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Kang TH, Lee CH, Delidakis G, Jung J, Richard-Le Goff O, Lee J, Kim JE, Charab W, Bruhns P, Georgiou G. An Engineered Human Fc variant With Exquisite Selectivity for FcγRIIIa V158 Reveals That Ligation of FcγRIIIa Mediates Potent Antibody Dependent Cellular Phagocytosis With GM-CSF-Differentiated Macrophages. Front Immunol 2019; 10:562. [PMID: 30984171 PMCID: PMC6448688 DOI: 10.3389/fimmu.2019.00562] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 03/04/2019] [Indexed: 01/27/2023] Open
Abstract
IgG antibodies mediate the clearance of target cells via the engagement of Fc gamma receptors (FcγRs) on effector cells by eliciting antibody-dependent cellular cytotoxicity and phagocytosis (ADCC and ADCP, respectively). Because (i) the IgG Fc domain binds to multiple FcγRs with varying affinities; (ii) even low Fc:FcγRs affinity interactions can play a significant role when antibodies are engaged in high avidity immune complexes and (iii) most effector cells express multiple FcγRs, the clearance mechanisms that can be mediated by individual FcγR are not well-understood. Human FcγRIIIa (hFcγRIIIa; CD16a), which exists as two polymorphic variants at position 158, hFcγRIIIaV158 and hFcγRIIIaF158, is widely considered to only trigger ADCC, especially with natural killer (NK) cells as effectors. To evaluate the role of hFcγRIIIa ligation in myeloid-derived effector cells, and in particular on macrophages and monocytes which express multiple FcγRs, we engineered an aglycosylated engineered human Fc (hFc) variant, Fc3aV, which binds exclusively to hFcγRIIIaV158. Antibodies formatted with the Fc3aV variant bind to the hFcγRIIIaV158 allotype with a somewhat lower KD than their wild type IgG1 counterparts, but not to any other hFcγR. The exceptional selectivity for hFcγRIIIaV158 was demonstrated by SPR using increased avidity, dimerized GST-fused versions of the ectodomains of hFcγRs and from the absence of binding of large immune complex (IC) to CHO cells expressing each of the hFcγRs, including notably, the FcγRIIIaF158 variant or the highly homologous FcγRIIIb. We show that even though monocyte-derived GM-CSF differentiated macrophages express hFcγRIIIa at substantially lower levels than the other two major activating receptors, namely hFcγRI or hFcγRIIa, Fc3aV-formatted Rituximab and Herceptin perform ADCP toward CD20- and Her2-expressing cancer cells, respectively, at a level comparable to that of the respective wild-type antibodies. We further show that hFcγRIIIa activation plays a significant role on ADCC by human peripheral monocytes. Our data highlight the utility of Fc3aV and other similarly engineered exquisitely selective, aglycosylated Fc variants toward other hFcγRs as tools for the detailed molecular understanding of hFcγR biology.
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Affiliation(s)
- Tae Hyun Kang
- Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Chang-Han Lee
- Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - George Delidakis
- Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Jiwon Jung
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Odile Richard-Le Goff
- Unit of Antibodies in Therapy and Pathology, Department of Immunology, Institut Pasteur, Paris, France
| | - Jiwon Lee
- Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Jin Eyun Kim
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Wissam Charab
- Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States
| | - Pierre Bruhns
- Unit of Antibodies in Therapy and Pathology, Department of Immunology, Institut Pasteur, Paris, France.,INSERM, U1222, Paris, France
| | - George Georgiou
- Department of Chemical Engineering, University of Texas at Austin, Austin, TX, United States.,Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, United States.,Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX, United States.,Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, United States
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52
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van Erp EA, Luytjes W, Ferwerda G, van Kasteren PB. Fc-Mediated Antibody Effector Functions During Respiratory Syncytial Virus Infection and Disease. Front Immunol 2019; 10:548. [PMID: 30967872 PMCID: PMC6438959 DOI: 10.3389/fimmu.2019.00548] [Citation(s) in RCA: 162] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 02/28/2019] [Indexed: 12/20/2022] Open
Abstract
Respiratory syncytial virus (RSV) is a major cause of severe lower respiratory tract infections and hospitalization in infants under 1 year of age and there is currently no market-approved vaccine available. For protection against infection, young children mainly depend on their innate immune system and maternal antibodies. Traditionally, antibody-mediated protection against viral infections is thought to be mediated by direct binding of antibodies to viral particles, resulting in virus neutralization. However, in the case of RSV, virus neutralization titers do not provide an adequate correlate of protection. The current lack of understanding of the mechanisms by which antibodies can protect against RSV infection and disease or, alternatively, contribute to disease severity, hampers the design of safe and effective vaccines against this virus. Importantly, neutralization is only one of many mechanisms by which antibodies can interfere with viral infection. Antibodies consist of two structural regions: a variable fragment (Fab) that mediates antigen binding and a constant fragment (Fc) that mediates downstream effector functions via its interaction with Fc-receptors on (innate) immune cells or with C1q, the recognition molecule of the complement system. The interaction with Fc-receptors can lead to killing of virus-infected cells through a variety of immune effector mechanisms, including antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP). Antibody-mediated complement activation may lead to complement-dependent cytotoxicity (CDC). In addition, both Fc-receptor interactions and complement activation can exert a broad range of immunomodulatory functions. Recent studies have emphasized the importance of Fc-mediated antibody effector functions in both protection and pathogenesis for various infectious agents. In this review article, we aim to provide a comprehensive overview of the current knowledge on Fc-mediated antibody effector functions in the context of RSV infection, discuss their potential role in establishing the balance between protection and pathogenesis, and point out important gaps in our understanding of these processes. Furthermore, we elaborate on the regulation of these effector functions on both the cellular and humoral side. Finally, we discuss the implications of Fc-mediated antibody effector functions for the rational design of safe and effective vaccines and monoclonal antibody therapies against RSV.
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Affiliation(s)
- Elisabeth A van Erp
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands.,Section Pediatric Infectious Diseases, Laboratory of Medical Immunology, Radboud Institute for Molecular Life Sciences, Nijmegen, Netherlands.,Radboud Center for Infectious Diseases, Nijmegen, Netherlands
| | - Willem Luytjes
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
| | - Gerben Ferwerda
- Section Pediatric Infectious Diseases, Laboratory of Medical Immunology, Radboud Institute for Molecular Life Sciences, Nijmegen, Netherlands.,Radboud Center for Infectious Diseases, Nijmegen, Netherlands
| | - Puck B van Kasteren
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
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53
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Abstract
Engineering the fragment crystallizable (Fc) of human IgG can bring improved effector functions to monoclonal antibodies and Fc-fusion-based medicines and vaccines. Such Fc-effector functions are largely controlled by posttranslational modifications (PTMs) within the Fc, including the addition of glycans that introduce structural and functional heterogeneity to this class of therapeutic. Here, we describe a detailed method to allow the detection of hyper-sialylated Fcs to glycan receptors that will facilitate the future development of new mAbs and Fc-fragment therapies and vaccines.
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54
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Campbell KS, Cohen AD, Pazina T. Mechanisms of NK Cell Activation and Clinical Activity of the Therapeutic SLAMF7 Antibody, Elotuzumab in Multiple Myeloma. Front Immunol 2018; 9:2551. [PMID: 30455698 PMCID: PMC6230619 DOI: 10.3389/fimmu.2018.02551] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/17/2018] [Indexed: 12/28/2022] Open
Abstract
Multiple myeloma (MM) is a bone marrow plasma cell neoplasm and is the second most-common hematologic malignancy. Despite advances in therapy, MM remains largely incurable. Elotuzumab is a humanized IgG1 monoclonal antibody targeting SLAMF7, which is highly expressed on myeloma cells, and the antibody is approved for the treatment of relapsed and/or refractory (RR) MM in combination with lenalidomide and dexamethasone. Elotuzumab can stimulate robust antibody-dependent cellular cytotoxicity (ADCC) through engaging with FcγRIIIA (CD16) on NK cells and antibody-dependent cellular phagocytosis (ADCP) by macrophages. Interestingly, SLAMF7 is also expressed on cytolytic NK cells, which also express the requisite adaptor protein, EAT-2, to mediate activation signaling. Accumulating evidence indicates that antibody crosslinking of SLAMF7 on human and mouse NK cells can stimulate EAT-2-dependent activation of PLCγ, ERK, and intracellular calcium mobilization. The binding of SLAMF7 by elotuzumab can directly induce signal transduction in human NK cells, including co-stimulation of the calcium signaling triggered through other surface receptors, such as NKp46 and NKG2D. In RRMM patients, elotuzumab monotherapy did not produce objective responses, but did enhance the activity of approved standard of care therapies, including lenalidomide or bortezomib, which are known to enhance anti-tumor responses by NK cells. Taken together, these preclinical results and accumulating experience in the clinic provide compelling evidence that the mechanism of action of elotuzumab in MM patients involves the activation of NK cells through both CD16-mediated ADCC and direct co-stimulation via engagement with SLAMF7, as well as promoting ADCP by macrophages. We review the current understanding of how elotuzumab utilizes multiple mechanisms to facilitate immune-mediated attack of myeloma cells, as well as outline goals for future research.
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Affiliation(s)
- Kerry S Campbell
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, PA, United States
| | - Adam D Cohen
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA, United States
| | - Tatiana Pazina
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, PA, United States.,FSBSI "Institute of Experimental Medicine", St. Petersburg, Russia
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55
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Turner RR, Mitchell CPJ, Kopec AD, Bodaly RA. Tidal fluxes of mercury and methylmercury for Mendall Marsh, Penobscot River estuary, Maine. Sci Total Environ 2018; 637-638:145-154. [PMID: 29751297 DOI: 10.1016/j.scitotenv.2018.04.395] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 04/27/2018] [Accepted: 04/29/2018] [Indexed: 05/28/2023]
Abstract
Tidal marshes are both important sites of in situ methylmercury production and can be landscape sources of methylmercury to adjacent estuarine systems. As part of a regional investigation of the Hg-contaminated Penobscot River and Bay system, the tidal fluxes of total suspended solids, total mercury and methylmercury into and out of a regionally important mesohaline fluvial marsh complex, Mendall Marsh, were intensively measured over several tidal cycles and at two spatial scales to assess the source-sink function of the marsh with respect to the Penobscot River. Over four tidal cycles on the South Marsh River, the main channel through which water enters and exits Mendall Marsh, the marsh was a consistent sink over typical 12-h tidal cycles for total suspended solids (8.2 to 41 g m-2), total Hg (9.2 to 47 μg m-2), total filter-passing Hg (0.4 to 1.1 μg m-2), and total methylmercury (0.2 to 1.4 μg m-2). The marsh's source-sink function was variable for filter-passing methylmercury, acting as a net source during a large spring tide that inundated much of the marsh area and that is likely to occur during approximately 17% of tidal cycles. Additional measurements on a small tidal channel draining approximately 1% of the larger marsh area supported findings at the larger scale, but differences in the flux magnitude of filter-passing fractions suggest a highly non-conservative transport of these fractions through the tidal channels. Overall the results of this investigation demonstrate that Mendall Marsh is not a significant source of mercury or methylmercury to the receiving aquatic systems (Penobscot River and Bay). While there is evidence of a small net export of filter-passing (<0.4 μm pore size) methylmercury under some tidal conditions, the mass involved represents <3% of the mass of filter-passing methylmercury carried by the Penobscot River.
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Affiliation(s)
- R R Turner
- RT Geosciences Inc, 3398 Kingburne Dr., Cobble Hill, B.C. V0R 1L5, Canada.
| | - C P J Mitchell
- Department of Physical & Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada.
| | - A D Kopec
- Penobscot River Mercury Study, 479 Beechwood Ave., Old Town, ME 04468, USA.
| | - R A Bodaly
- Penobscot River Mercury Study, 115 Oystercatcher Place, Salt Spring Island, B.C. V8K 2W5, Canada
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56
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Abstract
INTRODUCTION Antibodies directed against influenza virus execute their protective function by exploiting a variety of effector mechanisms. Neutralizing antibodies have been thoroughly studied because of their pivotal role in preventing influenza virus infection and their presence in host serum is correlated with protection. Influenza antibodies can also exploit non-neutralizing effector mechanisms, which until recently have been largely overlooked. AREAS COVERED Here, we discuss the antibody response to influenza virus in its entire breadth. Neutralizing antibodies mostly target variable epitopes on influenza surface proteins and interfere with virus binding, fusion, or egress. Non-neutralizing antibodies instead usually target conserved epitopes which can be located on surface as well as internal proteins. They drive viral clearance via interaction of their Fc region with components of the innate immune system such as immune effector cells (e.g. NK cells, macrophages) or the complement system. EXPERT COMMENTARY Recent research has unraveled that influenza-specific antibodies target multiple proteins and make use of diverse effector mechanisms. Often these antibodies are cross-reactive among virus strains of the same subtype or even between subtypes. As such they are induced early in life and are boosted by regular encounters with virus or vaccine. Designing strategies to optimally exploit these pre-existing antibodies may represent the key for the development of new broadly protective influenza vaccines.
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Affiliation(s)
- Federica Sicca
- a Department of Medical Microbiology , University of Groningen, University Medical Center Groningen , Groningen , The Netherlands
| | - Sam Neppelenbroek
- a Department of Medical Microbiology , University of Groningen, University Medical Center Groningen , Groningen , The Netherlands
| | - Anke Huckriede
- a Department of Medical Microbiology , University of Groningen, University Medical Center Groningen , Groningen , The Netherlands
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57
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Alrubayyi A, Schuetz A, Lal KG, Jongrakthaitae S, Paolino KM, Ake JA, Robb ML, de Souza MS, Michael NL, Paquin-Proulx D, Eller MA. A flow cytometry based assay that simultaneously measures cytotoxicity and monocyte mediated antibody dependent effector activity. J Immunol Methods 2018; 462:74-82. [PMID: 30148978 DOI: 10.1016/j.jim.2018.08.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 08/23/2018] [Accepted: 08/23/2018] [Indexed: 12/14/2022]
Abstract
Antibody effector functions such as antibody dependent cellular cytotoxicity (ADCC) and antibody dependent cellular phagocytosis (ADCP) are considered important immunologic parameters following results from the RV144 clinical trial where a reduced risk of infection was associated with non-neutralizing antibody against the V1/V2 region of HIV envelope. The rapid and fluorometric ADCC (RFADCC) assay has been widely used to measure ADCC, however, the mechanism behind the activity measured remains unclear. Here, we demonstrate that monocytes acquire the PKH26 dye used in the RFADCC assay and that the commonly used RFADCC readout correlates with phagocytosis. The RFADCC assay was combined with an amine reactive dye staining to confirm target cell killing. Interestingly, the majority of RFADCC and amine indices were mutually exclusive. In fact, the amine reactive assay results correlated with results from another assays that directly measure NK cell antibody effector functions not associated with phagocytosis. Together, this combined assay offers the opportunity to discriminate monocytes and NK cell antibody effector functions simultaneously.
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Affiliation(s)
- Aljawharah Alrubayyi
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, USA
| | - Alexandra Schuetz
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, USA; Department of Retrovirology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Kerri G Lal
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, USA
| | - Surat Jongrakthaitae
- Department of Retrovirology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Kristopher M Paolino
- Clinical Trials Center, Translational Medicine Branch, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Julie A Ake
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Merlin L Robb
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, USA
| | - Mark S de Souza
- SEARCH, Thai Red Cross AIDS Research Center, Bangkok, Thailand
| | - Nelson L Michael
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Dominic Paquin-Proulx
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, USA.
| | - Michael A Eller
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, USA
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58
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Salazar N, Carlson JC, Huang K, Zheng Y, Oderup C, Gross J, Jang AD, Burke TM, Lewén S, Scholz A, Huang S, Nease L, Kosek J, Mittelbronn M, Butcher EC, Tu H, Zabel BA. A Chimeric Antibody against ACKR3/CXCR7 in Combination with TMZ Activates Immune Responses and Extends Survival in Mouse GBM Models. Mol Ther 2018; 26:1354-1365. [PMID: 29606504 PMCID: PMC5993942 DOI: 10.1016/j.ymthe.2018.02.030] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 02/21/2018] [Accepted: 02/27/2018] [Indexed: 01/08/2023] Open
Abstract
Glioblastoma (GBM) is the least treatable type of brain tumor, afflicting over 15,000 people per year in the United States. Patients have a median survival of 16 months, and over 95% die within 5 years. The chemokine receptor ACKR3 is selectively expressed on both GBM cells and tumor-associated blood vessels. High tumor expression of ACKR3 correlates with poor prognosis and potential treatment resistance, making it an attractive therapeutic target. We engineered a single chain FV-human FC-immunoglobulin G1 (IgG1) antibody, X7Ab, to target ACKR3 in human and mouse GBM cells. We used hydrodynamic gene transfer to overexpress the antibody, with efficacy in vivo. X7Ab kills GBM tumor cells and ACKR3-expressing vascular endothelial cells by engaging the cytotoxic activity of natural killer (NK) cells and complement and the phagocytic activity of macrophages. Combining X7Ab with TMZ allows the TMZ dosage to be lowered, without compromising therapeutic efficacy. Mice treated with X7Ab and in combination with TMZ showed significant tumor reduction by MRI and longer survival overall. Brain-tumor-infiltrating leukocyte analysis revealed that X7Ab enhances the activation of M1 macrophages to support anti-tumor immune response in vivo. Targeting ACKR3 with immunotherapeutic monoclonal antibodies (mAbs) in combination with standard of care therapies may prove effective in treating GBM.
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Affiliation(s)
- Nicole Salazar
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA; Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA, USA
| | - Jeffrey C Carlson
- Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA, USA
| | | | - Yayue Zheng
- Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA, USA
| | - Cecilia Oderup
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA; Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA, USA
| | - Julia Gross
- Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA, USA
| | - Andrew D Jang
- Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA, USA
| | - Thomas M Burke
- Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA, USA
| | - Susanna Lewén
- Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA, USA
| | - Alexander Scholz
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA; Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA, USA
| | - Serina Huang
- Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA, USA
| | - Leona Nease
- Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA, USA
| | - Jon Kosek
- Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA, USA
| | - Michel Mittelbronn
- Institute of Neurology, Edinger Institute, Frankfurt, Germany; Luxembourg Centre of Neuropathology (LCNP), Luxembourg City, Luxembourg; Department of Pathology, Laboratoire National de Santé, Dudelange, Luxembourg; Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Esch-sur-Alzette, Luxembourg; NORLUX Neuro-Oncology Laboratory, Department of Oncology, Luxembourg Institute of Health, Luxembourg City, Luxembourg
| | - Eugene C Butcher
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA; Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA, USA
| | - Hua Tu
- LakePharma Inc., Belmont, CA, USA
| | - Brian A Zabel
- Palo Alto Veterans Institute for Research (PAVIR), Veterans Affairs Palo Alto Health Care System (VAPAHCS), Palo Alto, CA, USA.
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60
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Abstract
Immunostimulatory antibodies against the tumor necrosis factor receptors (TNFR) are emerging as promising cancer immunotherapies. The agonism activity of such antibodies depends on crosslinking to Fc gamma RIIB receptor (FcγRIIB) to enable the antibody multimerization that drives TNFR activation. Previously, Fc engineering was used to enhance the binding of such antibodies to Fcγ receptors. Here, we report the identification of Centyrins as alternative scaffold proteins with binding affinities to homologous FcγRIIB and FcγRIIA, but not to other types of Fcγ receptors. One Centyrin, S29, was engineered at distinct positions of an anti-OX40 SF2 antibody to generate bispecific and tetravalent molecules named as mAbtyrins. Regardless of the position of S29 on the SF2 antibody, SF2-S29 mAbtyrins could bind FcγRIIB and FcγRIIA specifically while maintaining binding to OX40 receptors. In a NFκB reporter assay, attachment of S29 Centyrin molecules at the C-termini, but not the N-termini, resulted in SF2 antibodies with increased agonism owing to FcγRIIB crosslinking. The mAbtyrins also showed agonism in T-cell activation assays with immobilized FcγRIIB and FcγRIIA, but this activity was confined to mAbtyrins with S29 specifically at the C-termini of antibody heavy chains. Furthermore, regardless of the position of the molecule, S29 Centyrin could equip an otherwise Fc-silent antibody with antibody-dependent cellular phagocytosis activity without affecting the antibody's intrinsic antibody-dependent cell-meditated cytotoxicity and complement-dependent cytotoxicity. In summary, the appropriate adoption FcγRII-binding Centyrins as functional modules represents a novel strategy to engineer therapeutic antibodies with improved functionalities.
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Affiliation(s)
- Di Zhang
- a Department of Biologics Research , Janssen R&D, LLC, Spring House , PA , USA
| | - Brian Whitaker
- a Department of Biologics Research , Janssen R&D, LLC, Spring House , PA , USA
| | - Mehabaw G Derebe
- a Department of Biologics Research , Janssen R&D, LLC, Spring House , PA , USA
| | - Mark L Chiu
- a Department of Biologics Research , Janssen R&D, LLC, Spring House , PA , USA
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Cymer F, Thomann M, Wegele H, Avenal C, Schlothauer T, Gygax D, Beck H. Oxidation of M252 but not M428 in hu-IgG1 is responsible for decreased binding to and activation of hu-FcγRIIa (His131). Biologicals 2017; 50:125-128. [PMID: 28988621 DOI: 10.1016/j.biologicals.2017.09.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 09/26/2017] [Accepted: 09/30/2017] [Indexed: 11/27/2022] Open
Abstract
Oxidation of monoclonal therapeutic antibodies (mAbs) can affect binding to Fc-receptors and potentially influence pharmacokinetics or effector functions like e.g. antibody dependent cellular phagocytosis (ADCP). Recently, it has been demonstrated that binding to FcγRIIa (H131) is affected by methionine oxidation of the Fc-portion but it is currently unknown which methionine is responsible for decreased binding. We separated an oxidized IgG1 monoclonal antibody based on the oxidation state of methionine 252 and analyzed fractionated material in receptor binding experiments as well as in functional (cell-based) assays. Although the unfractionated mixture demonstrated weaker interaction/activation of the receptor, differently oxidized isolated subspecies can lead both to stronger as well as weaker binding and activation of the histidine variant of FcγRIIa.
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Affiliation(s)
- Florian Cymer
- Pharma Technical Development Analytics Biologics, F. Hoffmann-La Roche Ltd., 4070 Basel, Switzerland.
| | - Marco Thomann
- Pharma Technical Development Analytics Biologics, Roche Diagnostics GmbH, Penzberg, Germany
| | - Harald Wegele
- Pharma Technical Development Analytics Biologics, Roche Diagnostics GmbH, Penzberg, Germany
| | - Cecile Avenal
- Pharma Technical Development Analytics Biologics, F. Hoffmann-La Roche Ltd., 4070 Basel, Switzerland
| | - Tilman Schlothauer
- Biochemical and Analytical Research, Large Molecule Research, Roche Pharma Research and Early Development (pRED), Roche Innovation Center, 82377 Penzberg, Germany
| | - Daniel Gygax
- School of Life Sciences, University of Applied Sciences and Arts Northwestern Switzerland, Gründenstrasse 40, 4132 Muttenz, Switzerland
| | - Hermann Beck
- Pharma Technical Development Analytics Biologics, F. Hoffmann-La Roche Ltd., 4070 Basel, Switzerland
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Weiss ER, Alter G, Ogembo JG, Henderson JL, Tabak B, Bakiş Y, Somasundaran M, Garber M, Selin L, Luzuriaga K. High Epstein-Barr Virus Load and Genomic Diversity Are Associated with Generation of gp350-Specific Neutralizing Antibodies following Acute Infectious Mononucleosis. J Virol 2017; 91:e01562-16. [PMID: 27733645 DOI: 10.1128/JVI.01562-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 09/29/2016] [Indexed: 01/02/2023] Open
Abstract
The Epstein-Barr virus (EBV) gp350 glycoprotein interacts with the cellular receptor to mediate viral entry and is thought to be the major target for neutralizing antibodies. To better understand the role of EBV-specific antibodies in the control of viral replication and the evolution of sequence diversity, we measured EBV gp350-specific antibody responses and sequenced the gp350 gene in samples obtained from individuals experiencing primary EBV infection (acute infectious mononucleosis [AIM]) and again 6 months later (during convalescence [CONV]). EBV gp350-specific IgG was detected in the sera of 17 (71%) of 24 individuals at the time of AIM and all 24 (100%) individuals during CONV; binding antibody titers increased from AIM through CONV, reaching levels equivalent to those in age-matched, chronically infected individuals. Antibody-dependent cell-mediated phagocytosis (ADCP) was rarely detected during AIM (4 of 24 individuals; 17%) but was commonly detected during CONV (19 of 24 individuals; 79%). The majority (83%) of samples taken during AIM neutralized infection of primary B cells; all samples obtained at 6 months postdiagnosis neutralized EBV infection of cultured and primary target cells. Deep sequencing revealed interpatient gp350 sequence variation but conservation of the CR2-binding site. The levels of gp350-specific neutralizing activity directly correlated with higher peripheral blood EBV DNA levels during AIM and a greater evolution of diversity in gp350 nucleotide sequences from AIM to CONV. In summary, we conclude that the viral load and EBV gp350 diversity during early infection are associated with the development of neutralizing antibody responses following AIM. IMPORTANCE Antibodies against viral surface proteins can blunt the spread of viral infection by coating viral particles, mediating uptake by immune cells, or blocking interaction with host cell receptors, making them a desirable component of a sterilizing vaccine. The EBV surface protein gp350 is a major target for antibodies. We report the detection of EBV gp350-specific antibodies capable of neutralizing EBV infection in vitro The majority of gp350-directed vaccines focus on glycoproteins from lab-adapted strains, which may poorly reflect primary viral envelope diversity. We report some of the first primary gp350 sequences, noting that the gp350 host receptor binding site is remarkably stable across patients and time. However, changes in overall gene diversity were detectable during infection. Patients with higher peripheral blood viral loads in primary infection and greater changes in viral diversity generated more efficient antibodies. Our findings provide insight into the generation of functional antibodies, necessary for vaccine development.
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Saxena A, Wu D. Advances in Therapeutic Fc Engineering - Modulation of IgG-Associated Effector Functions and Serum Half-life. Front Immunol 2016; 7:580. [PMID: 28018347 PMCID: PMC5149539 DOI: 10.3389/fimmu.2016.00580] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 11/24/2016] [Indexed: 12/20/2022] Open
Abstract
Today, monoclonal immunoglobulin gamma (IgG) antibodies have become a major option in cancer therapy especially for the patients with advanced or metastatic cancers. Efficacy of monoclonal antibodies (mAbs) is achieved through both its antigen-binding fragment (Fab) and crystallizable fragment (Fc). Fab can specifically recognize tumor-associated antigen (TAA) and thus modulate TAA-linked downstream signaling pathways that may lead to the inhibition of tumor growth, induction of tumor apoptosis, and differentiation. The Fc region can further improve mAbs’ efficacy by mediating effector functions such as antibody-dependent cellular cytotoxicity, complement-dependent cytotoxicity, and antibody-dependent cell-mediated phagocytosis. Moreover, Fc is the region interacting with the neonatal Fc receptor in a pH-dependent manner that can slow down IgG’s degradation and extend its serum half-life. Loss of the antibody Fc region dramatically shortens its serum half-life and weakens its anticancer effects. Given the essential roles that the Fc region plays in the modulation of the efficacy of mAb in cancer treatment, Fc engineering has been extensively studied in the past years. This review focuses on the recent advances in therapeutic Fc engineering that modulates its related effector functions and serum half-life. We also discuss the progress made in aglycosylated mAb development that may substantially reduce the cost of manufacture but maintain similar efficacies as conventional glycosylated mAb. Finally, we highlight several Fc engineering-based mAbs under clinical trials.
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Affiliation(s)
- Abhishek Saxena
- Laboratory of Antibody Engineering, Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University , Shanghai , China
| | - Donghui Wu
- Laboratory of Antibody Engineering, Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University , Shanghai , China
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Abstract
Macrophages are innate immune cells that derive from circulating monocytes, reside in all tissues, and participate in many states of pathology. Macrophages play a dichotomous role in cancer, where they promote tumor growth but also serve as critical immune effectors of therapeutic antibodies. Macrophages express all classes of Fcγ receptors, and they have immense potential to destroy tumors via the process of antibody-dependent phagocytosis. A number of studies have demonstrated that macrophage phagocytosis is a major mechanism of action of many antibodies approved to treat cancer. Consequently, a number of approaches to augment macrophage responses to therapeutic antibodies are under investigation, including the exploration of new targets and development of antibodies with enhanced functions. For example, the interaction of CD47 with signal-regulatory protein α (SIRPα) serves as a myeloid-specific immune checkpoint that limits the response of macrophages to antibody therapies, and CD47-blocking agents overcome this barrier to augment phagocytosis. The response of macrophages to antibody therapies can also be enhanced with engineered Fc variants, bispecific antibodies, or antibody-drug conjugates. Macrophages have demonstrated success as effectors of cancer immunotherapy, and further investigation will unlock their full potential for the benefit of patients.
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Key Words
- ADC, antibody-drug conjugate
- ADCC, antibody-dependent cell-mediated cytotoxicity
- ADCP
- ADCP, antibody-dependent cellular phagocytosis
- AML, acute myelogenous leukemia
- BTK, Bruton's tyrosine kinase
- CD, cluster of differentiation
- CD47
- CLL, chronic lymphocytic leukemia
- EGFR, epidermal growth factor receptor
- Fc receptor
- Fc, fragment crystallizable
- FcγR, Fcγ receptors
- GM-CSF, granulocyte-macrophage colony stimulating factor
- HER2, human epidermal growth factor receptor 2
- HSC, haematopoietic stem cell
- ITAM, immunoreceptor tyrosine-based activation motif
- ITIM, immunoreceptor tyrosine-based inhibitory motif
- IgG, immunoglobulin G
- M-CSF, macrophage colony stimulating factor
- NK, natural killer
- SHP, Src homology 2 domain-containing phosphatase
- SIRPα
- SIRPα, signal-regulatory protein α
- antibodies
- cancer
- immune checkpoint
- immunotherapy
- macrophages
- phagocytosis
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Affiliation(s)
- Kipp Weiskopf
- a Institute for Stem Cell Biology and Regenerative Medicine ; Stanford University School of Medicine ; Stanford , CA USA
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Duong MN, Matera EL, Mathé D, Evesque A, Valsesia-Wittmann S, Clémenceau B, Dumontet C. Effect of kinase inhibitors on the therapeutic properties of monoclonal antibodies. MAbs 2015; 7:192-8. [PMID: 25523586 DOI: 10.4161/19420862.2015.989020] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Targeted therapies of malignancies currently consist of therapeutic monoclonal antibodies and small molecule kinase inhibitors. The combination of these novel agents raises the issue of potential antagonisms. We evaluated the potential effect of 4 kinase inhibitors, including the Bruton tyrosine kinase inhibitor ibrutinib, and 3 PI3K inhibitors idelalisib, NVP-BEZ235 and LY294002, on the effects of the 3 monoclonal antibodies, rituximab and obinutuzumab (directed against CD20) and trastuzumab (directed against HER2). We found that ibrutinib potently inhibits antibody-dependent cell-mediated cytotoxicity exerted by all antibodies, with a 50% inhibitory concentration of 0.2 microM for trastuzumab, 0.5 microM for rituximab and 2 microM for obinutuzumab, suggesting a lesser effect in combination with obinutuzumab than with rituximab. The 4 kinase inhibitors were found to inhibit phagocytosis by fresh human neutrophils, as well as antibody-dependent cellular phagocytosis induced by the 3 antibodies. Conversely co-administration of ibrutinib with rituximab, obinutuzumab or trastuzumab did not demonstrate any inhibitory effect of ibrutinib in vivo in murine xenograft models. In conclusion, some kinase inhibitors, in particular, ibrutinib, are likely to exert inhibitory effects on innate immune cells. However, these effects do not compromise the antitumor activity of monoclonal antibodies in vivo in the models that were evaluated.
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Affiliation(s)
- Minh Ngoc Duong
- a Centre de Recherche en Cancérologie de Lyon (CRCL); INSERM UMR 1052/CNRS 5286 ; Lyon , France
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Abstract
The capacity of immunoglobulin G (IgG) antibodies to eliminate virtually any target cell has resulted in the widespread introduction of cytotoxic antibodies into the clinic in settings of cancer therapy, autoimmunity, and transplantation, for example. More recently, it has become apparent that also the protection from viral infection via IgG antibodies may require cytotoxic effector functions, suggesting that antibody-dependent cellular cytotoxicity (ADCC) directed against malignant or virally infected cells is one of the most essential effector mechanisms triggered by IgG antibodies to protect the host. A detailed understanding of the underlying molecular and cellular pathways is critical, therefore, to make full use of this antibody effector function. Several studies over the last years have provided novel insights into the effector pathways and innate immune effector cells responsible for ADCC reactions. One of the most notable outcomes of many of these reports is that cells of the mononuclear phagocytic system rather than natural killer cells are critical for removal of IgG opsonized target cells in vivo.
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Berge J, Cottier F, Varpe Ø, Renaud PE, Falk-Petersen S, Kwasniewski S, Griffiths C, Søreide JE, Johnsen G, Aubert A, Bjærke O, Hovinen J, Jung-Madsen S, Tveit M, Majaneva S. Arctic complexity: a case study on diel vertical migration of zooplankton. J Plankton Res 2014; 36:1279-1297. [PMID: 25221372 PMCID: PMC4161229 DOI: 10.1093/plankt/fbu059] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Accepted: 06/16/2014] [Indexed: 06/01/2023]
Abstract
Diel vertical migration (DVM) of zooplankton is a global phenomenon, characteristic of both marine and limnic environments. At high latitudes, patterns of DVM have been documented, but rather little knowledge exists regarding which species perform this ecologically important behaviour. Also, in the Arctic, the vertically migrating components of the zooplankton community are usually regarded as a single sound scattering layer (SSL) performing synchronized patterns of migration directly controlled by ambient light. Here, we present evidence for hitherto unknown complexity of Arctic marine systems, where zooplankton form multiple aggregations through the water column seen via acoustics as distinct SSLs. We show that while the initiation of DVM during the autumnal equinox is light mediated, the vertical positioning of the migrants during day is linked more to the thermal characteristics of water masses than to irradiance. During night, phytoplankton biomass is shown to be the most important factor determining the vertical positioning of all migrating taxa. Further, we develop a novel way of representing acoustic data in the form of a Sound Image (SI) that enables a direct comparison of the relative importance of each potential scatterer based upon the theoretical contribution of their backscatter. Based on our comparison of locations with contrasting hydrography, we conclude that a continued warming of the Arctic is likely to result in more complex ecotones across the Arctic marine system.
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Affiliation(s)
- Jørgen Berge
- Faculty of Biosciences, Fisheries and Economics, University of Tromsø, 9037 Tromsø, Norway
- The University Centre in Svalbard, N-9171 Longyearbyen, Norway
| | - Finlo Cottier
- Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll PA37 1QA, UK
| | - Øystein Varpe
- The University Centre in Svalbard, N-9171 Longyearbyen, Norway
- Akvaplan-Niva, Fram Centre for Climate and the Environment, N-9296 Tromsø, Norway
| | - Paul E. Renaud
- The University Centre in Svalbard, N-9171 Longyearbyen, Norway
- Akvaplan-Niva, Fram Centre for Climate and the Environment, N-9296 Tromsø, Norway
| | - Stig Falk-Petersen
- Faculty of Biosciences, Fisheries and Economics, University of Tromsø, 9037 Tromsø, Norway
- Akvaplan-Niva, Fram Centre for Climate and the Environment, N-9296 Tromsø, Norway
| | - Sawomir Kwasniewski
- Institute of Oceanology Polish Academy of Sciences, Powstancow Warszawy 55, 81-712 Sopot, Poland
| | - Colin Griffiths
- Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll PA37 1QA, UK
| | | | - Geir Johnsen
- The University Centre in Svalbard, N-9171 Longyearbyen, Norway
- Department of Biology, Trondhjem Biological Station, Applied Underwater Robotics Laboratory, Norwegian University of Science & Technology (NTNU), N-7491 Trondheim, Norway
| | - Anais Aubert
- Faculty of Biosciences, Fisheries and Economics, University of Tromsø, 9037 Tromsø, Norway
- The University Centre in Svalbard, N-9171 Longyearbyen, Norway
| | - Oda Bjærke
- The University Centre in Svalbard, N-9171 Longyearbyen, Norway
| | - Johanna Hovinen
- The University Centre in Svalbard, N-9171 Longyearbyen, Norway
- Norwegian Polar Institute, Fram Centre for Climate and the Environment, N-9296 Tromsø, Norway
| | | | - Martha Tveit
- The University Centre in Svalbard, N-9171 Longyearbyen, Norway
| | - Sanna Majaneva
- The University Centre in Svalbard, N-9171 Longyearbyen, Norway
- Faculty of Biological and Environmental Sciences, University of Helsinki, FI-00014 Helsinki, Finland
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Mimoto F, Kadono S, Katada H, Igawa T, Kamikawa T, Hattori K. Crystal structure of a novel asymmetrically engineered Fc variant with improved affinity for FcγRs. Mol Immunol 2014; 58:132-8. [PMID: 24334029 DOI: 10.1016/j.molimm.2013.11.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 11/20/2013] [Accepted: 11/23/2013] [Indexed: 11/22/2022]
Abstract
Enhancing the effector function by optimizing the interaction between Fc and Fcγ receptor (FcγR) is a promising approach to enhance the potency of anticancer monoclonal antibodies (mAbs). To date, a variety of Fc engineering approaches to modulate the interaction have been reported, such as afucosylation in the heavy chain Fc region or symmetrically introducing amino acid substitutions into the region, and there is still room to improve FcγR binding and thermal stability of the CH2 domain with these approaches. Recently, we have reported that asymmetric Fc engineering, which introduces different substitutions into each Fc region of heavy chain, can further improve the FcγR binding while maintaining the thermal stability of the CH2 domain by fine-tuning the asymmetric interface between the Fc domain and FcγR. However, the structural mechanism by which the asymmetrically engineered Fc improved FcγR binding remained unclear. In order to elucidate the mechanism, we solved the crystal structure of a novel asymmetrically engineered Fc, asym-mAb23, in complex with FcγRIIIa. Asym-mAb23 has enhanced binding affinity for both FcγRIIIa and FcγRIIa at the highest level of previously reported Fc variants. The structural analysis reveals the features of the asymmetrically engineered Fc in comparison with symmetric Fc and how each asymmetrically introduced substitution contributes to the improved interaction between asym-mAb23 and FcγRIIIa. This crystal structure could be utilized to enable us to design a more potent asymmetric Fc.
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69
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Vafa O, Gilliland GL, Brezski RJ, Strake B, Wilkinson T, Lacy ER, Scallon B, Teplyakov A, Malia TJ, Strohl WR. An engineered Fc variant of an IgG eliminates all immune effector functions via structural perturbations. Methods 2013; 65:114-26. [PMID: 23872058 DOI: 10.1016/j.ymeth.2013.06.035] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 06/24/2013] [Accepted: 06/27/2013] [Indexed: 01/26/2023] Open
Abstract
The Fc variant of IgG2, designated as IgG2σ, was engineered with V234A/G237A /P238S/H268A/V309L/A330S/P331S substitutions to eliminate affinity for Fcγ receptors and C1q complement protein and consequently, immune effector functions. IgG2σ was compared to other previously well-characterized Fc 'muted' variants, including aglycosylated IgG1, IgG2m4 (H268Q/V309L/A330S/P331S, changes to IgG4), and IgG4 ProAlaAla (S228P/L234A/L235A) in its capacity to bind FcγRs and activate various immune-stimulatory responses. In contrast to the previously characterized muted Fc variants, which retain selective FcγR binding and effector functions, IgG2σ shows no detectable binding to the Fcγ receptors in affinity and avidity measurements, nor any detectable antibody-dependent cytotoxicity, phagocytosis, complement activity, or Fc-mediated cytokine release. Moreover, IgG2σ shows minimal immunogenic potential by T-cell epitope analysis. The circulating half-life of IgG2σ in monkeys is extended relative to IgG1 and IgG2, in spite of similar in vitro binding to recombinant FcRn. The three-dimensional structure of the Fc, needed for assessing the basis for the absence of effector function, was compared with that of IgG2 revealing a number of conformational differences near the hinge region of the CH2 domain that result from the amino acid substitutions. Modeling reveals that at least one of the key interactions with FcγRs is disrupted by a conformational change that reorients P329 to a position that prevents it from interacting with conserved W90 and W113 residues of the FcγRs. Inspection of the structure also indicated significant changes to the conformations of D270 and P329 in the CH2 domain that could negatively impact C1q binding. Thus, structural perturbations of the Fc provide a rationale for the loss of function. In toto, these properties of IgG2σ suggest that it is a superior alternative to previously described IgG variants of minimal effector function, for future therapeutic applications of non-immunostimulatory mAb and Fc-fusion platforms.
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Affiliation(s)
- Omid Vafa
- Biologics Research, Biotechnology Center of Excellence, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477, United States.
| | - Gary L Gilliland
- Biologics Research, Biotechnology Center of Excellence, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477, United States.
| | - Randall J Brezski
- Biologics Research, Biotechnology Center of Excellence, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477, United States
| | - Brandy Strake
- Biologics Research, Biotechnology Center of Excellence, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477, United States
| | - Teresa Wilkinson
- Biologics Research, Biotechnology Center of Excellence, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477, United States
| | - Eilyn R Lacy
- Biologics Research, Biotechnology Center of Excellence, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477, United States
| | - Bernard Scallon
- Biologics Research, Biotechnology Center of Excellence, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477, United States
| | - Alexey Teplyakov
- Biologics Research, Biotechnology Center of Excellence, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477, United States
| | - Thomas J Malia
- Biologics Research, Biotechnology Center of Excellence, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477, United States
| | - William R Strohl
- Biologics Research, Biotechnology Center of Excellence, Janssen Research & Development, LLC, 1400 McKean Road, Spring House, PA 19477, United States
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