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Berkower I, Raymond M, Muller J, Spadaccini A, Aberdeen A. Assembly, structure, and antigenic properties of virus-like particles rich in HIV-1 envelope gp120. Virology 2004; 321:75-86. [PMID: 15033567 DOI: 10.1016/j.virol.2003.12.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2003] [Revised: 11/21/2003] [Accepted: 12/16/2003] [Indexed: 11/21/2022]
Abstract
In order to improve the immunogenicity of HIV-1 envelope glycoproteins, we have fused gp120 to a carrier protein, hepatitis B surface antigen (HBsAg), which is capable of spontaneous assembly into virus-like particles. The HBsAg-gp120 hybrid proteins assembled efficiently into 20-30 nm particles. The particles resemble native HBsAg particles in size and density, consistent with a lipid composition of about 25% and a gp120 content of about 100 per particle. Particulate gp120 folds in its native conformation and is biologically active, as shown by high affinity binding of CD4. The particles express conformational determinants targeted by a panel of broadly cross-reactive neutralizing antibodies, and they show tight packing of gp120. Because the particles are lipoprotein micelles, an array of gp120 on their surface closely mimics gp120 on the surface of HIV-1 virions. These gp120-rich particles can enhance the quality, as well as quantity, of antibodies elicited by a gp120 vaccine.
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Affiliation(s)
- Ira Berkower
- Laboratory of Immunoregulation, Division of Viral Products, Office of Vaccine Research and Review, Center for Biologics, Bethesda, MD 20892, USA.
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2
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Noorbakhsh F, Vergnolle N, Hollenberg MD, Power C. Proteinase-activated receptors in the nervous system. Nat Rev Neurosci 2004; 4:981-90. [PMID: 14682360 DOI: 10.1038/nrn1255] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Recent data point to important roles for proteinases and their cognate proteinase-activated receptors (PARs) in the ontogeny and pathophysiology of the nervous system. PARs are a family of G-protein-coupled receptors that can affect neural cell proliferation, morphology and physiology. PARs also have important roles in neuroinflammatory and degenerative diseases such as human immunodeficiency virus-associated dementia, Alzheimer's disease and pain. These receptors might also influence the pathogenesis of stroke and multiple sclerosis, conditions in which the blood-brain barrier is disrupted. The diversity of effects of PARs on neural function and their widespread distribution in the nervous system make them attractive therapeutic targets for neurological disorders. Here, we review the roles of PARs in the central and peripheral nervous systems during health and disease, with a focus on neuroinflammatory and degenerative disorders.
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Enshell-Seijffers D, Smelyanski L, Vardinon N, Yust I, Gershoni JM. Dissection of the humoral immune response toward an immunodominant epitope of HIV: a model for the analysis of antibody diversity in HIV+ individuals. FASEB J 2001; 15:2112-20. [PMID: 11641237 DOI: 10.1096/fj.00-0898com] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Understanding the dynamics of the humoral immune response to HIV epitopes in the presence of genetic drift and antigenic variation of the virus may reveal critical elements of protective immunity against HIV. Analysis of antibody maturation and diversity is difficult to study at the molecular level in humans. We used a combinatorial phage display peptide library to elucidate antibody diversity in HIV-infected individuals to a single immunodominant epitope in gp41. A serum sample derived from an HIV+ individual was used to screen a phage display a 12 mer cysteine-constrained loop peptide library. In doing so, we isolated mimotope-presenting phages corresponding to the immunodominant gp41 epitope CSGKLIC (residues 603-609). The mimotopes and control phages expressing epitope variants were reacted with a panel of 30 HIV+ sera. The patients showed distinct and variable recognition patterns compared with one another. Subfractions of the polyclonal sera were affinity purified and analyzed for epitope specificities. These analyses illustrated that epitope variants can be used to decipher antibody diversity. Elucidation of the plasticity of the humoral response and its polyclonality toward discrete epitopes contributes to our understanding of the antibody maturation process in individuals infected with viruses such as HIV.
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Affiliation(s)
- D Enshell-Seijffers
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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Denisova GF, Zerwanitzer M, Denisov DA, Spectorman E, Mondor I, Sattentau Q, Gershoni JM. Expansion of epitope cross-reactivity by anti-idiotype modulation of the primary humoral response. Mol Immunol 2000; 37:53-8. [PMID: 10781835 DOI: 10.1016/s0161-5890(00)00022-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The primary humoral response produces antigen-specific antibodies so to clear the initial infection, and generates a population of corresponding memory cells to prevent infection by future encounters with the same pathogen. The continuous genetic modification of a pathogen's exterior, however, is one mechanism used to evade the immune defenses of its host. Here we describe a novel means, involving anti-idiotypic antibodies, by which the host can counteract such pathogen genetic alterations by modulation of its primary humoral response. An autoimmune response against primary antibodies, Ab1's, creates anti-idiotypic antibodies (Ab2's), some of which (designated Ab2alpha) are able to bind the Ab1/antigen complex. We have discovered that binding of Ab2alpha to its corresponding Ab1 can expand Ab1's ability to bind variations of its antigen. This expanded epitope cross-reactivity is shown not only to increase the binding activity of Ab1 but also its ability to neutralize a variant infectious virus. MAb M77 is an Ab1, which is highly strain-specific for the HIV-1 envelope protein gp120(IIIB). This Ab1 can be rendered cross-reactive and neutralizing for an otherwise resistant HIV strain by its interaction with a unique anti-idiotypic Ab2alpha (GV12). Furthermore, molecular characterization of this expanded cross-reactivity was accomplished using combinatorial phage display peptide libraries.
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Affiliation(s)
- G F Denisova
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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Papandreou MJ, Fenouillet E. Effect of changes in the glycosylation of the human immunodeficiency virus type 1 envelope on the immunoreactivity and sensitivity to thrombin of its third variable domain. Virology 1998; 241:163-7. [PMID: 9454727 DOI: 10.1006/viro.1997.8930] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The influence of HIV Env glycosylation on the conformation of the third variable domain (V3) of Env was studied by both deglycosylation of mature Env and the use of Env produced by recombinant systems in which alpha-glucosidase activity was inhibited by either deoxynojirimycin (DNM) or mutation. Selective deglycosylation affected anti-V3 antibody binding. The immunoreactivity and sensitivity to thrombin cleavage of V3 presented on Env produced in baby hamster kidney cells were changed by DNM treatment. In contrast, Env expressed in alpha-glucosidase I-deficient Chinese hamster ovary cells or in their parental cells treated by DNM fully retained these V3 properties. These results are discussed in relation to the inconsistent data obtained on V3 property changes resulting from Env glycosylation changes.
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Watkins BA, Buge S, Aldrich K, Davis AE, Robinson J, Reitz MS, Robert-Guroff M. Resistance of human immunodeficiency virus type 1 to neutralization by natural antisera occurs through single amino acid substitutions that cause changes in antibody binding at multiple sites. J Virol 1996; 70:8431-7. [PMID: 8970964 PMCID: PMC190932 DOI: 10.1128/jvi.70.12.8431-8437.1996] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The ability of human immunodeficiency virus type 1 (HIV-1) to replicate in the presence of strong immune responses to the virus may be due to its high mutation rate, which provides envelope gene variability for selection of neutralization-resistant variants. Understanding neutralization escape mechanisms is therefore important for the design of HIV-1 vaccines and our understanding of the disease process. In this report, we analyze mutations at amino acid positions 281 and 582 in the HIV-1 envelope, where substitutions confer resistance to broadly reactive neutralizing antisera from seropositive individuals. Neither of these mutations lies within an antibody-binding site, and therefore the mechanism of immune escape in both cases is by alteration of the shape of the envelope proteins. The conformation of the CD4-binding site is shown to be critical with regard to presentation of other discontinuous epitopes. From our analysis of the neutralization of these variants, we conclude that escape from polyclonal sera occurs through alterations at several different epitopes, generally resulting from single amino acid substitutions which influence envelope conformation. Experiments on a double mutant showed that the combination of both mutations is not additive, suggesting that these variants utilized alternate pathways to elicit similar alterations of the HIV-1 envelope structure.
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Affiliation(s)
- B A Watkins
- Laboratory of Tumor Cell Biology, National Cancer Institute, Bethesda, Maryland 20892, USA
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Denisova G, Stern B, Raviv D, Zwickel J, Smorodinsky NI, Gershoni JM. Humoral immune response to immunocomplexed HIV envelope glycoprotein 120. AIDS Res Hum Retroviruses 1996; 12:901-9. [PMID: 8798975 DOI: 10.1089/aid.1996.12.901] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
To further our understanding of the nature of HIV-1 immunogenicity, we injected mice with the virus envelope protein gp120 in different configurations: free, complexed with its receptor CD4, and as an immunocomplex with a monoclonal antibody directed against the V3 loop of the protein. Analyses of the polyclonal sera, as well as of monoclonal antibodies produced in each case, allowed us to conclude that the quality of the humoral immune response depended on the complexation state of the antigen. For the free gp120 and gp120-CD4 complex the responses were directed mainly toward conformational epitopes. However, gp120 immunocomplexed with anti-V3 loop Mab produced, in addition, numerous MAbs directed toward linear epitopes. Epitopes were mapped using immunoblots of gp120 cleaved with S. aureus V8 protease and a combinatorial epitope phage-display library. It was found that some of the linear epitopes had been previously identified as T cell epitopes. These results suggest that the immunocomplexed gp120 may be particularly well taken up by antigen-presenting cells, leading to the processing of the gp120 and the efficient presentation of T cell epitopes. Thus immunocomplexation should afford a means for enhancing the immunogenicity of gp120 and improving its presentation.
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Affiliation(s)
- G Denisova
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel
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Gershoni JM, Denisova GF, Raviv D, Stern B, Zwickel J. Complexed HIV envelope as a target for an AIDS vaccine. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1996; 397:91-6. [PMID: 8718587 DOI: 10.1007/978-1-4899-1382-1_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- J M Gershoni
- Department of Cell Research and Immunology, Tel Aviv University, Israel
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Romano JW, Shurtliff RN, Sarngadharan MG, Pal R. Detection of HIV-1 infection in vitro using NASBA: an isothermal RNA amplification technique. J Virol Methods 1995; 54:109-19. [PMID: 8530563 DOI: 10.1016/0166-0934(95)00031-o] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Establishment of a sensitive infection assay for HIV-1 is essential for successful screening of antiviral agents and neutralizing antibodies. In this report, an infection assay is described which measures the expression of viral genomic RNA and spliced mRNA intermediates in infected cells by an amplification-based technique called NASBA. The extreme sensitivity of this method permits the detection of viral RNA in peripheral blood mononuclear cells (PBMC) within 48 h of infection by a low dose of virus. Similarly, spliced HIV-1 mRNA could be detected within 24 h of infection of CEM cells by HIV-1IIIB. This NASBA-based infection assay was shown to titer the neutralization of the HIV-1IIIB isolate by serum from an infected human and by a monoclonal antibody to gp120. Furthermore, the inhibitory effects of azidothymidine (AZT) and soluble CD4 on HIV-1IIIB infection were quantitated by this assay. The early detection of virus by NASBA minimizes the contribution of secondary infection, thereby permitting more accurate evaluation of antiviral agents and neutralizing antibodies. This assay may be useful for the study of infection of phenotypically distinct HIV-1 isolates, which differ in terms of their replication kinetics.
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Affiliation(s)
- J W Romano
- Advanced BioSciences Laboratories Inc., Kensington, MD 20895, USA
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Fraisier C, Ebersold A, Blomberg J, Desgranges C. Primary in vitro immunization with multimeric synthetic peptides of HIV-1 envelope glycoproteins: generation of neutralizing human monoclonal antibodies. J Immunol Methods 1994; 176:9-22. [PMID: 7963597 DOI: 10.1016/0022-1759(94)90346-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Peripheral blood lymphocytes from healthy HIV-1 seronegative donors were immunized in vitro with the following synthetic peptides: (i) an octameric poly-L-lysine conjugated peptide of the HIV-1MN V3 loop and (ii) a resin bound synthetic peptide aa642-665 of HIV-1 gp41. Lymphoblastoid cell lines (LCL) were obtained by immortalization with Epstein-Barr virus (EBV). We produced four LCL secreting human monoclonal antibodies (HuMoAbs) of the IgM isotype: three were directed against the V3 domain (FC10, FC81 and CF41) and one against aa642-665 (CA45C). Two of these HuMoAbs (FC81 and CA45C) reacted to viral surface antigen on HIV-1-infected cells. All the HuMoAbs inhibited 40-53% of cell fusion induced by HIV-1-infected H9 cells at 5 micrograms/ml. They also neutralized, at lower concentrations, cell-free infection with HIV-1MN, HIV-1IIIB and four primary clinical HIV-1 isolates. No enhancing activity of the HuMoAbs in the presence of complement was observed. The results presented here show the feasibility of generating neutralizing human monoclonal antibodies against HIV-1 by primary in vitro immunization with selected synthetic peptides of HIV-1 envelope glycoproteins. This approach has provided tools for further studies of synergistic neutralization assays, and generated potential immunoglobulin candidates for passive immunotherapy.
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Affiliation(s)
- C Fraisier
- INSERM U271, Unité de Recherche sur les Hépatites, le SIDA et les Rétrovirus humains, Lyon, France
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di Marzo Veronese F, Reitz MS, Gupta G, Robert-Guroff M, Boyer-Thompson C, Louie A, Gallo RC, Lusso P. Loss of a neutralizing epitope by a spontaneous point mutation in the V3 loop of HIV-1 isolated from an infected laboratory worker. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)74471-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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12
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Watkins BA, Reitz MS, Wilson CA, Aldrich K, Davis AE, Robert-Guroff M. Immune escape by human immunodeficiency virus type 1 from neutralizing antibodies: evidence for multiple pathways. J Virol 1993; 67:7493-500. [PMID: 7693973 PMCID: PMC238215 DOI: 10.1128/jvi.67.12.7493-7500.1993] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Sera from many HIV-1-infected individuals contain broadly reactive, specific neutralizing antibodies. Despite their broad reactivity, variant viruses, resistant to neutralization, can be selected in vitro in the presence of such antisera. We have previously shown that neutralization resistance of an escape mutant with an amino acid substitution in the transmembrane protein (A582T) occurs because of alteration of a conformational epitope that is recognized by neutralizing antibodies directed against the CD4 binding site. In this report we demonstrate that immune escape via a single-amino-acid substitution (A281V) within a conserved region of the envelope glycoprotein gp120 confers neutralization resistance against a broadly reactive neutralizing antiserum from a seropositive individual. We show this alteration affects V3 and additional regions unrelated to V3 or the CD4 binding site. Together with previous studies on escape mutants selected in vitro, our findings suggest that immune-selective pressure can arise by multiple pathways.
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Affiliation(s)
- B A Watkins
- Laboratory of Tumor Cell Biology, National Cancer Institute, Bethesda, Maryland 20892
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