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Chenoweth AM, Esparon S, Wines BD, Schuurman J, Labrijn AF, Hogarth PM. Mutation of the TGN1412 anti-CD28 monoclonal antibody lower hinge confers specific FcγRIIb binding and retention of super-agonist activity. Immunol Cell Biol 2023; 101:657-662. [PMID: 36997299 PMCID: PMC10952187 DOI: 10.1111/imcb.12646] [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: 12/27/2022] [Revised: 03/24/2023] [Accepted: 03/28/2023] [Indexed: 04/01/2023]
Abstract
The agonistic action of several immunomodulatory monoclonal antibodies (mAbs) requires both target antigen binding and clustering of this mAb:target complex by the Fcs interacting with Fcγ receptors (FcγRs), in particular FcγRIIb, on neighboring bystander cells. Fc mutations were made in the immunoglobulin G4 (IgG4)-based TGN1412 anti-CD28 mAb to define the role of FcγR interactions in its "super-agonist" activity. The dual mutation, IgG4-ED269,270 AA, ablated interaction with all human FcγRs and agonistic action was consequentially lost, confirming the FcγR dependence on the action of TGN1412. The IgG4 lower hinge region (F234 L235 G236 G237 ) was modified by L235 E mutation (F234 E235 G236 G237 ), a mutation commonly used to ablate FcγR binding, including in approved therapeutic mAbs. However, rather than ablating all FcγR binding, IgG4-L235 E conferred specific binding to FcγRIIb, the inhibitory Fc receptor. Furthermore, in combination with the core hinge-stabilizing mutation (IgG4-S228 P, L235 E), this mutation increased affinity for FcγRIIb compared with wild-type IgG4. In addition to having FcγRIIb specificity, these engineered TGN1412 antibodies retained their super-agonistic ability, demonstrating that CD28- and FcγRIIb-specific binding are together sufficient for agonistic function. The FcγRIIb-specific nature of IgG4-L235 E has utility for mAb-mediated immune agonism therapies that are dependent on FcγRIIb interaction and of anti-inflammatory mAbs in allergy and autoimmunity that harness FcγRIIb inhibitory signaling.
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Affiliation(s)
- Alicia M Chenoweth
- Immune Therapies GroupBurnet InstituteMelbourneVICAustralia
- Department of Immunology and Pathology, Central Clinical SchoolMonash UniversityMelbourneVICAustralia
- Present address:
St. John's Institute of Dermatology, School of Basic & Medical BiosciencesBreast Cancer Now Research Unit, School of Cancer & Pharmaceutical SciencesKing's College LondonLondonUK
| | - Sandra Esparon
- Immune Therapies GroupBurnet InstituteMelbourneVICAustralia
| | - Bruce D Wines
- Immune Therapies GroupBurnet InstituteMelbourneVICAustralia
- Department of Immunology and Pathology, Central Clinical SchoolMonash UniversityMelbourneVICAustralia
- Department of Clinical PathologyUniversity of MelbourneParkvilleVICAustralia
| | | | | | - P Mark Hogarth
- Immune Therapies GroupBurnet InstituteMelbourneVICAustralia
- Department of Immunology and Pathology, Central Clinical SchoolMonash UniversityMelbourneVICAustralia
- Department of Clinical PathologyUniversity of MelbourneParkvilleVICAustralia
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2
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Lu J, Spencer M, Zou Z, Traver M, Brzostowski J, Sun PD. FcγRI FG-loop functions as a pH sensitive switch for IgG binding and release. Front Immunol 2023; 14:1100499. [PMID: 36814926 PMCID: PMC9940316 DOI: 10.3389/fimmu.2023.1100499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/25/2023] [Indexed: 02/08/2023] Open
Abstract
Understanding the molecular mechanism underlying the hierarchic binding between FcγRs and IgG antibodies is critical for therapeutic antibody engineering and FcγR functions. The recent determination of crystal structures of FcγRI-Fc complexes, however, resulted in two controversial mechanisms for the high affinity receptor binding to IgG. Here, we describe high resolution structures of a bovine FG-loop variant of FcγRI in complex with the Fc fragment of IgG1 crystallized in three different conditions at neutral pH, confirming the characteristic FG loop-Fc interaction is critical to the high affinity immunoglobulin binding. We showed that the FcγRI D2-domain FG-loop functioned as a pH-sensing switch for IgG binding. Further live cell imaging of FcγRI-mediated internalization of immune complexes showed a pH sensitive temporal-spatial antibody-antigen uptake and release. Taken together, we demonstrate that the structures of FcγRI-Fc crystallized at neutral and acidic pH, respectively, represent the high and low affinity binding states of the receptor for IgG uptake and release. These results support a role for FcγRI in antigen delivery, highlight the importance of Fc glycan in antibody binding to the high affinity receptor and provide new insights to future antibody engineering.
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Affiliation(s)
- Jinghua Lu
- Structural Immunology Section, Lab of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Matthew Spencer
- Structural Immunology Section, Lab of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Zhongcheng Zou
- Structural Immunology Section, Lab of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Maria Traver
- Lymphocyte Activation Section, Lab of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Joseph Brzostowski
- Lymphocyte Activation Section, Lab of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Peter D Sun
- Structural Immunology Section, Lab of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
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3
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Delidakis G, Kim JE, George K, Georgiou G. Improving Antibody Therapeutics by Manipulating the Fc Domain: Immunological and Structural Considerations. Annu Rev Biomed Eng 2022; 24:249-274. [PMID: 35363537 PMCID: PMC9648538 DOI: 10.1146/annurev-bioeng-082721-024500] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Interactions between the crystallizable fragment (Fc) domain of antibodies and a plethora of cellular Fc receptors (FcRs) or soluble proteins form a critical link between humoral and innate immunity. In particular, the immunoglobulin G Fc domain is critical for the clearance of target cells by processes that include (a) cytotoxicity, phagocytosis, or complement lysis; (b) modulation of inflammation; (c) antigen presentation; (d) antibody-mediated receptor clustering; and (e) cytokine release. More than 30 Fc-engineered antibodies aimed primarily at tailoring these effects for optimal therapeutic outcomes are in clinical evaluation or have already been approved. Nonetheless, our understanding of how FcR engagement impacts various immune cell phenotypes is still largely incomplete. Recent insights into FcR biology coupled with advances in Fc:FcR structural analysis, Fc engineering, and mouse models that recapitulate human biology are helping to fill in existing knowledge gaps. These advances will provide a blueprint on how to fine-tune the Fc domain to achieve optimal therapeutic efficacy. Expected final online publication date for the Annual Review of Biomedical Engineering, Volume 24 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- George Delidakis
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas, USA;
| | - Jin Eyun Kim
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas, USA
| | - Katia George
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
| | - George Georgiou
- Department of Chemical Engineering, University of Texas at Austin, Austin, Texas, USA; .,Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas, USA.,Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
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4
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Larson PA, Bartlett ML, Garcia K, Chitty J, Balkema-Buschmann A, Towner J, Kugelman J, Palacios G, Sanchez-Lockhart M. Genomic features of humoral immunity support tolerance model in Egyptian rousette bats. Cell Rep 2021; 35:109140. [PMID: 34010652 DOI: 10.1016/j.celrep.2021.109140] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 10/08/2020] [Accepted: 04/26/2021] [Indexed: 01/05/2023] Open
Abstract
Bats asymptomatically harbor many viruses that can cause severe human diseases. The Egyptian rousette bat (ERB) is the only known reservoir for Marburgviruses and Sosuga virus, making it an exceptional animal model to study antiviral mechanisms in an asymptomatic host. With this goal in mind, we constructed and annotated the immunoglobulin heavy chain locus, finding an expansion on immunoglobulin variable genes associated with protective human antibodies to different viruses. We also annotated two functional and distinct immunoglobulin epsilon genes and four distinctive functional immunoglobulin gamma genes. We described the Fc receptor repertoire in ERBs, including features that may affect activation potential, and discovered the lack of evolutionary conserved short pentraxins. These findings reinforce the hypothesis that a differential threshold of regulation and/or absence of key immune mediators may promote tolerance and decrease inflammation in ERBs.
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Affiliation(s)
- Peter A Larson
- Center for Genome Sciences, US Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA
| | - Maggie L Bartlett
- Center for Genome Sciences, US Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Karla Garcia
- Center for Genome Sciences, US Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Joseph Chitty
- Center for Genome Sciences, US Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA
| | | | - Jonathan Towner
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
| | - Jeffrey Kugelman
- Center for Genome Sciences, US Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA
| | - Gustavo Palacios
- Center for Genome Sciences, US Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA.
| | - Mariano Sanchez-Lockhart
- Center for Genome Sciences, US Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
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5
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Amiah MA, Ouattara A, Okou DT, N'Guetta SPA, Yavo W. Polymorphisms in Fc Gamma Receptors and Susceptibility to Malaria in an Endemic Population. Front Immunol 2020; 11:561142. [PMID: 33281811 PMCID: PMC7689034 DOI: 10.3389/fimmu.2020.561142] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 10/05/2020] [Indexed: 11/13/2022] Open
Abstract
Repeated infections by Plasmodium falciparum result in a humoral response that could reduce disease symptoms and prevent the development of clinical malaria. The principal mechanism underlying this humoral response is that immunoglobulin G (IgG) binds directly to the parasites, thus causing their neutralization. However, the action of antibodies alone is not always sufficient to eliminate pathogens from an organism. One key element involved in the recognition of IgG that plays a crucial role in the destruction of the parasites responsible for spreading malaria is the family of Fc gamma receptors. These receptors are expressed on the surface of immune cells. Several polymorphisms have been detected in the genes encoding these receptors, associated with susceptibility or resistance to malaria in different populations. In this review, we describe identified polymorphisms within the family of Fc gamma receptors and the impact of these variations on the response of a host to infection as well as provide new perspectives for the design of an effective vaccine for malaria.
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Affiliation(s)
- Mireille Ahou Amiah
- Malaria Research and Control Center, National Public Health Institute, Abidjan, Côte d'Ivoire.,Laboratory of Genetics, Unité de Formation et de Recherche (UFR) BIOSCIENCES, Félix Houphouët-Boigny University, Abidjan, Côte d'Ivoire
| | - Amed Ouattara
- Malaria Research and Training Center, University of Sciences, Techniques and Technologies, Bamako, Mali
| | - David Tea Okou
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
| | - Simon-Pierre Assanvo N'Guetta
- Laboratory of Genetics, Unité de Formation et de Recherche (UFR) BIOSCIENCES, Félix Houphouët-Boigny University, Abidjan, Côte d'Ivoire
| | - William Yavo
- Malaria Research and Control Center, National Public Health Institute, Abidjan, Côte d'Ivoire.,Department of Parasitology and Mycology, Faculty of Pharmacy, Félix Houphouët-Boigny University, Abidjan, Côte d'Ivoire
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6
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Quantifying the contribution of Fc-mediated effector functions to the antiviral activity of anti-HIV-1 IgG1 antibodies in vivo. Proc Natl Acad Sci U S A 2020; 117:18002-18009. [PMID: 32665438 PMCID: PMC7395461 DOI: 10.1073/pnas.2008190117] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Virus-neutralizing monoclonal antibodies have been tested for the treatment or prevention of HIV-1 infection. Such an antibody can block virus infectivity and mediate killing of virus-infected cells by Fc-mediated effector functions. The relative contributions of these two antibody activities in vivo have not been quantified previously. By quantitatively analyzing results from experiments conducted in HIV-1–infected humanized mice and SHIV-infected rhesus macaques, we have determined that Fc-mediated effector functions contribute about 25–45% to the total antiviral activity of the anti–HIV-1 monoclonal antibodies tested. In combating viral infections, the Fab portion of an antibody could mediate virus neutralization, whereas Fc engagement of Fc-γ receptors (FcγRs) could mediate an array of effector functions. Evidence abounds that effector functions are important in controlling infections by influenza, Ebola, or HIV-1 in animal models. However, the relative contribution of virus neutralization versus effector functions to the overall antiviral activity of an antibody remains unknown. To address this fundamental question in immunology, we utilized our knowledge of HIV-1 dynamics to compare the kinetics of the viral load decline (ΔVL) in infected animals given a wild-type (WT) anti–HIV-1 immunoglobulin G1 (IgG1) versus those given a Fc-Null variant of the same antibody. In three independent experiments in HIV-1–infected humanized mice and one pivotal experiment in simian–human immunodeficiency virus (SHIV)-infected rhesus macaques, an earlier and sharper decline in viral load was consistently detected for the WT antibody. Quantifications of the observed differences indicate that Fc-mediated effector functions accounted for 25–45% of the total antiviral activity in these separate experiments. In this study, Fc-mediated effector functions have been quantified in vivo relative to the contribution of virus neutralization mediated by the Fab.
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7
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R409K mutation prevents acid-induced aggregation of human IgG4. PLoS One 2020; 15:e0229027. [PMID: 32182240 PMCID: PMC7077836 DOI: 10.1371/journal.pone.0229027] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 01/28/2020] [Indexed: 11/20/2022] Open
Abstract
Human immunoglobulin G isotype 4 (IgG4) antibodies are suitable for use in either the antagonist or agonist format because their low effector functions prevent target cytotoxicity or unwanted cytokine secretion. However, while manufacturing therapeutic antibodies, they are exposed to low pH during purification, and IgG4 is more susceptible to low-pH-induced aggregation than IgG1. Therefore, we investigated the underlying mechanisms of IgG4 aggregation at low pH and engineered an IgG4 with enhanced stability. By swapping the constant regions of IgG1 and IgG4, we determined that the constant heavy chain (CH3) domain is critical for aggregate formation, but a core-hinge-stabilizing S228P mutation in IgG4 is insufficient for preventing aggregation. To identify the aggregation-prone amino acid, we substituted the CH3 domain of IgG4 with that of IgG1, changing IgG4 Arg409 to a Lys, thereby preventing the aggregation of the IgG4 variant as effectively as in IgG1. A stabilizing effect was also recorded with other variable-region variants. Analysis of thermal stability using differential scanning calorimetry revealed that the R409K substitution increased the Tm value of CH3, suggesting that the R409K mutation contributed to the structural strengthening of the CH3-CH3 interaction. The R409K mutation did not influence the binding to antigens/human Fcγ receptors; whereas, the concurrent S228P and R409K mutations in IgG4 suppressed Fab-arm exchange drastically and as effectively as in IgG1, in both in vitro and in vivo in mice models. Our findings suggest that the IgG4 R409K variant represents a potential therapeutic IgG for use in low-effector-activity format that exhibits increased stability.
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8
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Campbell MJ. Tales from topographic oceans: topologically associated domains and cancer. Endocr Relat Cancer 2019; 26:R611-R626. [PMID: 31505466 PMCID: PMC7664306 DOI: 10.1530/erc-19-0348] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 09/09/2019] [Indexed: 01/03/2023]
Abstract
The 3D organization of the genome within the cell nucleus has come into sharp focus over the last decade. This has largely arisen because of the application of genomic approaches that have revealed numerous levels of genomic and chromatin interactions, including topologically associated domains (TADs). The current review examines how these domains were identified, are organized, how their boundaries arise and are regulated, and how genes within TADs are coordinately regulated. There are many examples of the disruption to TAD structure in cancer and the altered regulation, structure and function of TADs are discussed in the context of hormone responsive cancers, including breast, prostate and ovarian cancer. Finally, some aspects of the statistical insight and computational skills required to interrogate TAD organization are considered and future directions discussed.
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Affiliation(s)
- Moray J Campbell
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA
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9
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Patel KR, Roberts JT, Barb AW. Multiple Variables at the Leukocyte Cell Surface Impact Fc γ Receptor-Dependent Mechanisms. Front Immunol 2019; 10:223. [PMID: 30837990 PMCID: PMC6382684 DOI: 10.3389/fimmu.2019.00223] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/25/2019] [Indexed: 12/18/2022] Open
Abstract
Fc γ receptors (FcγR) expressed on the surface of human leukocytes bind clusters of immunoglobulin G (IgG) to induce a variety of responses. Many therapeutic antibodies and vaccine-elicited antibodies prevent or treat infectious diseases, cancers and autoimmune disorders by binding FcγRs, thus there is a need to fully define the variables that impact antibody-induced mechanisms to properly evaluate candidate therapies and design new intervention strategies. A multitude of factors influence the IgG-FcγR interaction; one well-described factor is the differential affinity of the six distinct FcγRs for the four human IgG subclasses. However, there are several other recently described factors that may prove more relevant for disease treatment. This review covers recent reports of several aspects found at the leukocyte membrane or outside the cell that contribute to the cell-based response to antibody-coated targets. One major focus is recent reports covering post-translational modification of the FcγRs, including asparagine-linked glycosylation. This review also covers the organization of FcγRs at the cell surface, and properties of the immune complex. Recent technical advances provide high-resolution measurements of these often-overlooked variables in leukocyte function and immune system activation.
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Affiliation(s)
- Kashyap R Patel
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, United States
| | - Jacob T Roberts
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, United States
| | - Adam W Barb
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, United States
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10
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The Binding of Human IgG to Minipig FcγRs - Implications for Preclinical Assessment of Therapeutic Antibodies. Pharm Res 2019; 36:47. [PMID: 30721414 PMCID: PMC6373530 DOI: 10.1007/s11095-019-2574-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 01/16/2019] [Indexed: 12/26/2022]
Abstract
Purpose The Göttingen minipig is a relevant non-rodent species for regulatory toxicological studies. Yet, its use with therapeutic antibodies has been limited by the unknown binding properties of human immunoglobulins (huIgG) to porcine Fc gamma receptors (poFcγR) influencing safety and efficacy readouts. Therefore, knowing IgG-FcγR interactions in the animal model is a prerequisite for the use of minipigs in preclinical safety and efficacy studies with therapeutic antibodies. Methods Here, we describe the cloning and expression of poFcγRs and their interactions with free and complexed human therapeutic IgG1 by surface plasmon resonance and flow cytometry. Results We show here that poFcγRIa, poFcγRIIa, and poFcγRIIb bind huIgG1 antibodies with comparable affinities as corresponding huFcγRs. Importantly, poFcγRs bind huIgG immune complexes with high avidity, thus probably allowing human-like effector functions. However, poFcγRIIIa binds poIgG1a but not to huIgG1. Conclusions The lack of binding of poFcγRIIIa to huIgG1 might cause underestimation of FcγRIIIa-mediated efficacy or toxicity as mediated by porcine natural killer cells. Therefore, the suitability of minipigs in preclinical studies with human therapeutic antibodies has to be assessed case by case. Our results facilitate the use of Göttingen minipigs for assessment of human therapeutic antibodies in preclinical studies. Electronic supplementary material The online version of this article (10.1007/s11095-019-2574-y) contains supplementary material, which is available to authorized users.
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11
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Wines BD, Billings H, Mclean MR, Kent SJ, Hogarth PM. Antibody Functional Assays as Measures of Fc Receptor-Mediated Immunity to HIV - New Technologies and their Impact on the HIV Vaccine Field. Curr HIV Res 2018; 15:202-215. [PMID: 28322167 PMCID: PMC5543561 DOI: 10.2174/1570162x15666170320112247] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Revised: 02/20/2017] [Accepted: 03/09/2017] [Indexed: 12/23/2022]
Abstract
Background: There is now intense interest in the role of HIV-specific antibodies and the engagement of FcγR functions in the control and prevention of HIV infection. The analyses of the RV144 vaccine trial, natural progression cohorts, and macaque models all point to a role for Fc-dependent effector functions, such as cytotoxicity (ADCC) or phagocytosis (ADCP), in the control of HIV. However, reliable assays that can be reproducibly used across different laboratories to measure Fc-dependent functions, such as antibody dependent cellular cytotoxicity (ADCC) are limited. Method: This brief review highlights the importance of Fc properties for immunity to HIV, particular-ly via FcγR diversity and function. We discuss assays used to study FcR mediated functions of HIV-specific Ab, including our recently developed novel cell-free ELISA using homo-dimeric FcγR ecto-domains to detect functionally relevant viral antigen-specific antibodies. Results: The binding of these dimeric FcγR ectodomains, to closely spaced pairs of IgG Fc, mimics the engagement and cross-linking of Fc receptors by IgG opsonized virions or infected cells as the es-sential prerequisite to the induction of Ab-dependent effector functions. The dimeric FcγR ELISA reli-ably correlates with ADCC in patient responses to influenza. The assay is amenable to high throughput and could be standardized across laboratories. Conclusion: We propose the assay has broader implications for the evaluation of the quality of anti-body responses in viral infections and for the rapid evaluation of responses in vaccine development campaigns for HIV and other viral infections.
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Affiliation(s)
- Bruce D Wines
- Centre for Biomedical Research, Burnet Institute, Melbourne, Vic 3004, Australia.,Department of Immunology, Monash University Central Clinical School, Melbourne, Victoria 3004, Australia.,Department of Pathology, The University of Melbourne, Victoria, 3010, Australia
| | - Hugh Billings
- Centre for Biomedical Research, Burnet Institute, Melbourne, Vic 3004, Australia
| | - Milla R Mclean
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Parkville, Victoria, Australia
| | - Stephen J Kent
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Parkville, Victoria, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of Melbourne, Parkville, Victoria, Australia.,Melbourne Sexual Health Centre, Infectious Diseases Department, Alfred Health, Central Clinical School, Monash University, Victoria, Australia
| | - P Mark Hogarth
- Centre for Biomedical Research, Burnet Institute, Melbourne, Vic 3004, Australia.,Department of Immunology, Monash University Central Clinical School, Melbourne, Victoria 3004, Australia.,Department of Pathology, The University of Melbourne, Victoria, 3010, Australia
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12
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Ramanathan K, Glaser A, Lythgoe H, Ong J, Beresford MW, Midgley A, Wright HL. Neutrophil activation signature in juvenile idiopathic arthritis indicates the presence of low-density granulocytes. Rheumatology (Oxford) 2017; 57:488-498. [DOI: 10.1093/rheumatology/kex441] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Indexed: 11/13/2022] Open
Affiliation(s)
- Kavitha Ramanathan
- Department of Women’s and Children’s Health, Institute of Translational Medicine, University of Liverpool, Institute in the Park, Alder Hey Children’s NHS Foundation Trust Hospital, Eaton Road
| | - Anna Glaser
- Department of Women’s and Children’s Health, Institute of Translational Medicine, University of Liverpool, Institute in the Park, Alder Hey Children’s NHS Foundation Trust Hospital, Eaton Road
| | - Hanna Lythgoe
- Department of Women’s and Children’s Health, Institute of Translational Medicine, University of Liverpool, Institute in the Park, Alder Hey Children’s NHS Foundation Trust Hospital, Eaton Road
- Department of Paediatric Rheumatology, Alder Hey Children’s NHS Foundation Trust
| | - Joanne Ong
- Department of Women’s and Children’s Health, Institute of Translational Medicine, University of Liverpool, Institute in the Park, Alder Hey Children’s NHS Foundation Trust Hospital, Eaton Road
| | - Michael W Beresford
- Department of Women’s and Children’s Health, Institute of Translational Medicine, University of Liverpool, Institute in the Park, Alder Hey Children’s NHS Foundation Trust Hospital, Eaton Road
- Department of Paediatric Rheumatology, Alder Hey Children’s NHS Foundation Trust
| | - Angela Midgley
- Department of Women’s and Children’s Health, Institute of Translational Medicine, University of Liverpool, Institute in the Park, Alder Hey Children’s NHS Foundation Trust Hospital, Eaton Road
| | - Helen L Wright
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, William Henry Duncan Building, Liverpool, UK
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13
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Affiliation(s)
- P Mark Hogarth
- Centre for Biomedicine, Burnet Institute, Melbourne, Vic., Australia.,Department of Immunology, Monash University, Melbourne, Vic., Australia.,Department of Pathology, University of Melbourne, Melbourne, Vic., Australia
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14
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Pharmacology of the retinal pigment epithelium, the interface between retina and body system. Eur J Pharmacol 2016; 787:84-93. [PMID: 27044435 DOI: 10.1016/j.ejphar.2016.03.066] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 03/14/2016] [Accepted: 03/31/2016] [Indexed: 12/12/2022]
Abstract
The retinal pigment epithelium (RPE) is a close, interactive partner to the photoreceptors as well as an interface with the endothelium of the choroid and thus with the body's circulatory system. To fulfill these roles, the RPE communicates with neighboring tissue by secretion of a large variety of factors and is able to react to secreted factors via a plethora of transmembrane receptors. Clinically relevant local pharmacological effects are caused by anti-VEGF-A treatment in choroidal neovascularization or by carboanhydrase inhibitors reducing fluid accumulation in the macula. Being exposed to the bloodstream, the RPE reacts to systemic disease, such as diabetes or hypertension, but also to systemic pharmacological intervention, for example to hypotensive drugs acting on the renin-angiotensin-system. Sustained pharmacological treatments, in particular, cause side effects at the RPE with consequences for both RPE function and photoreceptor survival. Among these are systemic inhibition of angiotensin-converting enzyme, insulin treatment in diabetes and anti-VEGF-A therapy. Given the special anatomical and functional relationships of the RPE, pharmacological intervention targeting either the eye or the body systemically should take potential alteration of RPE and subsequently photoreceptor function into account.
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