1
|
van Gool MMJ, van Egmond M. IgA and FcαRI: Versatile Players in Homeostasis, Infection, and Autoimmunity. Immunotargets Ther 2021; 9:351-372. [PMID: 33447585 PMCID: PMC7801909 DOI: 10.2147/itt.s266242] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 12/17/2020] [Indexed: 12/11/2022] Open
Abstract
Mucosal surfaces constitute the frontiers of the body and are the biggest barriers of our body for the outside world. Immunoglobulin A (IgA) is the most abundant antibody class present at these sites. It passively contributes to mucosal homeostasis via immune exclusion maintaining a tight balance between tolerating commensals and providing protection against pathogens. Once pathogens have succeeded in invading the epithelial barriers, IgA has an active role in host-pathogen defense by activating myeloid cells through divers receptors, including its Fc receptor, FcαRI (CD89). To evade elimination, several pathogens secrete proteins that interfere with either IgA neutralization or FcαRI-mediated immune responses, emphasizing the importance of IgA-FcαRI interactions in preventing infection. Depending on the IgA form, either anti- or pro-inflammatory responses can be induced. Moreover, the presence of excessive IgA immune complexes can result in continuous FcαRI-mediated activation of myeloid cells, potentially leading to severe tissue damage. On the one hand, enhancing pathogen-specific mucosal and systemic IgA by vaccination may increase protective immunity against infectious diseases. On the other hand, interfering with the IgA-FcαRI axis by monovalent targeting or blocking FcαRI may resolve IgA-induced inflammation and tissue damage. This review describes the multifaceted role of FcαRI as immune regulator between anti- and pro-inflammatory responses of IgA, and addresses potential novel therapeutic strategies that target FcαRI in disease. ![]()
Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use: https://youtu.be/xlijXy5W0xA
Collapse
Affiliation(s)
- Melissa Maria Johanna van Gool
- Department of Molecular Cell Biology and Immunology, Amsterdam UMC, Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.,Amsterdam institute for Infection and Immunity, Amsterdam UMC, Amsterdam, Netherlands
| | - Marjolein van Egmond
- Department of Molecular Cell Biology and Immunology, Amsterdam UMC, Amsterdam, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.,Amsterdam institute for Infection and Immunity, Amsterdam UMC, Amsterdam, Netherlands.,Department of Surgery, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| |
Collapse
|
2
|
Breedveld A, van Egmond M. IgA and FcαRI: Pathological Roles and Therapeutic Opportunities. Front Immunol 2019; 10:553. [PMID: 30984170 PMCID: PMC6448004 DOI: 10.3389/fimmu.2019.00553] [Citation(s) in RCA: 140] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/01/2019] [Indexed: 12/12/2022] Open
Abstract
Immunoglobulin A (IgA) is the most abundant antibody class present at mucosal surfaces. The production of IgA exceeds the production of all other antibodies combined, supporting its prominent role in host-pathogen defense. IgA closely interacts with the intestinal microbiota to enhance its diversity, and IgA has a passive protective role via immune exclusion. Additionally, inhibitory ITAMi signaling via the IgA Fc receptor (FcαRI; CD89) by monomeric IgA may play a role in maintaining homeostatic conditions. By contrast, IgA immune complexes (e.g., opsonized pathogens) potently activate immune cells via cross-linking FcαRI, thereby inducing pro-inflammatory responses resulting in elimination of pathogens. The importance of IgA in removal of pathogens is emphasized by the fact that several pathogens developed mechanisms to break down IgA or evade FcαRI-mediated activation of immune cells. Augmented or aberrant presence of IgA immune complexes can result in excessive neutrophil activation, potentially leading to severe tissue damage in multiple inflammatory, or autoimmune diseases. Influencing IgA or FcαRI-mediated functions therefore provides several therapeutic possibilities. On the one hand (passive) IgA vaccination strategies can be developed for protection against infections. Furthermore, IgA monoclonal antibodies that are directed against tumor antigens may be effective as cancer treatment. On the other hand, induction of ITAMi signaling via FcαRI may reduce allergy or inflammation, whereas blocking FcαRI with monoclonal antibodies, or peptides may resolve IgA-induced tissue damage. In this review both (patho)physiological roles as well as therapeutic possibilities of the IgA-FcαRI axis are addressed.
Collapse
Affiliation(s)
- Annelot Breedveld
- Department of Molecular Cell Biology and Immunology, Amsterdam UMC, Amsterdam, Netherlands
- Amsterdam Infection and Immunity Institute, Amsterdam UMC, Amsterdam, Netherlands
| | - Marjolein van Egmond
- Department of Molecular Cell Biology and Immunology, Amsterdam UMC, Amsterdam, Netherlands
- Amsterdam Infection and Immunity Institute, Amsterdam UMC, Amsterdam, Netherlands
- Department of Surgery, Amsterdam UMC, Amsterdam, Netherlands
| |
Collapse
|
3
|
Chen A, Yang SS, Lin TJ, Ka SM. IgA nephropathy: clearance kinetics of IgA-containing immune complexes. Semin Immunopathol 2018; 40:539-543. [PMID: 30218212 DOI: 10.1007/s00281-018-0708-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 09/04/2018] [Indexed: 01/24/2023]
Abstract
IgA nephropathy (IgAN) is associated predominantly IgA deposition in the affected glomeruli and has been shown to be the most common glomerular disorder among young people in the world. Although the exact pathogenic mechanism underlying IgAN remains largely unknown, circulating IgA-containing immune complexes (IgA ICs) is considered to play a major role in initiating the development and evolution of the renal disorder. In this review article, we discuss the fundamental mechanisms of clearance kinetics of IgA ICs and related issues, covering the following: (1) role of circulating IgA ICs in the pathogenesis of IgAN and (2) elimination of IgA ICs from the body, with emphasis of the role of the liver and Fc receptors in immune cells.
Collapse
Affiliation(s)
- Ann Chen
- Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, No. 325, Sec. 2, Cheng-Gung Road, Taipei, Taiwan.
| | - Sung-Sen Yang
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan.,Division of Nephrology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Tsai-Jung Lin
- Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, No. 325, Sec. 2, Cheng-Gung Road, Taipei, Taiwan
| | - Shuk-Man Ka
- Graduate Institute of Aerospace and Undersea Medicine, National Defense Medical Center, Taipei, Taiwan
| |
Collapse
|
4
|
Aleyd E, Heineke MH, van Egmond M. The era of the immunoglobulin A Fc receptor FcαRI; its function and potential as target in disease. Immunol Rev 2015; 268:123-38. [DOI: 10.1111/imr.12337] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Esil Aleyd
- Department of Molecular Cell Biology and Immunology; VU University Medical Center; Amsterdam The Netherlands
| | - Marieke H. Heineke
- Department of Molecular Cell Biology and Immunology; VU University Medical Center; Amsterdam The Netherlands
| | - Marjolein van Egmond
- Department of Molecular Cell Biology and Immunology; VU University Medical Center; Amsterdam The Netherlands
- Department of Surgery; VU University Medical Center; Amsterdam The Netherlands
| |
Collapse
|
5
|
Lohse S, Brunke C, Derer S, Peipp M, Boross P, Kellner C, Beyer T, Dechant M, van der Winkel JGJ, Leusen JHW, Valerius T. Characterization of a mutated IgA2 antibody of the m(1) allotype against the epidermal growth factor receptor for the recruitment of monocytes and macrophages. J Biol Chem 2012; 287:25139-50. [PMID: 22679018 DOI: 10.1074/jbc.m112.353060] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
IgA antibodies constitute an important part of the mucosal immune system, but their immunotherapeutic potential remains rather unexplored, in part due to biotechnological issues. For example, the IgA2m(1) allotype carries an unusual heavy and light chain pairing, which may confer production and stability concerns. Here, we report the generation and the biochemical and functional characterization of a P221R-mutated IgA2m(1) antibody against the epidermal growth factor receptor (EGFR). Compared with wild type, the mutated antibody demonstrated heavy chains covalently linked to light chains in monomeric as well as in joining (J)-chain containing dimeric IgA. Functional studies with wild type and mutated IgA2m(1) revealed similar binding to EGFR and direct effector functions such as EGFR down-modulation and growth inhibition. Furthermore, both IgA molecules triggered similar levels of indirect tumor cell killing such as antibody-dependent cell-mediated cytotoxicity (ADCC) by isolated monocytes, activated polymorphonuclear cells, and human whole blood. Interestingly, the dimeric IgA antibodies demonstrated higher efficiency in direct as well as in indirect effector mechanisms compared with their respective monomeric forms. Both wild type and mutated antibody triggered effective FcαRI-mediated tumor cell killing by macrophages already at low effector to target cell ratios. Interestingly, also polarized macrophages mediated significant IgA2-mediated ADCC. M2 macrophages, which have been described as promoting tumor growth and progression, may convert to ADCC-mediating effector cells in the presence of EGFR-directed antibodies. In conclusion, these results provide further insight into the immunotherapeutic potential of recombinant IgA antibodies for tumor immunotherapy and suggest macrophages as an additional effector cell population.
Collapse
Affiliation(s)
- Stefan Lohse
- Division of Stem Cell Transplantation and Immunotherapy, Department of Internal Medicine II, Christian-Albrechts-University, Schittenhelmstrasse 12, 24105 Kiel, Germany
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
The human immunoglobulin A Fc receptor FcαRI: a multifaceted regulator of mucosal immunity. Mucosal Immunol 2011; 4:612-24. [PMID: 21937986 DOI: 10.1038/mi.2011.36] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Immunoglobulin A (IgA) is commonly recognized as the most prevalent antibody (Ab) at mucosal sites with an important role in defense by shielding mucosal surfaces from invasion by pathogens. However, its potential to both actively dampen excessive immune responses or to initiate potent proinflammatory cellular processes is less well known. Interestingly, either functional outcome is mediated through interaction with the myeloid IgA Fc receptor FcαRI (CD89). Monomeric interaction of IgA with FcαRI triggers inhibitory signals that block activation via other receptors, whereas multimeric FcαRI crosslinking induces phagocytosis, reactive oxygen species production, antigen presentation, Ab-dependent cellular cytotoxicity, and cytokine release. Thus, FcαRI acts as a regulator between anti- and proinflammatory responses of IgA. As such, the biology of FcαRI, and its multifaceted role in immunity will be the focus of this review.
Collapse
|
7
|
Abstract
Although immunoglobulin (Ig) A is commonly recognized as the most prevalent antibody subclass at mucosal sites with an important role in mucosal defense, its potential as a therapeutic monoclonal antibody is less well known. However, IgA has multifaceted anti-, non-, and pro-inflammatory functions that can be exploited for different immunotherapeutical strategies, which will be the focus of this review.
Collapse
Affiliation(s)
- Jantine E Bakema
- Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, The Netherlands
| | | |
Collapse
|
8
|
Xue J, Zhao Q, Zhu L, Zhang W. Deglycosylation of FcαR at N58 increases its binding to IgA. Glycobiology 2010; 20:905-15. [DOI: 10.1093/glycob/cwq048] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
|
9
|
Peng M, Guo S, Yin N, Xue J, Shen L, Zhao Q, Zhang W. Ectodomain shedding of Fcalpha receptor is mediated by ADAM10 and ADAM17. Immunology 2010; 130:83-91. [PMID: 20059578 DOI: 10.1111/j.1365-2567.2009.03215.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
FcalphaR (CD89) plays important roles in immunoglobulin A (IgA)-mediated immune responses. Soluble forms of FcalphaR (sFcalphaR) are found in the culture supernatants of FcalphaR-expressing cells, in human serum and in the serum of FcalphaR transgenic mice, and have been suggested to be produced through a proteolytic process. However, little is known about the mechanism involved in the proteolytic release of sFcalphaR. In this study, we investigated the shedding mechanism of FcalphaR and determined the nature of the proteinase involved in FcalphaR shedding. In chemical inhibitor assays, shedding of FcalphaR was dramatically inhibited by EDTA, EGTA and a broad-spectrum metalloproteinase inhibitor, GM6001, suggesting that a metalloproteinase was responsible for FcalphaR shedding. Overexpression of dominant-negative mutants of ADAM (a disintegrin and metalloproteinase) 10 and ADAM17 markedly inhibited the production of sFcalphaR. Finally, knockdown of both endogenous ADAM10 and endogenous ADAM17 inhibited FcalphaR shedding, demonstrating that ADAM10 and ADAM17 were involved in the shedding of FcalphaR. The characterization of ADAM10 and ADAM17 as sFcalphaR-releasing enzymes provides a novel insight into the molecular mechanism of sFcalphaR production and will help in further elucidation of the physiological and pathological roles of sFcalphaR.
Collapse
Affiliation(s)
- Min Peng
- Institute of Basic Medical Sciences, School of Basic Medicine, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | | | | | | | | | | | | |
Collapse
|
10
|
Peng M, Yin N, Zhang W. Endocytosis of FcalphaR is clathrin and dynamin dependent, but its cytoplasmic domain is not required. Cell Res 2009; 20:223-37. [PMID: 19859085 DOI: 10.1038/cr.2009.120] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
FcalphaR, the Fc receptor for IgA, is essential for IgA-mediated immune responses. Previous studies have shown that IgA and IgA immune complexes can be rapidly endocytosed by FcalphaR. However, the underlying mechanism remains unclear. Here, we investigated the endocytic pathway of FcalphaR in monocytic cell line, U937, that naturally express FcalphaR and in transfected Chinese hamster ovary (CHO), COS-7 and Hela cells. By using selective chemical inhibitors of different endocytic pathways, overexpression of dominant-negative mutants of Eps15 and knockdown of clathrin heavy chain (CHC) via RNA interference, we demonstrated that endocytosis of FcalphaR was through a clathrin-mediated pathway. The endocytosed FcalphaR went into Rab5- and Rab11-positive endosomes. However, endocytosis of FcalphaR could not be blocked by a dominant-negative mutant of Rab5. We also demonstrated that endocytosis of FcalphaR was dynamin-dependent by overexpressing a dominant-negative mutant of dynamin. The potential endocytic motif for FcalphaR was also examined. Unexpectedly, we found that the entire cytoplasmic domain of FcalphaR was not required for the endocytic process of FcalphaR. We conclude that endocytosis of FcalphaR is clathrin- and dynamin-dependent, but is not regulated by Rab5, and the endocytic motif is not located in the cytoplasmic domain of FcalphaR.
Collapse
Affiliation(s)
- Min Peng
- Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing 100005, China
| | | | | |
Collapse
|