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Abstract
Currently used vaccines have had major effects on eliminating common infections, largely by duplicating the immune responses induced by natural infections. Now vaccinology faces more complex problems, such as waning antibody, immunosenescence, evasion of immunity by the pathogen, deviation of immunity by the microbiome, induction of inhibitory responses, and complexity of the antigens required for protection. Fortunately, vaccine development is now incorporating knowledge from immunology, structural biology, systems biology and synthetic chemistry to meet these challenges. In addition, international organisations are developing new funding and licensing pathways for vaccines aimed at pathogens with epidemic potential that emerge from tropical areas.
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Affiliation(s)
| | - Marta V Pinto
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK.
| | - Manish Sadarangani
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK; Vaccine Evaluation Center, BC Children's Hospital Research Institute, University of British Columbia, Vancouver BC, Canada.
| | - Stanley A Plotkin
- Department of Pediatrics, University of Pennsylvania, Philadelphia, USA.
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Hurwitz JL, Bonsignori M. Multi-Envelope HIV-1 Vaccine Development: Two Targeted Immune Pathways, One Desired Protective Outcome. Viral Immunol 2018; 31:124-132. [PMID: 29315059 DOI: 10.1089/vim.2017.0144] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In 2016, there were more than 30 million individuals living with HIV-1, ∼1.8 million new HIV-1 infections, and ∼1 million HIV-1-related deaths according to UNAIDS ( unaids.org ). Hence, a preventive HIV-1 vaccine remains a global priority. The variant envelopes of HIV-1 present a significant obstacle to vaccine development and the vaccine field has realized that immunization with a single HIV-1 envelope protein will not be sufficient to generate broadly neutralizing antibodies. Here we describe two nonmutually exclusive, targeted pathways with which a multi-envelope HIV-1 vaccine may generate protective immune responses against variant HIV-1. Pathways include (i) the induction of a polyclonal immune response, comprising a plethora of antibodies with subset-reactive and cross-reactive specificities, together able to neutralize diverse HIV-1 (termed Poly-nAb in this report) and (ii) the induction of one or a few monoclonal antibodies, each with a broadly neutralizing specificity (bnAb). With each pathway in mind, we describe challenges and strategies that may ultimately support HIV-1 vaccine success.
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Affiliation(s)
- Julia L Hurwitz
- 1 Department of Infectious Diseases, St. Jude Children's Research Hospital , Memphis, Tennessee.,2 Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Mattia Bonsignori
- 3 Duke Human Vaccine Institute , Duke University School of Medicine, Duke University Medical Center, Durham, North Carolina.,4 Department of Medicine, Duke University School of Medicine, Duke University Medical Center , Durham, North Carolina
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53
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Gach JS, Bouzin M, Wong MP, Chromikova V, Gorlani A, Yu KT, Sharma B, Gratton E, Forthal DN. Human immunodeficiency virus type-1 (HIV-1) evades antibody-dependent phagocytosis. PLoS Pathog 2017; 13:e1006793. [PMID: 29281723 PMCID: PMC5760106 DOI: 10.1371/journal.ppat.1006793] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 01/09/2018] [Accepted: 12/07/2017] [Indexed: 12/20/2022] Open
Abstract
Fc gamma receptor (FcyR)-mediated antibody functions play a crucial role in preventing HIV infection. One such function, antibody-dependent phagocytosis (ADP), is thought to be involved in controlling other viral infections, but its role in HIV infection is unknown. We measured the ability of HIV-specific polyclonal and monoclonal antibodies (mAbs) to mediate the internalization of HIV-1 virions and HIV-1-decorated cells by phagocytes. To measure ADP of virions, we primarily used a green-fluorescent protein-expressing molecular clone of HIV-1JRFL, an R5, clinical isolate, in combination with polyclonal HIVIG or mAbs known to capture and/or neutralize HIV-1. THP-1 and U937 cells, as well as freshly isolated primary monocytes from healthy individuals, were used as phagocytic effector cells, and uptake of virions was measured by cytometry. We surprisingly found minimal or no ADP of virions with any of the antibodies. However, after coating virions with gp41 or with gp41-derived peptides, gp41- (but not gp120-) specific mAbs efficiently mediated phagocytosis. We estimated that a minimum of a few hundred gp41 molecules were needed for successful phagocytosis, which is similar to the number of envelope spikes on viruses that are readily phagocytosed (e.g. influenza virus). Furthermore, by employing fluorescence correlation spectroscopy, a well-established technique to measure particle sizes and aggregation phenomena, we found a clear association between virus aggregation and ADP. In contrast to virions themselves, virion-decorated cells were targets for ADP or trogocytosis in the presence of HIV-specific antibodies. Our findings indicate that ADP of virions may not play a role in preventing HIV infection, likely due to the paucity of trimers and the consequent inability of virion-bound antibody to cross-link FcyRs on phagocytes. However, ADP or trogocytosis could play a role in clearing HIV-infected cells and cells on the verge of infection.
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Affiliation(s)
- Johannes S. Gach
- Department of Medicine, Division of Infectious Diseases, University of California, Irvine School of Medicine, Irvine, California, United States of America
- * E-mail: (JSG); (DNF)
| | - Margaux Bouzin
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States of America
- Laboratory for Fluorescence Dynamics, University of California, Irvine, Irvine, California, United States of America
| | - Marcus P. Wong
- Department of Medicine, Division of Infectious Diseases, University of California, Irvine School of Medicine, Irvine, California, United States of America
| | - Veronika Chromikova
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Andrea Gorlani
- Department of Medicine, Division of Infectious Diseases, University of California, Irvine School of Medicine, Irvine, California, United States of America
| | - Kuan-Ting Yu
- Department of Medicine, Division of Infectious Diseases, University of California, Irvine School of Medicine, Irvine, California, United States of America
| | - Brijesh Sharma
- Department of Medicine, Division of Infectious Diseases, University of California, Irvine School of Medicine, Irvine, California, United States of America
| | - Enrico Gratton
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California, United States of America
- Laboratory for Fluorescence Dynamics, University of California, Irvine, Irvine, California, United States of America
| | - Donald N. Forthal
- Department of Medicine, Division of Infectious Diseases, University of California, Irvine School of Medicine, Irvine, California, United States of America
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, California, United States of America
- * E-mail: (JSG); (DNF)
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54
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Kratochvil S, McKay PF, Chung AW, Kent SJ, Gilmour J, Shattock RJ. Immunoglobulin G1 Allotype Influences Antibody Subclass Distribution in Response to HIV gp140 Vaccination. Front Immunol 2017; 8:1883. [PMID: 29326728 PMCID: PMC5742328 DOI: 10.3389/fimmu.2017.01883] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Accepted: 12/11/2017] [Indexed: 01/13/2023] Open
Abstract
Antibody subclasses exhibit extensive polymorphisms (allotypes) that could potentially impact the quality of HIV-vaccine induced B cell responses. Allotypes of immunoglobulin (Ig) G1, the most abundant serum antibody, have been shown to display altered functional properties in regard to serum half-life, Fc-receptor binding and FcRn-mediated mucosal transcytosis. To investigate the potential link between allotypic IgG1-variants and vaccine-generated humoral responses in a cohort of 14 HIV vaccine recipients, we developed a novel protocol for rapid IgG1-allotyping. We combined PCR and ELISA assays in a dual approach to determine the IgG1 allotype identity (G1m3 and/or G1m1) of trial participants, using human plasma and RNA isolated from PBMC. The IgG1-allotype distribution of our participants mirrored previously reported results for caucasoid populations. We observed elevated levels of HIV gp140-specific IgG1 and decreased IgG2 levels associated with the G1m1-allele, in contrast to G1m3 carriers. These data suggest that vaccinees homozygous for G1m1 are predisposed to develop elevated Ag-specific IgG1:IgG2 ratios compared to G1m3-carriers. This elevated IgG1:IgG2 ratio was further associated with higher FcγR-dimer engagement, a surrogate for potential antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP) function. Although preliminary, these results suggest that IgG1 allotype may have a significant impact on IgG subclass distribution in response to vaccination and associated Fc-mediated effector functions. These results have important implications for ongoing HIV vaccine efficacy studies predicated on engagement of FcγR-mediated cellular functions including ADCC and ADCP, and warrant further investigation. Our novel allotyping protocol provides new tools to determine the potential impact of IgG1 allotypes on vaccine efficacy.
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Affiliation(s)
| | - Paul F McKay
- Imperial College London, Medicine, London, United Kingdom
| | - Amy W Chung
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia
| | - Stephen J Kent
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia.,ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of Melbourne, Melbourne, VIC, Australia.,Melbourne Sexual Health Centre, Department of Infectious Diseases, Alfred Health, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Jill Gilmour
- IAVI Human Immunology Laboratory, Imperial College London, London, United Kingdom
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The Legacy of CVI. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:CVI.00276-17. [PMID: 29070528 DOI: 10.1128/cvi.00276-17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Clinical and Vaccine Immunology (CVI) will merge with the American Society for Microbiology (ASM) open-access journal mSphere in January 2018. We commemorate this transition by exploring the history of CVI and that of its predecessor, Clinical and Diagnostic Laboratory Immunology (CDLI), and by acknowledging their contributors. Research on vaccines, clinical immunology, and clinical diagnostic immunology published through mSphere will be available without restrictions to an ever-larger audience, which will expedite progress in the field. ASM remains committed to supporting its members and the research community by facilitating the dissemination of scientific knowledge in these important areas.
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56
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Abstract
Safe and efficacious vaccines are arguably the most successful medical interventions of all time. Yet the ongoing discovery of new pathogens, along with emergence of antibiotic-resistant pathogens and a burgeoning population at risk of such infections, imposes unprecedented public health challenges. To meet these challenges, innovative strategies to discover and develop new or improved anti-infective vaccines are necessary. These approaches must intersect the most meaningful insights into protective immunity and advanced technologies with capabilities to deliver immunogens for optimal immune protection. This goal is considered through several recent advances in host-pathogen relationships, conceptual strides in vaccinology, and emerging technologies. Given a clear and growing risk of pandemic disease should the threat of infection go unmet, developing vaccines that optimize protective immunity against high-priority and antibiotic-resistant pathogens represents an urgent and unifying imperative.
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Affiliation(s)
- Michael R Yeaman
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California 90024.,Division of Molecular Medicine, Department of Medicine, Harbor-UCLA Medical Center, Torrance, California 90509; .,Division of Infectious Diseases, Department of Medicine, Harbor-UCLA Medical Center, Torrance, California 90509.,Los Angeles Biomedical Research Institute, Torrance, California 90502
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57
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Chea LS, Amara RR. Immunogenicity and efficacy of DNA/MVA HIV vaccines in rhesus macaque models. Expert Rev Vaccines 2017; 16:973-985. [PMID: 28838267 DOI: 10.1080/14760584.2017.1371594] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Despite 30 years of research on HIV, a vaccine to prevent infection and limit disease progression remains elusive. The RV144 trial showed moderate, but significant protection in humans and highlighted the contribution of antibody responses directed against HIV envelope as an important immune correlate for protection. Efforts to further build upon the progress include the use of a heterologous prime-boost regimen using DNA as the priming agent and the attenuated vaccinia virus, Modified Vaccinia Ankara (MVA), as a boosting vector for generating protective HIV-specific immunity. Areas covered: In this review, we summarize the immunogenicity of DNA/MVA vaccines in non-human primate models and describe the efficacy seen in SIV infection models. We discuss immunological correlates of protection determined by these studies and potential approaches for improving the protective immunity. Additionally, we describe the current progress of DNA/MVA vaccines in human trials. Expert commentary: Efforts over the past decade have provided the opportunity to better understand the dynamics of vaccine-induced immune responses and immune correlates of protection against HIV. Based on what we have learned, we outline multiple areas where the field will likely focus on in the next five years.
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Affiliation(s)
- Lynette Siv Chea
- a Emory Vaccine Center, Department of Microbiology and Immunology , Yerkes National Primate Research Center, Emory University , Atlanta , GA , USA
| | - Rama Rao Amara
- a Emory Vaccine Center, Department of Microbiology and Immunology , Yerkes National Primate Research Center, Emory University , Atlanta , GA , USA
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58
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Abstract
PURPOSE OF REVIEW Only four HIV-1 vaccine concepts have been tested in six efficacy trials with no product licensed to date. Several scientific and programmatic lessons can be learned from these studies generating new hypotheses and guiding future steps. RECENT FINDINGS RV144 [ALVAC-HIV (canarypox vector) and AIDSVAX B/E (bivalent gp120 HIV-1 subtype B and CRF01_AE)] remains the only efficacy trial that demonstrated a modest vaccine efficacy, which led to the identification of immune correlates of risk. Progress on subtype-specific, ALVAC (canarypox vector) and gp120 vaccine prime-boost approaches has been slow, but we are finally close to the launch of an efficacy study in Africa in 2016. The quest of a globally effective HIV-1 vaccine has led to the development of new approaches. Efficacy studies of combinations of Adenovirus type 26 (Ad26)/Modified Vaccinia Ankara (MVA)/gp140 vaccines with mosaic designs will enter efficacy studies mid-2017 and cytomegalovirus (CMV)-vectored vaccines begin Phase I studies at the same time. Future HIV-1 vaccine efficacy trials face practical challenges as effective nonvaccine prevention programs are projected to decrease HIV-1 incidence. SUMMARY An HIV-1 vaccine is urgently needed. Increased industry involvement, mobilization of resources, expansion of a robust pipeline of new concepts, and robust preclinical challenge studies will be essential to accelerate efficacy testing of next generation HIV-1 vaccine candidates.
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59
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Tomaras GD, Plotkin SA. Complex immune correlates of protection in HIV-1 vaccine efficacy trials. Immunol Rev 2017; 275:245-261. [PMID: 28133811 DOI: 10.1111/imr.12514] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Development of an efficacious HIV-1 vaccine is a major priority for improving human health worldwide. Vaccine-mediated protection against human pathogens can be achieved through elicitation of protective innate, humoral, and cellular responses. Identification of specific immune responses responsible for pathogen protection enables vaccine development and provides insights into host defenses against pathogens and the immunological mechanisms that most effectively fight infection. Defining immunological correlates of transmission risk in preclinical and clinical HIV-1 vaccine trials has moved the HIV-1 vaccine development field forward and directed new candidate vaccine development. Immune correlate studies are providing novel hypotheses about immunological mechanisms that may be responsible for preventing HIV-1 acquisition. Recent results from HIV-1 immune correlates work has demonstrated that there are multiple types of immune responses that together, comprise an immune correlate-thus implicating polyfunctional immune control of HIV-1 transmission. An in depth understanding of these complex immunological mechanisms of protection against HIV-1 will accelerate the development of an efficacious HIV-1 vaccine.
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Affiliation(s)
- Georgia D Tomaras
- Departments of Surgery, Immunology, Molecular Genetics and Microbiology, Duke Human Vaccine Institute, Durham, NC, USA
| | - Stanley A Plotkin
- Vaxconsult, Doylestown, PA, USA.,University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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60
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Verkoczy L, Alt FW, Tian M. Human Ig knockin mice to study the development and regulation of HIV-1 broadly neutralizing antibodies. Immunol Rev 2017; 275:89-107. [PMID: 28133799 DOI: 10.1111/imr.12505] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A major challenge for HIV-1 vaccine research is developing a successful immunization approach for inducing broadly neutralizing antibodies (bnAbs). A key shortcoming in meeting this challenge has been the lack of animal models capable of identifying impediments limiting bnAb induction and ranking vaccine strategies for their ability to promote bnAb development. Since 2010, immunoglobulin knockin (KI) technology, involving inserting functional rearranged human variable exons into the mouse IgH and IgL loci has been used to express bnAbs in mice. This approach has allowed immune tolerance mechanisms limiting bnAb production to be elucidated and strategies to overcome such limitations to be evaluated. From these studies, along with the wealth of knowledge afforded by analyses of recombinant Ig-based bnAb structures, it became apparent that key functional features of bnAbs often are problematic for their elicitation in mice by classic vaccine paradigms, necessitating more iterative testing of new vaccine concepts. In this regard, bnAb KI models expressing deduced precursor V(D)J rearrangements of mature bnAbs or unrearranged germline V, D, J segments (that can be assembled into variable region exons that encode bnAb precursors), have been engineered to evaluate novel immunogens/regimens for effectiveness in driving bnAb responses. One promising approach emerging from such studies is the ability of sequentially administered, modified immunogens (designed to bind progressively more mature bnAb precursors) to initiate affinity maturation. Here, we review insights gained from bnAb KI studies regarding the regulation and induction of bnAbs, and discuss new Ig KI methodologies to manipulate the production and/or expression of bnAbs in vivo, to further facilitate vaccine-guided bnAb induction studies.
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Affiliation(s)
- Laurent Verkoczy
- Departments of Medicine and Pathology, Duke University Human Vaccine Institute, Duke University School of Medicine, Durham, NC, USA
| | - Frederick W Alt
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital and Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Ming Tian
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital and Department of Genetics, Harvard Medical School, Boston, MA, USA
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61
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Bootz A, Karbach A, Spindler J, Kropff B, Reuter N, Sticht H, Winkler TH, Britt WJ, Mach M. Protective capacity of neutralizing and non-neutralizing antibodies against glycoprotein B of cytomegalovirus. PLoS Pathog 2017; 13:e1006601. [PMID: 28854233 PMCID: PMC5595347 DOI: 10.1371/journal.ppat.1006601] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 09/12/2017] [Accepted: 08/22/2017] [Indexed: 01/19/2023] Open
Abstract
Human cytomegalovirus (HCMV) is an important, ubiquitous pathogen that causes severe clinical disease in immunocompromised individuals, such as organ transplant recipients and infants infected in utero. Antiviral chemotherapy remains problematic due to toxicity of the available compounds and the emergence of viruses resistant to available antiviral therapies. Antiviral antibodies could represent a valuable alternative strategy to limit the clinical consequences of viral disease in patients. The envelope glycoprotein B (gB) of HCMV is a major antigen for the induction of virus neutralizing antibodies. However, the role of anti-gB antibodies in the course of the infection in-vivo remains unknown. We have used a murine CMV (MCMV) model to generate and study a number of anti-gB monoclonal antibodies (mAbs) with differing virus-neutralizing capacities. The mAbs were found to bind to similar antigenic structures on MCMV gB that are represented in HCMV gB. When mAbs were used in immunodeficient RAG-/- hosts to limit an ongoing infection we observed a reduction in viral load both with mAbs having potent neutralizing capacity in-vitro as well as mAbs classified as non-neutralizing. In a therapeutic setting, neutralizing mAbs showed a greater capacity to reduce the viral burden compared to non-neutralizing antibodies. Efficacy was correlated with sustained concentration of virus neutralizing mAbs in-vivo rather than their in-vitro neutralizing capacity. Combinations of neutralizing mAbs further augmented the antiviral effect and were found to be as potent in protection as polyvalent serum from immune animals. Prophylactic administration of mAbs before infection was also protective and both neutralizing and non-neutralizing mAbs were equally effective in preventing lethal infection of immunodeficient mice. In summary, our data argue that therapeutic application of potently neutralizing mAbs against gB represent a strategy to modify the outcome of CMV infection in immunodeficient hosts. When present before infection, both neutralizing and non-neutralizing anti-gB exhibited protective capacity.
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Affiliation(s)
- Anna Bootz
- Virologisches Institut, Klinische und Molekulare Virologie, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Astrid Karbach
- Virologisches Institut, Klinische und Molekulare Virologie, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Johannes Spindler
- Virologisches Institut, Klinische und Molekulare Virologie, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Barbara Kropff
- Virologisches Institut, Klinische und Molekulare Virologie, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Nina Reuter
- Virologisches Institut, Klinische und Molekulare Virologie, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Heinrich Sticht
- Institut für Biochemie, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Thomas H. Winkler
- Nikolaus-Fiebiger-Zentrum für Molekulare Medizin, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - William J. Britt
- Departments of Pediatrics, Microbiology and Neurobiology, Children's Hospital of Alabama, University of Alabama, School of Medicine, Birmingham, Alabama, United States of America
| | - Michael Mach
- Virologisches Institut, Klinische und Molekulare Virologie, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
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Intrastructural help: improving the HIV-1 envelope antibody response induced by virus-like particle vaccines. Curr Opin HIV AIDS 2017; 12:272-277. [PMID: 28422791 DOI: 10.1097/coh.0000000000000358] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
PURPOSE OF REVIEW The importance of IgG Fc-effector functions for the efficacy of HIV vaccines is increasingly recognized. Although different types of vaccines were shown to induce antibodies with different Fc-activities, there is no clear strategy how to raise antibody responses with a desired pattern of Fc-effector functions. Given the central role of T-helper cells in regulating the germinal center reaction and the differentiation of B cells in an antigen-specific manner, the review will discuss whether T-helper cells directed against non-HIV envelope (Env) antigens could be harnessed to improve the HIV-Env antibody response. RECENT FINDINGS Comparing CD4 T-cell responses in HIV-infected individuals with and without neutralizing antibody breadth suggests that robust Gag-specific CD4 T cells may provide important T-cell help to Env-specific B cells. In a murine model, GagPol-specific T-helper cells were shown to provide intrastructural help for HIV-Env-specific antibody responses after immunization with a virus-like particle vaccine. GagPol-specific T-helper cells imprinted the IgG subtype ratio observed for Gag onto the HIV-Env antibody response and modulated the glycosylation pattern of the HIV Env-specific antibodies. SUMMARY Intrastructural help is a promising strategy to improve overall levels and Fc-effector functions of the HIV-Env antibody response.
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63
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Affiliation(s)
- Nickita Mehta
- Ragon Institute of MGH, Harvard & MIT, Cambridge, MA 02139, USA
| | - Galit Alter
- Ragon Institute of MGH, Harvard & MIT, Cambridge, MA 02139, USA
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64
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Molecular and Physicochemical Factors Governing Solubility of the HIV gp41 Ectodomain. Biophys J 2017; 111:700-709. [PMID: 27558714 DOI: 10.1016/j.bpj.2016.07.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 07/01/2016] [Accepted: 07/20/2016] [Indexed: 11/20/2022] Open
Abstract
The HIV gp41 ectodomain (e-gp41) is an attractive target for the development of vaccines and drugs against HIV because of its crucial role in viral fusion to the host cell. However, because of the high insolubility of e-gp41, most biophysical and structural analyses have relied on the production of truncated versions removing the loop region of gp41 or the utilization of nonphysiological solubilizing conditions. The loop region of gp41 is also known as principal immunodominant domain (PID) because of its high immunogenicity, and it is essential for gp41-mediated HIV fusion. In this study we identify the aggregation-prone regions of the amino acid sequence of the PID and engineer a highly soluble mutant that preserves the trimeric structure of the wild-type e-gp41 under physiological pH. Furthermore, using a reverse mutagenesis approach, we analyze the role of mutated amino acids upon the physicochemical factors that govern solubility of e-gp41. On this basis, we propose a molecular model for e-gp41 self-association, which can guide the production of soluble e-gp41 mutants for future biophysical analyses and biotechnological applications.
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65
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Sørensen B, Sommerfelt MA, Stjernholm G, Smith PL, Ökvist M, Hovden AO, Hoddevik G, Redfield R, Ustina V, Jelmert Ø, Zeldis J, Dalgleish A. Correlation of Antibody Responses to a Peptide Antigen gp120-C5 501-512/gp41 732-744 with HIV Disease Progression. AIDS Res Hum Retroviruses 2017; 33:558-566. [PMID: 28051320 DOI: 10.1089/aid.2016.0184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Antibodies to the carboxy-terminal constant (C5) region 5 of the HIV-1 envelope glycoprotein gp120 have previously been associated with slow disease progression. This is one of the regions on gp120 that interact with the transmembrane glycoprotein, gp41, anchoring it to the viral and infected cell membrane. This study analyzed humoral responses to a novel heterodimeric peptide construct comprising the C5501-512 region and a compatible region on gp41732-744. Antibody levels to C5501-512/gp41732-744 were associated with slow disease progression in a treatment naive historical longitudinal cohort from Norway (n = 32; p = .00001). Elevated anti-C5501-512/gp41732-744 antibody levels correlated with moderate viral load (VL) (50-10,000 copies/ml) in a cohort, including natural viral suppressors (NVS) in the Unites States (n = 58; p = .002). Analysis of HIV-positive sera from treatment naive patients in Estonia (n = 300) showed an inverse correlation between anti-C5501-512/gp41732-744 antibodies and VL when comparing VL 2,000-10,000 copies/ml with VL >10,000 (p = .050). Further mapping using peptide inhibition of antibody binding revealed that responses to the C5501-506 subdomain correlated with preserved CD4 counts (n = 55; p = .0012) irrespective of VL in this cohort. The C5 region encompassing C5501-506 shows sequence similarity to the shared epitope (SE) of certain HLA-DR associated with immune dysfunction. Partial antigenic cross-reactivity between SE and C5 is indicated by partial inhibition of NVS antibody binding using SE 15-mer peptide (median 65% inhibition), the C5501-506 6-mer peptide (79% inhibition), and binding of rheumatoid arthritis patient sera to both SE and C5 peptide sequences. The potential influence of these observations on HIV-1 pathogenesis remains to be determined.
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Affiliation(s)
| | | | | | - Peter Lawrence Smith
- St. George's, University of London, Institute of Infection and Immunity, London, United Kingdom
| | | | | | - Gunnar Hoddevik
- Department of Virology, The Norwegian Institute of Public Health, Oslo, Norway
| | - Robert Redfield
- Department of Medicine, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Valentina Ustina
- State Reference Laboratory of HIV Diagnostics, West-Tallinn Central Hospital, Estonia
| | | | - Jerome Zeldis
- Celgene Corp./Celgene Global Health, Summit, New Jersey
| | - Angus Dalgleish
- St. George's, University of London, Institute of Infection and Immunity, London, United Kingdom
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66
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Abstract
Adjuvant properties of bacterial cell wall components like MPLA (monophosphoryl lipid A) are well described and have gained FDA approval for use in vaccines such as Cervarix. MPLA is the product of chemically modified lipooligosaccharide (LOS), altered to diminish toxic proinflammatory effects while retaining adequate immunogenicity. Despite the virtually unlimited number of potential sources among bacterial strains, the number of useable compounds within this promising class of adjuvants are few. We have developed bacterial enzymatic combinatorial chemistry (BECC) as a method to generate rationally designed, functionally diverse lipid A. BECC removes endogenous or introduces exogenous lipid A-modifying enzymes to bacteria, effectively reprogramming the lipid A biosynthetic pathway. In this study, BECC is applied within an avirulent strain of Yersinia pestis to develop structurally distinct LOS molecules that elicit differential Toll-like receptor 4 (TLR4) activation. Using reporter cell lines that measure NF-κB activation, BECC-derived molecules were screened for the ability to induce a lower proinflammatory response than Escherichia coli LOS. Their structures exhibit varied, dose-dependent, TLR4-driven NF-κB activation with both human and mouse TLR4 complexes. Additional cytokine secretion screening identified molecules that induce levels of tumor necrosis factor alpha (TNF-α) and interleukin-8 (IL-8) comparable to the levels induced by phosphorylated hexa-acyl disaccharide (PHAD). The lead candidates demonstrated potent immunostimulation in mouse splenocytes, human primary blood mononuclear cells (PBMCs), and human monocyte-derived dendritic cells (DCs). This newly described system allows directed programming of lipid A synthesis and has the potential to generate a diverse array of TLR4 agonist candidates.IMPORTANCE There is an urgent need to develop effective vaccines against infectious diseases that continue to be major causes of morbidity and mortality worldwide. Making effective vaccines requires selecting an adjuvant to strengthen an appropriate and protective immune response. This work describes a practical method, bacterial enzymatic combinatorial chemistry (BECC), for generating functionally diverse molecules for adjuvant use. These molecules were analyzed in cell culture for their ability to initiate immune stimulatory activity. Several of the assays described herein show promising in vitro cytokine production and costimulatory molecule expression results, suggesting that the BECC molecules may be useful in future vaccine preparations.
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Brandenberg OF, Magnus C, Rusert P, Günthard HF, Regoes RR, Trkola A. Predicting HIV-1 transmission and antibody neutralization efficacy in vivo from stoichiometric parameters. PLoS Pathog 2017; 13:e1006313. [PMID: 28472201 PMCID: PMC5417720 DOI: 10.1371/journal.ppat.1006313] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 03/24/2017] [Indexed: 01/08/2023] Open
Abstract
The potential of broadly neutralizing antibodies targeting the HIV-1 envelope trimer to prevent HIV-1 transmission has opened new avenues for therapies and vaccines. However, their implementation remains challenging and would profit from a deepened mechanistic understanding of HIV-antibody interactions and the mucosal transmission process. In this study we experimentally determined stoichiometric parameters of the HIV-1 trimer-antibody interaction, confirming that binding of one antibody is sufficient for trimer neutralization. This defines numerical requirements for HIV-1 virion neutralization and thereby enables mathematical modelling of in vitro and in vivo antibody neutralization efficacy. The model we developed accurately predicts antibody efficacy in animal passive immunization studies and provides estimates for protective mucosal antibody concentrations. Furthermore, we derive estimates of the probability for a single virion to start host infection and the risks of male-to-female HIV-1 transmission per sexual intercourse. Our work thereby delivers comprehensive quantitative insights into both the molecular principles governing HIV-antibody interactions and the initial steps of mucosal HIV-1 transmission. These insights, alongside the underlying, adaptable modelling framework presented here, will be valuable for supporting in silico pre-trial planning and post-hoc evaluation of HIV-1 vaccination or antibody treatment trials.
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Affiliation(s)
| | - Carsten Magnus
- Institute of Medical Virology, University of Zürich, Zurich, Switzerland
| | - Peter Rusert
- Institute of Medical Virology, University of Zürich, Zurich, Switzerland
| | - Huldrych F. Günthard
- Institute of Medical Virology, University of Zürich, Zurich, Switzerland
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, Zurich, Switzerland
| | - Roland R. Regoes
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
| | - Alexandra Trkola
- Institute of Medical Virology, University of Zürich, Zurich, Switzerland
- * E-mail:
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68
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Jennewein MF, Alter G. The Immunoregulatory Roles of Antibody Glycosylation. Trends Immunol 2017; 38:358-372. [DOI: 10.1016/j.it.2017.02.004] [Citation(s) in RCA: 150] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/03/2017] [Accepted: 02/10/2017] [Indexed: 12/12/2022]
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Aiyegbo MS, Shmelkov E, Dominguez L, Goger M, Battacharya S, deCamp AC, Gilbert PB, Berman PW, Cardozo T. Peptide Targeted by Human Antibodies Associated with HIV Vaccine-Associated Protection Assumes a Dynamic α-Helical Structure. PLoS One 2017; 12:e0170530. [PMID: 28107435 PMCID: PMC5249078 DOI: 10.1371/journal.pone.0170530] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 01/05/2017] [Indexed: 02/02/2023] Open
Abstract
The only evidence of vaccine-induced protection from HIV acquisition in humans was obtained in the RV144 HIV vaccine clinical trial. One immune correlate of risk in RV144 was observed to be higher titers of vaccine-induced antibodies (Abs) reacting with a 23-mer non-glycosylated peptide with the same amino acid sequence as a segment in the second variable (V2) loop of the MN strain of HIV. We used NMR to analyze the dynamic 3D structure of this peptide. Distance restraints between spatially proximate inter-residue protons were calculated from NOE cross peak intensities and used to constrain a thorough search of all possible conformations of the peptide. α–helical folding was strongly preferred by part of the peptide. A high-throughput structure prediction of this segment in all circulating HIV strains demonstrated that α–helical conformations are preferred by this segment almost universally across all subtypes. Notably, α–helical conformations of this segment of the V2 loop cluster cross-subtype-conserved amino acids on one face of the helix and the variable amino acid positions on the other in a semblance of an amphipathic α–helix. Accordingly, some Abs that protected against HIV in RV144 may have targeted a specific, conserved α–helical peptide epitope in the V2 loop of HIV’s surface envelope glycoprotein.
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Affiliation(s)
- Mohammed S. Aiyegbo
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, United States of America
| | - Evgeny Shmelkov
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, United States of America
| | - Lorenzo Dominguez
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, United States of America
| | - Michael Goger
- The New York Structural Biology Center, New York, New York, United States of America
| | - Shibani Battacharya
- The New York Structural Biology Center, New York, New York, United States of America
| | - Allan C. deCamp
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Peter B. Gilbert
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
| | - Phillip W. Berman
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Timothy Cardozo
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, United States of America
- * E-mail:
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Chege GK, Burgers WA, Müller TL, Gray CM, Shephard EG, Barnett SW, Ferrari G, Montefiori D, Williamson C, Williamson AL. DNA-MVA-protein vaccination of rhesus macaques induces HIV-specific immunity in mucosal-associated lymph nodes and functional antibodies. Vaccine 2017; 35:929-937. [PMID: 28069361 PMCID: PMC5287223 DOI: 10.1016/j.vaccine.2016.12.060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 12/06/2016] [Accepted: 12/23/2016] [Indexed: 11/30/2022]
Abstract
Successful future HIV vaccines are expected to generate an effective cellular and humoral response against the virus in both the peripheral blood and mucosal compartments. We previously reported the development of DNA-C and MVA-C vaccines based on HIV-1 subtype C and demonstrated their immunogenicity when given in a DNA prime-MVA boost combination in a nonhuman primate model. In the current study, rhesus macaques previously vaccinated with a DNA-C and MVA-C vaccine regimen were re-vaccinated 3.5 years later with MVA-C followed by a protein vaccine based on HIV-1 subtype C envelope formulated with MF59 adjuvant (gp140Env/MF59), and finally a concurrent boost with both vaccines. A single MVA-C re-vaccination elicited T cell responses in all animals similar to previous peak responses, with 4/7 demonstrating responses >1000 SFU/106 PBMC. In contrast to an Env/MF59-only vaccine, concurrent boosting with MVA-C and Env/MF59 induced HIV-specific cellular responses in multiple mucosal associated lymph nodes in 6/7 animals, with high magnitude responses in some animals. Both vaccine regimens induced high titer Env-specific antibodies with ADCC activity, as well as neutralization of Tier 1 viruses and modest Tier 2 neutralization. These data demonstrate the feasibility of inducing HIV-specific immunity in the blood and mucosal sites of viral entry by means of DNA and poxvirus-vectored vaccines, in combination with a HIV envelope-based protein vaccine.
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Affiliation(s)
- Gerald K Chege
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Wendy A Burgers
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Tracey L Müller
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Clive M Gray
- Division of Immunology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Enid G Shephard
- Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; South African Medical Research Council, Cape Town, South Africa
| | | | | | | | - Carolyn Williamson
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; National Health Laboratory Service, Groote Schuur Hospital, Cape Town, South Africa
| | - Anna-Lise Williamson
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; National Health Laboratory Service, Groote Schuur Hospital, Cape Town, South Africa.
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Verkoczy L. Humanized Immunoglobulin Mice: Models for HIV Vaccine Testing and Studying the Broadly Neutralizing Antibody Problem. Adv Immunol 2017; 134:235-352. [PMID: 28413022 PMCID: PMC5914178 DOI: 10.1016/bs.ai.2017.01.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A vaccine that can effectively prevent HIV-1 transmission remains paramount to ending the HIV pandemic, but to do so, will likely need to induce broadly neutralizing antibody (bnAb) responses. A major technical hurdle toward achieving this goal has been a shortage of animal models with the ability to systematically pinpoint roadblocks to bnAb induction and to rank vaccine strategies based on their ability to stimulate bnAb development. Over the past 6 years, immunoglobulin (Ig) knock-in (KI) technology has been leveraged to express bnAbs in mice, an approach that has enabled elucidation of various B-cell tolerance mechanisms limiting bnAb production and evaluation of strategies to circumvent such processes. From these studies, in conjunction with the wealth of information recently obtained regarding the evolutionary pathways and paratopes/epitopes of multiple bnAbs, it has become clear that the very features of bnAbs desired for their function will be problematic to elicit by traditional vaccine paradigms, necessitating more iterative testing of new vaccine concepts. To meet this need, novel bnAb KI models have now been engineered to express either inferred prerearranged V(D)J exons (or unrearranged germline V, D, or J segments that can be assembled into functional rearranged V(D)J exons) encoding predecessors of mature bnAbs. One encouraging approach that has materialized from studies using such newer models is sequential administration of immunogens designed to bind progressively more mature bnAb predecessors. In this review, insights into the regulation and induction of bnAbs based on the use of KI models will be discussed, as will new Ig KI approaches for higher-throughput production and/or altering expression of bnAbs in vivo, so as to further enable vaccine-guided bnAb induction studies.
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Affiliation(s)
- Laurent Verkoczy
- Duke University Human Vaccine Institute, Duke University School of Medicine, Durham, NC, United States.
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72
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Plotkin S. Foreword. HUMAN VACCINES 2017. [DOI: 10.1016/b978-0-12-802302-0.00011-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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73
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Rationally Designed Vaccines Targeting the V2 Region of HIV-1 gp120 Induce a Focused, Cross-Clade-Reactive, Biologically Functional Antibody Response. J Virol 2016; 90:10993-11006. [PMID: 27630234 DOI: 10.1128/jvi.01403-16] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 09/04/2016] [Indexed: 01/27/2023] Open
Abstract
Strong antibody (Ab) responses against V1V2 epitopes of the human immunodeficiency virus type 1 (HIV-1) gp120 envelope (Env) correlated with reduced infection rates in studies of HIV, simian-human immunodeficiency virus (SHIV), and simian immunodeficiency virus (SIV). In order to focus the Ab response on V1V2, we used six V1V2 sequences and nine scaffold proteins to construct immunogens which were tested using various immunization regimens for their ability to induce cross-reactive and biologically active V2 Abs in rabbits. A prime/boost immunization strategy was employed using gp120 DNA and various V1V2-scaffold proteins. The rabbit polyclonal Ab responses (i) were successfully focused on the V1V2 region, with weak or only transient responses to other Env epitopes, (ii) displayed broad cross-reactive binding activity with gp120s and the V1V2 regions of diverse strains from clades B, C, and E, (iii) included V2 Abs with specificities similar to those found in HIV-infected individuals, and (iv) remained detectable ≥1 year after the last boosting dose. Importantly, sera from rabbits receiving V1V2-scaffold immunogens displayed Ab-dependent cellular phagocytosis whereas sera from rabbits receiving only gp120 did not. The results represent the first fully successful example of reverse vaccinology in the HIV vaccine field with rationally designed epitope scaffold immunogens inducing Abs that recapitulate the epitope specificity and biologic activity of the human monoclonal Abs from which the immunogens were designed. Moreover, this is the first immunogenicity study using epitope-targeting, rationally designed vaccine constructs that induced an Fc-mediated activity associated with protection from infection with HIV, SIV, and SHIV. IMPORTANCE Novel immunogens were designed to focus the antibody response of rabbits on the V1V2 epitopes of HIV-1 gp120 since such antibodies were associated with reduced infection rates of HIV, SIV, and SHIV. The vaccine-induced antibodies were broadly cross-reactive with the V1V2 regions of HIV subtypes B, C and E and, importantly, facilitated Fc-mediated phagocytosis, an activity not induced upon immunization of rabbits with gp120. This is the first immunogenicity study of vaccine constructs that focuses the antibody response on V1V2 and induces V2-specific antibodies with the ability to mediate phagocytosis, an activity that has been associated with protection from infection with HIV, SIV, and SHIV.
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74
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Non-neutralizing antibody functions for protection and control HIV in humans and SIV and SHIV in non-human primates. AIDS 2016; 30:2551-2553. [PMID: 27753680 DOI: 10.1097/qad.0000000000001200] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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75
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Abstract
As the 2014-15 Ebola virus epidemic in West Africa evolved from emergency to lesson, developers of both vaccines and therapeutic antibodies were left with the puzzlement of what kinds of anti-Ebola antibodies are predictably desirable in treating the afflicted, and what antibodies might account for the specific and lasting protection elicited by the more effective vaccines. The facile answer in virology is that neutralizing antibody (NAb) is desired and required. However, with Ebola and other filoviruses (as with many prior viral examples), there are multiple discordances in which neutralizing antibodies fail to protect animals, and others in which antibody-mediated protection is observed in the absence of measured virus neutralization. Explanation presumably resides in the protective role of antibodies that bind and functionally 'target' virus-infected cells, here called 'cell-targeting antibody', or CTAb. To be clear, many NAbs are also CTAbs, and in the case of Ebola the great majority of NAbs are likely CTAbs. Isotype, glycosylation, and other features of CTAbs are likely crucial in their capacity to mediate protection. Overall, results and analysis invite an increasingly complex view of antibody-mediated immunity to enveloped viruses.
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Affiliation(s)
- Alan Schmaljohn
- Microbiology & Immunology, University of Maryland School of Medicine,
USA,Corresponding author: Department of Microbiology & Immunology, University
of Maryland School of Medicine, 685 West Baltimore Street, Baltimore, MD 21201, USA. Tel:
410-706-3059
| | - George K. Lewis
- Institute of Human Virology, University of Maryland School of Medicine, 725
W. Lombard St., Baltimore, Maryland, 21201, USA
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76
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Musich T, Robert-Guroff M. New developments in an old strategy: heterologous vector primes and envelope protein boosts in HIV vaccine design. Expert Rev Vaccines 2016; 15:1015-27. [PMID: 26910195 DOI: 10.1586/14760584.2016.1158108] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Prime/boost vaccination strategies for HIV/SIV vaccine development have been used since the early 1990s and have become an established method for eliciting cell and antibody mediated immunity. Here we focus on induction of protective antibodies, both broadly neutralizing and non-neutralizing, with the viral envelope being the key target antigen. Prime/boost approaches are complicated by the diversity of autologous and heterologous priming vectors, and by various forms of envelope booster immunogens, many still in development as structural studies aim to design stable constructs with exposure of critical epitopes for protective antibody elicitation. This review discusses individual vaccine components, reviews recent prime/boost strategies and their outcomes, and highlights complicating factors arising as greater knowledge concerning induction of adaptive, protective immunity is acquired.
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Affiliation(s)
- Thomas Musich
- a Vaccine Branch, Center for Cancer Research, National Cancer Institute , National Institutes of Health , Bethesda , MD , USA
| | - Marjorie Robert-Guroff
- a Vaccine Branch, Center for Cancer Research, National Cancer Institute , National Institutes of Health , Bethesda , MD , USA
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Abstract
PURPOSE OF REVIEW The purpose of this review is to highlight major advances in the development and use of animal models for HIV-1 research during the last year. RECENT FINDINGS Animal model research during the last year has focused on the development and refinement of models; use of these models to explore key questions about HIV entry, immune control, and persistence; and key discoveries with these models testing therapeutic and vaccine concepts. Some of the greatest breakthroughs have been in understanding early events surrounding transmission, the effectiveness of broadly neutralizing human monoclonal antibodies as passive prophylaxis, and some new ideas in the area of eliminating the viral reservoir in established infection. SUMMARY Despite the lack of a flawless HIV-1 infection and pathogenesis model, the field utilizes several models that have already made important contributions to our understanding of early events, immune control, and the potential for novel therapies.
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78
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Lelièvre JD, Lévy Y. HIV-1 prophylactic vaccines: state of the art. J Virus Erad 2016; 2:5-11. [PMID: 27482428 PMCID: PMC4946697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The quest for an effective HIV-1 vaccine began early in the course of the HIV pandemic. Over time, the paradigm has evolved from B cell- towards T cell-based vaccines. Results from initial Phase II/III trials have been disappointing; however, while modest, the unexpected results of the Phase II/III RV144 trial in Thailand have re-energised the field. Indeed a clear correlation was demonstrated in this trial between protection and immunological biomarkers, namely non-neutralising antibodies against the V1V2 region. Recent data obtained from cohorts of recently HIV-1-infected individuals have enabled exploration of the role of neutralising antibodies and their potential use in HIV-1 prevention. Results from non-human primate models using a cytomegalovirus vector have also shown the potential for a prophylactic HIV vaccine to induce effective T cell responses. Finally, the development of new vaccine vectors and trial strategies has also allowed progress in the field. Therefore, HIV-1 vaccine research remains a dynamic field that has also been stimulated by the recent positive results of pre-exposure prophylaxis strategies with antiretrovirals.
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Affiliation(s)
- Jean-Daniel Lelièvre
- AP-HP, Hôpital Henri Mondor – Albert Chenevier, Service d’Immunologie Clinique et Maladies Infectieuses, Créteil, 94000, France,Corresponding author: Jean-Daniel Lelièvre, Service d’Immunologie Clinique et Maladies Infectieuses, CHU Henri Mondor, 51 avenue Mal de Lattre de Tassigny, 94010, Créteil, France
| | - Yves Lévy
- AP-HP, Hôpital Henri Mondor – Albert Chenevier, Service d’Immunologie Clinique et Maladies Infectieuses, Créteil, 94000, France
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80
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Sheets RL, Zhou T, Knezevic I. Scientific and regulatory challenges in evaluating clinical trial protocols for HIV-1/AIDS vaccines - A review from a regulatory perspective. Biologicals 2015; 44:90-110. [PMID: 26732973 DOI: 10.1016/j.biologicals.2015.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 11/20/2015] [Accepted: 11/21/2015] [Indexed: 11/29/2022] Open
Abstract
Clinical development of prophylactic HIV/AIDS vaccines presents many scientific challenges that result in challenges for regulators reviewing clinical trial applications (CTAs). The World Health Organization (WHO) has the responsibility to provide technical support to these regulators. The search for an HIV/AIDS vaccine will only succeed through well-designed, -conducted and -controlled human efficacy studies reviewed and approved by regulators in countries worldwide, particularly in countries where the epidemic has hit hardest, such as in sub-Saharan Africa and Asia. This review summarizes the current candidates in development and focuses on challenges regulators face when reviewing CTAs, such as the evolving landscape of "standard of prevention," trials in adolescents, adaptive trial designs, correlates of protection and their analysis, and access to successful vaccines. There are many unknowns in the field of HIV/AIDS vaccine development and often, there is not a clear right or wrong approach because of the scientific challenges described in this review. Consequently, regulators should not feel that decisions need be made in isolation, when there are many available international collaborative efforts and opportunities to seek expert advice. The WHO provides many such opportunities and support to regulators across the globe.
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Affiliation(s)
| | - TieQun Zhou
- Technologies Standards and Norms Team, Regulation of Medicines and Other Health Technologies, Department of Essential Medicines and Health Products, Health Systems and Innovation, World Health Organization, Avenue Appia 20, 1211 Geneva 27, Switzerland.
| | - Ivana Knezevic
- Technologies Standards and Norms Team, Regulation of Medicines and Other Health Technologies, Department of Essential Medicines and Health Products, Health Systems and Innovation, World Health Organization, Avenue Appia 20, 1211 Geneva 27, Switzerland.
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81
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Abstract
A globally effective vaccine strategy must cope with the broad genetic diversity of HIV and contend with multiple transmission modalities. Understanding correlates of protection and the role of diversity in limiting protective vaccines with those correlates is key. RV144 was the first HIV-1 vaccine trial to demonstrate efficacy against HIV-1 infection. A correlates analysis comparing vaccine-induced immune responses in vaccinated-infected and vaccinated-uninfected volunteers suggested that IgG specific for the V1V2 region of gp120 was associated with reduced risk of HIV-1 infection and that plasma Env IgA was directly correlated with infection risk. RV144 and recent non-human primate (NHP) challenge studies suggest that Env is essential and perhaps sufficient to induce protective antibody responses against mucosally acquired HIV-1. Whether RV144 immune correlates can apply to different HIV vaccines, to populations with different modes and intensity of transmission, or to divergent HIV-1 subtypes remains unknown. Newer prime-boost mosaic and conserved sequence immunization strategies aiming at inducing immune responses of greater breadth and depth as well as the development of immunogens inducing broadly neutralizing antibodies should be actively pursued. Efficacy trials are now planned in heterosexual populations in southern Africa and men who have sex with men in Thailand. Although NHP challenge studies may guide vaccine development, human efficacy trials remain key to answer the critical questions leading to the development of a global HIV-1 vaccine for licensure.
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82
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Sealy RE, Jones BG, Surman SL, Branum K, Howlett NM, Flynn PM, Hurwitz JL. Murine Monoclonal Antibodies for Antigenic Discrimination of HIV-1 Envelope Proteins. Viral Immunol 2015; 29:64-70. [PMID: 26544795 DOI: 10.1089/vim.2015.0078] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In the influenza virus field, antibody reagents from research animals have been instrumental in the characterization of antigenically distinct hemagglutinin and neuraminidase membrane molecules. These small animal reagents continue to support the selection of components for inclusion in human influenza virus vaccines. Other cocktail vaccines against variant pathogens (e.g., polio virus, pneumococcus) are similarly designed to represent variant antigens, as defined by antibody reactivity patterns. However, a vaccine cocktail comprising diverse viral membrane antigens defined in this way has not yet been advanced to a clinical efficacy study in the HIV-1 field. In this study, we describe the preparation of mouse antibodies specific for HIV-1 gp140 or gp120 envelope molecules. Our experiments generated renewable reagents able to discriminate HIV-1 envelopes from one another. Monoclonals yielded more precise discriminatory capacity against their respective immunogens than did a small panel of polyclonal human sera derived from recently HIV-1-infected patients. Perhaps these and other antibody reagents will ultimately support high-throughput cartography studies with which antigenically-distinct envelope immunogens may be formulated into a successful HIV-1 envelope cocktail vaccine.
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Affiliation(s)
- Robert E Sealy
- 1 Department of Infectious Diseases, St. Jude Children's Research Hospital , Memphis, Tennessee
| | - Bart G Jones
- 1 Department of Infectious Diseases, St. Jude Children's Research Hospital , Memphis, Tennessee
| | - Sherri L Surman
- 1 Department of Infectious Diseases, St. Jude Children's Research Hospital , Memphis, Tennessee
| | - Kristen Branum
- 1 Department of Infectious Diseases, St. Jude Children's Research Hospital , Memphis, Tennessee
| | - Nanna M Howlett
- 1 Department of Infectious Diseases, St. Jude Children's Research Hospital , Memphis, Tennessee
| | - Patricia M Flynn
- 1 Department of Infectious Diseases, St. Jude Children's Research Hospital , Memphis, Tennessee.,2 Department of Pediatrics, University of Tennessee Health Science Center , Memphis, Tennessee.,3 Department of Preventive Medicine, University of Tennessee Health Science Center , Memphis, Tennessee
| | - Julia L Hurwitz
- 1 Department of Infectious Diseases, St. Jude Children's Research Hospital , Memphis, Tennessee.,4 Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center , Memphis, Tennessee
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83
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Phanuphak N, Lo YR, Shao Y, Solomon SS, O'Connell RJ, Tovanabutra S, Chang D, Kim JH, Excler JL. HIV Epidemic in Asia: Implications for HIV Vaccine and Other Prevention Trials. AIDS Res Hum Retroviruses 2015; 31:1060-76. [PMID: 26107771 DOI: 10.1089/aid.2015.0049] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
An overall decrease of HIV prevalence is now observed in several key Asian countries due to effective prevention programs. The decrease in HIV prevalence and incidence may further improve with the scale-up of combination prevention interventions. The implementation of future prevention trials then faces important challenges. The opportunity to identify heterosexual populations at high risk such as female sex workers may rapidly wane. With unabating HIV epidemics among men who have sex with men (MSM) and transgender (TG) populations, an effective vaccine would likely be the only option to turn the epidemic. It is more likely that efficacy trials will occur among MSM and TG because their higher HIV incidence permits smaller and less costly trials. The constantly evolving patterns of HIV-1 diversity in the region suggest close monitoring of the molecular HIV epidemic in potential target populations for HIV vaccine efficacy trials. CRF01_AE remains predominant in southeast Asian countries and MSM populations in China. This relatively steady pattern is conducive to regional efficacy trials, and as efficacy warrants, to regional licensure. While vaccines inducing nonneutralizing antibodies have promise against HIV acquisition, vaccines designed to induce broadly neutralizing antibodies and cell-mediated immune responses of greater breadth and depth in the mucosal compartments should be considered for testing in MSM and TG. The rationale and design of efficacy trials of combination prevention modalities such as HIV vaccine and preexposure prophylaxis (PrEP) remain hypothetical, require high adherence to PrEP, are more costly, and present new regulatory challenges. The prioritization of prevention interventions should be driven by the HIV epidemic and decided by the country-specific health and regulatory authorities. Modeling the impact and cost-benefit may help this decision process.
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Affiliation(s)
| | - Ying-Ru Lo
- HIV, Hepatitis, and STI Unit, WHO Regional Office for the Western Pacific, Manila, Philippines
| | - Yiming Shao
- National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Sunil Suhas Solomon
- Johns Hopkins University School of Medicine, Baltimore, Maryland
- Y.R. Gaitonde Centre for AIDS Research and Education (YRG CARE), Chennai, India
| | - Robert J. O'Connell
- Department of Retrovirology, U.S. Army Medical Component, Armed Forces Institute of Medical Sciences (AFRIMS), Bangkok, Thailand
| | - Sodsai Tovanabutra
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - David Chang
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Jerome H. Kim
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Jean Louis Excler
- U.S. Military HIV Research Program, Bethesda, Maryland
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland
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84
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Terajima M, Co MDT, Cruz J, Ennis FA. High Antibody-Dependent Cellular Cytotoxicity Antibody Titers to H5N1 and H7N9 Avian Influenza A Viruses in Healthy US Adults and Older Children. J Infect Dis 2015; 212:1052-60. [PMID: 25795791 PMCID: PMC4668882 DOI: 10.1093/infdis/jiv181] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 03/10/2015] [Indexed: 11/12/2022] Open
Abstract
Human influenza is a highly contagious acute respiratory illness that is responsible for significant morbidity and excess mortality worldwide. In addition to neutralizing antibodies, there are antibodies that bind to influenza virus-infected cells and mediate lysis of the infected cells by natural killer (NK) cells (antibody-dependent cellular cytotoxicity [ADCC]) or complement (complement-dependent lysis [CDL]). We analyzed sera obtained from 16 healthy adults (18-63 years of age), 52 children (2-17 years of age), and 10 infants (0.75-1 year of age) in the United States, who were unlikely to have been exposed to the avian H7N9 subtype of influenza A virus, by ADCC and CDL assays. As expected, none of these sera had detectable levels of hemagglutination-inhibiting antibodies against the H7N9 virus, but we unexpectedly found high titers of ADCC antibodies to the H7N9 subtype virus in all sera from adults and children aged ≥8 years.
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Affiliation(s)
| | | | - John Cruz
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester
| | - Francis A. Ennis
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester
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85
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Abstract
Vaccines already developed have been enormously successful. However, the development of future vaccines requires solution of a number of immunologic problems, including pathogen variability, short effector memory, evoking functional responses, and identification of antigens that generate protective responses. In addition, different populations may respond differently to the same vaccine because of genetic, age, or environmental factors.
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86
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Stieh DJ, King DF, Klein K, Aldon Y, McKay PF, Shattock RJ. Discrete partitioning of HIV-1 Env forms revealed by viral capture. Retrovirology 2015; 12:81. [PMID: 26399966 PMCID: PMC4581120 DOI: 10.1186/s12977-015-0207-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 09/15/2015] [Indexed: 11/25/2022] Open
Abstract
Background The structure of HIV-1 envelope glycoprotein (Env) is flexible and heterogeneous on whole virions. Although functional Env complexes are thought to require trimerization of cleaved gp41/gp120 heterodimers, variable processing can result in the potential incorporation of non-functional uncleaved proteins (gp160), non-trimeric arrangements of gp41/gp120 heterodimers, and gp120 depleted gp41 stumps. The potential distribution of functional and non-functional Env forms across replication-competent viral populations may have important implications for neutralizing and non-neutralizing antibody functions. This study applied an immuno-bead viral capture assay (VCA) to interrogate the potential distribution (heterologous vs homologous) of functional and non-functional forms of virion associated Env. Results The VCA revealed a significant association between depletion of infectious virions and virion Env incorporation, but not between infectivity and p24-gag. Three distinct subpopulations of virions were identified within pools of genetically homogenous viral particles. Critically, a significant subpopulation of infectious virions were exclusively captured by neutralizing antibodies (nAbs) indicative of a homologous distribution of functional trimeric Env forms. A second infectious subpopulation bound both neutralizing and non-neutralizing antibodies (nnAbs) representative of a heterologous distribution of Env forms, while a third non-infectious subpopulation was predominantly bound by nnAbs recognizing gp41 stumps. Conclusions The observation that a distinct and significant subpopulation of infectious virions is exclusively captured by neutralizing antibodies has important implications for understanding antibody binding and neutralization, as well as other antibody effector functions. Electronic supplementary material The online version of this article (doi:10.1186/s12977-015-0207-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daniel J Stieh
- Department of Cellular and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
| | - Deborah F King
- Mucosal Infection and Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
| | - Katja Klein
- Mucosal Infection and Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
| | - Yoann Aldon
- Mucosal Infection and Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
| | - Paul F McKay
- Mucosal Infection and Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
| | - Robin J Shattock
- Mucosal Infection and Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
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87
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Gohain N, Tolbert WD, Acharya P, Yu L, Liu T, Zhao P, Orlandi C, Visciano ML, Kamin-Lewis R, Sajadi MM, Martin L, Robinson JE, Kwong PD, DeVico AL, Ray K, Lewis GK, Pazgier M. Cocrystal Structures of Antibody N60-i3 and Antibody JR4 in Complex with gp120 Define More Cluster A Epitopes Involved in Effective Antibody-Dependent Effector Function against HIV-1. J Virol 2015; 89:8840-54. [PMID: 26085162 PMCID: PMC4524080 DOI: 10.1128/jvi.01232-15] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 06/05/2015] [Indexed: 01/02/2023] Open
Abstract
UNLABELLED Accumulating evidence indicates a role for Fc receptor (FcR)-mediated effector functions of antibodies, including antibody-dependent cell-mediated cytotoxicity (ADCC), in prevention of human immunodeficiency virus type 1 (HIV-1) acquisition and in postinfection control of viremia. Consequently, an understanding of the molecular basis for Env epitopes that constitute effective ADCC targets is of fundamental interest for humoral anti-HIV-1 immunity and for HIV-1 vaccine design. A substantial portion of FcR effector function of potentially protective anti-HIV-1 antibodies is directed toward nonneutralizing, transitional, CD4-inducible (CD4i) epitopes associated with the gp41-reactive region of gp120 (cluster A epitopes). Our previous studies defined the A32-like epitope within the cluster A region and mapped it to the highly conserved and mobile layers 1 and 2 of the gp120 inner domain within the C1-C2 regions of gp120. Here, we elucidate additional cluster A epitope structures, including an A32-like epitope, recognized by human monoclonal antibody (MAb) N60-i3, and a hybrid A32-C11-like epitope, recognized by rhesus macaque MAb JR4. These studies define for the first time a hybrid A32-C11-like epitope and map it to elements of both the A32-like subregion and the seven-layered β-sheet of the gp41-interactive region of gp120. These studies provide additional evidence that effective antibody-dependent effector function in the cluster A region depends on precise epitope targeting--a combination of epitope footprint and mode of antibody attachment. All together these findings help further an understanding of how cluster A epitopes are targeted by humoral responses. IMPORTANCE HIV/AIDS has claimed the lives of over 30 million people. Although antiretroviral drugs can control viral replication, no vaccine has yet been developed to prevent the spread of the disease. Studies of natural HIV-1 infection, simian immunodeficiency virus (SIV)- or simian-human immunodeficiency virus (SHIV)-infected nonhuman primates (NHPs), and HIV-1-infected humanized mouse models, passive transfer studies in infants born to HIV-infected mothers, and the RV144 clinical trial have linked FcR-mediated effector functions of anti-HIV-1 antibodies with postinfection control of viremia and/or blocking viral acquisition. With this report we provide additional definition of the molecular determinants for Env antigen engagement which lead to effective antibody-dependent effector function directed to the nonneutralizing CD4-dependent epitopes in the gp41-reactive region of gp120. These findings have important implications for the development of an effective HIV-1 vaccine.
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Affiliation(s)
- Neelakshi Gohain
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - William D Tolbert
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Priyamvada Acharya
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Lei Yu
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Tongyun Liu
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Pingsen Zhao
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Chiara Orlandi
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Maria L Visciano
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Roberta Kamin-Lewis
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Mohammad M Sajadi
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA Medical Care Clinical Center, VA Maryland Health Care Center, Baltimore, Maryland, USA
| | - Loïc Martin
- CEA, iBiTecS, Service d'Ingénierie Moléculaire des Protéines, Gif-sur-Yvette, France
| | - James E Robinson
- Department of Pediatrics, Tulane University Medical Center, New Orleans, Louisiana, USA
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Anthony L DeVico
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Krishanu Ray
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - George K Lewis
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Marzena Pazgier
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, Maryland, USA Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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88
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Excler JL, Robb ML, Kim JH. Prospects for a globally effective HIV-1 vaccine. Vaccine 2015; 33 Suppl 4:D4-12. [PMID: 26100921 DOI: 10.1016/j.vaccine.2015.03.059] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/07/2015] [Accepted: 03/10/2015] [Indexed: 11/28/2022]
Abstract
A globally effective vaccine strategy must cope with the broad genetic diversity of HIV and contend with multiple transmission modalities. Understanding correlates of protection and the role of diversity in limiting protective vaccines with those correlates is key. RV144 was the first HIV-1 vaccine trial to demonstrate efficacy against HIV-1 infection. A correlates analysis compared vaccine-induced immune responses in vaccinated-infected and vaccinated-uninfected volunteers suggested that IgG specific for the V1V2 region of gp120 was associated with reduced risk of HIV-1 infection and that plasma Env IgA was directly correlated with infection risk. RV144 and recent NHP challenge studies suggest that Env is essential and perhaps sufficient to induce protective antibody responses against mucosally acquired HIV-1. Whether RV144 immune correlates can apply to different HIV vaccines, to populations with different modes and intensity of transmission, or to divergent HIV-1 subtypes remains unknown. Newer prime-boost mosaic and conserved sequence immunization strategies aiming at inducing immune responses of greater breadth and depth as well as the development of immunogens inducing broadly neutralizing antibodies should be actively pursued. Efficacy trials are now planned in heterosexual populations in southern Africa and MSM in Thailand. Although NHP challenge studies may guide vaccine development, human efficacy trials remain key to answer the critical questions leading to the development of a global HIV-1 vaccine for licensure.
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Affiliation(s)
- Jean-Louis Excler
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Bethesda, MD, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA.
| | - Merlin L Robb
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Bethesda, MD, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA
| | - Jerome H Kim
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Bethesda, MD, USA
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89
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An Enhanced Synthetic Multiclade DNA Prime Induces Improved Cross-Clade-Reactive Functional Antibodies when Combined with an Adjuvanted Protein Boost in Nonhuman Primates. J Virol 2015; 89:9154-66. [PMID: 26085155 DOI: 10.1128/jvi.00652-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 06/06/2015] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED The search for an efficacious human immunodeficiency virus type 1 (HIV-1) vaccine remains a pressing need. The moderate success of the RV144 Thai clinical vaccine trial suggested that vaccine-induced HIV-1-specific antibodies can reduce the risk of HIV-1 infection. We have made several improvements to the DNA platform and have previously shown that improved DNA vaccines alone are capable of inducing both binding and neutralizing antibodies in small-animal models. In this study, we explored how an improved DNA prime and recombinant protein boost would impact HIV-specific vaccine immunogenicity in rhesus macaques (RhM). After DNA immunization with either a single HIV Env consensus sequence or multiple constructs expressing HIV subtype-specific Env consensus sequences, we detected both CD4(+) and CD8(+) T-cell responses to all vaccine immunogens. These T-cell responses were further increased after protein boosting to levels exceeding those of DNA-only or protein-only immunization. In addition, we observed antibodies that exhibited robust cross-clade binding and neutralizing and antibody-dependent cellular cytotoxicity (ADCC) activity after immunization with the DNA prime-protein boost regimen, with the multiple-Env formulation inducing a more robust and broader response than the single-Env formulation. The magnitude and functionality of these responses emphasize the strong priming effect improved DNA immunogens can induce, which are further expanded upon protein boost. These results support further study of an improved synthetic DNA prime together with a protein boost for enhancing anti-HIV immune responses. IMPORTANCE Even with effective antiretroviral drugs, HIV remains an enormous global health burden. Vaccine development has been problematic in part due to the high degree of diversity and poor immunogenicity of the HIV Env protein. Studies suggest that a relevant HIV vaccine will likely need to induce broad cellular and humoral responses from a simple vaccine regimen due to the resource-limited setting in which the HIV pandemic is most rampant. DNA vaccination lends itself well to increasing the amount of diversity included in a vaccine due to the ease of manufacturing multiple plasmids and formulating them as a single immunization. By increasing the number of Envs within a formulation, we were able to show an increased breadth of responses as well as improved functionality induced in a nonhuman primate model. This increased breadth could be built upon, leading to better coverage against circulating strains with broader vaccine-induced protection.
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90
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Brown J, Excler JL, Kim JH. New prospects for a preventive HIV-1 vaccine. J Virus Erad 2015; 1:78-88. [PMID: 26523292 PMCID: PMC4625840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The immune correlates of risk analysis and recent non-human primate (NHP) challenge studies have generated hypotheses that suggest HIV-1 envelope may be essential and, perhaps, sufficient to induce protective antibody responses against HIV-1 acquisition at the mucosal entry. New prime-boost mosaic and conserved-sequence, together with replicating vector immunisation strategies aiming at inducing immune responses or greater breadth, as well as the development of immunogens inducing broadly neutralising antibodies and mucosal responses, should be actively pursued and tested in humans. Whether the immune correlates of risk identified in RV144 can be extended to other vaccines, other populations, or different modes and intensity of transmission, and against increasing HIV-1 genetic diversity, remains to be demonstrated. Although NHP challenge studies may guide vaccine development, human efficacy trials remain key for answering the critical questions leading to the development of a global HIV-1 vaccine for licensure.
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Affiliation(s)
| | - Jean-Louis Excler
- US Military HIV Research Program,
Bethesda,
MD,
USA,The Henry M Jackson Foundation for the Advancement of Military Medicine,
Bethesda,
MD,
USA,Corresponding author: Jean-Louis Excler,
US Military HIV Research Program,
6720-A Rockledge Drive, Suite 400Bethesda,
MD20817,
USA
| | - Jerome H Kim
- US Military HIV Research Program,
Walter Reed Army Institute of Research,
Silver Spring,
MD,
USA
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91
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Esparza J. A New Scientific Paradigm may be Needed to Finally Develop an HIV Vaccine. Front Immunol 2015; 6:124. [PMID: 25852692 PMCID: PMC4364287 DOI: 10.3389/fimmu.2015.00124] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 03/06/2015] [Indexed: 12/13/2022] Open
Abstract
The bulk of current HIV vaccine research is conducted within the infectious disease paradigm that has been very successful in developing vaccines against many other viral diseases. Different HIV vaccine concepts, based on the induction of neutralizing antibodies and/or cell mediated immunity, have been developed and clinically tested over the last 30 years, resulting in a few small successes and many disappointments. As new scientific knowledge is obtained, HIV vaccine concepts are constantly modified with the hope that the newly introduced tweaks (or paradigm drifts) will provide the solution to one of the most difficult challenges that modern biomedical research is confronting. Efficacy trials have been critical in guiding HIV vaccine development. However, from the five phase III efficacy trials conducted to date, only one (RV144) resulted in modest efficacy. The results from RV144 were surprising in many ways, including the identified putative correlates of protection (or risk), which did not include neutralizing antibodies or cytotoxic T-cells. The solution to the HIV vaccine challenge may very well come from approaches based on the current paradigm. However, at the same time, out-of-the-paradigm ideas should be systematically explored to complement the current efforts. New mechanisms are needed to identify and support the innovative research that will hopefully accelerate the development of an urgently needed HIV vaccine.
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Affiliation(s)
- José Esparza
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD, USA
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92
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Whaley KJ, Mayer KH. Strategies for preventing mucosal cell-associated HIV transmission. J Infect Dis 2015; 210 Suppl 3:S674-80. [PMID: 25414423 DOI: 10.1093/infdis/jiu398] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Human immunodeficiency virus (HIV) may be transmitted through either cell-free virions or leukocytes harboring intracellular HIV in bodily fluids. In recent years, the early initiation of combination antiretroviral therapy leading to virological suppression has resulted in decreased HIV transmission to uninfected partners. Additionally, the efficacy of primary chemoprophylaxis with oral or topical antiretroviral regimens containing tenofovir (with or without emtricitabine) has been demonstrated. However, the efficacy of these approaches may be compromised by suboptimal adherence, decreased drug concentrations in mucosal compartments in women, and genital inflammation. Furthermore, in vitro studies on the effects of tenofovir on cell-associated HIV transmission have produced conflicting results. Preclinical studies suggest that combination preventive approaches may be most effective in stopping the transmission of HIV after mucosal exposure. Since the development of antibodies were found to correlate with protection in the only effective HIV vaccine trial, the administration of preformed mucosal and systemic antibodies may inform the development of safe and effective antibody-based oral, topical, and/or systemic preexposure prophylaxis agents and provide guidance in the development of HIV vaccines that effectively block cell-associated HIV transmission.
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Affiliation(s)
| | - Kenneth H Mayer
- The Fenway Institute, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, Massachusetts
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93
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Knudsen ML, Ljungberg K, Tatoud R, Weber J, Esteban M, Liljeström P. Alphavirus replicon DNA expressing HIV antigens is an excellent prime for boosting with recombinant modified vaccinia Ankara (MVA) or with HIV gp140 protein antigen. PLoS One 2015; 10:e0117042. [PMID: 25643354 PMCID: PMC4314072 DOI: 10.1371/journal.pone.0117042] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 12/18/2014] [Indexed: 12/31/2022] Open
Abstract
Vaccination with DNA is an attractive strategy for induction of pathogen-specific T cells and antibodies. Studies in humans have shown that DNA vaccines are safe, but their immunogenicity needs further improvement. As a step towards this goal, we have previously demonstrated that immunogenicity is increased with the use of an alphavirus DNA-launched replicon (DREP) vector compared to conventional DNA vaccines. In this study, we investigated the effect of varying the dose and number of administrations of DREP when given as a prime prior to a heterologous boost with poxvirus vector (MVA) and/or HIV gp140 protein formulated in glucopyranosyl lipid A (GLA-AF) adjuvant. The DREP and MVA vaccine constructs encoded Env and a Gag-Pol-Nef fusion protein from HIV clade C. One to three administrations of 0.2 μg DREP induced lower HIV-specific T cell and IgG responses than the equivalent number of immunizations with 10 μg DREP. However, the two doses were equally efficient as a priming component in a heterologous prime-boost regimen. The magnitude of immune responses depended on the number of priming immunizations rather than the dose. A single low dose of DREP prior to a heterologous boost resulted in greatly increased immune responses compared to MVA or protein antigen alone, demonstrating that a mere 0.2 μg DREP was sufficient for priming immune responses. Following a DREP prime, T cell responses were expanded greatly by an MVA boost, and IgG responses were also expanded when boosted with protein antigen. When MVA and protein were administered simultaneously following multiple DREP primes, responses were slightly compromised compared to administering them sequentially. In conclusion, we have demonstrated efficient priming of HIV-specific T cell and IgG responses with a low dose of DREP, and shown that the priming effect depends on number of primes administered rather than dose.
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MESH Headings
- Alphavirus/genetics
- Animals
- Antibodies, Viral/immunology
- Chemistry, Pharmaceutical
- DNA, Recombinant/genetics
- DNA, Viral/genetics
- Female
- Gene Expression
- Genetic Vectors/genetics
- HIV Antigens/genetics
- HIV Antigens/immunology
- HIV-1/immunology
- Immunization, Secondary
- Immunoglobulin G/immunology
- Lipid A/chemistry
- Mice
- Mice, Inbred BALB C
- Replicon/genetics
- T-Lymphocytes/immunology
- Vaccines, DNA/genetics
- Vaccines, DNA/immunology
- Vaccinia virus/genetics
- env Gene Products, Human Immunodeficiency Virus/chemistry
- env Gene Products, Human Immunodeficiency Virus/immunology
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Affiliation(s)
- Maria L. Knudsen
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- * E-mail: (MLK); (PL)
| | - Karl Ljungberg
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Roger Tatoud
- Imperial College London, Department of Infectious Diseases, Division of Medicine, Norfolk Place, London, United Kingdom
| | - Jonathan Weber
- Imperial College London, Department of Infectious Diseases, Division of Medicine, Norfolk Place, London, United Kingdom
| | - Mariano Esteban
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Peter Liljeström
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- * E-mail: (MLK); (PL)
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94
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Requirement for Fc effector mechanisms in the APOBEC3/Rfv3-dependent neutralizing antibody response. J Virol 2015; 89:4011-4. [PMID: 25589647 DOI: 10.1128/jvi.03399-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antiretroviral neutralizing antibody (NAb) responses are often evaluated in the absence of Fc-dependent immune effectors. In murine Friend retrovirus infection, Apobec3/Rfv3 promotes a potent polyclonal NAb response. Here, we show that the Apobec3/Rfv3-dependent NAb response correlated with virus-specific IgG2 titers and that the in vivo neutralization potency of Apobec3/Rfv3-resistant antisera was dependent on activating Fcγ receptors but not complement. The data strengthen retroviral vaccine strategies aimed at eliciting NAbs that activate specific Fcγ receptors.
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95
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Görander S, Ekblad M, Bergström T, Liljeqvist JÅ. Anti-glycoprotein g antibodies of herpes simplex virus 2 contribute to complete protection after vaccination in mice and induce antibody-dependent cellular cytotoxicity and complement-mediated cytolysis. Viruses 2014; 6:4358-72. [PMID: 25398047 PMCID: PMC4246227 DOI: 10.3390/v6114358] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 10/31/2014] [Accepted: 11/04/2014] [Indexed: 11/16/2022] Open
Abstract
We investigated the role of antibodies against the mature portion of glycoprotein G (mgG-2) of herpes simplex virus 2 (HSV-2) in protective immunity after vaccination. Mice were immunized intramuscularly with mgG-2 and oligodeoxynucleotides containing two CpG motifs plus alum as adjuvant. All C57BL/6 mice survived and presented no genital or systemic disease. High levels of immunoglobulin G subclass 1 (IgG1) and IgG2 antibodies were detected and re-stimulated splenic CD4+ T cells proliferated and produced IFN-γ. None of the sera from immunized mice exhibited neutralization, while all sera exerted antibody-dependent cellular cytotoxicity (ADCC) and complement-mediated cytolysis (ACMC) activity. Passive transfer of anti-mgG-2 monoclonal antibodies, or immune serum, to naive C57BL/6 mice did not limit disease progression. Immunized B‑cell KO mice presented lower survival rate and higher vaginal viral titers, as compared with vaccinated B-cell KO mice after passive transfer of immune serum and vaccinated C57BL/6 mice. Sera from mice that were vaccinated subcutaneously and intranasally with mgG-2 presented significantly lower titers of IgG antibodies and lower ADCC and ACMC activity. We conclude that anti-mgG-2 antibodies were of importance to limit genital HSV‑2 infection. ADCC and ACMC activity are potentially important mechanisms in protective immunity, and could tentatively be evaluated in future animal vaccine studies and in clinical trials.
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Affiliation(s)
- Staffan Görander
- Department of Infectious Diseases, Section of Virology, Guldhedsgatan 10 B, S-413 46 Gothenburg, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg, Box 100, 405 30 Göteborg, Sweden.
| | - Maria Ekblad
- Department of Infectious Diseases, Section of Virology, Guldhedsgatan 10 B, S-413 46 Gothenburg, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg, Box 100, 405 30 Göteborg, Sweden.
| | - Tomas Bergström
- Department of Infectious Diseases, Section of Virology, Guldhedsgatan 10 B, S-413 46 Gothenburg, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg, Box 100, 405 30 Göteborg, Sweden.
| | - Jan-Åke Liljeqvist
- Department of Infectious Diseases, Section of Virology, Guldhedsgatan 10 B, S-413 46 Gothenburg, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg, Box 100, 405 30 Göteborg, Sweden.
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Esparza J, Van Regenmortel MHV. More Surprises in the Development of an HIV Vaccine. Front Immunol 2014; 5:329. [PMID: 25071786 PMCID: PMC4095567 DOI: 10.3389/fimmu.2014.00329] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 06/29/2014] [Indexed: 01/16/2023] Open
Affiliation(s)
- José Esparza
- Institute of Human Virology, University of Maryland School of Medicine , Baltimore, MD , USA
| | - Marc H V Van Regenmortel
- CNRS, UMR7242-Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), Université de Strasbourg , Illkirch-Graffenstaden , France
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