with gastric cancer.
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Affiliation(s)
- Kristel Kodar
- Department of Oncology and Immunology, National Institute for Health Development, Tallinn, Estonia
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Murata K, Baldwin WM. Mechanisms of complement activation, C4d deposition, and their contribution to the pathogenesis of antibody-mediated rejection. Transplant Rev (Orlando) 2009; 23:139-50. [PMID: 19362461 PMCID: PMC2797368 DOI: 10.1016/j.trre.2009.02.005] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Complement split products have emerged as useful markers of antibody-mediated rejection in solid organ transplants. One split product, C4d, is now widely accepted as a marker for antibody-mediated rejection in renal and cardiac allografts. This review summarizes the rationale for the use of C4d as a marker of antibody-mediated rejection, along with the clinical evidence supporting its use in the clinical diagnosis of antibody-mediated rejection. Antibody-independent mechanisms by which C4d can be activated by the classical and lectin pathways of complement activation are also identified. Finally, mechanisms by which complement activation stimulates effector cells (neutrophils, monocytes, macrophages, platelets, and B and T lymphocytes) as well as target cells (endothelial cells) are discussed in relation to antibody-mediated allograft rejection.
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Affiliation(s)
- Kazunori Murata
- Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - William M Baldwin
- Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, MD, USA
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Banda NK, Wood AK, Takahashi K, Levitt B, Rudd PM, Royle L, Abrahams JL, Stahl GL, Holers VM, Arend WP. Initiation of the alternative pathway of murine complement by immune complexes is dependent on N-glycans in IgG antibodies. ACTA ACUST UNITED AC 2008; 58:3081-9. [PMID: 18821684 DOI: 10.1002/art.23865] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Collagen antibody-induced arthritis in mice exhibits a requirement for amplification by the alternative pathway of complement. Although the alternative pathway is activated by spontaneous hydrolysis, it is not known whether this pathway can also be initiated directly by IgG antibodies in immune complexes (ICs). IgG lacking terminal sialic acid and galactose (G0 IgG) can activate the lectin pathway of complement, but it is not known if G0 IgG can also activate the classical or alternative pathway. The purpose of this study was to examine the mechanism of initiation of the alternative pathway of complement by ICs. METHODS We used adherent ICs containing bovine type II collagen (CII) and 4 monoclonal antibodies (mAb) to CII (adCII-IC). C3 activation was measured in the presence of sera from wild-type C57BL/6 mice or from mice deficient in informative complement components. The mAb were used intact or after enzyme digestion to create G0 IgG or to completely remove the N-glycan. RESULTS Both the classical and alternative pathways, but not the lectin pathway, mediated C3 activation induced by the adCII-IC. Mannose inhibited the alternative pathway-mediated C3 activation but had no effect on the classical pathway, and N-glycans in IgG were required by the alternative pathway but not the classical pathway. Both the classical and alternative pathways mediated C3 activation induced by G0 IgG. Mannose-binding lectin bound avidly to G0 IgG, but lectin pathway-mediated C3 activation was only slightly increased by G0 IgG. CONCLUSION The alternative pathway of complement is capable of initiating C3 activation induced by adCII-IC and requires the presence of N-glycans on the IgG. G0 IgG activates both the classical and alternative pathways more strongly than the lectin pathway.
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Affiliation(s)
- Nirmal K Banda
- Division of Rheumatology, University of Colorado Denver, School of Medicine, Aurora, CO 80045, USA
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Increased levels of galactose-deficient anti-Gal immunoglobulin G in the sera of hepatitis C virus-infected individuals with fibrosis and cirrhosis. J Virol 2007; 82:1259-70. [PMID: 18045939 DOI: 10.1128/jvi.01600-07] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Hepatitis B and C viruses are major causative agents of liver fibrosis, cirrhosis, and liver cancer. Using comparative glycoproteomics, we identified a glycoprotein that is altered both in amount and in glycosylation as a function of liver fibrosis and cirrhosis. Specifically, this altered glycoprotein is an immunoglobulin G (IgG) molecule reactive to the heterophilic alpha-Gal epitope [Galalpha-1-3Galbeta1-(3)4GlcNAc-R]. While similar changes in glycosylation have been observed in several autoimmune diseases, the specific immunoglobulins and their antigen recognition profiles were not determined. Thus, we provide the first report identifying the specific antigenic recognition profile of an immunoglobulin molecule containing altered glycosylation as a function of liver disease. This change in glycosylation allowed increased reactivity with several fucose binding lectins and permitted the development of a plate-based assay to measure this change. Increased lectin reactivity was observed in 100% of the more than 200 individuals with stage III or greater fibrosis and appeared to be correlated with the degree of fibrosis. The reason for the alteration in the glycosylation of anti-Gal IgG is currently unclear but may be related to the natural history of the disease and may be useful in the noninvasive detection of fibrosis and cirrhosis.
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