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Abstract
A novel tool for the presentation of peptides and small proteins on the surface of human cells has been developed. Our tANCHOR system utilizes tetraspanin anchors containing heterologous amino acid sequences inserted instead of the large extracellular loop. This technology allows a highly effective extracellular display of epitopes for antibody binding studies and many other potential applications.
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Abstract
Although vaccines have been successfully developed against several pathogens, designing an effective vaccine to protect against human immunodeficiency virus (HIV) has remained an intractable challenge. To address this, the research community has looked to human and non-human primate studies to understand the correlates of protective immunity, based on which a targeted vaccine strategy may be designed. Two distinct approaches, focused on different immune correlates of protection, have emerged. The first focuses on structure-based design of HIV envelope immunogens that are able to induce antibodies that neutralize the virus. The second focuses on strategies aimed at driving non-neutralizing polyclonal and polyfunctional antibodies that engage other arms of immunity to clear the virus. Here we review these two different vaccine design strategies and posit that ultimately the convergence of these two efforts will likely be necessary for the development of a globally protective HIV vaccine.
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Affiliation(s)
- Galit Alter
- Ragon Institute of MGH, MIT, and Harvard, Boston, MA, USA.
| | - Dan Barouch
- Ragon Institute of MGH, MIT, and Harvard, Boston, MA, USA; Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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3
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The development of HIV vaccines targeting gp41 membrane-proximal external region (MPER): challenges and prospects. Protein Cell 2018; 9:596-615. [PMID: 29667004 PMCID: PMC6019655 DOI: 10.1007/s13238-018-0534-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Accepted: 03/05/2018] [Indexed: 10/31/2022] Open
Abstract
A human immunodeficiency virus type-1 (HIV-1) vaccine which is able to effectively prevent infection would be the most powerful method of extinguishing pandemic of the acquired immunodeficiency syndrome (AIDS). Yet, achieving such vaccine remains great challenges. The membrane-proximal external region (MPER) is a highly conserved region of the envelope glycoprotein (Env) gp41 subunit near the viral envelope surface, and it plays a key role in membrane fusion. It is also the target of some reported broadly neutralizing antibodies (bNAbs). Thus, MPER is deemed to be one of the most attractive vaccine targets. However, no one can induce these bNAbs by immunization with immunogens containing the MPER sequence(s). The few attempts at developing a vaccine have only resulted in the induction of neutralizing antibodies with quite low potency and limited breadth. Thus far, vaccine failure can be attributed to various characteristics of MPER, such as those involving structure and immunology; therefore, we will focus on these and review the recent progress in the field from the following perspectives: (1) MPER structure and its role in membrane fusion, (2) the epitopes and neutralization mechanisms of MPER-specific bNAbs, as well as the limitations in eliciting neutralizing antibodies, and (3) different strategies for MPER vaccine design and current harvests.
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Nabi R, Moldoveanu Z, Wei Q, Golub ET, Durkin HG, Greenblatt RM, Herold BC, Nowicki MJ, Kassaye S, Cho MW, Pinter A, Landay AL, Mestecky J, Kozlowski PA. Differences in serum IgA responses to HIV-1 gp41 in elite controllers compared to viral suppressors on highly active antiretroviral therapy. PLoS One 2017; 12:e0180245. [PMID: 28671952 PMCID: PMC5495342 DOI: 10.1371/journal.pone.0180245] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 06/12/2017] [Indexed: 02/05/2023] Open
Abstract
Mechanisms responsible for natural control of human immunodeficiency type 1 (HIV) replication in elite controllers (EC) remain incompletely defined. To determine if EC generate high quality HIV-specific IgA responses, we used Western blotting to compare the specificities and frequencies of IgA to HIV antigens in serum of gender-, age- and race-matched EC and aviremic controllers (HC) and viremic noncontrollers (HN) on highly active antiretroviral therapy (HAART). Concentrations and avidity of IgA to HIV antigens were measured using ELISA or multiplex assays. Measurements for IgG were performed in parallel. EC were found to have stronger p24- and V1V2-specific IgG responses than HN, but there were no IgG differences for EC and HC. In contrast, IgA in EC serum bound more frequently to gp160 and gag proteins than IgA in HC or HN. The avidity of anti-gp41 IgA was also greater in EC, and these subjects had stronger IgA responses to the gp41 heptad repeat region 1 (HR1), a reported target of anti-bacterial RNA polymerase antibodies that cross react with gp41. However, EC did not demonstrate greater IgA responses to E. coli RNA polymerase or to peptides containing the shared LRAI sequence, suggesting that most of their HR1-specific IgA antibodies were not induced by intestinal microbiota. In both EC and HAART recipients, the concentrations of HIV-specific IgG were greater than HIV-specific IgA, but their avidities were comparable, implying that they could compete for antigen. Exceptions were C1 peptides and V1V2 loops. IgG and IgA responses to these antigens were discordant, with IgG reacting to V1V2, and IgA reacting to C1, especially in EC. Interestingly, EC with IgG hypergammaglobulinemia had greater HIV-specific IgA and IgG responses than EC with normal total IgG levels. Heterogeneity in EC antibody responses may therefore be due to a more focused HIV-specific B cell response in some of these individuals. Overall, these data suggest that development of HIV-specific IgA responses and affinity maturation of anti-gp41 IgA antibodies occurs to a greater extent in EC than in subjects on HAART. Future studies will be required to determine if IgA antibodies in EC may contribute in control of viral replication.
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Affiliation(s)
- Rafiq Nabi
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, United States of America
| | - Zina Moldoveanu
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Qing Wei
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Elizabeth T. Golub
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States of America
| | - Helen G. Durkin
- Departments of Pathology and Medicine, SUNY Downstate, Brooklyn, NY, United States of America
| | - Ruth M. Greenblatt
- Departments of Medicine and Epidemiology/Biostastistics, University of California, San Francisco, CA, United States of America
| | - Betsy C. Herold
- Department of Obstetrics and Gynecology and Women's Health, Albert Einstein College of Medicine, Bronx, NY, United States of America
| | - Marek J. Nowicki
- Department of Pediatrics, University of Southern California, Los Angeles, CA, United States of America
| | - Seble Kassaye
- Department of Medicine, Georgetown University, Washington, D.C., United States of America
| | - Michael W. Cho
- Department of Biomedical Sciences, Iowa State University, Ames, IA, United States of America
| | - Abraham Pinter
- Public Health Research Institute, Rutgers New Jersey Medical School, Newark, NJ, United States of America
| | - Alan L. Landay
- Department of Immunity and Emerging Pathogens, Rush University Medical Center, Chicago, IL, United States of America
| | - Jiri Mestecky
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States of America
- Institute of immunology and Microbiology 1st Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Pamela A. Kozlowski
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, United States of America
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5
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Melnychuk L, Ajamian L, Jean-Pierre P, Liang J, Gheorghe R, Wainberg MA, Zaharatos GJ. Development of a DNA vaccine expressing a secreted HIV-1 gp41 ectodomain that includes the membrane-proximal external region. Vaccine 2017; 35:2736-2744. [PMID: 28392143 DOI: 10.1016/j.vaccine.2017.03.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 02/15/2017] [Accepted: 03/11/2017] [Indexed: 12/17/2022]
Abstract
A limited number of sites on the HIV-1 Envelope protein are vulnerable to broadly neutralizing antibodies (bnAbs). One of these sites, the membrane proximal external region (MPER), is located at the C-terminus of the gp41 ectodomain (gp41ecto). This highly conserved sequence is bound by several well-characterized bnAbs. Efforts to produce a gp41 immunogen are in part hampered by the MPER's hydrophobicity and propensity to induce aggregation. We sought to produce a DNA vaccine expressing a gp41ecto that is both secreted from mammalian cells and maintains binding by bnAbs to the MPER. Through in silico analysis, we predicted regions of gp41ecto that could induce aggregation and possibly hinder secretion. We generated deletion mutants of gp41ecto and tested their ability to be secreted by mammalian cells. Upon deletion of regions in either the fusion peptide (FP) or MPER, secretion of the gp41ecto increased. In an effort to both augment secretion and maintain binding by bnAbs, we developed constructs with the FP deletion and introduced point mutations in the MPER. Two constructs (gp41 ΔFP and gp41 ΔFP+I682E) maintained binding by gp41 MPER-specific bnAbs (4E10, Z13e1 and 10E8). These were evaluated as DNA vaccines in a mouse model. Both vaccines proved to be immunogenic and appeared to elicit some MPER-specific antibodies that bound gp41 ectodomain-derived proteins but not short peptides spanning the MPER. No neutralizing capacity was detected against a clade C virus containing a homologous MPER.
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Affiliation(s)
- Luca Melnychuk
- Lady Davis Institute, Jewish General Hospital, Montréal, Québec, Canada; Division of Experimental Medicine, Department of Medicine, McGill University, Montréal, Québec, Canada
| | - Lara Ajamian
- Lady Davis Institute, Jewish General Hospital, Montréal, Québec, Canada; Division of Experimental Medicine, Department of Medicine, McGill University, Montréal, Québec, Canada
| | | | - Jiaming Liang
- Lady Davis Institute, Jewish General Hospital, Montréal, Québec, Canada; Division of Experimental Medicine, Department of Medicine, McGill University, Montréal, Québec, Canada
| | - Romina Gheorghe
- Lady Davis Institute, Jewish General Hospital, Montréal, Québec, Canada
| | - Mark A Wainberg
- Lady Davis Institute, Jewish General Hospital, Montréal, Québec, Canada; Division of Experimental Medicine, Department of Medicine, McGill University, Montréal, Québec, Canada
| | - Gerasimos J Zaharatos
- Lady Davis Institute, Jewish General Hospital, Montréal, Québec, Canada; Division of Infectious Diseases, Department of Medicine, Jewish General Hospital, Montréal, Québec, Canada.
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Tan Y, Tong P, Wang J, Zhao L, Li J, Yu Y, Chen YH, Wang J. The Membrane-Proximal Region of C-C Chemokine Receptor Type 5 Participates in the Infection of HIV-1. Front Immunol 2017; 8:478. [PMID: 28484468 PMCID: PMC5402540 DOI: 10.3389/fimmu.2017.00478] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 04/05/2017] [Indexed: 01/22/2023] Open
Abstract
The initial infection and transmission of HIV-1 requires C-C chemokine receptor type 5 (CCR5). Here, we report that the membrane-proximal region (MPR, aa 22-38) of CCR5 participates in the infection of HIV-1. First, MPR-specific antibodies elicited in mice dose-dependently inhibited the infection of CCR5-tropic HIV-1. Second, substituting MPR with the same region from other co-receptors significantly impaired HIV-1 infection, while the key residues identified by alanine scanning mutagenesis formed an exposed leucine zipper-like structure. Moreover, a peptide derived from MPR could block the infection of a number of HIV-1 strains only before the formation of gp41 six-helix bundle, coincide with the early interaction between CCR5 and the gp120 protein during HIV-1 infection. These promising results ensured the potential of this previously uncharacterized domain as a starting point for the development of antiviral drugs, blocking antibodies, and HIV vaccines.
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Affiliation(s)
- Yue Tan
- Laboratory of Immunology, School of Life Sciences, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Tsinghua University, Beijing, China
| | - Pei Tong
- Laboratory of Immunology, School of Life Sciences, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Tsinghua University, Beijing, China
| | - Junyi Wang
- Laboratory of Immunology, School of Life Sciences, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Tsinghua University, Beijing, China
| | - Lei Zhao
- The Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, China
| | - Jing Li
- Laboratory of Immunology, School of Life Sciences, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Tsinghua University, Beijing, China
| | - Yang Yu
- Laboratory of Immunology, School of Life Sciences, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Tsinghua University, Beijing, China
| | - Ying-Hua Chen
- Laboratory of Immunology, School of Life Sciences, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Tsinghua University, Beijing, China
| | - Ji Wang
- Laboratory of Immunology, School of Life Sciences, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Tsinghua University, Beijing, China.,Wellman Center for Photomedicine, Massachusetts General Hospital, Department of Dermatology, Harvard Medical School, Boston, MA, USA
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Habte HH, Banerjee S, Shi H, Qin Y, Cho MW. Immunogenic properties of a trimeric gp41-based immunogen containing an exposed membrane-proximal external region. Virology 2015; 486:187-97. [PMID: 26454663 DOI: 10.1016/j.virol.2015.09.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 09/09/2015] [Accepted: 09/22/2015] [Indexed: 01/15/2023]
Abstract
The membrane-proximal external region (MPER) of HIV-1 gp41 is an attractive target for vaccine development. Thus, better understanding of its immunogenic properties in various structural contexts is important. We previously described the crystal structure of a trimeric protein complex named gp41-HR1-54Q, which consists of the heptad repeat regions 1 and 2 and the MPER. The protein was efficiently recognized by broadly neutralizing antibodies. Here, we describe its immunogenic properties in rabbits. The protein was highly immunogenic, especially the C-terminal end of the MPER containing 4E10 and 10E8 epitopes ((671)NWFDITNWLWYIK(683)). Although antibodies exhibited strong competition activity against 4E10 and 10E8, neutralizing activity was not detected. Detailed mapping analyses indicated that amino acid residues critical for recognition resided on faces of the alpha helix that are either opposite of or perpendicular to the epitopes recognized by 4E10 and 10E8. These results provide critical information for designing the next generation of MPER-based immunogens.
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Affiliation(s)
- Habtom H Habte
- College of Veterinary Medicine, Department of Biomedical Sciences, Center for Advanced Host Defenses, Immunobiotics and Translational Comparative Medicine, Iowa State University, 1600 S 16th Street, Ames, IA 50011-1250, USA
| | - Saikat Banerjee
- College of Veterinary Medicine, Department of Biomedical Sciences, Center for Advanced Host Defenses, Immunobiotics and Translational Comparative Medicine, Iowa State University, 1600 S 16th Street, Ames, IA 50011-1250, USA
| | - Heliang Shi
- College of Veterinary Medicine, Department of Biomedical Sciences, Center for Advanced Host Defenses, Immunobiotics and Translational Comparative Medicine, Iowa State University, 1600 S 16th Street, Ames, IA 50011-1250, USA
| | - Yali Qin
- College of Veterinary Medicine, Department of Biomedical Sciences, Center for Advanced Host Defenses, Immunobiotics and Translational Comparative Medicine, Iowa State University, 1600 S 16th Street, Ames, IA 50011-1250, USA
| | - Michael W Cho
- College of Veterinary Medicine, Department of Biomedical Sciences, Center for Advanced Host Defenses, Immunobiotics and Translational Comparative Medicine, Iowa State University, 1600 S 16th Street, Ames, IA 50011-1250, USA.
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8
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Immunogens Modeling a Fusion-Intermediate Conformation of gp41 Elicit Antibodies to the Membrane Proximal External Region of the HIV Envelope Glycoprotein. PLoS One 2015; 10:e0128562. [PMID: 26087072 PMCID: PMC4472232 DOI: 10.1371/journal.pone.0128562] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 04/28/2015] [Indexed: 12/02/2022] Open
Abstract
The membrane proximal external region (MPER) of the gp41 subunit of the HIV-1 envelope glycoprotein (Env) contains determinants for broadly neutralizing antibodies and has remained an important focus of vaccine design. However, creating an immunogen that elicits broadly neutralizing antibodies to this region has proven difficult in part due to the relative inaccessibility of the MPER in the native conformation of Env. Here, we describe the antigenicity and immunogenicity of a panel of oligomeric gp41 immunogens designed to model a fusion-intermediate conformation of Env in order to enhance MPER exposure in a relevant conformation. The immunogens contain segments of the gp41 N- and C-heptad repeats to mimic a trapped intermediate, followed by the MPER, with variations that include different N-heptad lengths, insertion of extra epitopes, and varying C-termini. These well-characterized immunogens were evaluated in two different immunization protocols involving gp41 and gp140 proteins, gp41 and gp160 DNA primes, and different immunization schedules and adjuvants. We found that the immunogens designed to reduce extension of helical structure into the MPER elicited the highest MPER antibody binding titers, but these antibodies lacked neutralizing activity. The gp41 protein immunogens also elicited higher MPER titers than the gp140 protein immunogen. In prime-boost studies, the best MPER responses were seen in the groups that received DNA priming with gp41 vectors followed by gp41 protein boosts. Finally, although titers to the entire protein immunogen were similar in the two immunization protocols, MPER-specific titers differed, suggesting that the immunization route, schedule, dose, or adjuvant may differentially influence MPER immunogenicity. These findings inform the design of future MPER immunogens and immunization protocols.
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Fu S, Tong P, Tan Y, Zhu Y, Chen YH. P20A inhibits HIV-1 fusion through its electrostatic interaction with the distal region of the gp41 fusion core. Microbes Infect 2015; 17:665-70. [PMID: 26003522 DOI: 10.1016/j.micinf.2015.05.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 05/08/2015] [Accepted: 05/12/2015] [Indexed: 10/23/2022]
Abstract
We previously identified an HIV-1 fusion inhibitor P20A targeting HIV-1 gp41 6-HB fusion core. Using alanine scanning mutagenesis, we investigated the effect of 6-HB surface residue mutations on the binding affinity between P20A and 6-HB. Substitution of positively or negatively charged residues in the distal region of 6-HB with alanines resulted in significant decrease or increase of its binding affinity to P20A, respectively. The 6-HB with E630K, D632K, or E634K mutation exhibited enhanced binding affinity with P20A, suggesting that P20A blocks HIV-1 fusion through electrostatic interaction with the positively charged residues in the distal region of the gp41 fusion core.
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Affiliation(s)
- Shushu Fu
- Laboratory of Immunology, School of Life Sciences, Tsinghua University, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Beijing 100084, China
| | - Pei Tong
- Laboratory of Immunology, School of Life Sciences, Tsinghua University, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Beijing 100084, China
| | - Yue Tan
- Laboratory of Immunology, School of Life Sciences, Tsinghua University, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Beijing 100084, China
| | - Yun Zhu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Ying-Hua Chen
- Laboratory of Immunology, School of Life Sciences, Tsinghua University, Beijing Key Laboratory for Protein Therapeutics, Protein Science Laboratory of the Ministry of Education, Beijing 100084, China.
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10
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Sample-free quantification of blood biomarkers via laser-treated skin. Biomaterials 2015; 59:30-8. [PMID: 25950985 DOI: 10.1016/j.biomaterials.2015.04.040] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 04/17/2015] [Accepted: 04/21/2015] [Indexed: 02/06/2023]
Abstract
Surface modified microneedle (MN) arrays are being developed to capture circulating biomarkers from the skin, but inefficiency and unreliability of the current method limit its clinical applications. We describe here that illumination of a tiny area of the skin with hemoglobin-preferably absorbent laser increased the amount of circulating biomarkers in the upper dermis by more than 1000-fold. The hemoglobin-specific light altered the permeability of capillaries leading to extravasation of molecules but not blood cells beneath the skin involved. When specific probe-coated MN arrays were applied into the laser-treated skin, the biomarkers accumulated in the upper dermis were reliably, accurately, and sufficiently captured as early as 15 min of the assay. The maximal binding occurred in 1 h in a manner independent of penetration depth or a molecular mass of the biomarker. With anti-fluorescein isothiocyanate (FITC)-MNs, we were able to measure blood concentrations of FITC in mice receiving FITC intravenously. The sensitivity and accuracy were comparable to those attained by fluorescence spectrophotometer. Likewise, MNs containing influenza hemagglutinin (HA) could detect anti-HA antibody in mice or swine receiving influenza vaccines as effectively as standard immunoassays. The novel, minimally invasive approach holds great promise for measurement of multiple biomarkers by a single array for point-of-care diagnosis.
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Cappelletti F, Clementi N, Mancini N, Clementi M, Burioni R. Virus-induced preferential antibody gene-usage and its importance in humoral autoimmunity. Semin Immunol 2015; 27:138-43. [PMID: 25857210 DOI: 10.1016/j.smim.2015.03.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 03/13/2015] [Indexed: 12/12/2022]
Abstract
It is known that even the adaptive components of the immune system are based on genetic traits common to all individuals, and that diversity is shaped by the lifelong contacts with different non-self antigens, including those found on infectious pathogens. Besides the individual differences, some of these common traits may be more prone to react against a given antigen, and this may be exploited by the infectious pathogens. Indeed, viral infections can deregulate immune response by subverting antibody (Ab) gene usage, leading to the overexpression of specific Ab subfamilies. This overexpression often results in a protective antiviral response but, in some cases, also correlates with a higher likelihood of developing humoral autoimmune disorders. These aspects of virus-induced autoimmunity have never been thoroughly reviewed, and this is the main purpose of this review. An accurate examination of virus specific Ab subfamilies elicited during infections may help further characterize the complex interplay between viruses and the humoral immune response, and be useful in the design of future monoclonal antibody (mAb)-based anti-infective prophylactic and therapeutic strategies.
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Affiliation(s)
- Francesca Cappelletti
- Laboratory of Microbiology and Virology, Università "Vita-Salute" San Raffaele, Milano, Italy
| | - Nicola Clementi
- Laboratory of Microbiology and Virology, Università "Vita-Salute" San Raffaele, Milano, Italy
| | - Nicasio Mancini
- Laboratory of Microbiology and Virology, Università "Vita-Salute" San Raffaele, Milano, Italy
| | - Massimo Clementi
- Laboratory of Microbiology and Virology, Università "Vita-Salute" San Raffaele, Milano, Italy
| | - Roberto Burioni
- Laboratory of Microbiology and Virology, Università "Vita-Salute" San Raffaele, Milano, Italy.
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12
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Dai Z, Tao Y, Liu N, Brenowitz MD, Girvin ME, Lai JR. Conditional trimerization and lytic activity of HIV-1 gp41 variants containing the membrane-associated segments. Biochemistry 2015; 54:1589-99. [PMID: 25658332 DOI: 10.1021/bi501376f] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fusion of host and viral membranes is a critical step during infection by membrane-bound viruses. The HIV-1 glycoproteins gp120 (surface subunit) and gp41 (fusion subunit) represent the prototypic system for studying this process; in the prevailing model, the gp41 ectodomain forms a trimeric six-helix bundle that constitutes a critical intermediate and provides the energetic driving force for overcoming barriers associated with membrane fusion. However, most structural studies of gp41 variants have been performed either on ectodomain constructs lacking one or more of the membrane-associated segments (the fusion peptide, FP, the membrane-proximal external region, MPER, and the transmembrane domain, TM) or on variants consisting of these isolated segments alone without the ectodomain. Several recent reports have suggested that the HIV-1 ectodomain, as well as larger construct containing the membrane-bound segments, dissociates from a trimer to a monomer in detergent micelles. Here we compare the properties of a series of gp41 variants to delineate the roles of the ectodomain, FP, and MPER and TM, all in membrane-mimicking environments. We find that these proteins are prone to formation of a monomer in detergent micelles. In one case, we observed exclusive monomer formation at pH 4 but conditional trimerization at pH 7 even at low micromolar (∼5 μM) protein concentrations. Liposome release assays demonstrate that these gp41-related proteins have the capacity to induce content leakage but that this activity is also strongly modulated by pH with much higher activity at pH 4. Circular dichroism, nuclear magnetic resonance, and binding assays with antibodies specific to the MPER provide insight into the structural and functional roles of the FP, MPER, and TM and their effect on structure within the larger context of the fusion subunit.
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Affiliation(s)
- Zhou Dai
- Department of Biochemistry, Albert Einstein College of Medicine , 1300 Morris Park Avenue, Bronx, New York 10461, United States
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13
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Krebs SJ, McBurney SP, Kovarik DN, Waddell CD, Jaworski JP, Sutton WF, Gomes MM, Trovato M, Waagmeester G, Barnett SJ, DeBerardinis P, Haigwood NL. Multimeric scaffolds displaying the HIV-1 envelope MPER induce MPER-specific antibodies and cross-neutralizing antibodies when co-immunized with gp160 DNA. PLoS One 2014; 9:e113463. [PMID: 25514675 PMCID: PMC4267727 DOI: 10.1371/journal.pone.0113463] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 10/27/2014] [Indexed: 01/11/2023] Open
Abstract
Developing a vaccine that overcomes the diversity of HIV-1 is likely to require a strategy that directs antibody (Ab) responses toward conserved regions of the viral Envelope (Env). However, the generation of neutralizing Abs (NAbs) targeting these regions through vaccination has proven to be difficult. One conserved region of particular interest is the membrane proximal external region (MPER) of Env located within the gp41 ectodomain. In order to direct the immune response to this region, the MPER and gp41 ectodomain were expressed separately as N-terminal fusions to the E2 protein of Geobacillus stearothermophilus. The E2 protein acts as a scaffold by self-assembling into 60-mer particles, displaying up to 60 copies of the fused target on the surface. Rabbits were immunized with E2 particles displaying MPER and/or the gp41 ectodomain in conjunction with DNA encoding full-length gp160. Only vaccines including E2 particles displaying MPER elicited MPER-specific Ab responses. NAbs were elicited after two immunizations that largely targeted the V3 loop. To overcome V3 immunodominance in the DNA component, E2 particles displaying MPER were used in conjunction with gp160 DNA lacking hypervariable regions V2, V3, or combined V1V2V3. All rabbits had HIV binding Ab responses and NAbs following the second vaccination. Using HIV-2/HIV-1 MPER chimeric viruses as targets, NAbs were detected in 12/16 rabbits after three immunizations. Low levels of NAbs specific for Tier 1 and 2 viruses were observed in all groups. This study provides evidence that co-immunizing E2 particles displaying MPER and gp160 DNA can focus Ab responses toward conserved regions of Env.
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Affiliation(s)
- Shelly J. Krebs
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Oregon Health and Sciences University, Beaverton, OR, United States of America
| | - Sean P. McBurney
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Oregon Health and Sciences University, Beaverton, OR, United States of America
| | - Dina N. Kovarik
- Viral Vaccines Program, Seattle Biomedical Research Institute, Seattle, WA, United States of America
| | - Chelsea D. Waddell
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Oregon Health and Sciences University, Beaverton, OR, United States of America
| | - J. Pablo Jaworski
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Oregon Health and Sciences University, Beaverton, OR, United States of America
| | - William F. Sutton
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Oregon Health and Sciences University, Beaverton, OR, United States of America
| | - Michelle M. Gomes
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Oregon Health and Sciences University, Beaverton, OR, United States of America
| | - Maria Trovato
- Institute of Protein Biochemistry, C.N.R., Naples, Italy
| | - Garret Waagmeester
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Oregon Health and Sciences University, Beaverton, OR, United States of America
| | - Susan J. Barnett
- Novartis Vaccines & Diagnostics, Emeryville, CA, United States of America
| | | | - Nancy L. Haigwood
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Oregon Health and Sciences University, Beaverton, OR, United States of America
- Viral Vaccines Program, Seattle Biomedical Research Institute, Seattle, WA, United States of America
- * E-mail:
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14
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Banerjee K, Weliky DP. Folded monomers and hexamers of the ectodomain of the HIV gp41 membrane fusion protein: potential roles in fusion and synergy between the fusion peptide, hairpin, and membrane-proximal external region. Biochemistry 2014; 53:7184-98. [PMID: 25372604 PMCID: PMC4245979 DOI: 10.1021/bi501159w] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
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HIV
is an enveloped virus and fusion between the HIV and host cell
membranes is catalyzed by the ectodomain of the HIV gp41 membrane
protein. Both the N-terminal fusion peptide (FP)
and C-terminal membrane-proximal external region
(MPER) are critical for fusion and are postulated to bind to the host
cell and HIV membranes, respectively. Prior to fusion, the gp41 on
the virion is a trimer in noncovalent complex with larger gp120 subunits.
The gp120 bind host cell receptors and move away or dissociate from
gp41 which subsequently catalyzes fusion. In the present work, large
gp41 ectodomain constructs were produced and biophysically and structurally
characterized. One significant finding is observation of synergy between
the FP, hairpin, and MPER in vesicle fusion. The ectodomain-induced
fusion can be very efficient with only ∼15 gp41 per vesicle,
which is comparable to the number of gp41 on a virion. Conditions
are found with predominant monomer or hexamer but not trimer and these
may be oligomeric states during fusion. Monomer gp41 ectodomain is
hyperthermostable and has helical hairpin structure. A new HIV fusion
model is presented where (1) hemifusion is catalyzed by folding of
gp41 ectodomain monomers into hairpins and (2) subsequent fusion steps
are catalyzed by assembly into a hexamer with FPs in an antiparallel
β sheet. There is also significant interest in the gp41 MPER
because it is the epitope of several broadly neutralizing antibodies.
Two of these antibodies bind our gp41 ectodomain constructs and support
investigation of the gp41 ectodomain as an immunogen in HIV vaccine
development.
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Affiliation(s)
- Koyeli Banerjee
- Department of Chemistry, Michigan State University , East Lansing, Michigan 48824, United States
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15
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Lai RPJ, Hock M, Radzimanowski J, Tonks P, Hulsik DL, Effantin G, Seilly DJ, Dreja H, Kliche A, Wagner R, Barnett SW, Tumba N, Morris L, LaBranche CC, Montefiori DC, Seaman MS, Heeney JL, Weissenhorn W. A fusion intermediate gp41 immunogen elicits neutralizing antibodies to HIV-1. J Biol Chem 2014; 289:29912-26. [PMID: 25160627 PMCID: PMC4208001 DOI: 10.1074/jbc.m114.569566] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 08/01/2014] [Indexed: 11/06/2022] Open
Abstract
The membrane-proximal external region (MPER) of the human immunodeficiency virus, type 1 (HIV-1) envelope glycoprotein subunit gp41 is targeted by potent broadly neutralizing antibodies 2F5, 4E10, and 10E8. These antibodies recognize linear epitopes and have been suggested to target the fusion intermediate conformation of gp41 that bridges viral and cellular membranes. Anti-MPER antibodies exert different degrees of membrane interaction, which is considered to be the limiting factor for the generation of such antibodies by immunization. Here we characterize a fusion intermediate conformation of gp41 (gp41(int)-Cys) and show that it folds into an elongated ∼ 12-nm-long extended structure based on small angle x-ray scattering data. Gp41(int)-Cys was covalently linked to liposomes via its C-terminal cysteine and used as immunogen. The gp41(int)-Cys proteoliposomes were administered alone or in prime-boost regimen with trimeric envelope gp140(CA018) in guinea pigs and elicited high anti-gp41 IgG titers. The sera interacted with a peptide spanning the MPER region, demonstrated competition with broadly neutralizing antibodies 2F5 and 4E10, and exerted modest lipid binding, indicating the presence of MPER-specific antibodies. Although the neutralization potency generated solely by gp140(CA018) was higher than that induced by gp41(int)-Cys, the majority of animals immunized with gp41(int)-Cys proteoliposomes induced modest breadth and potency in neutralizing tier 1 pseudoviruses and replication-competent simian/human immunodeficiency viruses in the TZM-bl assay as well as responses against tier 2 HIV-1 in the A3R5 neutralization assay. Our data thus demonstrate that liposomal gp41 MPER formulation can induce neutralization activity, and the strategy serves to improve breadth and potency of such antibodies by improved vaccination protocols.
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Affiliation(s)
- Rachel P J Lai
- From the Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom
| | - Miriam Hock
- Université Grenoble Alpes, Unit of Virus Host Cell Interactions (UVHCI), F-38000 Grenoble, France, CNRS, UVHCI, F-38000 Grenoble, France
| | - Jens Radzimanowski
- Université Grenoble Alpes, Unit of Virus Host Cell Interactions (UVHCI), F-38000 Grenoble, France, CNRS, UVHCI, F-38000 Grenoble, France
| | - Paul Tonks
- From the Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom
| | - David Lutje Hulsik
- Université Grenoble Alpes, Unit of Virus Host Cell Interactions (UVHCI), F-38000 Grenoble, France, CNRS, UVHCI, F-38000 Grenoble, France
| | - Gregory Effantin
- Université Grenoble Alpes, Unit of Virus Host Cell Interactions (UVHCI), F-38000 Grenoble, France, CNRS, UVHCI, F-38000 Grenoble, France
| | - David J Seilly
- From the Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom
| | - Hanna Dreja
- From the Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom
| | - Alexander Kliche
- Institute of Medical Microbiology and Hygiene, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Ralf Wagner
- Institute of Medical Microbiology and Hygiene, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Susan W Barnett
- Novartis Vaccines and Diagnostics Inc., Cambridge, Massachusetts 02139
| | - Nancy Tumba
- National Institute for Communicable Diseases, Centre for HIV and Sexually Transmitted Infections, 1 Modderfontein Road, Sandringham 2131, South Africa
| | - Lynn Morris
- National Institute for Communicable Diseases, Centre for HIV and Sexually Transmitted Infections, 1 Modderfontein Road, Sandringham 2131, South Africa
| | - Celia C LaBranche
- Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, and
| | - David C Montefiori
- Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, and
| | - Michael S Seaman
- Division of Viral Pathogenesis, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115
| | - Jonathan L Heeney
- From the Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom,
| | - Winfried Weissenhorn
- Université Grenoble Alpes, Unit of Virus Host Cell Interactions (UVHCI), F-38000 Grenoble, France, CNRS, UVHCI, F-38000 Grenoble, France,
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16
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Novel neutralising antibodies targeting the N-terminal helical region of the transmembrane envelope protein p15E of the porcine endogenous retrovirus (PERV). Immunol Res 2014; 58:9-19. [PMID: 23729215 DOI: 10.1007/s12026-013-8430-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Previously, immunising different species with the transmembrane envelope protein p15E of the porcine endogenous retrovirus (PERV), neutralising antibodies were induced which recognised epitopes in the fusion peptide proximal region (FPPR) and in the membrane-proximal external region (MPER). Only the MPER-specific antibodies were shown to neutralise and these antibodies targeted epitopes in the MPER similarly localised as the epitopes recognised by antibodies broadly neutralising HIV-1 such as 2F5 and 4E10. To study whether neutralising antibodies could be induced immunising with subunits of p15E, recombinant proteins corresponding to the N-terminal, the C-terminal helical region (NHR, CHR) and a p15E with a mutation in the Cys-Cys loop were produced. Whereas none of these antigens induced MPER-specific neutralising antibodies, the animals immunised with the FPPR/NHR subunit and the mutated p15E produced neutralising antibodies binding to the NHR. Therefore, for the first time, antibodies specific for the NHR and neutralising PERV were described.
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17
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Gong Z, Kessans SA, Song L, Dörner K, Lee HH, Meador LR, LaBaer J, Hogue BG, Mor TS, Fromme P. Recombinant expression, purification, and biophysical characterization of the transmembrane and membrane proximal domains of HIV-1 gp41. Protein Sci 2014; 23:1607-18. [PMID: 25155369 DOI: 10.1002/pro.2540] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 07/22/2014] [Accepted: 08/20/2014] [Indexed: 11/07/2022]
Abstract
The transmembrane subunit (gp41) of the envelope glycoprotein of HIV-1 associates noncovalently with the surface subunit (gp120) and together they play essential roles in viral mucosal transmission and infection of target cells. The membrane proximal region (MPR) of gp41 is highly conserved and contains epitopes of broadly neutralizing antibodies. The transmembrane (TM) domain of gp41 not only anchors the envelope glycoprotein complex in the viral membrane but also dynamically affects the interactions of the MPR with the membrane. While high-resolution X-ray structures of some segments of the MPR were solved in the past, they represent the post-fusion forms. Structural information on the TM domain of gp41 is scant and at low resolution. Here we describe the design, expression and purification of a protein construct that includes MPR and the transmembrane domain of gp41 (MPR-TMTEV-6His), which reacts with the broadly neutralizing antibodies 2F5 and 4E10 and thereby may represent an immunologically relevant conformation mimicking a prehairpin intermediate of gp41. The expression level of MPR-TMTEV-6His was improved by fusion to the C-terminus of Mistic protein, yielding ∼ 1 mg of pure protein per liter. The isolated MPR-TMTEV-6His protein was biophysically characterized and is a monodisperse candidate for crystallization. This work will enable further investigation into the structure of MPR-TMTEV-6His, which will be important for the structure-based design of a mucosal vaccine against HIV-1.
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Affiliation(s)
- Zhen Gong
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona, 85287-1604; The Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, Arizona, 85287
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18
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Benen TD, Tonks P, Kliche A, Kapzan R, Heeney JL, Wagner R. Development and immunological assessment of VLP-based immunogens exposing the membrane-proximal region of the HIV-1 gp41 protein. J Biomed Sci 2014; 21:79. [PMID: 25160824 PMCID: PMC4256929 DOI: 10.1186/s12929-014-0079-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Accepted: 08/11/2014] [Indexed: 11/10/2022] Open
Abstract
Background The membrane-proximal external region (MPER) of HIV-1 gp41 is particularly conserved and target for the potent broadly neutralizing monoclonal antibodies (bnMAbs) 2F5, 4E10 and 10E8. Epitope focusing and stabilization present promising strategies to enhance the quality of immune responses to specific epitopes. Results The aim of this work was to design and evaluate novel immunogens based on the gp41 MPER with the potential to elicit cross-clade neutralizing antibodies. For that purpose, gp41 was truncated N-terminally in order to dispose immunodominant, non-neutralizing sites and enhance the exposure of conserved regions. To stabilize a trimeric conformation, heterologous GCN4 and HA2 zipper domains were fused based on an in silico “best-fit” model to the protein’s amino terminus. Cell surface exposure of resulting proteins and their selective binding to bnMAbs 2F5 and 4E10 could be shown by cytometric analyses. Incorporation into VLPs and preservation of antigenic structures were verified by electron microscopy, and the oligomeric state was successfully stabilized by zipper domains. These gp41 immunogens were evaluated for antigenicity in an immunization study in rabbits primed with homologous DNA expression plasmids and boosted with virus-like particle (VLP) proteins. Low titers of anti-MPER antibodies were measured by IgG ELISA, and low neutralizing activity could be detected against a clade C and B viral isolate in sera. Conclusions Thus, although neutralizing titers were very moderate, induction of cross-clade neutralizing antibodies seems possible following immunization with MPER-focusing immunogens. However, further refinement of MPER presentation and immunogenicity is clearly needed to induce substantial neutralization responses to these epitopes. Electronic supplementary material The online version of this article (doi:10.1186/s12929-014-0079-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | - Ralf Wagner
- Molecular Microbiology and Gene Therapy Unit, Institute of Medical Microbiology and Hygiene, University of Regensburg, Franz-Josef-Strauss-Allee 11, Regensburg, 93053, Germany.
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19
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Strasz N, Morozov VA, Kreutzberger J, Keller M, Eschricht M, Denner J. Immunization with hybrid proteins containing the membrane proximal external region of HIV-1. AIDS Res Hum Retroviruses 2014; 30:498-508. [PMID: 24392780 DOI: 10.1089/aid.2013.0191] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The transmembrane envelope (TM) protein gp41 of HIV-1 is an attractive target when designing a vaccine to induce neutralizing antibodies. A few broadly neutralizing antibodies (2F5, 4E10, and 10E8) that target conserved epitopes in the membrane proximal external region (MPER) of gp41 have been isolated from infected individuals. However, attempts to induce such antibodies by immunizations with gp41 and Env derivatives containing the MPER were successful only to some extent. In contrast, immunizations with the ectodomain of the TM protein p15E of different gamma retroviruses resulted in the induction of neutralizing antibodies. These sera recognized epitopes located in the MPER and in the fusion peptide proximal region (FPPR) of p15E. Based on these results, both regions of p15E were substituted with the corresponding sequences derived from gp41 of HIV-1. Thus, four different hybrid antigens were produced. One of the inserted sequences contained the epitopes of 2F5 and 4E10 in the MPER; the other corresponded to the FPPR. Vaccination of rats, guinea pigs, and a goat induced binding antibodies directed against the FPPR of gp41 and the 2F5 epitope (ELDKWA) located in the MPER. Despite the exact recognition of the 2F5 epitope, no or very weak neutralization of HIV-1NL4-3 by the immune sera was demonstrated. Nonetheless, using the strategy of hybrid proteins, antibodies targeting the desired epitope were successfully induced.
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20
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10E8-like neutralizing antibodies against HIV-1 induced using a precisely designed conformational peptide as a vaccine prime. SCIENCE CHINA-LIFE SCIENCES 2013; 57:117-27. [PMID: 24369352 DOI: 10.1007/s11427-013-4591-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 11/22/2013] [Indexed: 10/25/2022]
Abstract
Recent studies have demonstrated that the membrane-proximal external region (MPER) of human immunodeficiency virus 1 (HIV-1) glycoprotein 41 contains a series of epitopes for human monoclonal antibodies, including 2F5, Z13e1, 4E10, and 10E8, which were isolated from HIV-1-infected individuals and show broad neutralizing activities. This suggests that MPER is a good target for the development of effective HIV-1 vaccines. However, many studies have shown that it is difficult to induce antibodies with similar broad neutralizing activities using MPER-based peptide antigens. Here, we report that 10E8-like neutralizing antibodies with effective anti-HIV-1 activity were readily induced using a precisely designed conformational immunogenic peptide containing the 10E8-specific epitope. This immunogenic peptide (designated T10HE) contains a 15-mer MPER-derived 10E8-specific epitope fused to T-helper-cell epitopes from tetanus toxin (tt), which showed a significantly stabilized α-helix structure after a series of modifications, including substitution with an (S)-α-(2'-pentenyl) alanine containing an olefin-bearing tether and ruthenium-catalyzed olefin metathesis, compared with the unmodified T10E peptide. The stabilized α-helix structure of T10HE did not affect its capacity to bind the 10E8 antibody, as evaluated with an enzyme linked immunosorbent assay (ELISA) and surface plasmon resonance binding assay (SPR assay). The efficacies of the T10HE and T10E epitope vaccines were evaluated after a standard vaccination procedure in which the experimental mice were primed with either the T10HE or T10E immunogen and boosted with HIV-1 JRFL pseudoviruses. Higher titers of 10E8-like antibodies were induced by T10HE than that by T10E. More importantly, the antibodies induced by T10HE showed enhanced antiviral potency against HIV-1 strains with both X4 and R5 tropism and a greater degree of broad neutralizing activity than the antibodies induced by T10E. These results indicate that a 10E8-epitope-based structure-specific peptide immunogen can elicit neutralizing antibodies when used as a vaccine prime.
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21
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Mühle M, Hoffmann K, Löchelt M, Denner J. Immunisation with foamy virus Bet fusion proteins as novel strategy for HIV-1 epitope delivery. Immunol Res 2013; 56:61-72. [PMID: 23440699 DOI: 10.1007/s12026-013-8387-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The induction of 2F5- and 4E10-like antibodies broadly neutralising HIV-1 and targeting the membrane external proximal region (MPER) of the transmembrane envelope protein gp41 would be a major advancement for the development of a preventive HIV-1 vaccine, but successful attempts remain rare. Recent studies demonstrated that broadly reactive antibodies develop relatively late during infection and after intensive affinity maturation. Therefore, a prolonged antigen delivery might be beneficial to induce them. Replicating foamy viruses which are characterised by apathogenic but persistent infection could represent suitable carrier viruses for this purpose. In order to develop such a system, we modified the accessory foamy virus Bet protein to contain the MPER of gp41, or the MPER linked to the stabilising fusion peptide proximal region of gp41 and analysed here the antigenic and immunogenic properties of such hybrid proteins. The antigens, expressed and purified to homogeneity, were recognised by the monoclonal antibodies 2F5 and 4E10 with nanomolar affinities and induced high levels of antibodies specific to gp41 after immunisation of rats. The antisera also bound to virus particles attached to infected cells, and peptide-based epitope mapping showed that they recognised the 2F5 epitope. Although no HIV-1 neutralising activity was observed, the presented data demonstrate that using the foamy virus Bet for HIV-1 epitope delivery is successfully applicable. Together with the attractive potential for sustained antigen expression after transfer to replicating virus, these results should therefore provide a first basis for the development of chimeric foamy viruses as novel HIV-1 vaccine vectors.
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Affiliation(s)
- Michael Mühle
- Center for HIV and Retrovirology, Robert Koch Institute, Berlin, Germany
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22
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Zhai Y, Zhong Z, Zariffard M, Spear GT, Qiao L. Bovine papillomavirus-like particles presenting conserved epitopes from membrane-proximal external region of HIV-1 gp41 induced mucosal and systemic antibodies. Vaccine 2013; 31:5422-9. [PMID: 24055348 DOI: 10.1016/j.vaccine.2013.09.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Revised: 07/14/2013] [Accepted: 09/06/2013] [Indexed: 12/27/2022]
Abstract
Two conserved epitopes, located in the membrane-proximal external region (MPER) of the human immunodeficiency virus type 1 (HIV-1) gp41, are recognized by two HIV-1 broadly neutralizing antibodies 2F5 and 4E10, and are promising targets for vaccine design in efforts to elicit anti-HIV-1 broadly neutralizing antibodies. Since most HIV-1 infections initiate at mucosal surfaces, induction of mucosal neutralizing antibodies is necessary and of utmost importance to counteract HIV-1 infection. Here, we utilized a mucosal vaccine vector, bovine papillomavirus (BPV) virus-like particles (VLPs), as a platform to present HIV-1 neutralizing epitopes by inserting the extended 2F5 or 4E10 epitope or the MPER domain into D-E loop of BPV L1 respectively. The chimeric VLPs presenting MPER domain resembled the HIV-1 natural epitopes better than the chimeric VLPs presenting single epitopes. Oral immunization of mice with the chimeric VLPs displaying the 2F5 epitope or MPER domain elicited epitope-specific serum IgGs and mucosal secretory IgAs. The induced antibodies specifically recognized the native conformation of MPER in the context of HIV-1 envelope protein. The antibodies induced by chimeric VLPs presenting MPER domain are able to partially neutralize HIV-1 viruses from clade B and clade C.
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Affiliation(s)
- Yougang Zhai
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, United States
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23
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Yi G, Lapelosa M, Bradley R, Mariano TM, Dietz DE, Hughes S, Wrin T, Petropoulos C, Gallicchio E, Levy RM, Arnold E, Arnold GF. Chimeric rhinoviruses displaying MPER epitopes elicit anti-HIV neutralizing responses. PLoS One 2013; 8:e72205. [PMID: 24039745 PMCID: PMC3765159 DOI: 10.1371/journal.pone.0072205] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 07/07/2013] [Indexed: 12/01/2022] Open
Abstract
Background The development of an effective AIDS vaccine has been a formidable task, but remains a critical necessity. The well conserved membrane-proximal external region (MPER) of the HIV-1 gp41 glycoprotein is one of the crucial targets for AIDS vaccine development, as it has the necessary attribute of being able to elicit antibodies capable of neutralizing diverse isolates of HIV. Methodology/Principle Findings Guided by X-ray crystallography, molecular modeling, combinatorial chemistry, and powerful selection techniques, we designed and produced six combinatorial libraries of chimeric human rhinoviruses (HRV) displaying the MPER epitopes corresponding to mAbs 2F5, 4E10, and/or Z13e1, connected to an immunogenic surface loop of HRV via linkers of varying lengths and sequences. Not all libraries led to viable chimeric viruses with the desired sequences, but the combinatorial approach allowed us to examine large numbers of MPER-displaying chimeras. Among the chimeras were five that elicited antibodies capable of significantly neutralizing HIV-1 pseudoviruses from at least three subtypes, in one case leading to neutralization of 10 pseudoviruses from all six subtypes tested. Conclusions Optimization of these chimeras or closely related chimeras could conceivably lead to useful components of an effective AIDS vaccine. While the MPER of HIV may not be immunodominant in natural infection by HIV-1, its presence in a vaccine cocktail could provide critical breadth of protection.
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Affiliation(s)
- Guohua Yi
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, United States of America
- Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey, United States of America
| | - Mauro Lapelosa
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, United States of America
- Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey, United States of America
| | - Rachel Bradley
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, United States of America
- Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey, United States of America
| | - Thomas M. Mariano
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, United States of America
- Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey, United States of America
| | - Denise Elsasser Dietz
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, United States of America
- Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey, United States of America
| | - Scott Hughes
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, United States of America
- Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey, United States of America
| | - Terri Wrin
- Monogram Biosciences, South San Francisco, California, United States of America
| | - Chris Petropoulos
- Monogram Biosciences, South San Francisco, California, United States of America
| | - Emilio Gallicchio
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, United States of America
| | - Ronald M. Levy
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, United States of America
| | - Eddy Arnold
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, United States of America
- Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey, United States of America
- * E-mail: (GA); (EA)
| | - Gail Ferstandig Arnold
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, United States of America
- Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey, United States of America
- * E-mail: (GA); (EA)
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24
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Tong P, Lu Z, Chen X, Wang Q, Yu F, Zou P, Yu X, Li Y, Lu L, Chen YH, Jiang S. An engineered HIV-1 gp41 trimeric coiled coil with increased stability and anti-HIV-1 activity: implication for developing anti-HIV microbicides. J Antimicrob Chemother 2013; 68:2533-44. [DOI: 10.1093/jac/dkt230] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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25
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Waechter A, Eschricht M, Denner J. Neutralization of porcine endogenous retrovirus by antibodies against the membrane-proximal external region of the transmembrane envelope protein. J Gen Virol 2013; 94:643-651. [DOI: 10.1099/vir.0.047399-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Immunization of different species including goats, rats, hamsters and guinea pigs with the recombinant ectodomain of the transmembrane envelope (TM) protein p15E of porcine endogenous retrovirus (PERV) has been shown to result in the production of virus-neutralizing antibodies. The sera recognize two groups of epitopes, one located in the fusion peptide-proximal region (FPPR) and the second in the membrane-proximal external region (MPER) of p15E. Most interestingly, the epitopes in the MPER are similar to epitopes in the TM protein gp41 of human immunodeficiency virus type 1 (HIV-1) recognized by mAbs 2F5 and 4E10, which broadly neutralize HIV-1. To study which epitope and which antibody population are involved in the process of neutralization of PERV, this study generated a new antiserum in a goat using an elongated ectodomain of p15E. The immune serum neutralized PERV at a higher titre and recognized broader epitopes in the FPPR and MPER of p15E. For the first time, antibody subpopulations were isolated from this serum using affinity chromatography with immobilized proteins and peptides corresponding to the FPPR and MPER of p15E. Only the affinity-purified antibodies specifically binding the MPER neutralized PERV, indicating that, as in the case of HIV-1, the MPER is an important target of neutralizing activity.
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26
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Gao G, Wieczorek L, Peachman KK, Polonis VR, Alving CR, Rao M, Rao VB. Designing a soluble near full-length HIV-1 gp41 trimer. J Biol Chem 2012. [PMID: 23184960 DOI: 10.1074/jbc.m112.424432] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The HIV-1 envelope spike is a trimer of heterodimers composed of an external glycoprotein gp120 and a transmembrane glycoprotein gp41. gp120 initiates virus entry by binding to host receptors, whereas gp41 mediates fusion between viral and host membranes. Although the basic pathway of HIV-1 entry has been extensively studied, the detailed mechanism is still poorly understood. Design of gp41 recombinants that mimic key intermediates is essential to elucidate the mechanism as well as to develop potent therapeutics and vaccines. Here, using molecular genetics and biochemical approaches, a series of hypotheses was tested to overcome the extreme hydrophobicity of HIV-1 gp41 and design a soluble near full-length gp41 trimer. The two long heptad repeat helices HR1 and HR2 of gp41 ectodomain were mutated to disrupt intramolecular HR1-HR2 interactions but not intermolecular HR1-HR1 interactions. This resulted in reduced aggregation and improved solubility. Attachment of a 27-amino acid foldon at the C terminus and slow refolding channeled gp41 into trimers. The trimers appear to be stabilized in a prehairpin-like structure, as evident from binding of a HR2 peptide to exposed HR1 grooves, lack of binding to hexa-helical bundle-specific NC-1 mAb, and inhibition of virus neutralization by broadly neutralizing antibodies 2F5 and 4E10. Fusion to T4 small outer capsid protein, Soc, allowed display of gp41 trimers on the phage nanoparticle. These approaches for the first time led to the design of a soluble gp41 trimer containing both the fusion peptide and the cytoplasmic domain, providing insights into the mechanism of entry and development of gp41-based HIV-1 vaccines.
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Affiliation(s)
- Guofen Gao
- Department of Biology, The Catholic University of America, Washington, DC 20064, USA
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Hessell AJ, Haigwood NL. Neutralizing antibodies and control of HIV: moves and countermoves. Curr HIV/AIDS Rep 2012; 9:64-72. [PMID: 22203469 DOI: 10.1007/s11904-011-0105-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
It is now evident that powerful antibodies directed to conserved regions of HIV-1 envelope protein develop during chronic infection in some individuals and that these antibodies can neutralize a broad array of diverse isolates in vitro, so termed broadly neutralizing antibodies (bNAbs). A great deal of effort is directed internationally at understanding the ontogeny of NAbs during infection as well as in designing and testing immunogens that can elicit bNAbs in animal models and in humans. Given the parrying tactics of Env, multiple approaches, along with high-resolution structural studies, will be needed to reach a degree of understanding sufficient to design an effective vaccine. We discuss and note here some of the most important recent advances in our knowledge of how neutralizing antibodies develop in vivo, the recent discovery of extremely powerful neutralizing monoclonal antibodies isolated from natural infection, enhanced methodologies that have accelerated discoveries on both fronts, and the progress made in eliciting potent NAbs with limited breadth by vaccination.
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Affiliation(s)
- Ann J Hessell
- Pathobiology and Immunology Division, Oregon National Primate Center, Oregon Health and Science University, Beaverton, OR 97006, USA
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28
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Stanfield RL, Julien JP, Pejchal R, Gach JS, Zwick MB, Wilson IA. Structure-based design of a protein immunogen that displays an HIV-1 gp41 neutralizing epitope. J Mol Biol 2011; 414:460-76. [PMID: 22033480 PMCID: PMC3245871 DOI: 10.1016/j.jmb.2011.10.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 10/03/2011] [Accepted: 10/10/2011] [Indexed: 01/21/2023]
Abstract
Antibody Z13e1 is a relatively broadly neutralizing anti-human immunodeficiency virus type 1 antibody that recognizes the membrane-proximal external region (MPER) of the human immunodeficiency virus type 1 envelope glycoprotein gp41. Based on the crystal structure of an MPER epitope peptide in complex with Z13e1 Fab, we identified an unrelated protein, interleukin (IL)-22, with a surface-exposed region that is structurally homologous in its backbone to the gp41 Z13e1 epitope. By grafting the gp41 Z13e1 epitope sequence onto the structurally homologous region in IL-22, we engineered a novel protein (Z13-IL22-2) that contains the MPER epitope sequence for use as a potential immunogen and as a reagent for the detection of Z13e1-like antibodies. The Z13-IL22-2 protein binds Fab Z13e1 with a K(d) of 73 nM. The crystal structure of Z13-IL22-2 in complex with Fab Z13e1 shows that the epitope region is faithfully replicated in the Fab-bound scaffold protein; however, isothermal calorimetry studies indicate that Fab binding to Z13-IL22-2 is not a lock-and-key event, leaving open the question of whether conformational changes upon binding occur in the Fab, in Z13-IL-22, or in both.
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Affiliation(s)
- Robyn L Stanfield
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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29
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Dennison SM, Sutherland LL, Jaeger FH, Anasti KM, Parks R, Stewart S, Bowman C, Xia SM, Zhang R, Shen X, Scearce RM, Ofek G, Yang Y, Kwong PD, Santra S, Liao HX, Tomaras G, Letvin NL, Chen B, Alam SM, Haynes BF. Induction of antibodies in rhesus macaques that recognize a fusion-intermediate conformation of HIV-1 gp41. PLoS One 2011; 6:e27824. [PMID: 22140469 PMCID: PMC3227606 DOI: 10.1371/journal.pone.0027824] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 10/26/2011] [Indexed: 12/20/2022] Open
Abstract
A component to the problem of inducing broad neutralizing HIV-1 gp41 membrane proximal external region (MPER) antibodies is the need to focus the antibody response to the transiently exposed MPER pre-hairpin intermediate neutralization epitope. Here we describe a HIV-1 envelope (Env) gp140 oligomer prime followed by MPER peptide-liposomes boost strategy for eliciting serum antibody responses in rhesus macaques that bind to a gp41 fusion intermediate protein. This Env-liposome immunization strategy induced antibodies to the 2F5 neutralizing epitope ⁶⁶⁴DKW residues, and these antibodies preferentially bound to a gp41 fusion intermediate construct as well as to MPER scaffolds stabilized in the 2F5-bound conformation. However, no serum lipid binding activity was observed nor was serum neutralizing activity for HIV-1 pseudoviruses present. Nonetheless, the Env-liposome prime-boost immunization strategy induced antibodies that recognized a gp41 fusion intermediate protein and was successful in focusing the antibody response to the desired epitope.
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Affiliation(s)
- S. Moses Dennison
- Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Laura L. Sutherland
- Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Frederick H. Jaeger
- Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Kara M. Anasti
- Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Robert Parks
- Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Shelley Stewart
- Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Cindy Bowman
- Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Shi-Mao Xia
- Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Ruijun Zhang
- Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Xiaoying Shen
- Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Richard M. Scearce
- Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Gilad Ofek
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Yongping Yang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Peter D. Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sampa Santra
- Department of Medicine, Beth Israel Deaconess Medical Center, Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Hua-Xin Liao
- Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Georgia Tomaras
- Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Norman L. Letvin
- Department of Medicine, Beth Israel Deaconess Medical Center, Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Bing Chen
- Division of Molecular Medicine, Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - S. Munir Alam
- Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
- * E-mail: (SMA); (BFH)
| | - Barton F. Haynes
- Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
- * E-mail: (SMA); (BFH)
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30
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Wang J, Xu L, Tong P, Chen YH. Mucosal antibodies induced by tandem repeat of 2F5 epitope block transcytosis of HIV-1. Vaccine 2011; 29:8542-8. [PMID: 21939723 DOI: 10.1016/j.vaccine.2011.09.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 08/31/2011] [Accepted: 09/09/2011] [Indexed: 11/19/2022]
Abstract
Induction of mucosal antibodies to prevent HIV infection is an important strategy for the HIV-1 prophylaxis. Here we report an epitope-vaccine based antigen that was able to elicit mucosal antibodies capable of blocking HIV-1 transcytosis. Because the ELDKWA epitope of neutralizing antibody 2F5 plays a crucial role in transcytosis, a series of immunogens that contain tandem copies of ELDKWA were prepared. Mice were immunized with these immunogens intranasally, and received intraperitoneal+intranasal boosters. The immunogens that contained more ELDKWA epitopes elicited higher level of mucosal ELDKWA-epitope specific IgAs and systemic IgGs. Although the antisera from the immunized mice exhibited mild neutralizing potency to HIV-1 isolates HXB2 and JRFL, the affinity purified mucosal ELDKWA-epitope specific antibodies could block the transcytosis of cell-free CNE3 (a primary isolate of subtype CRF01_AE) in human tight epithelial models.
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Affiliation(s)
- Ji Wang
- School of Life Sciences, Tsinghua University, People's Republic of China
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