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Cyster JG, Wilson PC. Antibody modulation of B cell responses-Incorporating positive and negative feedback. Immunity 2024; 57:1466-1481. [PMID: 38986442 PMCID: PMC11257158 DOI: 10.1016/j.immuni.2024.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 06/07/2024] [Accepted: 06/13/2024] [Indexed: 07/12/2024]
Abstract
Antibodies are powerful modulators of ongoing and future B cell responses. While the concept of antibody feedback has been appreciated for over a century, the topic has seen a surge in interest due to the evidence that the broadening of antibody responses to SARS-CoV-2 after a third mRNA vaccination is a consequence of antibody feedback. Moreover, the discovery that slow antigen delivery can lead to more robust humoral immunity has put a spotlight on the capacity for early antibodies to augment B cell responses. Here, we review the mechanisms whereby antibody feedback shapes B cell responses, integrating findings in humans and in mouse models. We consider the major influence of epitope masking and the diverse actions of complement and Fc receptors and provide a framework for conceptualizing the ways antigen-specific antibodies may influence B cell responses to any form of antigen, in conditions as diverse as infectious disease, autoimmunity, and cancer.
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Affiliation(s)
- Jason G Cyster
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA.
| | - Patrick C Wilson
- Drukier Institute for Children's Health, Department of Pediatrics, Weill Cornell Medicine, New York, NY, USA.
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2
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Wu YH, Chang WT, Hsu CL, Lu YF, Wang JT, Tzeng SJ. FcγRIIB modulates splenic germinal center response against immune subversion during acute influenza A virus infection. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2024; 57:64-75. [PMID: 38087748 DOI: 10.1016/j.jmii.2023.11.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 11/02/2023] [Accepted: 11/28/2023] [Indexed: 02/12/2024]
Abstract
BACKGROUND B cells are essential for providing humoral protection against acute influenza A virus (IAV) infection. FcγRIIB, a regulator of antibody (Ab) production, influences immune responses during pathogen infections, but its specific impact on humoral protection and B cell-mediated responses against IAV remains unclear. METHODS To investigate FcγRIIB's role in host defense and B cell function during acute IAV infection, we generated mice with systemic FcγRIIB deficiency, functional impairment, and B cell-specific FcγRIIB deletion. We infected these mice with PR8 (H1N1) or Hkx31 (H3N2) IAVs and evaluated body weight preservation, survival rates, Ab production, viral neutralization, Ab affinity maturation, and germinal center B cell development. RESULTS Mice lacking FcγRIIB or with impaired function showed improved protection, preserved body weight, and increased survival rates during IAV infection. Notably, mice with haploinsufficient FcγRIIB function displayed protective effects. Selective deficiency of FcγRIIB in B cells led to enhanced Ab production, resulting in elevated IAV-specific Abs in the serum with superior viral neutralizing potency. However, the impact on the affinity maturation index of virus-specific Abs was modest. Accordingly, FcγRIIB-deficient B cells maintained normal germinal center B cell development during IAV infection, whereas wild-type mice exhibited delayed differentiation. CONCLUSION Our research underscores the pivotal role of FcγRIIB in host defense and B cell-mediated immunity during acute IAV infection. Additionally, our discoveries hold implications for antiviral treatments, particularly during the initial stages of IAV infection, aimed at enhancing the host's humoral immune response.
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Affiliation(s)
- Yu-Hsuan Wu
- Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taiwan.
| | - Wan-Ting Chang
- Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taiwan.
| | - Chia-Lang Hsu
- Department of Medical Research, National Taiwan University Hospital, Taiwan.
| | - Yan-Fong Lu
- Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taiwan; Department of Obstetrics and Gynecology, Shin-Kong Wu Ho-Su Memorial Hospital, Taiwan.
| | - Jann-Tay Wang
- Department of Internal Medicine, National Taiwan University Hospital, Taiwan.
| | - Shiang-Jong Tzeng
- Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Taiwan.
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3
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Wu T, Yan S, Yeh YW, Fang Y, Xiang Z. FcγR-dependent apoptosis regulates tissue persistence of mucosal and connective tissue mast cells. Eur J Immunol 2023; 53:e2250221. [PMID: 37137469 DOI: 10.1002/eji.202250221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 04/29/2023] [Accepted: 05/02/2023] [Indexed: 05/05/2023]
Abstract
Rodent mast cells can be divided into two major subtypes: the mucosal mast cell (MMC) and the connective tissue mast cell (CTMC). A decade-old observation revealed a longer lifespan for CTMC compared with MMC. The precise mechanisms underlying such differential tissue persistence of mast cell subsets have not been described. In this study, we have discovered that mast cells expressing only one receptor, either FcγRIIB or FcγRIIIA, underwent caspase-independent apoptosis in response to IgG immune complex treatment. Lower frequencies of CTMC in mice that lacked either FcγRIIB or FcγRIIIA compared with WT mice were recorded, especially in aged mice. We proposed that this paradigm of FcγR-mediated mast cell apoptosis could account for the more robust persistence of CTMC, which express both FcγRIIB and FcγRIIIA, than MMC, which express only FcγRIIB. Importantly, we reproduced these results using a mast cell engraftment model, which ruled out possible confounding effects of mast cell recruitment or FcγR expression by other cells on mast cell number regulation. In conclusion, our work has uncovered an FcγR-dependent mast cell number regulation paradigm that might provide a mechanistic explanation for the long-observed differential mast cell subset persistence in tissues.
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Affiliation(s)
- Tongqian Wu
- Center for Clinical Laboratory, Affiliated Hospital of Guizhou Medical University, Guiyang, 550004, P. R. China
- School for Clinical Laboratory, Guizhou Medical University, Guiyang, 550004, P. R. China
| | - Shirong Yan
- Center for Clinical Laboratory, Affiliated Hospital of Guizhou Medical University, Guiyang, 550004, P. R. China
- School for Clinical Laboratory, Guizhou Medical University, Guiyang, 550004, P. R. China
| | - Yu-Wen Yeh
- Department of Health Technology and Informatics, Faculty of Health and Social Sciences, Hong Kong Polytechnic University, Hong Kong, P. R. China
| | - Yu Fang
- Center for Clinical Laboratory, Affiliated Hospital of Guizhou Medical University, Guiyang, 550004, P. R. China
- School for Clinical Laboratory, Guizhou Medical University, Guiyang, 550004, P. R. China
| | - Zou Xiang
- Department of Health Technology and Informatics, Faculty of Health and Social Sciences, Hong Kong Polytechnic University, Hong Kong, P. R. China
- Department of Microbiology and Immunology, Mucosal Immunobiology and Vaccine Research Center, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
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4
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Luo L, Jiang P, Chen Q, Chang J, Jing Y, Luo X, Gu H, Huang Y, Chen R, Liu J, Kang D, Liu Q, Wang Y, Fang G, Zhu Y, Guan F, Lei J, Yang L, Liu C, Dai X. c-Abl controls BCR signaling and B cell differentiation by promoting B cell metabolism. Immunology 2022; 167:181-196. [PMID: 35753034 DOI: 10.1111/imm.13525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 03/15/2022] [Indexed: 11/30/2022] Open
Abstract
As a non-receptor tyrosine kinase, c-Abl was first studied in chronic myelogenous leukemia, and its role in lymphocytes has been well characterized. c-Abl is involved in B cell development and CD19 associated B cell antigen receptor (BCR) signaling. Although c-Abl regulates different metabolic pathways, the role of c-Abl is still unknown in B cell metabolism. In this study, B cell specific c-Abl knockout (KO) mice (Mb1Cre+/- c-Ablfl/fl ) were used to investigate how c-Abl regulates B cell metabolism and BCR signaling. We found that the levels of activation positive BCR signaling proximal molecules, phosphorylated spleen tyrosine kinase (pSYK) and phosphorylated Bruton tyrosine kinase (pBTK), were decreased, while the level of key negative regulator, phosphorylated SH2-containing inositol phosphatase (pSHIP1), was increased in Mb1Cre+/- c-Ablfl/fl mice. Furthermore, we found c-Abl deficiency weakened the B cell spreading, formation of BCR signalosomes, and the polymerization of actin during BCR activation, and also impaired the differentiation of germinal center (GC) B cells both in quiescent condition and after immunization. Moreover, B cell mitochondrial respiration and the expression of B cell metabolism regulating molecules were downregulated in c-Abl deficiency mice. Overall, c-Abl, which involved in actin remodeling and B cell metabolism, positively regulates BCR signaling and promotes GC differentiation. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Li Luo
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Panpan Jiang
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qianglin Chen
- Department of Immunology, School of Medicine, Yangtze University, Jingzhou, China
| | - Jiang Chang
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yukai Jing
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xi Luo
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Heng Gu
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yanmei Huang
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ran Chen
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ju Liu
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Danqing Kang
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qi Liu
- Department of Immunology, School of Medicine, Yangtze University, Jingzhou, China
| | - Yi Wang
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Guofeng Fang
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yingzi Zhu
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fei Guan
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiahui Lei
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lu Yang
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chaohong Liu
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xin Dai
- Department of Pathogen Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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5
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Ouyang K, Oparaugo N, Nelson AM, Agak GW. T Cell Extracellular Traps: Tipping the Balance Between Skin Health and Disease. Front Immunol 2022; 13:900634. [PMID: 35795664 PMCID: PMC9250990 DOI: 10.3389/fimmu.2022.900634] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/23/2022] [Indexed: 11/30/2022] Open
Abstract
The role of extracellular traps (ETs) in the innate immune response against pathogens is well established. ETs were first identified in neutrophils and have since been identified in several other immune cells. Although the mechanistic details are not yet fully understood, recent reports have described antigen-specific T cells producing T cell extracellular traps (TETs). Depending on their location within the cutaneous environment, TETs may be beneficial to the host by their ability to limit the spread of pathogens and provide protection against damage to body tissues, and promote early wound healing and degradation of inflammatory mediators, leading to the resolution of inflammatory responses within the skin. However, ETs have also been associated with worse disease outcomes. Here, we consider host-microbe ET interactions by highlighting how cutaneous T cell-derived ETs aid in orchestrating host immune responses against Cutibacterium acnes (C. acnes), a commensal skin bacterium that contributes to skin health, but is also associated with acne vulgaris and surgical infections following joint-replacement procedures. Insights on the role of the skin microbes in regulating T cell ET formation have broad implications not only in novel probiotic design for acne treatment, but also in the treatment for other chronic inflammatory skin disorders and autoimmune diseases.
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Affiliation(s)
- Kelsey Ouyang
- Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, United States
- Division of Dermatology, Department of Medicine, University of California, Los Angeles (UCLA), Los Angeles, CA, United States
- David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, CA, United States
| | - Nicole Oparaugo
- David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, CA, United States
| | - Amanda M. Nelson
- Department of Dermatology, Penn State University College of Medicine, Hershey, PA, United States
| | - George W. Agak
- Division of Dermatology, Department of Medicine, University of California, Los Angeles (UCLA), Los Angeles, CA, United States
- *Correspondence: George W. Agak,
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Lassaunière R, Tiemessen CT. FcγR Genetic Variation and HIV-1 Vaccine Efficacy: Context And Considerations. Front Immunol 2021; 12:788203. [PMID: 34975881 PMCID: PMC8714752 DOI: 10.3389/fimmu.2021.788203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/29/2021] [Indexed: 12/02/2022] Open
Abstract
Receptors for the crystallisable fragment (Fc) of immunoglobulin (Ig) G, Fcγ receptors (FcγRs), link the humoral and cellular arms of the immune response, providing a diverse armamentarium of antimicrobial effector functions. Findings from HIV-1 vaccine efficacy trials highlight the need for further study of Fc-FcR interactions in understanding what may constitute vaccine-induced protective immunity. These include host genetic correlates identified within the low affinity Fcγ-receptor locus in three HIV-1 efficacy trials – VAX004, RV144, and HVTN 505. This perspective summarizes our present knowledge of FcγR genetics in the context of findings from HIV-1 efficacy trials, and draws on genetic variation described in other contexts, such as mother-to-child HIV-1 transmission and HIV-1 disease progression, to explore the potential contribution of FcγR variability in modulating different HIV-1 vaccine efficacy outcomes. Appreciating the complexity and the importance of the collective contribution of variation within the FCGR gene locus is important for understanding the role of FcγRs in protection against HIV-1 acquisition.
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Affiliation(s)
- Ria Lassaunière
- Virus and Microbiological Special Diagnostics, Statens Serum Institut, Copenhagen, Denmark
- *Correspondence: Caroline T. Tiemessen, ; Ria Lassaunière,
| | - Caroline T. Tiemessen
- Centre for HIV and STI’s, National Institute for Communicable Diseases, Johannesburg, South Africa
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- *Correspondence: Caroline T. Tiemessen, ; Ria Lassaunière,
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7
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Baecher KM, Ford ML. Intersection of FcγRIIB, the microbiome, and checkpoint inhibitors in antitumor immunity. Cancer Immunol Immunother 2021; 70:3397-3404. [PMID: 34241677 PMCID: PMC10992943 DOI: 10.1007/s00262-021-03004-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 06/29/2021] [Indexed: 10/20/2022]
Abstract
Fc receptors (FcRs) and the microbiome are both known to have an effect on the development and progression of cancers. Checkpoint inhibitors are a novel class of therapeutics which are used to combat cancer and are integrally linked to both FcRs and the microbiome. The use of checkpoint inhibitors has grown exponentially over the past decade, although many host factors affect both the efficacy and the safety of these therapeutics. Some of these host factors, including the microbiome and the expression of FcRs, are currently being investigated. Here we discuss the current understanding of FcRs (particularly the inhibitory FcγRIIB) and the microbiome in context of T cell immunity, inflammation, cancer, and checkpoint inhibition.
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Affiliation(s)
- Kirsten M Baecher
- Division of Transplant, Department of Surgery, Emory University School of Medicine, Atlanta, GA, USA
| | - Mandy L Ford
- Division of Transplant, Department of Surgery, Emory University School of Medicine, Atlanta, GA, USA.
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8
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Sun J, Wang L, Yang W, Li Y, Jin Y, Wang L, Song L. A novel C-type lectin activates the complement cascade in the primitive oyster Crassostrea gigas. J Biol Chem 2021; 297:101352. [PMID: 34715129 PMCID: PMC8605247 DOI: 10.1016/j.jbc.2021.101352] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 10/17/2021] [Accepted: 10/22/2021] [Indexed: 12/20/2022] Open
Abstract
The ancient origin of the lectin pathway of the complement system can be traced back to protochordates (such as amphioxus and tunicates) by the presence of components such as ficolin, glucose-binding lectin, mannose-binding lectin-associated serine protease (MASP), and C3. Evidence for a more primitive origin is offered in the present study on the Pacific oyster Crassostrea gigas. C3 protein in C. gigas (CgC3) was found to be cleaved after stimulation with the bacteria Vibrio splendidus. In addition, we identified a novel C-type lectin (defined as CgCLec) with a complement control protein (CCP) domain, which recognized various pathogen-associated molecular patterns (PAMPs) and bacteria. This protein was involved in the activation of the complement system by binding CgMASPL-1 to promote cleavage of CgC3. The production of cytokines and antibacterial peptides, as well as the phagocytotic ratio of haemocytes in CgCLec-CCP-, CgMASPL-1-, or CgC3-knockdown oysters, decreased significantly after V. splendidus stimulation. Moreover, this activated CgC3 participated in perforation of bacterial envelopes and inhibiting survival of the infecting bacteria. These results collectively suggest that there existed an ancient lectin pathway in molluscs, which was activated by a complement cascade to regulate the production of immune effectors, phagocytosis, and bacterial lysis.
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Affiliation(s)
- Jiejie Sun
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China; Liaoning Key Laboratory of Marine Animal Immunology & Disease Control, Dalian Ocean University, Dalian, China
| | - Liyan Wang
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China; Liaoning Key Laboratory of Marine Animal Immunology & Disease Control, Dalian Ocean University, Dalian, China
| | - Wenwen Yang
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China; Liaoning Key Laboratory of Marine Animal Immunology & Disease Control, Dalian Ocean University, Dalian, China
| | - Yinan Li
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China; Liaoning Key Laboratory of Marine Animal Immunology & Disease Control, Dalian Ocean University, Dalian, China
| | - Yingnan Jin
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China; Liaoning Key Laboratory of Marine Animal Immunology & Disease Control, Dalian Ocean University, Dalian, China
| | - Lingling Wang
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China; Liaoning Key Laboratory of Marine Animal Immunology & Disease Control, Dalian Ocean University, Dalian, China; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai, China; Dalian Key Laboratory of Aquatic Animal Diseases Prevention and Control, Dalian Ocean University, Dalian, China.
| | - Linsheng Song
- Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian, China; Liaoning Key Laboratory of Marine Animal Immunology & Disease Control, Dalian Ocean University, Dalian, China; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai, China.
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9
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Carroll DJ, Cao Y, Bochner BS, O’Sullivan JA. Siglec-8 Signals Through a Non-Canonical Pathway to Cause Human Eosinophil Death In Vitro. Front Immunol 2021; 12:737988. [PMID: 34721399 PMCID: PMC8549629 DOI: 10.3389/fimmu.2021.737988] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 09/14/2021] [Indexed: 12/19/2022] Open
Abstract
Sialic acid-binding immunoglobulin-like lectin (Siglec)-8 is a glycan-binding receptor bearing immunoreceptor tyrosine-based inhibitory and switch motifs (ITIM and ITSM, respectively) that is selectively expressed on eosinophils, mast cells, and, to a lesser extent, basophils. Previous work has shown that engagement of Siglec-8 on IL-5-primed eosinophils causes cell death via CD11b/CD18 integrin-mediated adhesion and NADPH oxidase activity and identified signaling molecules linking adhesion, reactive oxygen species (ROS) production, and cell death. However, the proximal signaling cascade activated directly by Siglec-8 engagement has remained elusive. Most members of the Siglec family possess similar cytoplasmic signaling motifs and recruit the protein tyrosine phosphatases SHP-1/2, consistent with ITIM-mediated signaling, to dampen cellular activation. However, the dependence of Siglec-8 function in eosinophils on these phosphatases has not been studied. Using Siglec-8 antibody engagement and pharmacological inhibition in conjunction with assays to measure cell-surface upregulation and conformational activation of CD11b integrin, ROS production, and cell death, we sought to identify molecules involved in Siglec-8 signaling and determine the stage of the process in which each molecule plays a role. We demonstrate here that the enzymatic activities of Src family kinases (SFKs), Syk, SHIP1, PAK1, MEK1, ERK1/2, PLC, PKC, acid sphingomyelinase/ceramidase, and Btk are all necessary for Siglec-8-induced eosinophil cell death, with no apparent role for SHP-1/2, SHIP2, or c-Raf. While most of these signaling molecules are necessary for Siglec-8-induced upregulation of CD11b integrin at the eosinophil cell surface, Btk is phosphorylated and activated later in the signaling cascade and is instead necessary for CD11b activation. In contrast, SFKs and ERK1/2 are phosphorylated far earlier in the process, consistent with their role in augmenting cell-surface levels of CD11b. In addition, pretreatment of eosinophils with latrunculin B or jasplakinolide revealed that actin filament disassembly is necessary and sufficient for surface CD11b integrin upregulation and that actin polymerization is necessary for downstream ROS production. These results show that Siglec-8 signals through an unanticipated set of signaling molecules in IL-5-primed eosinophils to induce cell death and challenges the expectation that ITIM-bearing Siglecs signal through inhibitory pathways involving protein tyrosine phosphatases to achieve their downstream functions.
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Affiliation(s)
| | | | | | - Jeremy A. O’Sullivan
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
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10
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Le Berre L, Chesneau M, Danger R, Dubois F, Chaussabel D, Garand M, Brouard S. Connection of BANK1, Tolerance, Regulatory B cells, and Apoptosis: Perspectives of a Reductionist Investigation. Front Immunol 2021; 12:589786. [PMID: 33815360 PMCID: PMC8015775 DOI: 10.3389/fimmu.2021.589786] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 01/06/2021] [Indexed: 12/07/2022] Open
Abstract
BANK1 transcript is upregulated in whole blood after kidney transplantation in tolerant patients. In comparison to patients with rejection, tolerant patients display higher level of regulatory B cells (Bregs) expressing granzyme B (GZMB+) that have the capability to prevent effector T cells proliferation. However, BANK1 was found to be decreased in these GZMB+ Bregs. In this article, we investigated seven different transcriptomic studies and mined the literature in order to make link between BANK1, tolerance and Bregs. As for GZMB+ Bregs, we found that BANK1 was decreased in other subtypes of Bregs, including IL10+ and CD24hiCD38hi transitional regulatory B cells, along with BANK1 was down-regulated in activated/differentiated B cells, as in CD40-activated B cells, in leukemia and plasma cells. Following a reductionist approach, biological concepts were extracted from BANK1 literature and allowed us to infer association between BANK1 and immune signaling pathways, as STAT1, FcγRIIB, TNFAIP3, TRAF6, and TLR7. Based on B cell signaling literature and expression data, we proposed a role of BANK1 in B cells of tolerant patients that involved BCR, IP3R, and PLCG2, and a link with the apoptosis pathways. We confronted these data with our experiments on apoptosis in total B cells and Bregs, and this suggests different involvement for BANK1 in these two cells. Finally, we put in perspective our own data with other published data to hypothesize two different roles for BANK1 in B cells and in Bregs.
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Affiliation(s)
- Ludmilla Le Berre
- CHU Nantes, Université de Nantes, Inserm, Centre de Recherche en Transplantation et Immunologie, UMR 1064, ITUN, Nantes, France
| | - Mélanie Chesneau
- CHU Nantes, Université de Nantes, Inserm, Centre de Recherche en Transplantation et Immunologie, UMR 1064, ITUN, Nantes, France
| | - Richard Danger
- CHU Nantes, Université de Nantes, Inserm, Centre de Recherche en Transplantation et Immunologie, UMR 1064, ITUN, Nantes, France
| | - Florian Dubois
- CHU Nantes, Université de Nantes, Inserm, Centre de Recherche en Transplantation et Immunologie, UMR 1064, ITUN, Nantes, France
| | | | - Mathieu Garand
- Systems Biology and Immunology, Sidra Medicine, Doha, Qatar
| | - Sophie Brouard
- CHU Nantes, Université de Nantes, Inserm, Centre de Recherche en Transplantation et Immunologie, UMR 1064, ITUN, Nantes, France
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The Effects of Pre-Existing Antibodies on Live-Attenuated Viral Vaccines. Viruses 2020; 12:v12050520. [PMID: 32397218 PMCID: PMC7290594 DOI: 10.3390/v12050520] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/05/2020] [Accepted: 05/06/2020] [Indexed: 12/11/2022] Open
Abstract
Live-attenuated vaccines (LAVs) have achieved remarkable successes in controlling virus spread, as well as for other applications such as cancer immunotherapy. However, with rapid increases in international travel, globalization, geographic spread of viral vectors, and widespread use of vaccines, there is an increasing need to consider how pre-exposure to viruses which share similar antigenic regions can impact vaccine efficacy. Pre-existing antibodies, derived from either from maternal–fetal transmission, or by previous infection or vaccination, have been demonstrated to interfere with vaccine immunogenicity of measles, adenovirus, and influenza LAVs. Immune interference of LAVs can be caused by the formation of virus–antibody complexes that neutralize virus infection in antigen-presenting cells, or by the cross-linking of the B-cell receptor with the inhibitory receptor, FcγRIIB. On the other hand, pre-existing antibodies can augment flaviviral LAV efficacy such as that of dengue and yellow fever virus, especially when pre-existing antibodies are present at sub-neutralizing levels. The increased vaccine immunogenicity can be facilitated by antibody-dependent enhancement of virus infection, enhancing virus uptake in antigen-presenting cells, and robust induction of innate immune responses that promote vaccine immunogenicity. This review examines the literature on this topic and examines the circumstances where pre-existing antibodies can inhibit or enhance LAV efficacy. A better knowledge of the underlying mechanisms involved could allow us to better manage immunization in seropositive individuals and even identify possibilities that could allow us to exploit pre-existing antibodies to boost vaccine-induced responses for improved vaccine efficacy.
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12
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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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13
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Verbeek JS, Hirose S, Nishimura H. The Complex Association of FcγRIIb With Autoimmune Susceptibility. Front Immunol 2019; 10:2061. [PMID: 31681256 PMCID: PMC6803437 DOI: 10.3389/fimmu.2019.02061] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 08/15/2019] [Indexed: 12/20/2022] Open
Abstract
FcγRIIb is the only inhibitory Fc receptor and controls many aspects of immune and inflammatory responses. The observation 19 years ago that Fc γ RIIb -/- mice generated by gene targeting in 129 derived ES cells developed severe lupus like disease when backcrossed more than 7 generations into C57BL/6 background initiated extensive research on the functional understanding of this strong autoimmune phenotype. The genomic region in the distal part of Chr1 both in human and mice in which the Fc γ R gene cluster is located shows a high level of complexity in relation to the susceptibility to SLE. Specific haplotypes of closely linked genes including the Fc γ RIIb and Slamf genes are associated with increased susceptibility to SLE both in mice and human. Using forward and reverse genetic approaches including in human GWAS and in mice congenic strains, KO mice (germline and cell type specific, on different genetic background), knockin mice, overexpressing transgenic mice combined with immunological models such as adoptive transfer of B cells from Ig transgenic mice the involved genes and the causal mutations and their associated functional alterations were analyzed. In this review the results of this 19 years extensive research are discussed with a focus on (genetically modified) mouse models.
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Affiliation(s)
- J Sjef Verbeek
- Department of Biomedical Engineering, Toin University of Yokohama, Yokohama, Japan
| | - Sachiko Hirose
- Department of Biomedical Engineering, Toin University of Yokohama, Yokohama, Japan
| | - Hiroyuki Nishimura
- Department of Biomedical Engineering, Toin University of Yokohama, Yokohama, Japan
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14
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Jhou JP, Yu IS, Hwai H, Chen CS, Chen PL, Tzeng SJ. The Lupus-Associated Fcγ Receptor IIb-I232T Polymorphism Results in Impairment in the Negative Selection of Low-Affinity Germinal Center B Cells Via c-Abl in Mice. Arthritis Rheumatol 2018; 70:1866-1878. [PMID: 29774664 PMCID: PMC6221021 DOI: 10.1002/art.40555] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 05/08/2018] [Indexed: 11/17/2022]
Abstract
Objective Fcγ receptor IIb (FcγRIIb) is an essential negative regulator of B cells that blocks B cell receptor (BCR) signaling and triggers c‐Abl–dependent apoptosis of B cells. FcγRIIb‐deficient mice display splenomegaly with expansion of B cells, leading to lupus. FcγRIIb‐I232T is a hypofunctional polymorphism associated with lupus susceptibility in humans, an autoimmune disease linked to diminished deletion of autoreactive B cells. In the context of the FcγRIIb‐I232T polymorphism, we investigated the role of FcγRIIb in the deletion of low‐affinity germinal center (GC) B cells, an important mechanism for preventing autoimmunity. Methods We generated FcγRIIb232T/T mice to mimic human FcγRIIb‐I232T carriers and immunized mice with chicken gamma globulin (CGG)–conjugated NP, a T cell–dependent antigen, to examine the response of GC B cells. Results Compared to wild‐type (WT) mice, FcγRIIb232T/T mice showed increased numbers of low‐affinity NP‐specific IgG and NP‐specific B cells and plasma cells; additionally, the expression of a somatic mutation (W33L) in their VH186.2 genes encoding high‐affinity BCR was reduced. Notably, FcγRIIb232T/T mice had a higher number of GC light zone B cells and showed less apoptosis than WT mice, despite having equivalent follicular helper T cell numbers and function. Moreover, phosphorylation of c‐Abl was reduced in FcγRIIb232T/T mice, and treatment of WT mice with the c‐Abl inhibitor nilotinib during the peak of GC response resulted in reduced affinity maturation reminiscent of FcγRIIb232T/T mice. Conclusion Our findings provide evidence of a critical role of FcγRIIb/c‐Abl in the negative selection of GC B cells in FcγRIIb232T/T mice. Importantly, our findings indicate potential benefits of up‐regulating FcγRIIb expression in B cells for treatment of systemic lupus erythematosus.
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Affiliation(s)
| | - I-Shing Yu
- National Taiwan University, Taipei, Taiwan
| | - Haw Hwai
- National Taiwan University, Taipei, Taiwan
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15
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Liu XG, Liu Y, Chen F. Soluble fibrinogen like protein 2 (sFGL2), the novel effector molecule for immunoregulation. Oncotarget 2018; 8:3711-3723. [PMID: 27732962 PMCID: PMC5356913 DOI: 10.18632/oncotarget.12533] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 09/29/2016] [Indexed: 02/07/2023] Open
Abstract
Soluble fibrinogen-like protein 2 (sFGL2) is the soluble form of fibrinogen-like protein 2 belonging to the fibrinogen-related protein superfamily. It is now well characterized that sFGL2 is mainly secreted by regulatory T cell (Treg) populations, and exerts potently immunosuppressive activities. By repressing not only the differentiation and proliferation of T cells but also the maturation of dendritic cells (DCs), sFGL2 acts largely as an immunosuppressant. Moreover, sFGL2 also induces apoptosis of B cells, tubular epithelial cells (TECs), sinusoidal endothelial cells (SECs), and hepatocytes. This mini-review focuses primarily on the recent literature with respect to the signaling mechanism of sFGL2 in immunomodulation, and discusses the clinical implications of sFGL2 in transplantation, hepatitis, autoimmunity, and tumors.
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Affiliation(s)
- Xin-Guang Liu
- Department of Hematology, Qilu Hospital, Shandong University, Jinan, P. R. China
| | - Yu Liu
- School of Chemistry and Pharmaceutical Engineering, Qilu University of Technology, Jinan, P. R. China
| | - Feng Chen
- Department of Hematology, Qilu Hospital, Shandong University, Jinan, P. R. China.,Capital Medical University Cancer Center, Beijing Shijitan Hospital, Beijing Key Laboratory for Therapeutic Cancer Vaccines, Beijing, China
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16
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Tseng TC, Huang DY, Lai LC, Hwai H, Hsiao YW, Jhou JP, Chuang EY, Tzeng SJ. Dual immuno-renal targeting of 7-benzylidenenaltrexone alleviates lupus nephritis via FcγRIIB and HO-1. J Mol Med (Berl) 2018; 96:413-425. [PMID: 29508016 DOI: 10.1007/s00109-018-1626-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 12/18/2017] [Accepted: 02/05/2018] [Indexed: 12/11/2022]
Abstract
Known as a selective δ1 opioid receptor (DOR1) antagonist, the 7-benzylidenenaltrexone (BNTX) is also a DOR1-independent immunosuppressant with unknown mechanisms. Here we investigated if BNTX could be beneficial for diseased MRL/lpr lupus mice. We treated mice with 0.5, 2, 5 or 10 mg/kg/day of BNTX for 2 weeks. At as low as 2 mg/kg/day, BNTX significantly improved splenomegaly and lymphadenopathy. Notably, B cell numbers, particularly autoreactive plasma cells, were preferentially reduced; moreover, BNTX enhanced surface expression of FcγRIIB, an immune complex (IC)-dependent apoptotic trigger of B cells. Consequently, serum autoantibody concentrations were significantly decreased, leading to diminished glomerular IC deposition and renal fibrosis, thereby improving proteinuria. Microarray and pathway analyses revealed heme oxygenase-1 (HO-1) and p38 MAPK as key mediators of BNTX-induced upregulation of FcγRIIB. Moreover, HO-1 expression was also induced by BNTX via p38 MAPK at renal proximal tubules to further cytoprotection. Taken together, we demonstrate that BNTX can alleviate lupus nephritis by reducing autoreactive B cells via FcγRIIB and by augmenting renal protection via HO-1. Accordingly, we propose a new strategy to treat lupus nephritis via such a dual immuno-renal targeting using either a single agent or combined agents to simultaneously deplete B cells and enhance renal protection. KEY MESSAGES 7-Benzylidenenaltrexone (BNTX) alleviates lupus nephritis in diseased MRL/lpr mice. BNTX reduces autoreactive plasma cell numbers and serum autoantibody titers. BNTX upregulates FcγRIIB levels via p38 MAPK and HO-1 to reduce B cell numbers. Reduction of immune complex deposition and fibrosis by BNTX improves proteinuria. BNTX induces HO-1 via p38 MAPK to enhance protection of renal proximal tubules.
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Affiliation(s)
- Tsung-Chih Tseng
- Graduate Institute of Pharmacology, National Taiwan University, Taipei, Taiwan
| | - Duen-Yi Huang
- Graduate Institute of Pharmacology, National Taiwan University, Taipei, Taiwan
| | - Liang-Chuan Lai
- Graduate Institute of Physiology, National Taiwan University, Taipei, Taiwan
- Bioinformatics and Biostatistics Core, Center of Genomic Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Haw Hwai
- Graduate Institute of Pharmacology, National Taiwan University, Taipei, Taiwan
| | - Yi-Wen Hsiao
- Bioinformatics and Biostatistics Core, Center of Genomic Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Jyun-Pei Jhou
- Graduate Institute of Pharmacology, National Taiwan University, Taipei, Taiwan
| | - Eric Y Chuang
- Bioinformatics and Biostatistics Core, Center of Genomic Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan
| | - Shiang-Jong Tzeng
- Graduate Institute of Pharmacology, National Taiwan University, Taipei, Taiwan.
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17
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Rocha Arrieta YC, Rojas M, Vasquez G, Lopez J. The Lymphocytes Stimulation Induced DNA Release, a Phenomenon Similar to NETosis. Scand J Immunol 2017; 86:229-238. [PMID: 28805301 DOI: 10.1111/sji.12592] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 07/30/2017] [Indexed: 12/23/2022]
Abstract
The release of DNA into the extracellular milieu by neutrophil during a process called NETosis has been postulated as an additional source of autoantigens; a process believed to be important in the pathogenesis of some autoimmune disease, such as systemic lupus erythematosus (SLE). However, it is not established if the B and T cells undergo the release of DNA to the extracellular milleu, in response to different stimuli. In this study, it was observed that the treatment of B and T cells with PMA, ionomycin and the serum from patients with SLE induced the extracellular DNA presence in B and T cells. These findings suggest that the phenomenon were similar to those observed in neutrophil's Etosis; B and T cells also released their DNA into the extracellular milieu. The findings express that serum from patients with SLE and SLEDAI ≤ 8 triggers the release of extracellular DNA in neutrophils, B and T cells, that suggested the presence of soluble factors in the serum that favoured this phenomenon.
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Affiliation(s)
- Y C Rocha Arrieta
- Grupo de Inmunodeficiencias Primarias/Lab 530-531, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia
| | - M Rojas
- Unidad de Citometría/Lab 420, Instituto de Investigaciones Médicas, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia.,Grupo de Inmunología Celular e Inmunogenética/Lab 510-511, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia
| | - G Vasquez
- Grupo de Inmunología Celular e Inmunogenética/Lab 510-511, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia
| | - J Lopez
- Grupo de Inmunodeficiencias Primarias/Lab 530-531, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia
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18
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Jhou JP, Chen SJ, Huang HY, Lin WW, Huang DY, Tzeng SJ. Upregulation of FcγRIIB by resveratrol via NF-κB activation reduces B-cell numbers and ameliorates lupus. Exp Mol Med 2017; 49:e381. [PMID: 28960214 PMCID: PMC5628277 DOI: 10.1038/emm.2017.144] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 03/22/2017] [Accepted: 03/29/2017] [Indexed: 12/14/2022] Open
Abstract
Resveratrol, an anti-inflammatory agent, can inhibit pro-inflammatory mediators by activating Sirt1, which is a class III histone deacetylase. However, whether resveratrol can regulate inhibitory or anti-inflammatory molecules has been less studied. FcγRIIB, a receptor for IgG, is an essential inhibitory receptor of B cells for blocking B-cell receptor-mediated activation and for directly inducing apoptosis of B cells. Because mice deficient in either Sirt1 or FcγRIIB develop lupus-like diseases, we investigated whether resveratrol can alleviate lupus through FcγRIIB. We found that resveratrol enhanced the expression of FcγRIIB in B cells, resulting in a marked depletion of plasma cells in the spleen and notably in the bone marrow, thereby decreasing serum autoantibody titers in MRL/lpr mice. The upregulation of FcγRIIB by resveratrol involved an increase of Sirt1 protein and deacetylation of p65 NF-κB (K310). Moreover, increased binding of phosphor-p65 NF-κB (S536) but decreased association of acetylated p65 NF-κB (K310) and phosphor-p65 NF-κB (S468) to the −480 promoter region of Fcgr2b gene was responsible for the resveratrol-mediated enhancement of FcγRIIB gene transcription. Consequently, B cells, especially plasma cells, were considerably reduced in MRL/lpr mice, leading to improvement of nephritis and prolonged survival. Taken together, we provide evidence that pharmacological upregulation of FcγRIIB expression in B cells via resveratrol can selectively reduce B cells, decrease serum autoantibodies and ameliorate lupus nephritis. Our findings lead us to propose FcγRIIB as a new target for therapeutic exploitation, particularly for lupus patients whose FcγRIIB expression levels in B cells are downregulated.
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Affiliation(s)
- Jyun-Pei Jhou
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Se-Jie Chen
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ho-Yin Huang
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Wan-Wan Lin
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Duen-Yi Huang
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Shiang-Jong Tzeng
- Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
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19
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Vollack N, Friese J, Bergmann S, Cragg MS, Tiede A, Werwitzke S. Anti-FcγRIIB (CD32) Antibodies Differentially Modulate Murine FVIII-Specific Recall Response in vitro. Scand J Immunol 2017; 86:91-99. [PMID: 28561280 DOI: 10.1111/sji.12573] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 05/18/2017] [Indexed: 12/11/2022]
Abstract
Fc gamma receptors (FcγRs) for IgG regulate adaptive immune responses by modulating activating and inhibitory signalling pathways within immune cells. Data from a haemophilia A mouse model demonstrate that genetic deletion or blockade of the inhibitory FcγR (CD32) suppresses the formation of antibody-secreting cells (ASCs) in vitro. Mechanisms preventing the FVIII-specific recall response, however, remain unclear. Here, the potential role of CD32 inhibition was studied by differentially modulating receptor activity with selected anti-CD32 monoclonal antibodies (mAbs). Splenocytes from immunized FVIII-/- mice were restimulated with FVIII in the absence or presence of different anti-CD32 mAbs over 6 days. At day 6, cytokine release was quantified from cell culture supernatant and the formation of FVIII-specific ASCs assessed. Binding of FVIII-containing immune complexes (F8-ICs) to bone marrow-derived dendritic cells (BMdDCs) was also investigated. The antagonistic CD32 mAb AT128 suppressed the formation of FVIII-specific ASCs and reduced secretion of IFN-γ and IL-10. In contrast, the agonistic mAbs AT130-2 and AT130-5, and their F(ab')2 fragments, allowed the formation of FVIII-specific ASCs, even though the full IgG of AT130-2 reduced binding of F8-ICs to CD32. Data suggest that an inhibitory signal is transmitted when F8-ICs bind to CD32 and that this signal is required during memory B cell (MBC) activation to support formation of FVIII-specific ASCs. If the inhibitory signal is lacking due to CD32 deletion or blockade with antagonistic anti-CD32 mAbs, FVIII-specific T cell stimulation and ASC formation are suppressed, whereas agonistic stimulation of CD32 restores T cell stimulation and ASC formation.
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Affiliation(s)
- N Vollack
- Department of Haematology, Haemostasis, Oncology and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany
| | - J Friese
- Department of Haematology, Haemostasis, Oncology and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany
| | - S Bergmann
- Department of Haematology, Haemostasis, Oncology and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany
| | - M S Cragg
- Antibody and Vaccine Group, Cancer Science Unit, Faculty of Medicine, General Hospital, University of Southampton, Southampton, UK
| | - A Tiede
- Department of Haematology, Haemostasis, Oncology and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany
| | - S Werwitzke
- Department of Haematology, Haemostasis, Oncology and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany
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20
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Sun JB, Holmgren J, Cragg MS, Xiang Z. Lack of Fc Gamma Receptor IIIA Promotes Rather than Suppresses Humoral and Cellular Immune Responses after Mucosal or Parenteral Immunization with Antigen and Adjuvants. Scand J Immunol 2017; 85:264-271. [PMID: 28128471 DOI: 10.1111/sji.12528] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 01/18/2017] [Indexed: 11/28/2022]
Abstract
The Fcγ receptor IIIA (FcγRIIIA) has traditionally been known as a positive regulator of immune responses. Consistent with this, mice deficient in FcγRIIIA are protected from various inflammation-associated pathologies including several autoimmune diseases. In contrast to this accepted dogma, we show here that mice lacking FcγRIIIA developed increased rather than reduced both humoral and cellular immune responses to mucosal (sublingual) immunization with ovalbumin (OVA) given together with the strong mucosal adjuvant cholera toxin as well as to parenteral (subcutaneous) immunization with OVA in complete Freund's adjuvant. After either route of immunization, in comparison with concomitantly immunized wild-type mice, FcγRIIIA-/- mice had increased serum anti-OVA IgG (IgG1 but not IgG2) antibody responses as well as augmented cellular responses that included memory B cells and effector T cells. The increments in immune responses in FcγRIIIA-/- mice were similar to those seen in FcγRIIB-/- mice. Furthermore, OVA-pulsed FcγRIIIA-/- DCs, similar to OVA-specific FcγRIIB-/- DCs, had enhanced capacity to activate OVA-specific OT-II T cells, which was even further pronounced when DCs were pulsed with IgG1-complexed OVA. Our data support an inhibitory-regulatory role of FcγRIIIA on vaccine/adjuvant-induced immune responses and demonstrate that lack of FcγRIIIA can promote rather than suppress both humoral and cellular immune responses.
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Affiliation(s)
- J-B Sun
- Department of Microbiology and Immunology and University of Gothenburg Vaccine Research Institute (GUVAX), Institute of Biomedicine, Sahlgrenska Academy at University of Gothenburg, Göteborg, Sweden
| | - J Holmgren
- Department of Microbiology and Immunology and University of Gothenburg Vaccine Research Institute (GUVAX), Institute of Biomedicine, Sahlgrenska Academy at University of Gothenburg, Göteborg, Sweden
| | - M S Cragg
- Antibody and Vaccine Group, Cancer Sciences Unit, Faculty of Medicine, Southampton General Hospital, University of Southampton, Southampton, Hampshire, UK
| | - Z Xiang
- Department of Microbiology and Immunology and University of Gothenburg Vaccine Research Institute (GUVAX), Institute of Biomedicine, Sahlgrenska Academy at University of Gothenburg, Göteborg, Sweden
- Department of Health Technology and Informatics, Faculty of Health and Social Sciences, The Hong Kong Polytechnic University, Hong Kong, China
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21
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Getahun A, Cambier JC. Of ITIMs, ITAMs, and ITAMis: revisiting immunoglobulin Fc receptor signaling. Immunol Rev 2016; 268:66-73. [PMID: 26497513 DOI: 10.1111/imr.12336] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Receptors for immunoglobulin Fc regions play multiple critical roles in the immune system, mediating functions as diverse as phagocytosis, triggering degranulation of basophils and mast cells, promoting immunoglobulin class switching, and preventing excessive activation. Transmembrane signaling associated with these functions is mediated primarily by two amino acid sequence motifs, ITAMs (immunoreceptor tyrosine-based activation motifs) and ITIMs (immunoreceptor tyrosine-based inhibition motifs) that act as the receptors' interface with activating and inhibitory signaling pathways, respectively. While ITAMs mobilize activating tyrosine kinases and their consorts, ITIMs mobilize opposing tyrosine and inositol-lipid phosphatases. In this review, we will discuss our current understanding of signaling by these receptors/motifs and their sometimes blurred lines of function.
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Affiliation(s)
- Andrew Getahun
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
| | - John C Cambier
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
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22
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Serum From Patients With Erectile Dysfunction and Vascular Risk Factors Triggered an Oxidative Stress-Dependent Mitochondrial Apoptotic Pathway in Ex Vivo Expanded Circulating Angiogenic Cells of Healthy Men. J Sex Med 2016; 13:1063-70. [DOI: 10.1016/j.jsxm.2016.04.067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/07/2016] [Accepted: 04/13/2016] [Indexed: 11/23/2022]
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23
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Jacobsen FA, Hulst C, Bäckström T, Koleske AJ, Andersson Å. Arg Deficiency Does not Influence the Course of Myelin Oligodendrocyte Glycoprotein (MOG35-55)-induced Experimental Autoimmune Encephalomyelitis. ACTA ACUST UNITED AC 2016; 7. [PMID: 34527426 PMCID: PMC8439389 DOI: 10.4172/2155-9899.1000420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Background Inhibition of Abl kinases has an ameliorating effect on the rodent model for multiple sclerosis, experimental autoimmune encephalomyelitis, and arrests lymphocyte activation. The family of Abl kinases consists of the Abl1/Abl and Abl2/Arg tyrosine kinases. While the Abl kinase has been extensively studied in immune activation, roles for Arg are incompletely characterized. To investigate the role for Arg in experimental autoimmune encephalomyelitis, we studied disease development in Arg-/- mice. Methods Arg-/- and Arg+/+ mice were generated from breeding of Arg+/- mice on the C57BL/6 background. Mice were immunized with the myelin oligodendrocyte glycoprotein (MOG)35-55 peptide and disease development recorded. Lymphocyte phenotypes of wild type Arg+/+ and Arg-/- mice were studied by in vitro stimulation assays and flow cytometry. Results The breeding of Arg+/+ and Arg-/- mice showed skewing in the frequency of born Arg-/- mice. Loss of Arg function did not affect development of experimental autoimmune encephalomyelitis, but reduced the number of splenic B-cells in Arg-/- mice following immunization with MOG peptide. Conclusions Development of MOG-induced experimental autoimmune encephalomyelitis is not dependent on Arg, but Arg plays a role for the number of B cells in immunized mice. This might suggest a novel role for the Arg kinase in B-cell trafficking or regulation. Furthermore, the results suggest that Arg is important for normal embryonic development.
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Affiliation(s)
- Freja Aksel Jacobsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk A/S, Gentofte, Denmark
| | - Camilla Hulst
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk A/S, Gentofte, Denmark
| | | | - Anthony J Koleske
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven CT 06520, USA
| | - Åsa Andersson
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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24
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Tzeng SJ, Li WY, Wang HY. FcγRIIB mediates antigen-independent inhibition on human B lymphocytes through Btk and p38 MAPK. J Biomed Sci 2015; 22:87. [PMID: 26475492 PMCID: PMC4609082 DOI: 10.1186/s12929-015-0200-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 10/06/2015] [Indexed: 12/21/2022] Open
Abstract
Background The inhibitory Fc receptor, FcγRIIB, has emerged as a key negative regulator of B cell activation and as such is predicted to play an essential role in controlling antibody-mediated autoimmune diseases in humans. Recent studies have shown that crosslinking the FcγRIIB independently of the B-cell receptor (BCR) results in apoptosis in both mouse and chicken B cells. However, the human B cell subpopulations that are susceptible to BCR-independent, FcγRIIB-mediated regulation are not known. How FcγRIIB mediates this inhibition to affect B cell homeostasis is also not determined. Results We isolated naïve B cells, memory B cells and plasma cells (PCs) from peripheral blood of healthy donors and used differentiated PCs in culture to examine the effects on them by FcγRIIB crosslinking. We showed that human PCs, memory and naïve B cells all expressed FcγRIIB with expression on PCs being the highest in circulation. Moreover, they were sensitive to direct inhibition by FcγRIIB through Btk and p38 MAPK. Similarly, PCs resulting from the antigen-independent differentiation of memory B cells in vitro were inhibited by FcγRIIB cross-linking but memory B cell activation itself, as measured by proliferation, was unaffected. In contrast, both the proliferation and differentiation of naïve B cells to PCs were blocked by FcγRIIB crosslinking. Conclusion These results suggest a mechanism to control antibody levels involving the differential expression of FcγRIIB on B cell subpopulations, in which the FcγRIIB functions independently of the BCR to eliminate antibody-secreting effector cells and inhibit naïve B cell proliferation without compromising the long-lived antigen-specific memory B cells. Importantly, FcγRIIB requires Btk and p38 MAPK to mediate antigen-independent inhibition in human B cells. Taken together, our data underscore the importance of antigen-independent inhibition by FcγRIIB in the prevention from antibody-mediated autoimmune diseases and in the regulation of B cell homeostasis.
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Affiliation(s)
- Shiang-Jong Tzeng
- Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Room 1118, No.1, Section 1, Ren-Ai Road, Taipei, 10051, Taiwan.
| | - Wan-Yu Li
- Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Room 1118, No.1, Section 1, Ren-Ai Road, Taipei, 10051, Taiwan
| | - Hui-Ying Wang
- Graduate Institute of Pharmacology, College of Medicine, National Taiwan University, Room 1118, No.1, Section 1, Ren-Ai Road, Taipei, 10051, Taiwan
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FcγRIIB mediates the inhibitory effect of aggregated α-synuclein on microglial phagocytosis. Neurobiol Dis 2015; 83:90-9. [PMID: 26342897 DOI: 10.1016/j.nbd.2015.08.025] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 08/24/2015] [Accepted: 08/25/2015] [Indexed: 12/22/2022] Open
Abstract
Parkinson's disease (PD) is the second most prevalent neurodegenerative disease. Although the etiology of PD has not yet been fully understood, accumulating evidence indicates that neuroinflammation plays a critical role in the progression of PD. α-Synuclein (α-Syn) has been considered to be a key player of the pathogenesis of PD, and recent reports that prion-like propagation of misfolded α-syn released from neurons may play an important role in the progression of PD have led to increased attention to the studies elucidating the roles of extracellular α-syn in the CNS. Extracellular α-syn has also been reported to regulate microglial inflammatory response. In this study, we demonstrated that aggregated α-syn inhibited microglial phagocytosis by activating SHP-1. SHP-1 activation was also observed in A53T α-syn transgenic mice. In addition, aggregated α-syn bound to FcγRIIB on microglia, inducing SHP-1 activation, further inhibiting microglial phagocytosis. Aggregated α-syn upregulated FcγRIIB expression in microglia and upregulated FcγRIIB was also observed in A53T α-syn transgenic mice. These data suggest that aggregated α-syn released from neurons dysregulates microglial immune response through inhibiting microglial phagocytosis, further causing neurodegeneration observed in PD. The interaction of aggregated α-syn and FcγRIIB and further SHP-1 activation can be a new therapeutic target against PD.
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Vuyyuru R, Shen S, Manser T. Testing the role of the FcγRIIB immunoreceptor tyrosine-based inhibitory motif in regulation of the B cell immune response. IMMUNITY INFLAMMATION AND DISEASE 2015; 3:247-64. [PMID: 26417440 PMCID: PMC4578524 DOI: 10.1002/iid3.64] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 04/09/2015] [Accepted: 04/25/2015] [Indexed: 01/07/2023]
Abstract
In vitro studies have demonstrated that the immunoreceptor tyrosine-based inhibitory motif (ITIM) of the inhibitory Fc receptor FcγRIIB is critical for mediating attenuation of signaling via immunoreceptor tyrosine-based activation motif (ITAM) containing receptors, such as the B cell antigen receptor (BCR), when FcγRIIB is co-cross-linked to these activation receptors. To test the role of the FcγRIIB ITIM motif in regulation of the B cell immune response in vivo, we constructed lines of transgenic mice expressing a form of FcγRIIB with an inactivating tyrosine (Y) to phenylalanine (F) mutation in the ITIM motif. Detailed studies of one of these lines, in which the mutant FcγRIIB was expressed on B cells and other cell types that normally express this receptor, were performed. No quantitative differences in germinal center (GC) B cell responses were observed between the mutant FcγRIIB transgenic line and control mice. However, serum antibody and antibody forming cell responses were often observed to be elevated in the ITIM mutant FcγRIIB transgenic mice as compared to controls, though not to the same extent as mice deficient in expression of FcγRIIB. Moreover, primary B cells from the ITIM mutant FcγRIIB line did not display the same level of augmented BCR signaling as primary FcγRIIB deficient B cells under conditions inducing co-cross-linking of FcγRIIB and the BCR. In total, these data suggest that a functional ITIM motif is not required for all in vivo inhibitory activity of this receptor. However, we also found that the transgenic ITIM mutant FcγRIIB receptor was expressed at abnormal levels in several hematopoietic lineages. Thus, confirmation of our findings will require the generation and analysis of mice in which an ITIM mutant form of FcγRIIB is expressed in vivo as is the endogenous receptor.
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Affiliation(s)
- Raja Vuyyuru
- Department of Microbiology and Immunology, Thomas Jefferson University Philadelphia, PA, USA
| | - Shixue Shen
- Department of Microbiology and Immunology, Thomas Jefferson University Philadelphia, PA, USA
| | - Tim Manser
- Department of Microbiology and Immunology, Thomas Jefferson University Philadelphia, PA, USA
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Ding J, Fang Y, Xiang Z. Antigen/IgG immune complex-primed mucosal mast cells mediate antigen-specific activation of co-cultured T cells. Immunology 2015; 144:387-394. [PMID: 25196548 DOI: 10.1111/imm.12379] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 08/27/2014] [Accepted: 08/30/2014] [Indexed: 02/06/2023] Open
Abstract
Mast cells are proposed to be one of the targets for mucosal vaccine adjuvants. We previously demonstrated that mucosal adjuvants containing IgG immune complexes could activate connective tissue mast cells enhancing immune responses. Here we suggest that mucosal mast cells (MMC) may also contribute to augmentation of antigen-specific immune responses following treatment with antigens complexed with IgG. We demonstrated that both bone marrow-derived cultured MMC and tissue resident MMC incorporated ovalbumin (OVA) at a greater level in the presence of anti-OVA IgG. Co-culture of OVA/IgG-pulsed bone marrow-derived MMC with splenocytes from OT-II mice promoted OVA-specific activation and proliferation of T cells, a process known as cross-presentation. Furthermore, bone marrow-derived cultured MMC underwent apoptosis following treatment with IgG immune complexes, a feature that has been described as favouring phagocytosis of mast cells by professional antigen-presenting cells.
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Affiliation(s)
- Jie Ding
- Department of Microbiology, Nanjing Centre for Disease Control and Prevention, Nanjing, China
| | - Yu Fang
- Department of Microbiology and Immunology, Affiliated Hospital of Guiyang Medical College, Guiyang, China
| | - Zou Xiang
- Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming, China.,Department of Microbiology and Immunology, Mucosal Immunobiology and Vaccine Research Centre, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
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28
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Abstract
The calcium ion (Ca(2+)) is the main common second messenger involved in signaling transduction subsequent to immunoreceptor activation. Its rapid intracellular elevation induces multiple cellular responses, such as secretion, proliferation, mobility, and gene transcription. Intracellular levels of Ca(2+) need to reach a specific threshold to efficiently transduce the signal to activate transcription factors through the recruitment of Ca(2+)-binding molecules. However, since Ca(2+) cannot be metabolized, its intracellular concentration is tightly regulated to avoid the induction of programmed cell death. This highly controlled regulation of Ca(2+) homeostasis has recently been clarified by the uncovering of new ion channels. The regulation of these channels allows the role of Ca(2+) in Fc receptor transduction pathways to be more precisely defined.
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Affiliation(s)
- Tarik Attout
- Inserm U1149, Bichat Medical School, Paris, France,
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29
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Rieth N, Carle A, Müller M, ter Meer D, Direnberger C, Pohl T, Sondermann P. Characterization of SM201, an anti-hFcγRIIB antibody not interfering with ligand binding that mediates immune complex dependent inhibition of B cells. Immunol Lett 2014; 160:145-50. [DOI: 10.1016/j.imlet.2014.01.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 01/14/2014] [Indexed: 01/08/2023]
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30
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Lehmann B, Schwab I, Böhm S, Lux A, Biburger M, Nimmerjahn F. FcγRIIB: a modulator of cell activation and humoral tolerance. Expert Rev Clin Immunol 2014; 8:243-54. [DOI: 10.1586/eci.12.5] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Inhibitory FcγRIIb (CD32b) becomes activated by therapeutic mAb in both cis and trans and drives internalization according to antibody specificity. Blood 2013; 123:669-77. [PMID: 24227819 DOI: 10.1182/blood-2013-04-490821] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
A major feature that distinguishes type I from type II anti-CD20 monoclonal antibodies (mAbs) and reduces their therapeutic efficacy is the tendency to internalize from the cell surface. We have shown previously that the extent of internalization correlates with the capacity of type I mAb to simultaneously engage both CD20 and the inhibitory Fcγ receptor, FcγRIIb, in a bipolar configuration. Here, we investigated whether mAbs directed at other B-cell surface receptors also engaged FcγRIIb and whether this interaction promoted internalization. Most mAbs engaged and activated FcγRIIb, with the strength of activation related to the level of mAb bound to the cell surface. However, engagement did not affect internalization of most mAb-ligated receptors, either in cell lines or primary chronic lymphocytic leukemia cells with the exception of CD19 and CD38. Furthermore, at high cell concentrations/density both cis and trans interactions between cell-surface bound mAb and FcγRIIb were evident, but trans interactions did not inhibit type I anti-CD20 mAb-mediated internalization. These data identify that FcγRIIb is engaged by many mAbs in both cis and trans configurations, triggering its activation, but that internalization via FcγRIIb occurs for only a select subset. These findings have implications when designing new antibody-based therapeutics.
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Huse M, Catherine Milanoski S, Abeyweera TP. Building tolerance by dismantling synapses: inhibitory receptor signaling in natural killer cells. Immunol Rev 2013; 251:143-53. [PMID: 23278746 DOI: 10.1111/imr.12014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Cell surface receptors bearing immunotyrosine-based inhibitory motifs (ITIMs) maintain natural killer (NK) cell tolerance to normal host tissues. These receptors are difficult to analyze mechanistically because they block activating responses in a rapid and comprehensive manner. The advent of high-resolution single cell imaging techniques has enabled investigators to explore the cell biological basis of the inhibitory response. Recent studies using these approaches indicate that ITIM-containing receptors function at least in part by structurally undermining the immunological synapse between the NK cell and its target. In this review, we discuss these new advances and how they might relate to what is known about the biochemistry of inhibitory signaling in NK cells and other cell types.
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Affiliation(s)
- Morgan Huse
- Immunology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
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33
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Zhang X, Burch E, Cai L, So E, Hubbard F, Matteson EL, Strome SE. CD40 mediates downregulation of CD32B on specific memory B cell populations in rheumatoid arthritis. THE JOURNAL OF IMMUNOLOGY 2013; 190:6015-22. [PMID: 23686494 DOI: 10.4049/jimmunol.1203366] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Altered B cell function is important in the pathogenesis of rheumatoid arthritis (RA). In this report, we show that patients with active RA have an increased frequency of CD32B low/neg cells in the CD27(+)IgD(-) memory B cell subset and that these changes are associated with phenotypic and functional B cell activation. Studies using PBMCs from healthy donors revealed that downregulation of CD32B on B cells is mediated by CD40-CD40L interactions and is potentiated by IL-4 and inhibited by both IL-10 and IL-21. These findings appear physiologically relevant because CD4 T cell expression of CD40L correlated with the frequency of CD32B low/neg cells in the CD27(+)IgD(-) memory B subset in patients with RA. Our data support a model in which high levels of CD40L, present on circulating T cells in patients with RA, causes B cell activation and CD32B downregulation, resulting in secondary protection of memory B cells from CD32B-mediated cell death.
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Affiliation(s)
- Xiaoyu Zhang
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland, Baltimore, MD 21201, USA
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34
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Barbonetti A, Vassallo MRC, Di Rosa A, Leombruni Y, Felzani G, Gandini L, Lenzi A, Necozione S, Francavilla S, Francavilla F. Involvement of mitochondrial dysfunction in the adverse effect exerted by seminal plasma from men with spinal cord injury on sperm motility. Andrology 2013; 1:456-63. [DOI: 10.1111/j.2047-2927.2013.00077.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 01/05/2013] [Accepted: 01/28/2013] [Indexed: 11/30/2022]
Affiliation(s)
| | - M. R. C. Vassallo
- Andrology Unit; Department of Life, Health and Environment Sciences; University of L'Aquila; L'Aquila; Italy
| | - A. Di Rosa
- Andrology Unit; Department of Life, Health and Environment Sciences; University of L'Aquila; L'Aquila; Italy
| | - Y. Leombruni
- Andrology Unit; Department of Life, Health and Environment Sciences; University of L'Aquila; L'Aquila; Italy
| | - G. Felzani
- Centre for Clinical Research; San Raffaele Sulmona; Sulmona; Italy
| | - L. Gandini
- Laboratory of Seminology and Immunology of Human Reproduction; Department of Medical Pathophysiology; University of Rome, ‘La Sapienza’; Rome; Italy
| | - A. Lenzi
- Laboratory of Seminology and Immunology of Human Reproduction; Department of Medical Pathophysiology; University of Rome, ‘La Sapienza’; Rome; Italy
| | - S. Necozione
- Epidemiology; Department of Life, Health and Environment Sciences; University of L'Aquila; L'Aquila; Italy
| | - S. Francavilla
- Andrology Unit; Department of Life, Health and Environment Sciences; University of L'Aquila; L'Aquila; Italy
| | - F. Francavilla
- Andrology Unit; Department of Life, Health and Environment Sciences; University of L'Aquila; L'Aquila; Italy
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35
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Abstract
A large antibody repertoire is generated in developing B cells in the bone marrow. Before these B cells achieve immunocompetence, those expressing autospecificities must be purged. To that end, B cells within the bone marrow and just following egress from the bone marrow are subject to tolerance induction. Once B cells achieve immunocompetence, the antibody repertoire can be further diversified by somatic hypermutation of immunoglobulin genes in B cells that have been activated by antigen and cognate T cell help and have undergone a germinal center (GC) response. This process also leads to the generation of autoreactive B cells which must be again purged to protect the host. Thus, B cells within the GC and just following egress from the GC are also subject to tolerance induction. Available data suggest that B cell intrinsic processes triggered by signaling through the B cell receptor activate tolerance mechanisms at both time points. Recent data suggest that GC and post-GC B cells are also subject to B cell extrinsic tolerance mechanisms mediated through soluble and membrane-bound factors derived from various T cell subsets.
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36
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Fang Y, Larsson L, Bruhns P, Xiang Z. Apoptosis of mouse mast cells is reciprocally regulated by the IgG receptors FcγRIIB and FcγRIIIA. Allergy 2012; 67:1233-40. [PMID: 22845035 DOI: 10.1111/j.1398-9995.2012.02878.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/22/2012] [Indexed: 11/30/2022]
Abstract
BACKGROUND Mast cells are important effector cells in allergy. They usually have a long life span and resist cell death induction. Fcγ receptor- and IgG immune complex-mediated apoptosis has been demonstrated in B-lineage cells, but not in mast cells. The aim of the current study was to investigate whether mast cells could respond to apoptosis induction by IgG immune complex aggregation of Fcγ receptors. It is known that mouse mast cells express the low-affinity Fcγ receptors FcγRIIB and FcγRIIIA, which bind IgG especially in the form of antigen-IgG immune complexes. METHODS Mouse bone marrow-derived cultured mast cells were examined for surface expression of FcγRIIB and FcγRIIIA. Apoptosis of such cells from wild-type, FcγRIIB(-/-) or FcγRIIIA(-/-) mice was measured following receptor aggregation by IgG immune complexes. RESULTS Our data demonstrate that aggregation of either FcγRIIB or FcγRIIIA by IgG immune complexes induced apoptosis of mouse bone marrow-derived cultured mast cells. However, mast cells expressing both FcγRIIB and FcγRIIIA were able to resist cell death induction by IgG immune complexes. CONCLUSION Our findings reveal a fine-tuning system for regulating mast cell apoptosis through aggregating Fcγ receptors by IgG immune complexes. Such apoptosis regulation may have a substantial impact on mast cell homeostasis during allergic inflammation.
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Affiliation(s)
- Y Fang
- Department of Microbiology and Immunology, Affiliated Hospital of Guiyang Medical College, Guiyang, China
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37
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Fang Y, Larsson L, Bruhns P, Xiang Z. Apoptosis of mouse mast cells is reciprocally regulated by the IgG receptors FcγRIIB and FcγRIIIA. Allergy 2012. [PMID: 22845035 DOI: 10.1111/j.1398-9995.2012.02878.x.] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Mast cells are important effector cells in allergy. They usually have a long life span and resist cell death induction. Fcγ receptor- and IgG immune complex-mediated apoptosis has been demonstrated in B-lineage cells, but not in mast cells. The aim of the current study was to investigate whether mast cells could respond to apoptosis induction by IgG immune complex aggregation of Fcγ receptors. It is known that mouse mast cells express the low-affinity Fcγ receptors FcγRIIB and FcγRIIIA, which bind IgG especially in the form of antigen-IgG immune complexes. METHODS Mouse bone marrow-derived cultured mast cells were examined for surface expression of FcγRIIB and FcγRIIIA. Apoptosis of such cells from wild-type, FcγRIIB(-/-) or FcγRIIIA(-/-) mice was measured following receptor aggregation by IgG immune complexes. RESULTS Our data demonstrate that aggregation of either FcγRIIB or FcγRIIIA by IgG immune complexes induced apoptosis of mouse bone marrow-derived cultured mast cells. However, mast cells expressing both FcγRIIB and FcγRIIIA were able to resist cell death induction by IgG immune complexes. CONCLUSION Our findings reveal a fine-tuning system for regulating mast cell apoptosis through aggregating Fcγ receptors by IgG immune complexes. Such apoptosis regulation may have a substantial impact on mast cell homeostasis during allergic inflammation.
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Affiliation(s)
- Y Fang
- Department of Microbiology and Immunology, Affiliated Hospital of Guiyang Medical College, Guiyang, China
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38
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Williams EL, Tutt AL, French RR, Chan HTC, Lau B, Penfold CA, Mockridge CI, Roghanian A, Cox KL, Verbeek JS, Glennie MJ, Cragg MS. Development and characterisation of monoclonal antibodies specific for the murine inhibitory FcγRIIB (CD32B). Eur J Immunol 2012; 42:2109-20. [DOI: 10.1002/eji.201142302] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Revised: 04/03/2012] [Accepted: 05/09/2012] [Indexed: 11/10/2022]
Affiliation(s)
- Emily L. Williams
- Antibody and Vaccine Group; Cancer Sciences Unit; Faculty of Medicine; University of Southampton; General Hospital; Southampton; UK
| | - Alison L. Tutt
- Antibody and Vaccine Group; Cancer Sciences Unit; Faculty of Medicine; University of Southampton; General Hospital; Southampton; UK
| | - Ruth R. French
- Antibody and Vaccine Group; Cancer Sciences Unit; Faculty of Medicine; University of Southampton; General Hospital; Southampton; UK
| | - H. T. Claude Chan
- Antibody and Vaccine Group; Cancer Sciences Unit; Faculty of Medicine; University of Southampton; General Hospital; Southampton; UK
| | - Betty Lau
- Antibody and Vaccine Group; Cancer Sciences Unit; Faculty of Medicine; University of Southampton; General Hospital; Southampton; UK
| | - Christine A. Penfold
- Antibody and Vaccine Group; Cancer Sciences Unit; Faculty of Medicine; University of Southampton; General Hospital; Southampton; UK
| | - C. Ian Mockridge
- Antibody and Vaccine Group; Cancer Sciences Unit; Faculty of Medicine; University of Southampton; General Hospital; Southampton; UK
| | - Ali Roghanian
- Antibody and Vaccine Group; Cancer Sciences Unit; Faculty of Medicine; University of Southampton; General Hospital; Southampton; UK
| | - Kerry L. Cox
- Antibody and Vaccine Group; Cancer Sciences Unit; Faculty of Medicine; University of Southampton; General Hospital; Southampton; UK
| | - J. Sjef Verbeek
- Department of Human Genetics; Leiden University Medical Centre; Leiden; The Netherlands
| | - Martin J. Glennie
- Antibody and Vaccine Group; Cancer Sciences Unit; Faculty of Medicine; University of Southampton; General Hospital; Southampton; UK
| | - Mark S. Cragg
- Antibody and Vaccine Group; Cancer Sciences Unit; Faculty of Medicine; University of Southampton; General Hospital; Southampton; UK
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Zhang Y, Zhou Y, Yang Q, Mu C, Duan E, Chen J, Yang M, Xia P, Cui B. Ligation of Fc gamma receptor IIB enhances levels of antiviral cytokine in response to PRRSV infection in vitro. Vet Microbiol 2012; 160:473-80. [PMID: 22771209 DOI: 10.1016/j.vetmic.2012.06.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 06/19/2012] [Indexed: 10/28/2022]
Abstract
PRRSV infection ADE facilitates the attachment and internalization of the virus onto its host cells, such as monocytes and macrophages, through Fc receptor-mediated endocytosis. FcγRIIB is the only inhibitory receptor with a tyrosine-based inhibitory motif (ITIM) in its cytoplasmic tail, where counters the "ITAM triggered" activation signals and down-regulates phagocytosis. However, porcine FcγRIIB's role in the antiviral immune response to PRRSV infection has not been studied. In this study, our results indicated that selective activation of porcine FcγRIIB in PAM cells up-regulated significantly mRNA levels of IFN-α and TNF-α at any time point post-pretreatment, suggesting that porcine FcγRIIB signal can enhance the innate antiviral response of host cells. PRRSV infection assay mediated by FcγRIIB indicated that selective activation of porcine FcγRIIB in PAM cells enhanced mRNA levels of antiviral cytokine (IFN-α and TNF-α) and repressed mRNA levels of IL-10 in response to PRRSV infection, suggesting that FcγRIIB ligation can enhance the antiviral immune response to PRRSV infection. In addition, FcγRIIB ligation to infection indicated that PRRSV replication in PAM was not positive correlation with increasing of IFN-α mRNA levels and decreasing of IL-10 mRNA levels, suggesting that there is complex viral replication mechanism in immune cells such as PAM for PRRSV.
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Affiliation(s)
- Yina Zhang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China
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40
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c-Abl promotes osteoblast expansion by differentially regulating canonical and non-canonical BMP pathways and p16INK4a expression. Nat Cell Biol 2012; 14:727-37. [PMID: 22729085 DOI: 10.1038/ncb2528] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 05/22/2012] [Indexed: 11/08/2022]
Abstract
Defects in stem cell renewal or progenitor cell expansion underlie ageing-related diseases such as osteoporosis. Yet much remains unclear about the mechanisms regulating progenitor expansion. Here we show that the tyrosine kinase c-Abl plays an important role in osteoprogenitor expansion. c-Abl interacts with and phosphorylates BMPRIA and the phosphorylation differentially influences the interaction of BMPRIA with BMPRII and the Tab1-Tak1 complex, leading to uneven activation of Smad1/5/8 and Erk1/2, the canonical and non-canonical BMP pathways that direct the expression of p16(INK4a). c-Abl deficiency shunts BMP signalling from Smad1/5/8 to Erk1/2, leading to p16(INK4a) upregulation and osteoblast senescence. Mouse genetic studies revealed that p16(INK4a) controls mesenchymal stem cell maintenance and osteoblast expansion and mediates the effects of c-Abl deficiency on osteoblast expansion and bone formation. These findings identify c-Abl as a regulator of BMP signalling pathways and uncover a role for c-Abl in p16(INK4a) expression and osteoprogenitor expansion.
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Paunovic V, Carter NA, Thalhamer T, Blair D, Gordon B, Lacey E, Michie AM, Harnett MM. Immune complex-mediated co-ligation of the BCR with FcγRIIB results in homeostatic apoptosis of B cells involving Fas signalling that is defective in the MRL/Lpr model of systemic lupus erythematosus. J Autoimmun 2012; 39:332-46. [PMID: 22647731 DOI: 10.1016/j.jaut.2012.04.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Revised: 04/18/2012] [Accepted: 04/25/2012] [Indexed: 12/15/2022]
Abstract
Negative regulation of B cell activation by cognate immune complexes plays an important homeostatic role in suppressing B cell hyperactivity and preventing consequent autoimmunity. Immune complexes co-ligate the BCR and FcγRIIB resulting in both growth arrest and apoptosis. We now show that such apoptotic signalling involves induction and activation of p53 and its target genes, the pro-apoptotic Bcl-2 family members, Bad and Bid, as well as nuclear export of p53. Collectively, these events result in destabilisation of the mitochondrial and lysosomal compartments with consequent activation and interplay of executioner caspases and endosomal-derived proteases. In addition, the upregulation of Fas and FasL with consequent activation of caspase 8-dependent death receptor signalling is required to facilitate efficient apoptosis of B cells. Consistent with this role for Fas death receptor signalling, apoptosis resulting from co-ligation of the BCR and FcγRIIB is defective in B cells from Fas-deficient MRL/MpJ-Fas(lpr) mice. As these mice develop spontaneous, immune complex-driven lupus-like glomerulonephritis, targeting this FcγRIIB-mediated apoptotic pathway may therefore have novel therapeutic implications for systemic autoimmune disease.
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Affiliation(s)
- Verica Paunovic
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G12 8TA, UK
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Amezcua Vesely MC, Schwartz M, Bermejo DA, Montes CL, Cautivo KM, Kalergis AM, Rawlings DJ, Acosta-Rodríguez EV, Gruppi A. FcγRIIb and BAFF differentially regulate peritoneal B1 cell survival. THE JOURNAL OF IMMUNOLOGY 2012; 188:4792-800. [PMID: 22516957 DOI: 10.4049/jimmunol.1102070] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
B1 cells produce most natural Abs in unimmunized mice and play a key role in the response to thymus-independent Ags and microbial infection. Enlargement of B1 cell number in mice is often associated with autoimmunity. However, the factors that control peripheral B1 cell survival remain poorly characterized. Mice lacking the inhibitory receptor FcγRIIb exhibit a massive expansion in peritoneal B1 cells, implicating this receptor in B1 cell homeostasis. In this study, we show that peritoneal B1 cells express the highest levels of FcγRIIb among B cell subsets and are highly susceptible to FcγRIIb-mediated apoptosis. B1 cells upregulate FcγRIIb in response to innate signals, including CpG, and the B cell homeostatic cytokine BAFF efficiently protects activated B1 cells from FcγRIIb-mediated apoptosis via receptor downregulation. BAFF-transgenic mice manifest an expansion of peritoneal B1 cells that express lower levels of FcγRIIb and exhibit reduced susceptibility to apoptosis. Whereas both peritoneal B1 cells from wild-type and BAFF-transgenic mice immunized with CpG exhibit an increase in FcγRIIb levels, this change is blunted in BAFF-transgenic animals. Our combined results demonstrate that FcγRIIb controls peritoneal B1 cell survival and this program can be modulated by the BAFF signaling axis.
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Affiliation(s)
- María C Amezcua Vesely
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba CP 5000, Argentina
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43
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Porcine Fc gamma RIIb sub-isoforms are generated by alternative splicing. Vet Immunol Immunopathol 2012; 145:386-94. [DOI: 10.1016/j.vetimm.2011.12.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 12/13/2011] [Accepted: 12/15/2011] [Indexed: 11/20/2022]
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44
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Xia P, Liu Y, Liu X, Zhang Z, Duan E, Lu X, Zhao J, Cui B. Molecular cloning and characterization of a porcine Fc gamma RIIb sub-isoform(FcγRIIb1). Vet Immunol Immunopathol 2011; 141:144-50. [DOI: 10.1016/j.vetimm.2011.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 01/28/2011] [Accepted: 02/07/2011] [Indexed: 10/18/2022]
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45
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Barbonetti A, Vassallo MRC, Fortunato D, Francavilla S, Maccarrone M, Francavilla F. Energetic metabolism and human sperm motility: impact of CB₁ receptor activation. Endocrinology 2010; 151:5882-92. [PMID: 20962050 PMCID: PMC2999496 DOI: 10.1210/en.2010-0484] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Accepted: 09/22/2010] [Indexed: 12/19/2022]
Abstract
It has been reported that the endocannabinoid anandamide (AEA) exerts an adverse effect on human sperm motility, which has been ascribed to inhibition of mitochondrial activity. This seems to be at variance with evidence suggesting a major role of glycolysis in supplying ATP for sperm motility; furthermore, the role of AEA-binding receptors in mediating mitochondrial inhibition has not yet been explored. In this study, human sperm exposure to Met-AEA (methanandamide, nonhydrolyzable analog of AEA) in the micromolar range significantly decreased mitochondrial transmembrane potential (ΔΨm), similarly to rotenone, mitochondrial complex I inhibitor. The effect of Met-AEA (1 μm) was prevented by SR141716, CB(1) cannabinoid receptor antagonist, but not by SR144528, CB(2) antagonist, nor by iodoresiniferatoxin, vanilloid receptor antagonist. The effect of Met-AEA did not involve activation of caspase-9 or caspase-3 and was reverted by washing. In the presence of glucose, sperm exposure either to Met-AEA up to 1 μm or to rotenone for up to 18 h did not affect sperm motility. At higher doses Met-AEA produced a CB(1)-independent poisoning of spermatozoa, reducing their viability. Under glycolysis blockage, 1 μm Met-AEA, similarly to rotenone, dramatically abolished sperm motility, an effect that was prevented by SR1 and reverted by washing. In conclusion, CB(1) activation induced a nonapoptotic decrease of ΔΨm, the detrimental reflection on sperm motility of which could be revealed only under glycolysis blockage, unless very high doses of Met-AEA, producing CB(1)-independent sperm toxicity, were used. The effects of CB(1) activation reported here contribute to elucidate the relationship between energetic metabolism and human sperm motility.
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Affiliation(s)
- A Barbonetti
- Department of Internal Medicine, University of L'Aquila, L'Aquila, Italy
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46
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Xia YC, Schuliga M, Shepherd M, Powell M, Harris T, Langenbach SY, Tan PS, Gerthoffer WT, Hogarth PM, Stewart AG, Mackay GA. Functional expression of IgG-Fc receptors in human airway smooth muscle cells. Am J Respir Cell Mol Biol 2010; 44:665-72. [PMID: 20595464 DOI: 10.1165/rcmb.2009-0371oc] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
IgE-Fc receptors and IgG-Fc receptors are expressed on hematopoietic cells, but some evidence suggests that these receptors are also found on nonhematopoietic cells, including human airway smooth muscle (hASM) cells. Our study characterizes the expression of IgE-Fc receptors (FcεRI/CD23) and IgG-Fc receptors (FcγRs-I, -II, and -III) in cultured hASM cells by flow cytometry and Western blotting, and the functional activity of receptors was determined through quantification of cell proliferation and released cytokines. Expression of Fc receptor-linked intracellular signaling proteins and phosphorylation of the mitogen-activated protein kinases (MAPKs) extracellular signal-regulated kinase 1/2 and p38(MAPK) in hASM cells was examined by Western blotting. Expression of FcεRI and CD23 was not detectable in hASM cells. However, FcγRI and FcγRII were shown to be expressed on these cells. Specific antibodies, validated using transfected cell lines, revealed that the inhibitory IgG receptor, FcγRIIb, was the most abundant Fc receptor subtype expressed. Although cross-linking FcγR with heat-aggregated γ globulin (HAGG) did not induce detectable cell stimulation, pretreating hASM cells with HAGG significantly inhibited IL-1α-induced increases in cytokine levels and basic fibroblast growth factor-induced cell proliferation. This inhibitory effect of HAGG was abrogated by preincubation of cells with an anti-FcγRIIb antigen-binding fragment (Fab). Expression of proteins involved in the canonical FcγRIIb inhibitory signaling pathway was established in hASM cells. Pretreatment of hASM cells with HAGG significantly inhibited IL-1α- and basic fibroblast growth factor-induced extracellular signal-regulated kinase 1/2 and p38(MAPK) phosphorylation. This study identifies functional expression of FcγRIIb in hASM cells, with the potential to suppress their remodeling and immunomodulatory roles.
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Affiliation(s)
- YuXiu C Xia
- Department of Pharmacology, University of Melbourne, Parkville, Victoria, Australia
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47
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Metastatic melanomas express inhibitory low affinity fc gamma receptor and escape humoral immunity. Dermatol Res Pract 2010; 2010:657406. [PMID: 20672001 PMCID: PMC2905727 DOI: 10.1155/2010/657406] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Accepted: 04/01/2010] [Indexed: 12/22/2022] Open
Abstract
Our research, inspired by the pioneering works of Isaac Witz in the 1980s, established that 40% of human metastatic melanomas express ectopically inhibitory Fc gamma receptors (FcγRIIB), while they are detected on less than 5% of primary cutaneous melanoma and not on melanocytes. We demonstrated that these tumoral FcγRIIB act as decoy receptors that bind the Fc portion of antimelanoma IgG, which may prevent Fc recognition by the effector cells of the immune system and allow the metastatic melanoma to escape the humoral/natural immune response. The FcγRIIB is able to inhibit the ADCC (antibody dependent cell cytotoxicity) in vitro. Interestingly, the percentage of melanoma expressing the FcγRIIB is high (70%) in organs like the liver, which is rich in patrolling NK (natural killer) cells that exercise their antitumoral activity by ADCC. We found that this tumoral FcγRIIB is fully functional and that its inhibitory potential can be triggered depending on the specificity of the anti-tumor antibody with which it interacts.
Together these observations elucidate how metastatic melanomas interact with and potentially evade humoral immunity and provide direction for the improvement of anti-melanoma monoclonal antibody therapy.
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48
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Smith KGC, Clatworthy MR. FcgammaRIIB in autoimmunity and infection: evolutionary and therapeutic implications. Nat Rev Immunol 2010; 10:328-43. [PMID: 20414206 PMCID: PMC4148599 DOI: 10.1038/nri2762] [Citation(s) in RCA: 383] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
FcgammaRIIB is the only inhibitory Fc receptor. It controls many aspects of immune and inflammatory responses, and variation in the gene encoding this protein has long been associated with susceptibility to autoimmune disease, particularly systemic lupus erythematosus (SLE). FcgammaRIIB is also involved in the complex regulation of defence against infection. A loss-of-function polymorphism in FcgammaRIIB protects against severe malaria, the investigation of which is beginning to clarify the evolutionary pressures that drive ethnic variation in autoimmunity. Our increased understanding of the function of FcgammaRIIB also has potentially far-reaching therapeutic implications, being involved in the mechanism of action of intravenous immunoglobulin, controlling the efficacy of monoclonal antibody therapy and providing a direct therapeutic target.
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Affiliation(s)
- Kenneth G C Smith
- Cambridge Institute for Medical Research and the Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge CB2 0XY, UK.
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49
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Multiple bovine FcγRIIb sub-isoforms generated by alternative splicing. Vet Immunol Immunopathol 2010; 135:43-51. [DOI: 10.1016/j.vetimm.2009.10.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 10/21/2009] [Accepted: 10/22/2009] [Indexed: 11/22/2022]
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50
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Therapeutic (high) doses of rituximab activate calcium mobilization and inhibit B-cell growth via an unusual mechanism triggered independently of both CD20 and Fcgamma receptors. J Immunother 2010; 33:30-9. [PMID: 19952958 DOI: 10.1097/cji.0b013e3181b290f1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Rituximab is a CD20-specific monoclonal antibody that effectively targets and depletes B lymphocytes in vivo, primarily via indirect cytotoxic mechanisms. Direct effects on B cells may also contribute to B-cell depletion but are less clearly defined. In this report, we demonstrate that monomeric rituximab, at the high concentrations found in plasma following infusion of therapeutic doses, induces prolonged low-amplitude release of calcium from thapsigargin-sensitive intracellular stores and reduces the growth of Ramos B cells in culture. Intracellular calcium release was triggered via a signaling pathway distinct from the lipid raft-dependent and src family kinase-dependent pathway that is activated by CD20 hypercrosslinking or B-cell receptor association. The response was independent of both CD20 and Fc receptor binding, and was also triggered by some, but not all, irrelevant monoclonal IgG1 antibodies. The data indicate that unique regions within IgG may contribute to direct effects of therapeutic monoclonal antibodies delivered at suprasaturating concentrations.
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