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Seki S, Parbie PK, Yamamoto H, Matano T. Virion-surface display of a chimeric immunoglobulin Fc domain facilitating uptake by antigen-presenting cells. J Biotechnol 2024; 391:57-63. [PMID: 38851397 DOI: 10.1016/j.jbiotec.2024.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 05/20/2024] [Accepted: 06/04/2024] [Indexed: 06/10/2024]
Abstract
Antigen-presenting cells (APCs) play an important role in virus infection control by bridging innate and adaptive immune responses. Macrophages and dendritic cells (DCs) possess various surface receptors to recognize/internalize antigens, and antibody binding can enhance pathogen-opsonizing uptake by these APCs via interaction of antibody fragment crystallizable (Fc) domains with Fc receptors, evoking profound pathogen control in certain settings. Here, we examined phagocytosis-enhancing potential of Fc domains directly oriented on a retroviral virion/virus-like particle (VLP) surface. We generated an expression vector coding a murine Fc fragment fused to the transmembrane region (TM) of a retroviral envelope protein, deriving expression of the Fc-TM fusion protein on the transfected cell surface and production of virions incorporating the chimeric Fc upon co-transfection. Incubation of Fc-displaying simian immunodeficiency virus (SIV) with murine J774 macrophages and bone marrow-derived DCs derived Fc receptor-dependent enhanced uptake, being visualized by imaging cytometry. Alternative preparation of a murine leukemia virus (MLV) backbone-based Fc-displaying VLP loading an influenza virus hemagglutinin (HA) antigen resulted in enhanced HA internalization by macrophages, stating antigen compatibility of the design. Results show that the Fc-TM fusion molecule can be displayed on certain viruses/VLPs and may be utilized as a molecular adjuvant to facilitate APC antigen uptake.
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Affiliation(s)
- Sayuri Seki
- AIDS Research Center, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Prince Kofi Parbie
- AIDS Research Center, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan; Graduate School of Medical Sciences and Joint Research Center for Human Retrovirus Infection, Kumamoto University, Honjo 2-2-1, Chuo-ku, Kumamoto 860-0811, Japan
| | - Hiroyuki Yamamoto
- Graduate School of Medical Sciences and Joint Research Center for Human Retrovirus Infection, Kumamoto University, Honjo 2-2-1, Chuo-ku, Kumamoto 860-0811, Japan; AIDS Research Center, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashi-Murayama City, Tokyo 208-0011, Japan; Immunodeficiency Laboratory, Department of Biomedicine, University Hospital, 20 Hebelstrasse, Basel 4031, Switzerland.
| | - Tetsuro Matano
- AIDS Research Center, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan; Graduate School of Medical Sciences and Joint Research Center for Human Retrovirus Infection, Kumamoto University, Honjo 2-2-1, Chuo-ku, Kumamoto 860-0811, Japan; The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
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2
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Becerra JC, Hitchcock L, Vu K, Gach JS. Neutralizing the threat: harnessing broadly neutralizing antibodies against HIV-1 for treatment and prevention. MICROBIAL CELL (GRAZ, AUSTRIA) 2024; 11:207-220. [PMID: 38975023 PMCID: PMC11224682 DOI: 10.15698/mic2024.07.826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 05/06/2024] [Accepted: 05/15/2024] [Indexed: 07/09/2024]
Abstract
Broadly neutralizing antibodies (bnAbs) targeting the human immunodeficiency virus-1 (HIV-1) have played a crucial role in elucidating and characterizing neutralization-sensitive sites on the HIV-1 envelope spike and in informing vaccine development. Continual advancements in identifying more potent bnAbs, along with their capacity to trigger antibody-mediated effector functions, coupled with modifications to extend their half-life, position them as promising candidates for both HIV-1 treatment and prevention. While current pharmacological interventions have made significant progress in managing HIV-1 infection and enhancing quality of life, no definitive cure or vaccines have been developed thus far. Standard treatments involve daily oral anti-retroviral therapy, which, despite its efficacy, can lead to notable long-term side effects. Recent clinical trial data have demonstrated encouraging therapeutic and preventive potential for bnAb therapies in both HIV-1-infected individuals and those without the infection. This review provides an overview of the advancements in HIV-1-specific bnAbs and discusses the insights gathered from recent clinical trials regarding their application in treating and preventing HIV-1 infection.
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Affiliation(s)
- Juan C Becerra
- Department of Medicine, Division of Infectious Diseases, University of CaliforniaCA, Irvine, Irvine, 92697USA
| | - Lauren Hitchcock
- Department of Medicine, Division of Infectious Diseases, University of CaliforniaCA, Irvine, Irvine, 92697USA
| | - Khoa Vu
- Department of Medicine, Division of Infectious Diseases, University of CaliforniaCA, Irvine, Irvine, 92697USA
| | - Johannes S Gach
- Department of Medicine, Division of Infectious Diseases, University of CaliforniaCA, Irvine, Irvine, 92697USA
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3
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Beaudoin-Bussières G, Finzi A. Deciphering Fc-effector functions against SARS-CoV-2. Trends Microbiol 2024:S0966-842X(24)00005-2. [PMID: 38365562 DOI: 10.1016/j.tim.2024.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/12/2024] [Accepted: 01/16/2024] [Indexed: 02/18/2024]
Abstract
Major efforts were deployed to study the antibody response against SARS-CoV-2. Antibodies neutralizing SARS-CoV-2 have been extensively studied in the context of infections, vaccinations, and breakthrough infections. Antibodies, however, are pleiotropic proteins that have many functions in addition to neutralization. These include Fc-effector functions such as antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP). Although important to combat viral infections, these Fc-effector functions were less studied in the context of SARS-CoV-2 compared with binding and neutralization. This is partly due to the difficulty in developing reliable assays to measure Fc-effector functions compared to antibody binding and neutralization. Multiple assays have now been developed and can be used to measure different Fc-effector functions. Here, we review these assays and what is known regarding anti-SARS-CoV-2 Fc-effector functions. Overall, this review summarizes and updates our current state of knowledge regarding anti-SARS-CoV-2 Fc-effector functions.
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Affiliation(s)
- Guillaume Beaudoin-Bussières
- Centre de recherche du CHUM, Montréal, Québec H2X 0A9, Canada; Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Québec H2X 0A9, Canada
| | - Andrés Finzi
- Centre de recherche du CHUM, Montréal, Québec H2X 0A9, Canada; Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montreal, Québec H2X 0A9, Canada.
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4
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Abstract
Neutralizing antibodies (nAbs) are being increasingly used as passive antiviral reagents in prophylactic and therapeutic modalities and to guide viral vaccine design. In vivo, nAbs can mediate antiviral functions through several mechanisms, including neutralization, which is defined by in vitro assays in which nAbs block viral entry to target cells, and antibody effector functions, which are defined by in vitro assays that evaluate nAbs against viruses and infected cells in the presence of effector systems. Interpreting in vivo results in terms of these in vitro assays is challenging but important in choosing optimal passive antibody and vaccine strategies. Here, I review findings from many different viruses and conclude that, although some generalizations are possible, deciphering the relative contributions of different antiviral mechanisms to the in vivo efficacy of antibodies currently requires consideration of individual antibody-virus interactions.
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Affiliation(s)
- Dennis R Burton
- Department of Immunology and Microbiology, Consortium for HIV/AIDS Vaccine Development, International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA, USA.
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA, USA.
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5
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Fox A, Liu X, Zolla-Pazner S, Powell RL. Impact of IgG Isotype on the Induction of Antibody-Dependent Cellular Phagocytosis of HIV by Human Milk Leukocytes. Front Immunol 2022; 13:831767. [PMID: 35592337 PMCID: PMC9110811 DOI: 10.3389/fimmu.2022.831767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 04/04/2022] [Indexed: 11/13/2022] Open
Abstract
Approximately 100,000 mother-to-child transmission (MTCT) events of HIV via human milk feeding occur each year. However, only about 15% of infants milk-fed by untreated HIV+ mothers become infected, suggesting a protective effect of the milk itself. Infants ingest 105-108 maternal leukocytes daily via milk, which remain functional beyond ingestion. Such function may be elicited by maternal milk antibody (Ab). Though IgA is dominant in milk, most HIV-specific milk Abs are of the IgG subclass, highlighting the importance of investigating the function of each IgG isotype in the milk context. Though Ab effector function mediated by the constant (Fc) domain via interaction with Fc Receptors (FcRs), such as Ab-dependent cellular phagocytosis (ADCP), are critical in protecting against HIV infection, ADCP is largely unexplored as it relates to mitigation of MTCT. Presently we report the ADCP activity of milk leukocytes against HIV particles and immune complexes (ICs), using 57 unique samples from 34 women, elicited by IgG1/2/3/4 of monoclonal (m)Ab 246-D. Granulocyte ADCP of HIV was most potent compared to other phagocytes when elicited by IgG1/3/4. IgG1/3 activated granulocytes similarly, exhibiting 1.6x-4.4x greater activity compared to IgG2/4, and a preference for virus compared to ICs. Notably, CD16- monocyte ADCP of a given target were unaffected by isotype, and CD16+ monocytes were poorly stimulated by IgG1. IgG2/4 elicited potent IC ADCP, and in terms of total leukocyte IC ADCP, IgG4 and IgG3 exhibited similar function, with IgG4 eliciting 1.6x-2.1x greater activity compared to IgG1/IgG2, and CD16+ monocytes most stimulated by IgG2. These data contribute to a more comprehensive understanding of Fc-mediated functionality of milk leukocytes, which is critical in order to develop therapeutic approaches to eliminating this route of MTCT, including mucosal administration of mAbs and/or a maternal vaccination aimed to elicit a potent milk Ab response.
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Affiliation(s)
| | | | | | - Rebecca L. Powell
- Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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6
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Klasse PJ, Moore JP. Reappraising the Value of HIV-1 Vaccine Correlates of Protection Analyses. J Virol 2022; 96:e0003422. [PMID: 35384694 PMCID: PMC9044961 DOI: 10.1128/jvi.00034-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2022] [Indexed: 01/09/2023] Open
Abstract
With the much-debated exception of the modestly reduced acquisition reported for the RV144 efficacy trial, HIV-1 vaccines have not protected humans against infection, and a vaccine of similar design to that tested in RV144 was not protective in a later trial, HVTN 702. Similar vaccine regimens have also not consistently protected nonhuman primates (NHPs) against viral acquisition. Conversely, experimental vaccines of different designs have protected macaques from viral challenges but then failed to protect humans, while many other HIV-1 vaccine candidates have not protected NHPs. While efficacy varies more in NHPs than humans, vaccines have failed to protect in the most stringent NHP model. Intense investigations have aimed to identify correlates of protection (CoPs), even in the absence of net protection. Unvaccinated animals and humans vary vastly in their susceptibility to infection and in their innate and adaptive responses to the vaccines; hence, merely statistical associations with factors that do not protect are easily found. Systems biological analyses, including artificial intelligence, have identified numerous candidate CoPs but with no clear consistency within or between species. Proposed CoPs sometimes have only tenuous mechanistic connections to immune protection. In contrast, neutralizing antibodies (NAbs) are a central mechanistic CoP for vaccines that succeed against other viruses, including SARS-CoV-2. No HIV-1 vaccine candidate has yet elicited potent and broadly active NAbs in NHPs or humans, but narrow-specificity NAbs against the HIV-1 isolate corresponding to the immunogen do protect against infection by the autologous virus. Here, we analyze why so many HIV-1 vaccines have failed, summarize the outcomes of vaccination in NHPs and humans, and discuss the value and pitfalls of hunting for CoPs other than NAbs. We contrast the failure to find a consistent CoP for HIV-1 vaccines with the identification of NAbs as the principal CoP for SARS-CoV-2.
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Affiliation(s)
- P. J. Klasse
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, New York, USA
| | - John P. Moore
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, New York, USA
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Internalization of HIV-1 by phagocytes is increased when virions are opsonized with multimeric antibody in the presence of complement. J Virol 2021; 96:e0168921. [PMID: 34730392 DOI: 10.1128/jvi.01689-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The low abundance of envelope spikes and the inability of IgG to aggregate virions render HIV-1 an inadequate target for antibody-mediated clearance by phagocytes. In an attempt to improve the ability of antibody to mediate the internalization of HIV-1 virions, we generated multimers of the broadly neutralizing HIV-1-specific monoclonal antibody (mAb) VRC01 using site-directed mutagenesis of the Fc segment. We then measured virion internalization using primary human monocytes and neutrophils. We found that, in the absence of complement, immune complexes consisting of HIV-1 virions and VRC01 multimers were slightly more efficiently internalized than were complexes formed with monomeric VRC01. The presence of complement, however, greatly augmented internalization of immune complexes formed with the multimeric mAb but had little impact on monomeric mAb-mediated internalization. Multimerization and the presence of complement overcome the limited ability of monomeric antibody to mediate internalization of HIV-1 virions and may thus provide a therapeutic approach to clearing virus. IMPORTANCE Antibody-mediated internalization of HIV-1 by phagocytes, a potential mechanism for clearing virus, is very inefficient. In an effort to improve viral clearance, we produced a multimeric form of the broadly neutralizing monoclonal antibody VRC01. We found that VRC01 antibody multimers (primarily hexamers) were only slightly more efficient in mediating HIV-1 internalization than was monomeric VRC01. However, the addition of complement resulted in substantially greater internalization of multimer-opsonized virus. In contrast, complement had little if any impact on internalization of monomer-opsonized virus. Therefore, antibody multimerization in combination with complement may overcome the limited ability of monomeric antibody to mediate internalization of HIV-1 virions. Our findings may provide a therapeutic approach to clearing virus.
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Cheng HD, Dowell KG, Bailey-Kellogg C, Goods BA, Love JC, Ferrari G, Alter G, Gach J, Forthal DN, Lewis GK, Greene K, Gao H, Montefiori DC, Ackerman ME. Diverse antiviral IgG effector activities are predicted by unique biophysical antibody features. Retrovirology 2021; 18:35. [PMID: 34717659 PMCID: PMC8557579 DOI: 10.1186/s12977-021-00579-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 10/20/2021] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND The critical role of antibody Fc-mediated effector functions in immune defense has been widely reported in various viral infections. These effector functions confer cellular responses through engagement with innate immune cells. The precise mechanism(s) by which immunoglobulin G (IgG) Fc domain and cognate receptors may afford protection are poorly understood, however, in the context of HIV/SHIV infections. Many different in vitro assays have been developed and utilized to measure effector functions, but the extent to which these assays capture distinct antibody activities has not been fully elucidated. RESULTS In this study, six Fc-mediated effector function assays and two biophysical antibody profiling assays were performed on a common set of samples from HIV-1 infected and vaccinated subjects. Biophysical antibody profiles supported robust prediction of diverse IgG effector functions across distinct Fc-mediated effector function assays. While a number of assays showed correlated activities, supervised machine learning models indicated unique antibody features as primary contributing factors to the associated effector functions. Additional experiments established the mechanistic relevance of relationships discovered using this unbiased approach. CONCLUSIONS In sum, this study provides better resolution on the diversity and complexity of effector function assays, offering a clearer perspective into this family of antibody mechanisms of action to inform future HIV-1 treatment and vaccination strategies.
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Affiliation(s)
- Hao D. Cheng
- grid.254880.30000 0001 2179 2404Thayer School of Engineering, Dartmouth College, Hanover, NH USA ,grid.254880.30000 0001 2179 2404Molecular and Cellular Biology Program, Dartmouth College, 14 Engineering Dr., Hanover, NH 03755 USA
| | - Karen G. Dowell
- grid.254880.30000 0001 2179 2404Department of Computer Science, Dartmouth College, Hanover, 03755 USA
| | - Chris Bailey-Kellogg
- grid.254880.30000 0001 2179 2404Department of Computer Science, Dartmouth College, Hanover, 03755 USA
| | - Brittany A. Goods
- grid.116068.80000 0001 2341 2786Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 USA ,grid.116068.80000 0001 2341 2786Department of Biological Engineering, Koch Institute at MIT, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
| | - J. Christopher Love
- grid.116068.80000 0001 2341 2786Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 USA ,grid.116068.80000 0001 2341 2786Department of Biological Engineering, Koch Institute at MIT, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
| | - Guido Ferrari
- grid.189509.c0000000100241216Department of Surgery, Duke University Medical Center, Durham, NC 27710 USA ,grid.189509.c0000000100241216Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27719 USA
| | - Galit Alter
- grid.461656.60000 0004 0489 3491Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139 USA
| | - Johannes Gach
- grid.266093.80000 0001 0668 7243Division of Infectious Diseases, Irvine School of Medicine, University California, Irvine, CA 92697 USA
| | - Donald N. Forthal
- grid.266093.80000 0001 0668 7243Division of Infectious Diseases, Irvine School of Medicine, University California, Irvine, CA 92697 USA
| | - George K. Lewis
- grid.411024.20000 0001 2175 4264Division of Vaccine Research, Institute of Human Virology, University Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Kelli Greene
- grid.189509.c0000000100241216Department of Surgery, Duke University Medical Center, Durham, NC 27710 USA
| | - Hongmei Gao
- grid.189509.c0000000100241216Department of Surgery, Duke University Medical Center, Durham, NC 27710 USA
| | - David C. Montefiori
- grid.189509.c0000000100241216Department of Surgery, Duke University Medical Center, Durham, NC 27710 USA ,grid.189509.c0000000100241216Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27719 USA
| | - Margaret E. Ackerman
- grid.254880.30000 0001 2179 2404Thayer School of Engineering, Dartmouth College, Hanover, NH USA ,grid.254880.30000 0001 2179 2404Molecular and Cellular Biology Program, Dartmouth College, 14 Engineering Dr., Hanover, NH 03755 USA
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9
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NK cells eliminate Epstein-Barr virus bound to B cells through a specific antibody-mediated uptake. PLoS Pathog 2021; 17:e1009868. [PMID: 34415956 PMCID: PMC8409624 DOI: 10.1371/journal.ppat.1009868] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 09/01/2021] [Accepted: 08/04/2021] [Indexed: 12/15/2022] Open
Abstract
Epstein Barr virus (EBV) causes a highly prevalent and lifelong infection contributing to the development of some malignancies. In addition to the key role played by T cells in controlling this pathogen, NK cells mediate cytotoxicity and IFNγ production in response to EBV-infected B cells in lytic cycle, both directly and through antibody (Ab)-dependent activation. We recently described that EBV-specific Ab-dependent NK cell interaction with viral particles (VP) bound to B cells triggered degranulation and TNFα secretion but not B cell lysis nor IFNγ production. In this report we show that NK cell activation under these conditions reduced B cell transformation by EBV. NK cells eliminated VP from the surface of B cells through a specific and active process which required tyrosine kinase activation, actin polymerization and Ca2+, being independent of proteolysis and perforin. VP were displayed at the NK cell surface before being internalized and partially shuttled to early endosomes and lysosomes. VP transfer was encompassed by a trogocytosis process including the EBV receptor CD21, together with CD19 and CD20. Our study reveals a novel facet of the antibody-dependent NK cell mediated response to this viral infection. Epstein-Barr virus (EBV) is a member of the herpesvirus family which causes a frequent and lifelong infection. The immune system is unable to fully eliminate the virus, which remains dormant in infected B lymphocytes. EBV reactivation leads to the production of new infective particles, spreading to other cells and favoring its transmission. EBV infection goes generally unnoticed in healthy individuals, though it may occasionally cause a disease termed Infectious Mononucleosis, as well as severe disorders in patients with a defective immune response. Remarkably, EBV has oncogenic potential contributing to the development of some tumors, and has been associated to autoimmune diseases. T lymphocytes and Natural Killer (NK) cells play an essential role in the defense against EBV, killing infected cells when the virus reactivates. Antiviral NK cell functions may be also triggered by antibodies (Ab) recognizing infected cells. In this report we provide the first evidence supporting that NK cells in combination with anti-EBV Ab are able to eliminate the virus attached to the surface of B cells, reducing their infection without killing them.
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An HIV Vaccine Targeting the V2 Region of the HIV Envelope Induces a Highly Durable Polyfunctional Fc-Mediated Antibody Response in Rhesus Macaques. J Virol 2020; 94:JVI.01175-20. [PMID: 32554699 DOI: 10.1128/jvi.01175-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 06/13/2020] [Indexed: 12/20/2022] Open
Abstract
The HIV vaccine field now recognizes the potential importance of generating polyfunctional antibodies (Abs). The only clinical HIV vaccine trial to date to show significant efficacy (RV144) found that reduced infection rates correlated with the level of nonneutralizing Abs specific for the V2 region of the envelope glycoprotein. We have conducted a comprehensive preclinical reverse vaccinology-based vaccine program that has included the design and production and testing of numerous scaffolded V2 region immunogens. The most immunogenic vaccine regimen in nonhuman primates among those studied as part of this program consisted of a cocktail of three immunogens presenting V2 from different viruses and clades in the context of different scaffolds. Presently we demonstrate that the V2-specific Ab response from this regimen was highly durable and functionally diverse for the duration of the study (25 weeks after the final immunization). The total IgG binding response at this late time point exhibited only an ∼5× reduction in potency. Three immunizations appeared essential for the elicitation of a strong Ab-dependent cellular cytotoxicity (ADCC) response for all animals, as opposed to the Ab-dependent cellular phagocytosis (ADCP) and virus capture responses, which were comparably potent after only 2 immunizations. All functionalities measured were highly durable through the study period. Therefore, testing this vaccine candidate for its protective capacity is warranted.IMPORTANCE The only HIV vaccine trial for which protective efficacy was detected correlated this efficacy with V2-specific Abs that were effectively nonneutralizing. This result has fueled a decade of HIV vaccine research focused on designing an HIV vaccine capable of eliciting V2-focused, polyfunctional Abs that effectively bind HIV and trigger various leukocytes to kill the virus and restrict viral spread. From the numerous vaccine candidates designed and tested as part of our V2-focused preclinical vaccine program, we have identified immunogens and a vaccine regimen that induces a highly durable and polyfunctional V2-focused Ab response in rhesus macaques, described herein.
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11
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Nanoparticles presenting clusters of CD4 expose a universal vulnerability of HIV-1 by mimicking target cells. Proc Natl Acad Sci U S A 2020; 117:18719-18728. [PMID: 32690692 PMCID: PMC7414181 DOI: 10.1073/pnas.2010320117] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
CD4-based decoy approaches against HIV-1 are attractive options for long-term viral control, but initial designs, including soluble CD4 (sCD4) and CD4-Ig, were ineffective. To evaluate a therapeutic that more accurately mimics HIV-1 target cells compared with monomeric sCD4 and dimeric CD4-Ig, we generated virus-like nanoparticles that present clusters of membrane-associated CD4 (CD4-VLPs) to permit high-avidity binding of trimeric HIV-1 envelope spikes. In neutralization assays, CD4-VLPs were >12,000-fold more potent than sCD4 and CD4-Ig and >100-fold more potent than the broadly neutralizing antibody (bNAb) 3BNC117, with >12,000-fold improvements against strains poorly neutralized by 3BNC117. CD4-VLPs also neutralized patient-derived viral isolates that were resistant to 3BNC117 and other bNAbs. Intraperitoneal injections of CD4-CCR5-VLP produced only subneutralizing plasma concentrations in HIV-1-infected humanized mice but elicited CD4-binding site mutations that reduced viral fitness. All mutant viruses showed reduced sensitivity to sCD4 and CD4-Ig but remained sensitive to neutralization by CD4-VLPs in vitro. In vitro evolution studies demonstrated that CD4-VLPs effectively controlled HIV-1 replication at neutralizing concentrations, and viral escape was not observed. Moreover, CD4-VLPs potently neutralized viral swarms that were completely resistant to CD4-Ig, suggesting that escape pathways that confer resistance against conventional CD4-based inhibitors are ineffective against CD4-VLPs. These findings suggest that therapeutics that mimic HIV-1 target cells could prevent viral escape by exposing a universal vulnerability of HIV-1: the requirement to bind CD4 on a target cell. We propose that therapeutic and delivery strategies that ensure durable bioavailability need to be developed to translate this concept into a clinically feasible functional cure therapy.
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12
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Duerr R, Gorny MK. V2-Specific Antibodies in HIV-1 Vaccine Research and Natural Infection: Controllers or Surrogate Markers. Vaccines (Basel) 2019; 7:vaccines7030082. [PMID: 31390725 PMCID: PMC6789775 DOI: 10.3390/vaccines7030082] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 07/26/2019] [Accepted: 07/27/2019] [Indexed: 12/20/2022] Open
Abstract
Most human immunodeficiency virus (HIV) vaccine trials have lacked efficacy and empirical vaccine lead targets are scarce. Thus far, the only independent correlate of reduced risk of HIV-1 acquisition in humans is elevated levels of V2-specific antibodies identified in the modestly protective RV144 vaccine trial. Ten years after RV144, human and non-human primate vaccine studies have reassessed the potential contribution of V2-specific antibodies to vaccine efficacy. In addition, studies of natural HIV-1 infection in humans have provided insight into the development of V1V2-directed antibody responses and their impact on clinical parameters and disease progression. Functionally diverse anti-V2 monoclonal antibodies were isolated and their structurally distinct V2 epitope regions characterized. After RV144, a plethora of research studies were performed using different model systems, immunogens, protocols, and challenge viruses. These diverse studies failed to provide a clear picture regarding the contribution of V2 antibodies to vaccine efficacy. Here, we summarize the biological functions and clinical findings associated with V2-specific antibodies and discuss their impact on HIV vaccine research.
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Affiliation(s)
- Ralf Duerr
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA.
| | - Miroslaw K Gorny
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
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13
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Zolla-Pazner S, Alvarez R, Kong XP, Weiss S. Vaccine-induced V1V2-specific antibodies control and or protect against infection with HIV, SIV and SHIV. Curr Opin HIV AIDS 2019; 14:309-317. [PMID: 30994501 PMCID: PMC6542703 DOI: 10.1097/coh.0000000000000551] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
PURPOSE OF REVIEW In humans, only one independent immunologic correlate of reduced risk of HIV infection has been identified: a robust antibody (Ab) response to the V1V2 domain of the gp120 envelope (Env) protein. In recent years, the presence and level of V1V2-specific Abs has also been correlated with protection from SIV and SHIV infections. Here, we review the multitude of studies showing the in-vivo protective effects of V1V2 Abs and review their immunologic characteristics and antiviral functions. RECENT FINDINGS Structural and immunologic studies have defined four epitope families in the V1V2 domain: one epitope family, V2q, which preferentially presents as a quaternary structure of the Env trimer, and another epitope family (V2qt) which requires the quaternary trimeric Env structure; these two epitope types are recognized by two families of monoclonal Abs (mAbs)-V2q-specific and V2qt-specific mAbs-which display broad and potent neutralizing activity. A third epitope family, V2i, is present as a discontinuous conformational structure that overlays the α4β7 integrin binding motif, and a fourth epitope family (V2p) exists on V2 peptides. Antibodies specific for V2i and V2p epitopes display only poor neutralizing activity but effectively mediate other antiviral activities and have been correlated with control of and/or protection from HIV, SIV and SHIV. Notably, V2q and V2qt Abs have not been induced by any vaccines, but V2p and V2i Abs have been readily induced with various vaccines in nonhuman primates and humans. SUMMARY The correlation of vaccine-induced V2p and V2i Abs with protection from HIV, SIV and SHIV suggests that these Ab types are extremely important to induce with prophylactic vaccines.
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Affiliation(s)
- Susan Zolla-Pazner
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai
| | - Raymond Alvarez
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai
| | - Xiang-Peng Kong
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Svenja Weiss
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai
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Lewis GK, Ackerman ME, Scarlatti G, Moog C, Robert-Guroff M, Kent SJ, Overbaugh J, Reeves RK, Ferrari G, Thyagarajan B. Knowns and Unknowns of Assaying Antibody-Dependent Cell-Mediated Cytotoxicity Against HIV-1. Front Immunol 2019; 10:1025. [PMID: 31134085 PMCID: PMC6522882 DOI: 10.3389/fimmu.2019.01025] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 04/23/2019] [Indexed: 12/15/2022] Open
Abstract
It is now well-accepted that Fc-mediated effector functions, including antibody-dependent cellular cytotoxicity (ADCC), can contribute to vaccine-elicited protection as well as post-infection control of HIV viremia. This picture was derived using a wide array of ADCC assays, no two of which are strictly comparable, and none of which is qualified at the clinical laboratory level. An earlier comparative study of assay protocols showed that while data from different ADCC assay formats were often correlated, they remained distinct in terms of target cells and the epitopes and antigen(s) available for recognition by antibodies, the effector cells, and the readout of cytotoxicity. This initial study warrants expanded analyses of the relationships among all current assay formats to determine where they detect overlapping activities and where they do not. Here we summarize knowns and unknowns of assaying ADCC against HIV-1.
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Affiliation(s)
- George K. Lewis
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, United States
| | | | - Gabriella Scarlatti
- Viral Evolution and Transmission Unit, Department of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Christiane Moog
- INSERM U1109, Fédération Hospitalo-Universitaire (FHU) OMICARE, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France
| | - Marjorie Robert-Guroff
- Vaccine Branch, Center for Cancer Research, National Cancer Institute, National Institues of Health, Bethesda, MD, United States
| | - Stephen J. Kent
- Department of Microbiology and Immunology, The University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Julie Overbaugh
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA, United States
| | - R. Keith Reeves
- Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, United States
| | - Guido Ferrari
- Department of Surgery and Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, United States
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15
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Kent SJ, Davenport MP. Moving the HIV vaccine field forward: concepts of protective immunity. Lancet HIV 2019; 6:e406-e410. [PMID: 31080107 DOI: 10.1016/s2352-3018(19)30134-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/07/2019] [Accepted: 03/25/2019] [Indexed: 12/31/2022]
Abstract
Vaccine-induced prevention of HIV infection is widely viewed as requiring both humoral and cellular immunity. Although the evidence for such a multipronged approach is not strong, this strategy increases the possibility that at least one mechanism of immunity could work to diminish new infections. The concept of broad immunity to HIV is attractive to funding bodies that seek at least some success from expensive trials. However, trying simultaneously to achieve both robust cellular and humoral immunity against HIV might be difficult. Furthermore, a multipronged approach increases the difficulty of later dissecting the immune correlates of protection and thereby iteratively improving HIV vaccines. This Viewpoint briefly discusses different approaches to tackling the challenge of inducing protective immunity to HIV and speculates on how results will move the field forward. We posit that, given the uncertain nature of immunity to HIV at present, focusing on inducing, evaluating, and optimising discrete individual mechanisms of immunity to HIV could provide the most rapid pathway to an effective HIV vaccine.
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Affiliation(s)
- Stephen J Kent
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, and Australian Centre of Excellence in Convergent Bio-Nano Science and Technology, The University of Melbourne, Melbourne, VIC, Australia; Melbourne Sexual Health Centre and Department of Infectious Diseases, Alfred Health, Central Clinical School, Monash University, Melbourne, VIC, Australia.
| | - Miles P Davenport
- Kirby Institute, University of New South Wales, Sydney, NSW, Australia
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16
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Rare Detection of Antiviral Functions of Polyclonal IgA Isolated from Plasma and Breast Milk Compartments in Women Chronically Infected with HIV-1. J Virol 2019; 93:JVI.02084-18. [PMID: 30700599 PMCID: PMC6430545 DOI: 10.1128/jvi.02084-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 01/15/2019] [Indexed: 02/06/2023] Open
Abstract
The humoral response to invading mucosal pathogens comprises multiple antibody isotypes derived from systemic and mucosal compartments. To understand the contribution of each antibody isotype/source to the mucosal humoral response, parallel investigation of the specificities and functions of antibodies within and across isotypes and compartments is required. The role of IgA against HIV-1 is complex, with studies supporting a protective role as well as a role for serum IgA in blocking effector functions. Thus, we explored the fine specificity and function of IgA in both plasma and mucosal secretions important to infant HIV-1 infection, i.e., breast milk. IgA and IgG were isolated from milk and plasma from 20 HIV-1-infected lactating Malawian women. HIV-1 binding specificities, neutralization potency, inhibition of virus-epithelial cell binding, and antibody-mediated phagocytosis were measured. Fine-specificity mapping showed IgA and IgG responses to multiple HIV-1 Env epitopes, including conformational V1/V2 and linear V2, V3, and constant region 5 (C5). Env IgA was heterogeneous between the milk and systemic compartments (Env IgA, τ = 0.00 to 0.63, P = 0.0046 to 1.00). Furthermore, IgA and IgG appeared compartmentalized as there was a lack of correlation between the specificities of Env-specific IgA and IgG (in milk, τ = -0.07 to 0.26, P = 0.35 to 0.83). IgA and IgG also differed in functions: while neutralization and phagocytosis were consistently mediated by milk and plasma IgG, they were rarely detected in IgA from both milk and plasma. Understanding the ontogeny of the divergent IgG and IgA antigen specificity repertoires and their effects on antibody function will inform vaccination approaches targeted toward mucosal pathogens.IMPORTANCE Antibodies within the mucosa are part of the first line of defense against mucosal pathogens. Evaluating mucosal antibody isotypes, specificities, and antiviral functions in relationship to the systemic antibody profile can provide insights into whether the antibody response is coordinated in response to mucosal pathogens. In a natural immunity cohort of HIV-infected lactating women, we mapped the fine specificity and function of IgA in breast milk and plasma and compared these with the autologous IgG responses. Antigen specificities and functions differed between IgG and IgA, with antiviral functions (neutralization and phagocytosis) predominantly mediated by the IgG fraction in both milk and plasma. Furthermore, the specificity of milk IgA differed from that of systemic IgA. Our data suggest that milk IgA and systemic IgA should be separately examined as potential correlates of risk. Preventive vaccines may need to employ different strategies to elicit functional antiviral immunity by both antibody isotypes in the mucosa.
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Tay MZ, Wiehe K, Pollara J. Antibody-Dependent Cellular Phagocytosis in Antiviral Immune Responses. Front Immunol 2019; 10:332. [PMID: 30873178 PMCID: PMC6404786 DOI: 10.3389/fimmu.2019.00332] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 02/08/2019] [Indexed: 12/20/2022] Open
Abstract
Antiviral activities of antibodies may either be dependent only on interactions between the antibody and cognate antigen, as in binding and neutralization of an infectious virion, or instead may require interactions between antibody-antigen immune complexes and immunoproteins or Fc receptor expressing immune effector cells. These Fc receptor-dependent antibody functions provide a direct link between the innate and adaptive immune systems by combining the potent antiviral activity of innate effector cells with the diversity and specificity of the adaptive humoral response. The Fc receptor-dependent function of antibody-dependent cellular phagocytosis (ADCP) provides mechanisms for clearance of virus and virus-infected cells, as well as for stimulation of downstream adaptive immune responses by facilitating antigen presentation, or by stimulating the secretion of inflammatory mediators. In this review, we discuss the properties of Fc receptors, antibodies, and effector cells that influence ADCP. We also provide and interpret evidence from studies that support a potential role for ADCP in either inhibiting or enhancing viral infection. Finally, we describe current approaches used to measure antiviral ADCP and discuss considerations for the translation of studies performed in animal models. We propose that additional investigation into the role of ADCP in protective viral responses, the specific virus epitopes targeted by ADCP antibodies, and the types of phagocytes and Fc receptors involved in ADCP at sites of virus infection will provide insight into strategies to successfully leverage this important immune response for improved antiviral immunity through rational vaccine design.
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Affiliation(s)
- Matthew Zirui Tay
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, United States
| | - Kevin Wiehe
- Human Vaccine Institute, Duke University School of Medicine, Durham, NC, United States
| | - Justin Pollara
- Human Vaccine Institute, Duke University School of Medicine, Durham, NC, United States
- Department of Surgery, Duke University School of Medicine, Durham, NC, United States
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Abstract
: Interactions between the Fc segment of IgG and its receptors (FcγRs) found on cells such as natural killer cells, monocytes, macrophages and neutrophils can potentially mediate antiviral effects in the setting of HIV and related infections. We review the potential role of FcγR interactions in HIV, SIV and SHIV infections, with an emphasis on antibody-dependent cellular cytotoxicity (ADCC). Notably, these viruses employ various strategies, including CD4 down-regulation and BST-2/tetherin antagonism to limit the effect of ADCC. Although correlative data suggest that ADCC participates in both protection and control of established infection, there is little direct evidence in support of either role. Direct evidence does, however, implicate an FcγR-dependent function in augmenting the beneficial in vivo activity of neutralizing antibodies.
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19
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Measuring the ability of HIV-specific antibodies to mediate trogocytosis. J Immunol Methods 2018; 463:71-83. [PMID: 30240705 DOI: 10.1016/j.jim.2018.09.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 09/14/2018] [Accepted: 09/14/2018] [Indexed: 12/20/2022]
Abstract
Antibody Fc effector functions contribute to HIV control and have been implicated in the partial efficacy seen in the RV144 vaccine trial. Fc-mediated trogocytosis has been previously described for anti-cancer antibodies and results in the removal of membrane fragments from target cells. Here we developed a flow cytometry-based assay which measures the transfer of membrane fragments from a gp120-coated CD4+ lymphocytic cell line (CEM.NKR-CCR5 cells stained with a membrane dye PKH26) to monocytic cells (THP-1 cells stained with CFSE). We showed that this transfer occurred rapidly, within 1 h, and was mediated through engagement of the FcγRIIa/b receptors on the THP-1 cells. HIV-specific IgG as well as gp120 and CD4 could be detected on the surface of THP-1 cells in a process that we demonstrated was distinct from phagocytosis. Furthermore, while the THP-1 effector cells remained intact following the receipt of new membrane proteins, the viability of the target CEM.NKR-CCR5 cells decreased over time. Analysis of HIV-specific plasma revealed that antibodies with trogocytic activity were common in acute and chronic HIV infection but were higher in individuals with broadly neutralizing antibody responses We also examined trogocytosis mediated by broadly neutralizing antibodies (bNAbs) targeting multiple epitopes on the BG505.SOSIP.664 trimer and show that levels of binding correlated with the trogocytosis score. Overall, our data describe a new antiviral Fc effector function mediated by HIV-specific antibodies that could be harnessed for vaccination and cure strategies.
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