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Dimapasoc M, Moran JA, Cole SW, Ranjan A, Hourani R, Kim JT, Wender PA, Marsden MD, Zack JA. Defining the Effects of PKC Modulator HIV Latency-Reversing Agents on Natural Killer Cells. Pathog Immun 2024; 9:108-137. [PMID: 38765786 PMCID: PMC11101012 DOI: 10.20411/pai.v9i1.673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 04/05/2024] [Indexed: 05/22/2024] Open
Abstract
Background Latency reversing agents (LRAs) such as protein kinase C (PKC) modulators can reduce rebound-competent HIV reservoirs in small animal models. Furthermore, administration of natural killer (NK) cells following LRA treatment improves this reservoir reduction. It is currently unknown why the combination of a PKC modulator and NK cells is so potent and whether exposure to PKC modulators may augment NK cell function in some way. Methods Primary human NK cells were treated with PKC modulators (bryostatin-1, prostratin, or the designed, synthetic bryostatin-1 analog SUW133), and evaluated by examining expression of activation markers by flow cytometry, analyzing transcriptomic profiles by RNA sequencing, measuring cytotoxicity by co-culturing with K562 cells, assessing cytokine production by Luminex assay, and examining the ability of cytokines and secreted factors to independently reverse HIV latency by co-culturing with Jurkat-Latency (J-Lat) cells. Results PKC modulators increased expression of proteins involved in NK cell activation. Transcriptomic profiles from PKC-treated NK cells displayed signatures of cellular activation and enrichment of genes associated with the NFκB pathway. NK cell cytotoxicity was unaffected by prostratin but significantly decreased by bryostatin-1 and SUW133. Cytokines from PKC-stimulated NK cells did not induce latency reversal in J-Lat cell lines. Conclusions Although PKC modulators have some significant effects on NK cells, their contribution in "kick and kill" strategies is likely due to upregulating HIV expression in CD4+ T cells, not directly enhancing the effector functions of NK cells. This suggests that PKC modulators are primarily augmenting the "kick" rather than the "kill" arm of this HIV cure approach.
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Affiliation(s)
- Melanie Dimapasoc
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, California
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, California
| | - Jose A. Moran
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California Irvine, California
| | - Steve W. Cole
- UCLA Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Alok Ranjan
- Department of Chemistry, Stanford University, Stanford, California
| | - Rami Hourani
- Department of Chemistry, Stanford University, Stanford, California
| | - Jocelyn T. Kim
- Department of Medicine, Division of Infectious Diseases, University of California Los Angeles, Los Angeles, California
| | - Paul A. Wender
- Department of Chemistry, Stanford University, Stanford, California
- Department of Chemical and Systems Biology, Stanford University, Stanford, California
| | - Matthew D. Marsden
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California Irvine, California
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of California, Irvine, Irvine, California
| | - Jerome A. Zack
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, California
- Department of Medicine, Division of Hematology and Oncology, University of California Los Angeles, Los Angeles, California
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Gaffney A, Nangarlia A, Ang CG, Gossert S, Rashad Ahmed AA, Hossain MA, Abrams CF, Smith AB, Chaiken I. HIV-1 Env-Dependent Cell Killing by Bifunctional Small-Molecule/Peptide Conjugates. ACS Chem Biol 2021; 16:440-442. [PMID: 33535751 DOI: 10.1021/acschembio.1c00039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Althea Gaffney
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Aakansha Nangarlia
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Charles G. Ang
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Steven Gossert
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Adel Ahmed Rashad Ahmed
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Md Alamgir Hossain
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Cameron F. Abrams
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Amos B. Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Irwin Chaiken
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
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Shao J, Zeng D, Tian S, Liu G, Fu J. Identification of the natural product berberine as an antiviral drug. AMB Express 2020; 10:164. [PMID: 32897426 PMCID: PMC7479080 DOI: 10.1186/s13568-020-01088-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 08/11/2020] [Indexed: 12/28/2022] Open
Abstract
Drugs targeting the fusion process of viral entry into host cells have been approved for clinical use in the treatment of AIDS. There remains a great need to improve the use of existing drugs for HIV therapy. Berberine is traditionally used to treat diarrhea, bacillary dysentery, and gastroenteritis in clinics, here our research shows that berberine is effective in inhibiting HIV-1 entry. Native polyacrylamide gel electrophoresis studies reveal that berberine can directly bind to both N36 and C34 to form a novel N36-berberine-C34 complex and effectively block the six-helix bundle formation between the N-terminal heptad repeat peptide N36 and the C-terminal heptad repeat peptide C34. Circular dichroism experiments show that binding of berberine produces conformational changes that damages the secondary structures of 6-HB. Computer-aided molecular docking studies suggest a hydrogen bond with T-639 and two polar bonds with Q-563 and T-639 are established, involving the oxygen atom and the C=O group of the indole ring. Berberine completely inhibits six HIV-1 clade B isolates and exhibits antiviral activities in a concentration-dependent manner with IC50 values varying from 5.5 to 10.25 µg/ml. This compound-peptide interaction may represent a mechanism of action of antiviral activities of berberine. As a summary, these studies successfully identify compound berberine as a potential candidate drug for HIV-1 treatment. As a summary, antiviral activity of berberine in combination with its use in clinical practice, this medicine can be used as a potential clinically anti-HIV drug.
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Influences on the Design and Purification of Soluble, Recombinant Native-Like HIV-1 Envelope Glycoprotein Trimers. J Virol 2015; 89:12189-210. [PMID: 26311893 DOI: 10.1128/jvi.01768-15] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 08/20/2015] [Indexed: 12/27/2022] Open
Abstract
UNLABELLED We have investigated factors that influence the production of native-like soluble, recombinant trimers based on the env genes of two isolates of human immunodeficiency virus type 1 (HIV-1), specifically 92UG037.8 (clade A) and CZA97.012 (clade C). When the recombinant trimers based on the env genes of isolates 92UG037.8 and CZA97.012 were made according to the SOSIP.664 design and purified by affinity chromatography using broadly neutralizing antibodies (bNAbs) against quaternary epitopes (PGT145 and PGT151, respectively), the resulting trimers are highly stable and they are fully native-like when visualized by negative-stain electron microscopy. They also have a native-like (i.e., abundant) oligomannose glycan composition and display multiple bNAb epitopes while occluding those for nonneutralizing antibodies. In contrast, uncleaved, histidine-tagged Foldon (Fd) domain-containing gp140 proteins (gp140UNC-Fd-His), based on the same env genes, very rarely form native-like trimers, a finding that is consistent with their antigenic and biophysical properties and glycan composition. The addition of a 20-residue flexible linker (FL20) between the gp120 and gp41 ectodomain (gp41ECTO) subunits to make the uncleaved 92UG037.8 gp140-FL20 construct is not sufficient to create a native-like trimer, but a small percentage of native-like trimers were produced when an I559P substitution in gp41ECTO was also present. The further addition of a disulfide bond (SOS) to link the gp120 and gp41 subunits in the uncleaved gp140-FL20-SOSIP protein increases native-like trimer formation to ∼20 to 30%. Analysis of the disulfide bond content shows that misfolded gp120 subunits are abundant in uncleaved CZA97.012 gp140UNC-Fd-His proteins but very rare in native-like trimer populations. The design and stabilization method and the purification strategy are, therefore, all important influences on the quality of trimeric Env proteins and hence their suitability as vaccine components. IMPORTANCE Soluble, recombinant multimeric proteins based on the HIV-1 env gene are current candidate immunogens for vaccine trials in humans. These proteins are generally designed to mimic the native trimeric envelope glycoprotein (Env) that is the target of virus-neutralizing antibodies on the surfaces of virions. The underlying hypothesis is that an Env-mimetic protein may be able to induce antibodies that can neutralize the virus broadly and potently enough for a vaccine to be protective. Multiple different designs for Env-mimetic trimers have been put forth. Here, we used the CZA97.012 and 92UG037.8 env genes to compare some of these designs and determine which ones best mimic virus-associated Env trimers. We conclude that the most widely used versions of CZA97.012 and 92UG037.8 oligomeric Env proteins do not resemble the trimeric Env glycoprotein on HIV-1 viruses, which has implications for the design and interpretation of ongoing or proposed clinical trials of these proteins.
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Kohli A, Islam A, Moyes DL, Murciano C, Shen C, Challacombe SJ, Naglik JR. Oral and vaginal epithelial cell lines bind and transfer cell-free infectious HIV-1 to permissive cells but are not productively infected. PLoS One 2014; 9:e98077. [PMID: 24857971 PMCID: PMC4032250 DOI: 10.1371/journal.pone.0098077] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Accepted: 04/26/2014] [Indexed: 11/28/2022] Open
Abstract
The majority of HIV-1 infections worldwide are acquired via mucosal surfaces. However, unlike the vaginal mucosa, the issue of whether the oral mucosa can act as a portal of entry for HIV-1 infection remains controversial. To address potential differences with regard to the fate of HIV-1 after exposure to oral and vaginal epithelium, we utilized two epithelial cell lines representative of buccal (TR146) and pharyngeal (FaDu) sites of the oral cavity and compared them with a cell line derived from vaginal epithelium (A431) in order to determine (i) HIV-1 receptor gene and protein expression, (ii) whether HIV-1 genome integration into epithelial cells occurs, (iii) whether productive viral infection ensues, and (iv) whether infectious virus can be transferred to permissive cells. Using flow cytometry to measure captured virus by HIV-1 gp120 protein detection and western blot to detect HIV-1 p24 gag protein, we demonstrate that buccal, pharyngeal and vaginal epithelial cells capture CXCR4- and CCR5-utilising virus, probably via non-canonical receptors. Both oral and vaginal epithelial cells are able to transfer infectious virus to permissive cells either directly through cell-cell attachment or via transcytosis of HIV-1 across epithelial cells. However, HIV-1 integration, as measured by real-time PCR and presence of early gene mRNA transcripts and de novo protein production were not detected in either epithelial cell type. Importantly, both oral and vaginal epithelial cells were able to support integration and productive infection if HIV-1 entered via the endocytic pathway driven by VSV-G. Our data demonstrate that under normal conditions productive HIV-1 infection of epithelial cells leading to progeny virion production is unlikely, but that epithelial cells can act as mediators of systemic viral dissemination through attachment and transfer of HIV-1 to permissive cells.
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Affiliation(s)
- Arinder Kohli
- Department of Oral Immunology, Clinical and Diagnostic Sciences, King's College London Dental Institute, King's College London, London, United Kingdom
| | - Ayesha Islam
- Department of Oral Immunology, Clinical and Diagnostic Sciences, King's College London Dental Institute, King's College London, London, United Kingdom; Department of Obstetrics and Gynecology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - David L Moyes
- Department of Oral Immunology, Clinical and Diagnostic Sciences, King's College London Dental Institute, King's College London, London, United Kingdom
| | - Celia Murciano
- Department of Oral Immunology, Clinical and Diagnostic Sciences, King's College London Dental Institute, King's College London, London, United Kingdom; Department of Microbiology and Ecology, University of Valencia, Valencia, Spain
| | - Chengguo Shen
- Department of Oral Immunology, Clinical and Diagnostic Sciences, King's College London Dental Institute, King's College London, London, United Kingdom
| | - Stephen J Challacombe
- Department of Oral Immunology, Clinical and Diagnostic Sciences, King's College London Dental Institute, King's College London, London, United Kingdom
| | - Julian R Naglik
- Department of Oral Immunology, Clinical and Diagnostic Sciences, King's College London Dental Institute, King's College London, London, United Kingdom
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Nkolola JP, Cheung A, Perry JR, Carter D, Reed S, Schuitemaker H, Pau MG, Seaman MS, Chen B, Barouch DH. Comparison of multiple adjuvants on the stability and immunogenicity of a clade C HIV-1 gp140 trimer. Vaccine 2014; 32:2109-16. [PMID: 24556505 DOI: 10.1016/j.vaccine.2014.02.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 01/28/2014] [Accepted: 02/04/2014] [Indexed: 01/06/2023]
Abstract
Immunogens based on the human immunodeficiency virus type-1 (HIV-1) Envelope (Env) glycoprotein have to date failed to elicit potent and broadly neutralizing antibodies against diverse HIV-1 strains. An understudied area in the development of HIV-1 Env-based vaccines is the impact of various adjuvants on the stability of the Env immunogen and the magnitude of the induced humoral immune response. We hypothesize that optimal adjuvants for HIV-1 gp140 Env trimers will be those with high potency but also those that preserve structural integrity of the immunogen and those that have a straightforward path to clinical testing. In this report, we systematically evaluate the impact of 12 adjuvants on the stability and immunogenicity of a clade C (CZA97.012) HIV-1 gp140 trimer in guinea pigs and a subset in non-human primates. Oil-in-water emulsions (GLA-emulsion, Ribi, Emulsigen) resulted in partial aggregation and loss of structural integrity of the gp140 trimer. In contrast, alum (GLA-alum, Adju-Phos, Alhydrogel), TLR (GLA-aqueous, CpG, MPLA), ISCOM (Matrix M) and liposomal (GLA-liposomes, virosomes) adjuvants appeared to preserve trimer integrity as measured by size exclusion chromatography. However, multiple classes of adjuvants similarly augmented Env-specific binding and neutralizing antibody responses in guinea pigs and non-human primates.
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Affiliation(s)
- Joseph P Nkolola
- Center for Virology & Vaccine Research, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Ann Cheung
- Center for Virology & Vaccine Research, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - James R Perry
- Center for Virology & Vaccine Research, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Darrick Carter
- Infectious Disease Research Institute, Seattle, WA 98102, USA
| | - Steve Reed
- Infectious Disease Research Institute, Seattle, WA 98102, USA
| | | | | | - Michael S Seaman
- Center for Virology & Vaccine Research, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Bing Chen
- Division of Molecular Medicine, Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Dan H Barouch
- Center for Virology & Vaccine Research, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Ragon Institute of MGH, MIT and Harvard, Boston, MA 02114, USA.
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7
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Sharma S, Das K, Woo J, Gimzewski JK. Nanofilaments on glioblastoma exosomes revealed by peak force microscopy. J R Soc Interface 2014; 11:20131150. [PMID: 24402921 DOI: 10.1098/rsif.2013.1150] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Exosomes are sub-100 nm extracellular vesicles secreted by normal and cancer cells. We present a high-resolution structure of previously unidentified nanofilaments on glioblastoma-derived exosomes, using nanoscale peak force imaging. These stiff, adhesive, trypsin- and RNAse-resistant surface nanofilaments add a new dimension to the current structural knowledge of exosome-mediated intercellular communication.
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Affiliation(s)
- Shivani Sharma
- Department of Chemistry and Biochemistry, University of California, , Los Angeles, CA 90095, USA
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Comparative immunogenicity of HIV-1 gp160, gp140 and gp120 expressed by live attenuated newcastle disease virus vector. PLoS One 2013; 8:e78521. [PMID: 24098600 PMCID: PMC3788131 DOI: 10.1371/journal.pone.0078521] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 09/19/2013] [Indexed: 11/19/2022] Open
Abstract
The development of a vaccine against human immunodeficiency virus-1 (HIV-1) capable of inducing broad humoral and cellular responses at both the systemic and mucosal levels will be critical for combating the global AIDS epidemic. We previously demonstrated the ability of Newcastle disease virus (NDV) as a vaccine vector to express oligomeric Env protein gp160 and induce potent humoral and mucosal immune responses. In the present study, we used NDV vaccine strain LaSota as a vector to compare the biochemical and immunogenic properties of vector-expressed gp160, gp120, and two versions of gp140 (a derivative of gp160 made by deleting the transmembrane and cytoplasmic domains), namely: gp140L, which contained the complete membrane-proximal external region (MPER), and gp140S, which lacks the distal half of MPER. We show that, similar to gp160, NDV-expressed gp140S and gp120, but not gp140L, formed higher-order oligomers that retained recognition by conformationally sensitive monoclonal antibodies. Immunization of guinea pigs by the intranasal route with rLaSota/gp140S resulted in significantly greater systemic and mucosal antibody responses compared to the other recombinants. Immunization with rLaSota/140S, rLaSota/140L rLaSota/120 resulted in mixed Th1/Th2 immune responses as compared to Th1-biased immune responses induced by rLaSota/160. Importantly, rLaSota/gp140S induced neutralizing antibody responses to homologous HIV-1 strain BaL.26 and laboratory adapted HIV-1 strain MN.3 that were stronger than those elicited by the other NDV recombinants. Additionally, rLaSota/gp140S induced greater CD4+ and CD8+ T-cell responses in mice. These studies illustrate that rLaSota/gp140S is a promising vaccine candidate to elicit potent mucosal, humoral and cellular immune responses to the HIV-1 Env protein.
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Chimeric Cyanovirin-MPER recombinantly engineered proteins cause cell-free virolysis of HIV-1. Antimicrob Agents Chemother 2013; 57:4743-50. [PMID: 23856780 DOI: 10.1128/aac.00309-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Human immunodeficiency virus (HIV) is the primary etiologic agent responsible for the AIDS pandemic. In this work, we used a chimeric recombinant protein strategy to test the possibility of irreversibly destroying the HIV-1 virion using an agent that simultaneously binds the Env protein and viral membrane. We constructed a fusion of the lectin cyanovirin-N (CVN) and the gp41 membrane-proximal external region (MPER) peptide with a variable-length (Gly4Ser)x linker (where x is 4 or 8) between the C terminus of the former and N terminus of the latter. The His-tagged recombinant proteins, expressed in BL21(DE3)pLysS cells and purified by immobilized metal affinity chromatography followed by gel filtration, were found to display a nanomolar efficacy in blocking BaL-pseudotyped HIV-1 infection of HOS.T4.R5 cells. This antiviral activity was HIV-1 specific, since it did not inhibit cell infection by vesicular stomatitis virus (VSV) or amphotropic-murine leukemia virus. Importantly, the chimeric proteins were found to release intraviral p24 protein from both BaL-pseudotyped HIV-1 and fully infectious BaL HIV-1 in a dose-dependent manner in the absence of host cells. The addition of either MPER or CVN was found to outcompete this virolytic effect, indicating that both components of the chimera are required for virolysis. The finding that engaging the Env protein spike and membrane using a chimeric ligand can destabilize the virus and lead to inactivation opens up a means to investigate virus particle metastability and to evaluate this approach for inactivation at the earliest stages of exposure to virus and before host cell encounter.
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10
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Bozek K, Lengauer T, Sierra S, Kaiser R, Domingues FS. Analysis of physicochemical and structural properties determining HIV-1 coreceptor usage. PLoS Comput Biol 2013; 9:e1002977. [PMID: 23555214 PMCID: PMC3605109 DOI: 10.1371/journal.pcbi.1002977] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 01/23/2013] [Indexed: 11/18/2022] Open
Abstract
The relationship of HIV tropism with disease progression and the recent development of CCR5-blocking drugs underscore the importance of monitoring virus coreceptor usage. As an alternative to costly phenotypic assays, computational methods aim at predicting virus tropism based on the sequence and structure of the V3 loop of the virus gp120 protein. Here we present a numerical descriptor of the V3 loop encoding its physicochemical and structural properties. The descriptor allows for structure-based prediction of HIV tropism and identification of properties of the V3 loop that are crucial for coreceptor usage. Use of the proposed descriptor for prediction results in a statistically significant improvement over the prediction based solely on V3 sequence with 3 percentage points improvement in AUC and 7 percentage points in sensitivity at the specificity of the 11/25 rule (95%). We additionally assessed the predictive power of the new method on clinically derived ‘bulk’ sequence data and obtained a statistically significant improvement in AUC of 3 percentage points over sequence-based prediction. Furthermore, we demonstrated the capacity of our method to predict therapy outcome by applying it to 53 samples from patients undergoing Maraviroc therapy. The analysis of structural features of the loop informative of tropism indicates the importance of two loop regions and their physicochemical properties. The regions are located on opposite strands of the loop stem and the respective features are predominantly charge-, hydrophobicity- and structure-related. These regions are in close proximity in the bound conformation of the loop potentially forming a site determinant for the coreceptor binding. The method is available via server under http://structure.bioinf.mpi-inf.mpg.de/. Human Immunodeficiency Virus (HIV) requires one of the chemokine coreceptors CCR5 or CXCR4 for entry into the host cell. The capacity of the virus to use one or both of these coreceptors is termed tropism. Monitoring HIV tropism is of high importance due to the relationship of the emergence of CXCR4-tropic virus with the progression of immunodeficiency and for patient treatment with the recently developed CCR5 antagonists. Computational methods for predicting HIV tropism are based on sequence and on structure of the third variable region (V3 loop) of the viral gp120 protein — the major determinant of the HIV tropism. Limitations of the existing methods include the limited insights they provide into the biochemical determinants of coreceptor usage, high computational load of the structure-based methods and low prediction accuracy on clinically derived patient samples. Here we propose a numerical descriptor of the V3 loop encoding the physicochemical and structural properties of the loop. The new descriptor allows for server-based prediction of viral tropism with accuracy comparable to that of established sequence-based methods both on clonal and clinically derived patient data as well as for the interpretation of the properties of the loop relevant for tropism. The server is available under http://structure.bioinf.mpi-inf.mpg.de/.
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Affiliation(s)
- Katarzyna Bozek
- Max Planck Institute for Computer Science, Saarbrucken, Germany.
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11
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Kang Y, Guo J, Chen Z. Closing the door to human immunodeficiency virus. Protein Cell 2013; 4:86-102. [PMID: 23479426 DOI: 10.1007/s13238-012-2111-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 11/22/2012] [Indexed: 10/27/2022] Open
Abstract
The pandemic of human immunodeficiency virus type one (HIV-1), the major etiologic agent of acquired immunodeficiency disease (AIDS), has led to over 33 million people living with the virus, among which 18 million are women and children. Until now, there is neither an effective vaccine nor a therapeutic cure despite over 30 years of efforts. Although the Thai RV144 vaccine trial has demonstrated an efficacy of 31.2%, an effective vaccine will likely rely on a breakthrough discovery of immunogens to elicit broadly reactive neutralizing antibodies, which may take years to achieve. Therefore, there is an urgency of exploring other prophylactic strategies. Recently, antiretroviral treatment as prevention is an exciting area of progress in HIV-1 research. Although effective, the implementation of such strategy faces great financial, political and social challenges in heavily affected regions such as developing countries where drug resistant viruses have already been found with growing incidence. Activating latently infected cells for therapeutic cure is another area of challenge. Since it is greatly difficult to eradicate HIV-1 after the establishment of viral latency, it is necessary to investigate strategies that may close the door to HIV-1. Here, we review studies on non-vaccine strategies in targeting viral entry, which may have critical implications for HIV-1 prevention.
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Affiliation(s)
- Yuanxi Kang
- AIDS Institute and Department of Microbiology of Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China
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12
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Julien JP, Lee PS, Wilson IA. Structural insights into key sites of vulnerability on HIV-1 Env and influenza HA. Immunol Rev 2013; 250:180-98. [PMID: 23046130 DOI: 10.1111/imr.12005] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Human immunodeficiency virus-1 (HIV-1) envelope protein (Env) and influenza hemagglutinin (HA) are the surface glycoproteins responsible for viral entry into host cells, the first step in the virus life cycle necessary to initiate infection. These glycoproteins exhibit a high degree of sequence variability and glycosylation, which are used as strategies to escape host immune responses. Nonetheless, antibodies with broadly neutralizing activity against these viruses have been isolated that have managed to overcome these barriers. Here, we review recent advances in the structural characterization of these antibodies with their viral antigens that defines a few sites of vulnerability on these viral spikes. These broadly neutralizing antibodies tend to focus their recognition on the sites of similar function between the two viruses: the receptor-binding site and membrane fusion machinery. However, some sites of recognition are unique to the virus neutralized, such as the dense shield of oligomannose carbohydrates on HIV-1 Env. These observations are discussed in the context of structure-based design strategies to aid in vaccine design or development of antivirals.
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Affiliation(s)
- Jean-Philippe Julien
- Department of Molecular Biology, Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA
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13
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Bozek K, Eckhardt M, Sierra S, Anders M, Kaiser R, Kräusslich HG, Müller B, Lengauer T. An expanded model of HIV cell entry phenotype based on multi-parameter single-cell data. Retrovirology 2012; 9:60. [PMID: 22830600 PMCID: PMC3464718 DOI: 10.1186/1742-4690-9-60] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 06/07/2012] [Indexed: 11/29/2022] Open
Abstract
Background Entry of human immunodeficiency virus type 1 (HIV-1) into the host cell involves interactions between the viral envelope glycoproteins (Env) and the cellular receptor CD4 as well as a coreceptor molecule (most importantly CCR5 or CXCR4). Viral preference for a specific coreceptor (tropism) is in particular determined by the third variable loop (V3) of the Env glycoprotein gp120. The approval and use of a coreceptor antagonist for antiretroviral therapy make detailed understanding of tropism and its accurate prediction from patient derived virus isolates essential. The aim of the present study is the development of an extended description of the HIV entry phenotype reflecting its co-dependence on several key determinants as the basis for a more accurate prediction of HIV-1 entry phenotype from genotypic data. Results Here, we established a new protocol of quantitation and computational analysis of the dependence of HIV entry efficiency on receptor and coreceptor cell surface levels as well as viral V3 loop sequence and the presence of two prototypic coreceptor antagonists in varying concentrations. Based on data collected at the single-cell level, we constructed regression models of the HIV-1 entry phenotype integrating the measured determinants. We developed a multivariate phenotype descriptor, termed phenotype vector, which facilitates a more detailed characterization of HIV entry phenotypes than currently used binary tropism classifications. For some of the tested virus variants, the multivariant phenotype vector revealed substantial divergences from existing tropism predictions. We also developed methods for computational prediction of the entry phenotypes based on the V3 sequence and performed an extrapolating calculation of the effectiveness of this computational procedure. Conclusions Our study of the HIV cell entry phenotype and the novel multivariate representation developed here contributes to a more detailed understanding of this phenotype and offers potential for future application in the effective administration of entry inhibitors in antiretroviral therapies.
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Affiliation(s)
- Katarzyna Bozek
- Department of Computational Biology and Applied Algorithmics, Max Planck for Computer Sciences, Campus E1 4 66123, Saarbrücken, Germany
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14
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Borel S, Espert L, Biard-Piechaczyk M. Macroautophagy Regulation during HIV-1 Infection of CD4+ T Cells and Macrophages. Front Immunol 2012; 3:97. [PMID: 22586428 PMCID: PMC3345938 DOI: 10.3389/fimmu.2012.00097] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 04/13/2012] [Indexed: 11/13/2022] Open
Abstract
Autophagy is an intracellular mechanism whereby pathogens, particularly viruses, are destroyed in autolysosomes after their entry into targets cells. Therefore, to survive and replicate in host cells, viruses have developed multiple strategies to either counteract or exploit this process. The aim of this review is to outline the known relationships between HIV-1 and autophagy in CD4+ T lymphocytes and macrophages, two main HIV-1 cell targets. The differential regulation of autophagy in these two cell-types is highlighted and its potential consequences in terms of viral replication and physiopathology discussed.
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Affiliation(s)
- Sophie Borel
- Centre d'études d'agents Pathogènes et Biotechnologies pour la Santé, CNRS UMR5236, UM1/UM2 Montpellier, France
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15
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Reuven EM, Dadon Y, Viard M, Manukovsky N, Blumenthal R, Shai Y. HIV-1 gp41 transmembrane domain interacts with the fusion peptide: implication in lipid mixing and inhibition of virus-cell fusion. Biochemistry 2012; 51:2867-78. [PMID: 22413880 PMCID: PMC3335273 DOI: 10.1021/bi201721r] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Fusion of the human immunodeficiency virus (HIV) with target cells is mediated by the gp41 subunit of the envelope protein. Mutation and deletion studies within the transmembrane domain (TMD) of intact gp41 influenced its fusion activity. In addition, current models suggest that the TMD is in proximity with the fusion peptide (FP) at the late fusion stages, but there are no direct experimental data to support this hypothesis. Here, we investigated the TMD focusing on two regions: the N-terminal containing the GxxxG motif and the C-terminal containing the GLRI motif, which is conserved among the TMDs of HIV and the T-cell receptor. Studies utilizing the ToxR expression system combined with synthetic peptides and their fluorescent analogues derived from TMD revealed that the GxxxG motif is important for TMD self-association, whereas the C-terminal region is for its heteroassociation with FP. Functionally, all three TMD peptides induced lipid mixing that was enhanced significantly upon mixing with FP. Furthermore, the TMD peptides inhibited virus-cell fusion apparently through their interaction with their endogenous counterparts. Notably, the R2E mutant (in the GLRI) was significantly less potent than the two others. Overall, our findings provide experimental evidence that HIV-1 TMD contributes to membrane assembly and function of the HIV-1 envelope. Owing to similarities between functional domains within viruses, these findings suggest that the TMDs and FPs may contribute similarly in other viruses as well.
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Affiliation(s)
- Eliran Moshe Reuven
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, 76100 Israel
| | - Yakir Dadon
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, 76100 Israel
| | - Mathias Viard
- Basic Research Program, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland 21702
- Nanobiology Program, Center of Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Nurit Manukovsky
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, 76100 Israel
| | - Robert Blumenthal
- Basic Research Program, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland 21702
| | - Yechiel Shai
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, 76100 Israel
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16
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Biard-Piechaczyk M, Borel S, Espert L, de Bettignies G, Coux O. HIV-1, ubiquitin and ubiquitin-like proteins: the dialectic interactions of a virus with a sophisticated network of post-translational modifications. Biol Cell 2012; 104:165-87. [PMID: 22188301 DOI: 10.1111/boc.201100112] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 12/14/2011] [Indexed: 11/26/2022]
Abstract
The modification of intracellular proteins by ubiquitin (Ub) and ubiquitin-like (UbL) proteins is a central mechanism for regulating and fine-tuning all cellular processes. Indeed, these modifications are widely used to control the stability, activity and localisation of many key proteins and, therefore, they are instrumental in regulating cellular functions as diverse as protein degradation, cell signalling, vesicle trafficking and immune response. It is thus no surprise that pathogens in general, and viruses in particular, have developed multiple strategies to either counteract or exploit the complex mechanisms mediated by the Ub and UbL protein conjugation pathways. The aim of this review is to provide an overview on the intricate and conflicting relationships that intimately link HIV-1 and these sophisticated systems of post-translational modifications.
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Affiliation(s)
- Martine Biard-Piechaczyk
- Centre d'étude d'agents Pathogènes et Biotechnologies pour la Santé (CPBS-CNRS), Montpellier Cedex 5, France.
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17
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Antibody-induced conformational changes in herpes simplex virus glycoprotein gD reveal new targets for virus neutralization. J Virol 2011; 86:1563-76. [PMID: 22130533 DOI: 10.1128/jvi.06480-11] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
As the receptor-binding protein of herpes simplex virus (HSV), gD plays an essential role in virus entry. In its native state, the last 56 amino acids of the ectodomain C terminus (C-term) occlude binding to its receptors, herpesvirus entry mediator (HVEM) and nectin-1. Although it is clear that movement of the C-term must occur to permit receptor binding, we believe that this conformational change is also a key event for triggering later steps leading to fusion. Specifically, gD mutants containing disulfide bonds that constrain the C-term are deficient in their ability to trigger fusion following receptor binding. In this report, we show that two newly made monoclonal antibodies (MAbs), MC2 and MC5, have virus-neutralizing activity but do not block binding of gD to either receptor. In contrast, all previously characterized neutralizing anti-gD MAbs block binding of gD to a receptor(s). Interestingly, instead of blocking receptor binding, MC2 significantly enhances the affinity of gD for both receptors. Several nonneutralizing MAbs (MC4, MC10, and MC14) also enhanced gD-receptor binding. While MC2 and MC5 recognized different epitopes on the core of gD, these nonneutralizing MAbs recognized the gD C-term. Both the neutralizing capacity and rate of neutralization of virus by MC2 are uniquely enhanced when MC2 is combined with MAb MC4, MC10, or MC14. We suggest that MC2 and MC5 prevent gD from performing a function that triggers later steps leading to fusion and that the epitope for MC2 is normally occluded by the C-term of the gD ectodomain.
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18
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Lay CS, Ludlow LE, Stapleton D, Bellamy-McIntyre AK, Ramsland PA, Drummer HE, Poumbourios P. Role for the terminal clasp of HIV-1 gp41 glycoprotein in the initiation of membrane fusion. J Biol Chem 2011; 286:41331-41343. [PMID: 21976663 DOI: 10.1074/jbc.m111.299826] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The binding by HIV-1 gp120 to CD4 and a chemokine receptor activates the membrane fusion glycoprotein, gp41. The fusion function of gp41 involves the refolding of its core into a 6-helix bundle, which apposes the lipophilic termini (the fusion peptide and transmembrane domain) and the associated cell and viral membranes, leading to their fusion. In this study, we examined the functional role of the polar segment and membrane proximal external region (MPER), which link the fusion peptide and transmembrane domain, respectively, to the core domain and interact to form a terminal clasp adjacent to the core. Limited proteolysis indicated that the terminal clasp is destabilized by simultaneous I535A/V539G mutations within the polar segment and mutations within the MPER. The destabilizing effects of I535A/V539G correlated with defective cell-cell fusion, viral entry, and viral replication. By using lipophilic and cytoplasmic fluorescent dye transfer assays, we found that terminal clasp destabilization is linked to a block in the lipid mixing/hemifusion phase of the membrane fusion cascade. Because the biosynthesis of the prefusion gp120-gp41 complex did not appear to be affected by I535A/V539G, we infer that the hemifusion block is due to a specific effect on the trimer of hairpins conformation of gp41. By contrast, the decreased fusion function of the MPER mutants correlated with a decrease in the interfacial hydropathy of the MPER sequence, suggesting that the prefusion Env complex had been adversely affected in these cases. These findings reveal a novel conserved functional target for the discovery of fusion inhibitors.
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Affiliation(s)
- Chan-Sien Lay
- Virus Fusion Laboratory, Burnet Institute, Melbourne, Victoria 3004
| | - Louise E Ludlow
- Departments of Microbiology and Immunology, The University of Melbourne, Victoria 3010
| | - David Stapleton
- Department of Physiology, The University of Melbourne, Victoria 3010
| | - Anna K Bellamy-McIntyre
- Virus Fusion Laboratory, Burnet Institute, Melbourne, Victoria 3004; Department of Microbiology, Monash University, Clayton, Victoria 3168
| | - Paul A Ramsland
- Virus Fusion Laboratory, Burnet Institute, Melbourne, Victoria 3004; Department of Immunology, Monash University, Alfred Medical Research and Education Precinct, Melbourne, Victoria 3004; Department of Surgery Austin Health, The University of Melbourne, Heidelberg, Victoria 3084, Australia
| | - Heidi E Drummer
- Virus Fusion Laboratory, Burnet Institute, Melbourne, Victoria 3004; Department of Microbiology, Monash University, Clayton, Victoria 3168; Departments of Microbiology and Immunology, The University of Melbourne, Victoria 3010
| | - Pantelis Poumbourios
- Virus Fusion Laboratory, Burnet Institute, Melbourne, Victoria 3004; Department of Microbiology, Monash University, Clayton, Victoria 3168.
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19
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Newcastle disease virus expressing human immunodeficiency virus type 1 envelope glycoprotein induces strong mucosal and serum antibody responses in Guinea pigs. J Virol 2011; 85:10529-41. [PMID: 21849467 DOI: 10.1128/jvi.05050-11] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) is transmitted mainly through mucosal sites. Optimum strategies to elicit both systemic and mucosal immunity are critical for the development of vaccines against HIV-1. We therefore sought to evaluate the induction of systemic and mucosal immune responses by the use of Newcastle disease virus (NDV) as a vaccine vector. We generated a recombinant NDV, designated rLaSota/gp160, expressing the gp160 envelope (Env) protein of HIV-1 from an added gene. The gp160 protein expressed by rLaSota/gp160 virus was detected on an infected cell surface and was incorporated into the NDV virion. Biochemical studies showed that gp160 present in infected cells and in the virion formed a higher-order oligomer that retained recognition by conformationally sensitive monoclonal antibodies. Expression of gp160 did not increase the virulence of recombinant NDV (rNDV) strain LaSota. Guinea pigs were administered rLaSota/gp160 via the intranasal (i.n.) or intramuscular (i.m.) route in different prime-boost combinations. Systemic and mucosal antibody responses specific to the HIV-1 envelope protein were assessed in serum and vaginal washes, respectively. Two or three immunizations via the i.n. or i.m. route induced a more potent systemic and mucosal immune response than a single immunization by either route. Priming by the i.n. route was more immunogenic than by the i.m. route, and the same was true for the boosts. Furthermore, immunization with rLaSota/gp160 by any route or combination of routes induced a Th1-type response, as reflected by the induction of stronger antigen-specific IgG2a than IgG1 antibody responses. Additionally, i.n. immunization elicited a stronger neutralizing serum antibody response to laboratory-adapted HIV-1 strain MN.3. These data illustrate that it is feasible to use NDV as a vaccine vector to elicit potent humoral and mucosal responses to the HIV-1 envelope protein.
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20
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Borggren M, Repits J, Sterjovski J, Uchtenhagen H, Churchill MJ, Karlsson A, Albert J, Achour A, Gorry PR, Fenyö EM, Jansson M. Increased sensitivity to broadly neutralizing antibodies of end-stage disease R5 HIV-1 correlates with evolution in Env glycosylation and charge. PLoS One 2011; 6:e20135. [PMID: 21698221 PMCID: PMC3116816 DOI: 10.1371/journal.pone.0020135] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Accepted: 04/26/2011] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Induction of broadly neutralizing antibodies, such as the monoclonal antibodies IgGb12, 2F5 and 2G12, is the objective of most antibody-based HIV-1 vaccine undertakings. However, despite the relative conserved nature of epitopes targeted by these antibodies, mechanisms underlying the sensitivity of circulating HIV-1 variants to broadly neutralizing antibodies are not fully understood. Here we have studied sensitivity to broadly neutralizing antibodies of HIV-1 variants that emerge during disease progression in relation to molecular alterations in the viral envelope glycoproteins (Env), using a panel of primary R5 HIV-1 isolates sequentially obtained before and after AIDS onset. PRINCIPAL FINDINGS HIV-1 R5 isolates obtained at end-stage disease, after AIDS onset, were found to be more sensitive to neutralization by TriMab, an equimolar mix of the IgGb12, 2F5 and 2G12 antibodies, than R5 isolates from the chronic phase. The increased sensitivity correlated with low CD4(+) T cell count at time of virus isolation and augmented viral infectivity. Subsequent sequence analysis of multiple env clones derived from the R5 HIV-1 isolates revealed that, concomitant with increased TriMab neutralization sensitivity, end-stage R5 variants displayed envelope glycoproteins (Envs) with reduced numbers of potential N-linked glycosylation sites (PNGS), in addition to increased positive surface charge. These molecular changes in Env also correlated to sensitivity to neutralization by the individual 2G12 monoclonal antibody (mAb). Furthermore, results from molecular modeling suggested that the PNGS lost at end-stage disease locate in the proximity to the 2G12 epitope. CONCLUSIONS Our study suggests that R5 HIV-1 variants with increased sensitivity to broadly neutralizing antibodies, including the 2G12 mAb, may emerge in an opportunistic manner during severe immunodeficiency as a consequence of adaptive molecular Env changes, including loss of glycosylation and gain of positive charge.
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Affiliation(s)
- Marie Borggren
- Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Johanna Repits
- Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Jasminka Sterjovski
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Australia
- Department of Medicine, Monash University, Melbourne, Australia
| | - Hannes Uchtenhagen
- Center for Infectious Medicine (CIM), Department of Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Melissa J. Churchill
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Australia
- Department of Medicine, Monash University, Melbourne, Australia
| | - Anders Karlsson
- Department of Infectious Medicine, South Hospital, Stockholm, Sweden
| | - Jan Albert
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Adnane Achour
- Center for Infectious Medicine (CIM), Department of Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Paul R. Gorry
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Australia
- Department of Medicine, Monash University, Melbourne, Australia
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Australia
| | - Eva Maria Fenyö
- Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Marianne Jansson
- Department of Laboratory Medicine, Lund University, Lund, Sweden
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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21
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Abstract
The quest for an effective and safe HIV-1 vaccine has been and still is the aspiration of many scientists and clinicians worldwide. Until recently, the hopes for an effective vaccine were thwarted by the disappointing results and early termination in September 2007 of the STEP study, which saw a subgroup of male vaccine recipients at an increased risk of HIV-1 infection, and the failure of earlier trials of vaccines based on recombinant envelope proteins to provide any level of protection. The results of the STEP study raised important questions in the field of HIV vaccines, including the use of recombinant adenovirus vectors as immunogens, the rationale for the development of T-cell-based vaccines and the development pathway for these vaccines, in terms of assessment of immunogenicity and the challenge models used. The study of neutralizing antibodies has demonstrated that the induction of high-titre, broadly neutralizing antibodies in the majority of recipients is likely to be highly problematic. However, the results of the RV144 Thai trial released in September 2009 have brought new optimism to the field. This study employed envelope-based immunogens delivered as a priming vaccination with a recombinant poxvirus vector and boosting with recombinant proteins. This regimen provided modest protection to HIV-1 infection in a low-risk population. Although the correlates of protection are currently unknown, extensive studies are underway to try to determine these. Neutralizing antibodies were not induced in the RV144 study; however, considerable titres of binding antibodies to HIV-1 viral envelope (Env) were. It is speculated that these antibodies may have provided a means of protection by a mechanism such as antibody-dependent cell-mediated cytotoxicity. In addition, no CD8+ T-cell responses were induced, but robust CD4+ T-cell responses were, and correlates of protection are being sought by analysing the quality of this aspect of the vaccine-induced immune response. The current paradigm for an optimal HIV-1 vaccine is to design immunogens and vaccination protocols that allow the induction of both broadly neutralizing humoral and broadly reactive and effective cell-mediated immunity, to act at sites of possible infection and post-infection, respectively. However, this is challenged by the results of the RV144 trial as neither of these responses were induced but modest protection was observed. Understanding the biology and immunopathology of HIV-1 early following infection, its modes of transmission and the human immune system's response to the virus should aid in the rational design of vaccines of increased efficacy.
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Affiliation(s)
- C Mee Ling Munier
- HIV Immunovirology Laboratory, St Vincent's Centre for Applied Medical Research, Sydney, New South Wales, Australia.
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22
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Forssmann WG, The YH, Stoll M, Adermann K, Albrecht U, Tillmann HC, Barlos K, Busmann A, Canales-Mayordomo A, Gimenez-Gallego G, Hirsch J, Jimenez-Barbero J, Meyer-Olson D, Munch J, Perez-Castells J, Standker L, Kirchhoff F, Schmidt RE. Short-Term Monotherapy in HIV-Infected Patients with a Virus Entry Inhibitor Against the gp41 Fusion Peptide. Sci Transl Med 2010; 2:63re3. [DOI: 10.1126/scitranslmed.3001697] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Papandréou MJ, Barbouche R, Guieu R, Rivera S, Fantini J, Khrestchatisky M, Jones IM, Fenouillet E. Mapping of domains on HIV envelope protein mediating association with calnexin and protein-disulfide isomerase. J Biol Chem 2010; 285:13788-96. [PMID: 20202930 PMCID: PMC2859542 DOI: 10.1074/jbc.m109.066670] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Revised: 03/02/2010] [Indexed: 01/11/2023] Open
Abstract
The cell catalysts calnexin (CNX) and protein-disulfide isomerase (PDI) cooperate in establishing the disulfide bonding of the HIV envelope (Env) glycoprotein. Following HIV binding to lymphocytes, cell-surface PDI also reduces Env to induce the fusogenic conformation. We sought to define the contact points between Env and these catalysts to illustrate their potential as therapeutic targets. In lysates of Env-expressing cells, 15% of the gp160 precursor, but not gp120, coprecipitated with CNX, whereas only 0.25% of gp160 and gp120 coprecipitated with PDI. Under in vitro conditions, which mimic the Env/PDI interaction during virus/cell contact, PDI readily associated with Env. The domains of Env interacting in cellulo with CNX or in vitro with PDI were then determined using anti-Env antibodies whose binding site was occluded by CNX or PDI. Antibodies against domains V1/V2, C2, and the C terminus of V3 did not bind CNX-associated Env, whereas those against C1, V1/V2, and the CD4-binding domain did not react with PDI-associated Env. In addition, a mixture of the latter antibodies interfered with PDI-mediated Env reduction. Thus, Env interacts with intracellular CNX and extracellular PDI via discrete, largely nonoverlapping, regions. The sites of interaction explain the mode of action of compounds that target these two catalysts and may enable the design of further new competitive agents.
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Affiliation(s)
| | - Rym Barbouche
- From CNRS, Faculté de Médecine Nord, Université Aix-Marseille II, F-13015 Marseille, France
| | - Régis Guieu
- Biochimie, Hôpital de la Timone, F-13005 Marseille, France
| | - Santiago Rivera
- From CNRS, Faculté de Médecine Nord, Université Aix-Marseille II, F-13015 Marseille, France
| | - Jacques Fantini
- the Université Aix-Marseille III, F-13013 Marseille, France, and
| | - Michel Khrestchatisky
- From CNRS, Faculté de Médecine Nord, Université Aix-Marseille II, F-13015 Marseille, France
| | - Ian M. Jones
- the School of Biological Sciences, University of Reading, Reading RG6 6AJ, United Kingdom
| | - Emmanuel Fenouillet
- From CNRS, Faculté de Médecine Nord, Université Aix-Marseille II, F-13015 Marseille, France
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Baleux F, Loureiro-Morais L, Hersant Y, Clayette P, Arenzana-Seisdedos F, Bonnaffé D, Lortat-Jacob H. A synthetic CD4-heparan sulfate glycoconjugate inhibits CCR5 and CXCR4 HIV-1 attachment and entry. Nat Chem Biol 2009; 5:743-8. [PMID: 19734912 DOI: 10.1038/nchembio.207] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Accepted: 06/10/2009] [Indexed: 11/10/2022]
Abstract
The HIV-1 envelope, gp120, which features the binding determinants for both CD4 and coreceptor recognition, is key for virus entry and represents an attractive pharmacological target. However, critical domains for entry (coreceptor and CD4 binding sites) are either cryptic or located in partially occluded cavities. Here we developed a chemical approach to synthesize a CD4-mimetic peptide linked to a heparan sulfate dodecasaccharide. This molecule binds to gp120, induces the exposure of the coreceptor binding domain and renders it available for interaction with the oligosaccharide. The linkage between the CD4 mimetic and the heparan sulfate derivative provides strong cooperative effects, resulting in low-nanomolar antiviral activity toward both CCR5- and CXCR4-tropic HIV-1 strains. This compound, which has the unique ability to simultaneously target two critical and highly conserved regions of gp120, establishes a new type of inhibitor and suggests a general concept for the inhibition of numerous other biological systems.
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Affiliation(s)
- Françoise Baleux
- Unité de Chimie des Biomolécules, Institut Pasteur, Centre National de la Recherche Scientifique 2128, Paris, France
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Eugenin EA, Morgello S, Klotman ME, Mosoian A, Lento PA, Berman JW, Schecter AD. Human immunodeficiency virus (HIV) infects human arterial smooth muscle cells in vivo and in vitro: implications for the pathogenesis of HIV-mediated vascular disease. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 172:1100-11. [PMID: 18310503 PMCID: PMC2276423 DOI: 10.2353/ajpath.2008.070457] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Accepted: 12/18/2007] [Indexed: 11/20/2022]
Abstract
Human immunodeficiency virus (HIV) infection is associated with accelerated atherosclerosis and vasculopathy, although the mechanisms underlying these findings have not been determined. Hypotheses for these observations include: 1) an increase in the prevalence of established cardiac risk factors observed in HIV-infected individuals who are currently experiencing longer life expectancies; 2) the dyslipidemia reported with certain HIV anti-retroviral therapies; and/or 3) the proinflammatory effects of infiltrating HIV-infected monocytes/macrophages. An unexplored possibility is whether HIV itself can infect vascular smooth muscle cells (SMCs) and, by doing so, whether SMCs can accelerate vascular disease. Our studies demonstrate that human SMCs can be infected with HIV both in vivo and in vitro. The HIV protein p24 was detected by fluorescence confocal microscopy in SMCs from tissue sections of human atherosclerotic plaques obtained from HIV-infected individuals. Human SMCs could also be infected in vitro with HIV by a mechanism dependent on CD4, the chemokine receptors CXCR4 or CCR5, and endocytosis, resulting in a marked increase in SMC secretion of the chemokine CCL2/MCP-1, which has been previously shown to be a critical mediator of atherosclerosis. In addition, SMC proliferation appeared concentric to the vessel lumen, and minimal inflammation was detected, unlike typical atherosclerosis. Our data suggest that direct infection of human arterial SMCs by HIV represents a potential mechanism in a multifactorial paradigm to explain the exacerbated atherosclerosis and vasculopathy reported in individuals infected with HIV.
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Affiliation(s)
- Eliseo A Eugenin
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
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26
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An alteration of human immunodeficiency virus gp41 leads to reduced CCR5 dependence and CD4 independence. J Virol 2008; 82:5460-71. [PMID: 18353949 DOI: 10.1128/jvi.01049-07] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus (HIV) type 1 infection requires functional interactions of the viral surface (gp120) glycoprotein with cell surface CD4 and a chemokine coreceptor (usually CCR5 or CXCR4) and of the viral transmembrane (gp41) glycoprotein with the target cell membrane. Extensive genetic variability, generally in gp120 and the gp41 ectodomain, can result in altered coreceptor use, fusion kinetics, and neutralization sensitivity. Here we describe an R5 HIV variant that, in contrast to its parental virus, infects T-cell lines expressing low levels of cell surface CCR5. This correlated with an ability to infect cells in the absence of CD4, increased sensitivity to a neutralizing antibody recognizing the coreceptor binding site of gp120, and increased resistance to the fusion inhibitor T-20. Surprisingly, these properties were determined by alterations in gp41, including the cytoplasmic tail, a region not previously shown to influence coreceptor use. These data indicate that HIV infection of cells with limiting levels of cell surface CCR5 can be facilitated by gp41 sequences that are not exposed on the envelope ectodomain yet induce allosteric changes in gp120 that facilitate exposure of the CCR5 binding site.
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Structure-function relationship of novel X4 HIV-1 entry inhibitors - L- and D-arginine peptide-aminoglycoside conjugates. FEBS J 2007; 274:6523-36. [DOI: 10.1111/j.1742-4658.2007.06169.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Pontow S, Harmon B, Campbell N, Ratner L. Antiviral activity of a Rac GEF inhibitor characterized with a sensitive HIV/SIV fusion assay. Virology 2007; 368:1-6. [PMID: 17640696 PMCID: PMC2174213 DOI: 10.1016/j.virol.2007.06.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2007] [Revised: 02/15/2007] [Accepted: 06/13/2007] [Indexed: 01/14/2023]
Abstract
A virus-dependent fusion assay was utilized to examine the activity of a panel of HIV-1, -2, and SIV isolates of distinct coreceptor phenotypes. This assay allowed identification of entry inhibitors, and characterization of an antagonist of a Rac guanine nucleotide exchange factor, as an inhibitor of HIV-mediated fusion.
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Affiliation(s)
- Suzanne Pontow
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, Box 8069, 660 S Euclid Ave, St. Louis, MO 63110, USA
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29
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Lama J, Planelles V. Host factors influencing susceptibility to HIV infection and AIDS progression. Retrovirology 2007; 4:52. [PMID: 17651505 PMCID: PMC1978541 DOI: 10.1186/1742-4690-4-52] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Accepted: 07/25/2007] [Indexed: 12/21/2022] Open
Abstract
Transmission of HIV first results in an acute infection, followed by an apparently asymptomatic period that averages ten years. In the absence of antiretroviral treatment, most patients progress into a generalized immune dysfunction that culminates in death. The length of the asymptomatic period varies, and in rare cases infected individuals never progress to AIDS. Other individuals whose behavioral traits put them at high-risk of HIV transmission, surprisingly appear resistant and never succumb to infection. These unique cases highlight the fact that susceptibility to HIV infection and progression to disease are complex traits modulated by environmental and genetic factors. Recent evidence has indicated that natural variations in host genes can influence the outcome of HIV infection and its transmission. In this review we summarize the available literature on the roles of cellular factors and their genetic variation in modulating HIV infection and disease progression.
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Affiliation(s)
- Juan Lama
- La Jolla Institute for Molecular Medicine, 4570 Executive Drive, Suite 100, San Diego, California 92121, USA
- RetroVirox, Inc. 4570 Executive Drive, Suite 100, San Diego, California 92121, USA
| | - Vicente Planelles
- Department of Pathology, University of Utah School of Medicine, 15 North Medical Drive East #2100 – Room 2520, Salt Lake City, Utah 84112, USA
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30
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Lin G, Bertolotti-Ciarlet A, Haggarty B, Romano J, Nolan KM, Leslie GJ, Jordan APO, Huang CC, Kwong PD, Doms RW, Hoxie JA. Replication-competent variants of human immunodeficiency virus type 2 lacking the V3 loop exhibit resistance to chemokine receptor antagonists. J Virol 2007; 81:9956-66. [PMID: 17609282 PMCID: PMC2045409 DOI: 10.1128/jvi.00385-07] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Entry of human immunodeficiency virus type 1 (HIV-1) and HIV-2 requires interactions between the envelope glycoprotein (Env) on the virus and CD4 and a chemokine receptor, either CCR5 or CXCR4, on the cell surface. The V3 loop of the HIV gp120 glycoprotein plays a critical role in this process, determining tropism for CCR5- or CXCR4-expressing cells, but details of how V3 interacts with these receptors have not been defined. Using an iterative process of deletion mutagenesis and in vitro adaptation of infectious viruses, variants of HIV-2 were derived that could replicate without V3, either with or without a deletion of the V1/V2 variable loops. The generation of these functional but markedly minimized Envs required adaptive changes on the gp120 core and gp41 transmembrane glycoprotein. V3-deleted Envs exhibited tropism for both CCR5- and CXCR4-expressing cells, suggesting that domains on the gp120 core were mediating interactions with determinants shared by both coreceptors. Remarkably, HIV-2 Envs with V3 deletions became resistant to small-molecule inhibitors of CCR5 and CXCR4, suggesting that these drugs inhibit wild-type viruses by disrupting a specific V3 interaction with the coreceptor. This study represents a proof of concept that HIV Envs lacking V3 alone or in combination with V1/V2 that retain functional domains required for viral entry can be derived. Such minimized Envs may be useful in understanding Env function, screening for new inhibitors of gp120 core interactions with chemokine receptors, and designing novel immunogens for vaccines.
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Affiliation(s)
- George Lin
- Department of Medicine, University of Pennsylvania, 421 Curie Blvd., Philadelphia, PA 19104, USA
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31
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Abstract
Humoral immunity is considered a key component of effective vaccines against HIV-1. Hence, an enormous effort has been put into investigating the neutralizing antibody response to HIV-1 over the past 20 years which generated key information on epitope specificity, potency, breadth and in vivo activity of the neutralizing antibodies. Less clear is still the role of antibody-mediated effector functions (antibody-dependent cellular cytotoxicity, phagocytosis, complement system) and uncertainty prevails whether Fc-mediated mechanisms are largely beneficial or detrimental for the host. The current knowledge on the manifold functions of the humoral immune response in HIV infection, their underlying mechanisms and potential in vaccine-induced immunity will be discussed in this review.
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Affiliation(s)
- M Huber
- Division of Infectious Diseases, University Hospital Zurich, Zurich, Switzerland
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32
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Henry KR, Weber J, Quiñones-Mateu ME, Arts EJ. The impact of viral and host elements on HIV fitness and disease progression. Curr HIV/AIDS Rep 2007; 4:36-41. [PMID: 17338859 DOI: 10.1007/s11904-007-0006-9] [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: 01/24/2023]
Abstract
Twenty-five years after the emergence of HIV onto the global scene, multiple advancements have been made in the understanding of HIV pathology. Thanks to the development of antiretroviral therapies, growing numbers of individuals with HIV infection experience slowed or halted acceleration to AIDS. Despite this, new HIV infections and AIDS-related morbidity and mortality are still common in the highly active antiretroviral therapy era. Recently, we and others have identified viral replicative fitness as a major determinant of HIV disease progression, which could have a major impact in the clinical setting. Therefore, in this review, we will discuss host and viral factors that affect viral fitness and its relationship on HIV pathogenesis.
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Affiliation(s)
- Kenneth R Henry
- Division of Infectious Diseases, BRB 1029, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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33
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Stiasny K, Kössl C, Lepault J, Rey FA, Heinz FX. Characterization of a structural intermediate of flavivirus membrane fusion. PLoS Pathog 2007; 3:e20. [PMID: 17305426 PMCID: PMC1797619 DOI: 10.1371/journal.ppat.0030020] [Citation(s) in RCA: 66] [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: 09/28/2006] [Accepted: 12/29/2006] [Indexed: 12/16/2022] Open
Abstract
Viral membrane fusion proceeds through a sequence of steps that are driven by triggered conformational changes of viral envelope glycoproteins, so-called fusion proteins. Although high-resolution structural snapshots of viral fusion proteins in their prefusion and postfusion conformations are available, it has been difficult to define intermediate structures of the fusion pathway because of their transient nature. Flaviviruses possess a class II viral fusion protein (E) mediating fusion at acidic pH that is converted from a dimer to a trimer with a hairpin-like structure during the fusion process. Here we show for tick-borne encephalitis virus that exposure of virions to alkaline instead of acidic pH traps the particles in an intermediate conformation in which the E dimers dissociate and interact with target membranes via the fusion peptide without proceeding to the merger of the membranes. Further treatment to low pH, however, leads to fusion, suggesting that these monomers correspond to an as-yet-elusive intermediate required to convert the prefusion dimer into the postfusion trimer. Thus, the use of nonphysiological conditions allows a dissection of the flavivirus fusion process and the identification of two separate steps, in which membrane insertion of multiple copies of E monomers precedes the formation of hairpin-like trimers. This sequence of events provides important new insights for understanding the dynamic process of viral membrane fusion.
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Affiliation(s)
- Karin Stiasny
- Institute of Virology, Medical University of Vienna, Vienna, Austria
| | - Christian Kössl
- Institute of Virology, Medical University of Vienna, Vienna, Austria
| | - Jean Lepault
- Laboratoire de Virologie Moléculaire et Structurale, UMR 2472/1157 CNRS/INRA, Gif-sur-Yvette, France
| | - Félix A Rey
- Unité de Virologie Structurale, Institut Pasteur, Paris, France
| | - Franz X Heinz
- Institute of Virology, Medical University of Vienna, Vienna, Austria
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Cocklin S, Gopi H, Querido B, Nimmagadda M, Kuriakose S, Cicala C, Ajith S, Baxter S, Arthos J, Martín-García J, Chaiken IM. Broad-spectrum anti-human immunodeficiency virus (HIV) potential of a peptide HIV type 1 entry inhibitor. J Virol 2007; 81:3645-8. [PMID: 17251295 PMCID: PMC1866025 DOI: 10.1128/jvi.01778-06] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The AIDS epidemic continues to spread at an alarming rate worldwide, especially in developing countries. One approach to solving this problem is the generation of anti-human immunodeficiency virus (HIV) compounds with inhibition spectra broad enough to include globally prevailing forms of the virus. We have examined the HIV type 1 (HIV-1) envelope specificity of a recently identified entry inhibitor candidate, HNG-105, using surface plasmon resonance spectroscopy and pseudovirus inhibition assays. The combined results suggest that the HNG-105 molecule may be effective across the HIV-1 subtypes, and they highlight its potential as a lead for developing therapeutic and microbicidal agents to help combat the spread of AIDS.
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Affiliation(s)
- Simon Cocklin
- Drexel University College of Medicine, 11313 New College Building, 245 N. 15th St., Philadelphia, PA 19102, USA.
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35
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Prabakaran P, Dimitrov AS, Fouts TR, Dimitrov DS. Structure and function of the HIV envelope glycoprotein as entry mediator, vaccine immunogen, and target for inhibitors. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2007; 55:33-97. [PMID: 17586312 PMCID: PMC7111665 DOI: 10.1016/s1054-3589(07)55002-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This chapter discusses the advances of the envelope glycoprotein (Env) structure as related to the interactions of conserved Env structures with receptor molecules and antibodies with implications for the design of vaccine immunogens and inhibitors. The human immunodeficiency virus (HIV) Env binds to cell surface–associated receptor (CD4) and coreceptor (CCR5 or CXCR4) by one of its two non-covalently associated subunits, gp120. The induced conformational changes activate the other subunit (gp41), which causes the fusion of the viral with the plasma cell membranes resulting in the delivery of the viral genome into the cell and the initiation of the infection cycle. As the only HIV protein exposed to the environment, the Env is also a major immunogen to which neutralizing antibodies are directed and a target that is relatively easy to access by inhibitors. A fundamental problem in the development of effective vaccines and inhibitors against HIV is the rapid generation of alterations at high levels of expression during long chronic infection and the resulting significant heterogeneity of the Env. The preservation of the Env function as an entry mediator and limitations on size and expression impose restrictions on its variability and lead to the existence of conserved structures.
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Affiliation(s)
- Ponraj Prabakaran
- Protein Interactions Group, CCRNP, CCR, NCI-Frederick, NIH Frederick, MD 21702, USA
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36
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Sagar M, Wu X, Lee S, Overbaugh J. Human immunodeficiency virus type 1 V1-V2 envelope loop sequences expand and add glycosylation sites over the course of infection, and these modifications affect antibody neutralization sensitivity. J Virol 2006; 80:9586-98. [PMID: 16973562 PMCID: PMC1617272 DOI: 10.1128/jvi.00141-06] [Citation(s) in RCA: 237] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Over the course of infection, human immunodeficiency virus type 1 (HIV-1) continuously adapts to evade the evolving host neutralizing antibody responses. Changes in the envelope variable loop sequences, particularly the extent of glycosylation, have been implicated in antibody escape. To document modifications that potentially influence antibody susceptibility, we compared envelope variable loops 1 and 2 (V1-V2) from multiple sequences isolated at the primary phase of infection to those isolated around 2 to 3 years into the chronic phase of infection in nine women with HIV-1 subtype A. HIV-1 sequences isolated during chronic infection had significantly longer V1-V2 loops, with a significantly higher number of potential N-linked glycosylation sites, than the sequences isolated early in infection. To assess the effects of these V1-V2 changes on antibody neutralization and infectivity, we created chimeric envelope sequences, which incorporated a subject's V1-V2 sequences into a common subtype A envelope backbone and then used them to generate pseudotyped viruses. Compared to the parent virus, the introduction of a subject's early-infection V1-V2 envelope variable loops rendered the chimeric envelope more sensitive to that subject's plasma samples but only to plasma samples collected >6 months after the sequences were isolated. Neutralization was not detected with the same plasma when the early-infection V1-V2 sequences were replaced with chronic-infection V1-V2 sequences, suggesting that changes in V1-V2 contribute to antibody escape. Pseudotyped viruses with V1-V2 segments from different times in infection, however, showed no significant difference in neutralization sensitivity to heterologous pooled plasma, suggesting that viruses with V1-V2 loops from early in infection were not inherently more neutralization sensitive. Pseudotyped viruses bearing chimeric envelopes with early-infection V1-V2 sequences showed a trend in infecting cells with low CD4 concentrations more efficiently, while engineered viruses with V1-V2 sequences isolated during chronic infection were moderately better at infecting cells with low CCR5 concentrations. These studies suggest that changes within the V1-V2 envelope domains over the course of an infection influence sensitivity to autologous neutralizing antibodies and may also impact host receptor/coreceptor interactions.
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Affiliation(s)
- Manish Sagar
- Department of Medicine, Brigham and Women's Hospital, Cambridge, Massachusetts 02139, USA
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37
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Delcroix-Genête D, Quan PL, Roger MG, Hazan U, Nisole S, Rousseau C. Antiviral properties of two trimeric recombinant gp41 proteins. Retrovirology 2006; 3:16. [PMID: 16515685 PMCID: PMC1435769 DOI: 10.1186/1742-4690-3-16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2006] [Accepted: 03/03/2006] [Indexed: 01/30/2023] Open
Abstract
Background As it is the very first step of the HIV replication cycle, HIV entry represents an attractive target for the development of new antiviral drugs. In this context, fusion inhibitors are the third class of anti-HIV drugs to be used for treatment, in combination with nucleoside analogues and antiproteases. But the precise mechanism of HIV fusion mechanism is still unclear. Gp41 ectodomain-derived synthetic peptides represent ideal tools for clarifying this mechanism, in order to design more potent anti-HIV drugs. Results Two soluble trimeric recombinant gp41 proteins, termed Rgp41B and Rgp41A were designed. Both comprise the N- and C-terminal heptad repeat regions of the ectodomain of HIV-1 gp41, connected by a 7-residue hydrophilic linker, in order to mimic the trimeric fusogenic state of the transmembrane glycoprotein. Both recombinant proteins were found to inhibit HIV-1 entry into target cells in a dose-dependent manner. Rgp41A, the most potent inhibitor, was able to inhibit both X4 and R5 isolates into HeLa cells and primary T lymphocytes. X4 viruses were found to be more susceptible than R5 isolates to inhibition by Rgp41A. In order to elucidate how the trimeric recombinant gp41 protein can interfere with HIV-1 entry into target cells, we further investigated its mode of action. Rgp41A was able to bind gp120 but did not induce gp120-gp41 dissociation. Furthermore, this inhibitor could also interfere with a late step of the fusion process, following the mixing of lipids. Conclusion Taken together, our results suggest that Rgp41A can bind to gp120 and also interfere with a late event of the fusion process. Interestingly, Rgp41A can block membrane fusion without preventing lipid mixing. Although further work will be required to fully understand its mode of action, our results already suggest that Rgp41A can interfere with multiple steps of the HIV entry process.
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Affiliation(s)
- Delphine Delcroix-Genête
- Institut Cochin, Department of Infectious Diseases, 22 rue Méchain, 75014 Paris, France, INSERM, U 567, CNRS, UMR 8104, Faculté de Médecine René Descartes, UMR-S 8104, 75014 Paris, France
| | - Phenix-Lan Quan
- Institut Cochin, Department of Infectious Diseases, 22 rue Méchain, 75014 Paris, France, INSERM, U 567, CNRS, UMR 8104, Faculté de Médecine René Descartes, UMR-S 8104, 75014 Paris, France
- Mymetics Corporation, 14, rue de la Colombière, 1260 Nyon, Switzerland
| | | | - Uriel Hazan
- Institut Cochin, Department of Infectious Diseases, 22 rue Méchain, 75014 Paris, France, INSERM, U 567, CNRS, UMR 8104, Faculté de Médecine René Descartes, UMR-S 8104, 75014 Paris, France
- Université Paris 7-Denis Diderot, UFR de Biochimie, 2 Place Jussieu, 75251 Paris, France
| | - Sébastien Nisole
- Institut Cochin, Department of Infectious Diseases, 22 rue Méchain, 75014 Paris, France, INSERM, U 567, CNRS, UMR 8104, Faculté de Médecine René Descartes, UMR-S 8104, 75014 Paris, France
- Université Paris 7-Denis Diderot, UFR de Biochimie, 2 Place Jussieu, 75251 Paris, France
| | - Cécile Rousseau
- Institut Cochin, Department of Infectious Diseases, 22 rue Méchain, 75014 Paris, France, INSERM, U 567, CNRS, UMR 8104, Faculté de Médecine René Descartes, UMR-S 8104, 75014 Paris, France
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38
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Brockman MA, Tanzi GO, Walker BD, Allen TM. Use of a novel GFP reporter cell line to examine replication capacity of CXCR4- and CCR5-tropic HIV-1 by flow cytometry. J Virol Methods 2006; 131:134-42. [PMID: 16182382 DOI: 10.1016/j.jviromet.2005.08.003] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2005] [Revised: 08/09/2005] [Accepted: 08/18/2005] [Indexed: 10/25/2022]
Abstract
The rate of HIV-1 disease progression correlates strongly with plasma viral load and is likely to be influenced by both host and viral determinants. Though interest in the impact of viral replication capacity during HIV-1 infection has been increasing, especially with respect to drug resistance mutations, its influence on disease course remains poorly understood. This is due in part to significant drawbacks in conventional means of measuring HIV-1 growth in vitro (i.e. expense, inconvenience, and experimental variability). A FACS-based method is described here to measure HIV-1 replication sensitively and a modification of this method can be used to determine viral titer accurately. Importantly, the target cells used are permissive to CXCR4- and CCR5-tropic HIV-1 strains. In pilot experiments, the growth kinetics of laboratory-adapted strains NL4-3 and IIIB were examined carefully. Using this method, differences were observed in growth kinetics between three laboratory strains and seven primary isolates, indicating the potential for a broad range of in vitro replication capacities among individual isolates. In conclusion, this FACS-based method provides a sensitive approach to measure the replication capacity of HIV-1 and may prove useful in studies examining the impact of viral fitness on disease progression.
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Affiliation(s)
- Mark A Brockman
- Howard Hughes Medical Institute, Massachusetts General Hospital and Division of AIDS, Harvard Medical School, Boston MA 02129, USA
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Pastore C, Nedellec R, Ramos A, Pontow S, Ratner L, Mosier DE. Human immunodeficiency virus type 1 coreceptor switching: V1/V2 gain-of-fitness mutations compensate for V3 loss-of-fitness mutations. J Virol 2006; 80:750-8. [PMID: 16378977 PMCID: PMC1346864 DOI: 10.1128/jvi.80.2.750-758.2006] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) entry into target cells is mediated by the virus envelope binding to CD4 and the conformationally altered envelope subsequently binding to one of two chemokine receptors. HIV-1 envelope glycoprotein (gp120) has five variable loops, of which three (V1/V2 and V3) influence the binding of either CCR5 or CXCR4, the two primary coreceptors for virus entry. Minimal sequence changes in V3 are sufficient for changing coreceptor use from CCR5 to CXCR4 in some HIV-1 isolates, but more commonly additional mutations in V1/V2 are observed during coreceptor switching. We have modeled coreceptor switching by introducing most possible combinations of mutations in the variable loops that distinguish a previously identified group of CCR5- and CXCR4-using viruses. We found that V3 mutations entail high risk, ranging from major loss of entry fitness to lethality. Mutations in or near V1/V2 were able to compensate for the deleterious V3 mutations and may need to precede V3 mutations to permit virus survival. V1/V2 mutations in the absence of V3 mutations often increased the capacity of virus to utilize CCR5 but were unable to confer CXCR4 use. V3 mutations were thus necessary but not sufficient for coreceptor switching, and V1/V2 mutations were necessary for virus survival. HIV-1 envelope sequence evolution from CCR5 to CXCR4 use is constrained by relatively frequent lethal mutations, deep fitness valleys, and requirements to make the right amino acid substitution in the right place at the right time.
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Affiliation(s)
- C Pastore
- The Scripps Research Institute, Dept. of Immunology, La Jolla, CA 92037, USA
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40
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Blanco J, Clotet-Codina I, Bosch B, Armand-Ugón M, Clotet B, Esté JA. Multiparametric assay to screen and dissect the mode of action of anti-human immunodeficiency virus envelope drugs. Antimicrob Agents Chemother 2005; 49:3926-9. [PMID: 16127073 PMCID: PMC1195414 DOI: 10.1128/aac.49.9.3926-3929.2005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A flow cytometry-based assay was used to simultaneously quantify X4 and R5 human immunodeficiency virus (HIV) envelope-mediated cell-to-cell viral transfer, cell death, and cell-to-cell fusion. In this assay, different anti-HIV envelope drugs showed characteristic inhibitory profiles for each measured parameter, allowing for the rapid identification of the mode of action of active compounds.
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Affiliation(s)
- Julià Blanco
- Fundació irsiCaixa, Hospital Universitari Germans Trias i Pujol, 08916 Badalona, Catalonia, Spain.
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41
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Wyss S, Dimitrov AS, Baribaud F, Edwards TG, Blumenthal R, Hoxie JA. Regulation of human immunodeficiency virus type 1 envelope glycoprotein fusion by a membrane-interactive domain in the gp41 cytoplasmic tail. J Virol 2005; 79:12231-41. [PMID: 16160149 PMCID: PMC1211532 DOI: 10.1128/jvi.79.19.12231-12241.2005] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Truncation of the human immunodeficiency virus (HIV) or simian immunodeficiency virus (SIV) gp41 cytoplasmic tail (CT) can modulate the fusogenicity of the envelope glycoprotein (Env) on infected cells and virions. However, the CT domains involved and the underlying mechanism responsible for this "inside-out" regulation of Env function are unknown. HIV and SIV CTs are remarkably long and contain amphipathic alpha-helical domains (LLP1, LLP2, and LLP3) that likely interact with cellular membranes. Using a cell-cell fusion assay and a panel of HIV Envs with stop codons at various positions in the CT, we show that truncations of gp41 proximal to the most N-terminal alpha helix, LLP2, increase fusion efficiency and expose CD4-induced epitopes in the Env ectodomain. These effects were not seen with a truncation distal to this domain and before LLP1. Using a dye transfer assay to quantitate fusion kinetics, we found that these truncations produced a two- to fourfold increase in the rate of fusion. These results were observed for X4-, R5-, and dual-tropic Envs on CXCR4- and CCR5-expressing target cells and could not be explained by differences in Env surface expression. These findings suggest that distal to the membrane-spanning domain, an interaction of the gp41 LLP2 domain with the cell membrane restricts Env fusogenicity during Env processing. As with murine leukemia viruses, where cleavage of a membrane-interactive R peptide at the C terminus is required for Env to become fusogenic, this restriction of Env function may serve to protect virus-producing cells from the membrane-disruptive effects of the Env ectodomain.
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Affiliation(s)
- Stéphanie Wyss
- Department of Medicine, Hematology-Oncology Division, University of Pennsylvania, Philadelphia, PA, USA
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42
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Yuste E, Johnson W, Pavlakis GN, Desrosiers RC. Virion envelope content, infectivity, and neutralization sensitivity of simian immunodeficiency virus. J Virol 2005; 79:12455-63. [PMID: 16160173 PMCID: PMC1211544 DOI: 10.1128/jvi.79.19.12455-12463.2005] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A truncating E767stop mutation was introduced into the envelope glycoprotein of simian immunodeficiency virus (SIV) strain SIV239-M5 (moderately sensitive to antibody-mediated neutralization and lacking five sites for N-linked carbohydrate attachment) and strain SIV316 (very sensitive to neutralization, with eight amino acid changes from the neutralization-resistant parental molecular clone, SIV239). The truncating mutation increased Env content in virions, increased infectivity, and decreased sensitivity to antibody-mediated neutralization in both strains. However, the magnitude of the effect on infectivity and neutralization sensitivity differed considerably between the two strains. In the context of strain SIV239-M5, truncation increased Env content in virions approximately 10-fold and infectivity in a reporter cell assay 24-fold. The truncated SIV239-M5 was only slightly more resistant to neutralization by polyclonal monkey sera and by monoclonal antibodies than SIV239-M5 with a full-length envelope glycoprotein. In the context of strain SIV316, truncation increased infectivity a dramatic 480-fold, while envelope content in virions was increased only about 14-fold. This dramatic increase in infectivity cannot be simply explained by the increase in envelope content and is likely due to an increase in inherent infectivity, i.e., infectivity per spike, that results from truncation. The truncated SIV316 was extremely resistant to antibody-mediated neutralization. In fact, it was not neutralized by any of the antibodies tested. When increasing amounts of SIV316 envelope glycoprotein (full length) were provided in trans to SIV316, infectivity was increased and sensitivity to neutralization was decreased, but to nowhere near the degree that was obtained when truncated SIV316 envelope glycoprotein was used. Truncated forms of SIV239 and SIV239-M5 required higher levels of soluble CD4 for inhibition of infection than their nontruncated forms; truncated SIV316 did not. Our results suggest that envelope content in SIV virions, infectivity, and resistance to antibody-mediated neutralization can be increased not only by truncation of the cytoplasmic domain but also by provision of excess envelope in trans. The striking increase in infectivity that results from truncation in the context of SIV316 appears to be due principally to an increase in inherent infectivity per spike.
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Affiliation(s)
- Eloísa Yuste
- New England Primate Research Center, Department of Microbiology and Molecular Genetics, Harvard Medical School, Southborough, MA 01772-9102, USA
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Lohrengel S, Hermann F, Hagmann I, Oberwinkler H, Scrivano L, Hoffmann C, von Laer D, Dittmar MT. Determinants of human immunodeficiency virus type 1 resistance to membrane-anchored gp41-derived peptides. J Virol 2005; 79:10237-46. [PMID: 16051817 PMCID: PMC1182644 DOI: 10.1128/jvi.79.16.10237-10246.2005] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The expression of a membrane-anchored gp41-derived peptide (M87) has been shown to confer protection from infection through human immunodeficiency virus type 1 (HIV-1) (Hildinger et al., J. Virol. 75:3038-3042, 2001). In an effort to characterize the mechanism of action of this membrane-anchored peptide in comparison to the soluble peptide T-20, we selected resistant variants of HIV-1(NL4-3) and HIV-1(BaL) by serial virus passage using PM1 cells stably expressing peptide M87. Sequence analysis of the resistant isolates showed different patterns of selected point mutations in heptad repeat regions 1 and 2 (HR1 and HR2, respectively) for the two viruses analyzed. For HIV-1(NL4-3) a single amino acid change at position 33 in HR1 (L33S) was selected, whereas for HIV-1(BaL) the majority of the sequences obtained showed two amino acid changes, one in HR1 and one in HR2 (I48V/N126K). In both selections the most important contiguous 3-amino-acid sequence, GIV, within HR1, associated with resistance to soluble T-20, was not changed. Site-directed mutagenesis studies confirmed the importance of the characterized point mutations to confer resistance to M87 as well as to soluble T-20 and T-649. Replication capacity and dual-color competition assays revealed that the double mutation I48V/N126K in HIV-1(BaL) results in a strong reduction of viral fitness, whereas the L33S mutation in HIV-1(NL4-3) did enhance viral fitness compared to the respective parental viruses. However, the selected point mutations did not confer resistance to the more recently described optimized membrane-anchored fusion inhibitor M87o (Egelhofer et al., J. Virol. 78:568-575, 2004), strengthening the importance of this novel antiviral concept for gene therapy approaches.
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Affiliation(s)
- Sabine Lohrengel
- Abt. Virologie, Hygiene-Institut, Universität Heidelberg, D-69120 Heidelberg, Germany
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Rusert P, Kuster H, Joos B, Misselwitz B, Gujer C, Leemann C, Fischer M, Stiegler G, Katinger H, Olson WC, Weber R, Aceto L, Günthard HF, Trkola A. Virus isolates during acute and chronic human immunodeficiency virus type 1 infection show distinct patterns of sensitivity to entry inhibitors. J Virol 2005; 79:8454-69. [PMID: 15956589 PMCID: PMC1143729 DOI: 10.1128/jvi.79.13.8454-8469.2005] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We studied the effect of entry inhibitors on 58 virus isolates derived during acute and chronic infection to validate these inhibitors in vitro and to probe whether viruses at early and chronic disease stages exhibit general differences in the interaction with entry receptors. We included members of all types of inhibitors currently identified: (i) agents that block gp120 binding to CD4 (CD4-IgG2 and monoclonal antibody [MAb] IgG1b12), (ii) compounds that block the interaction with CCR5 (the chemokine RANTES/CCL5, the small-molecule inhibitor AD101, and the anti-CCR5 antibody PRO 140), (iii) the fusion inhibitor enfuvirtide (T-20), and (iv) neutralizing antibodies directed against gp120 (MAb 2G12) and gp41 (MAbs 2F5 and 4E10). No differences between viruses from acute and chronic infections in the susceptibility to inhibitors targeting the CD4 binding site, CCR5, or fusion or to MAb 2G12 were apparent, rendering treatment with entry inhibitors feasible across disease stages. The notable exceptions were antibodies 2F5 and 4E10, which were more potent in inhibiting viruses from acute infection (P = 0.0088 and 0.0005, respectively), although epitopes of these MAbs were equally well preserved in both groups. Activities of these MAbs correlated significantly with each other, suggesting that common features of the viral envelope modulate their potencies.
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Affiliation(s)
- Peter Rusert
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, Ramistrasse 100, 8091 Zurich, Switzerland
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45
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Walter BL, Wehrly K, Swanstrom R, Platt E, Kabat D, Chesebro B. Role of low CD4 levels in the influence of human immunodeficiency virus type 1 envelope V1 and V2 regions on entry and spread in macrophages. J Virol 2005; 79:4828-37. [PMID: 15795268 PMCID: PMC1069537 DOI: 10.1128/jvi.79.8.4828-4837.2005] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) isolates vary in their ability to infect macrophages. Previous experiments have mapped viral determinants of macrophage infectivity to the V3 hypervariable region of the HIV-1 envelope glycoprotein. In our earlier studies, V1 and V2 sequences of HIV-1 were also shown to alter the ability of virus to spread in macrophage cultures, whereas no effect was seen in lymphocyte cultures. In the present study, determinants that allowed certain HIV-1 clones to infect and spread in macrophages were primarily mapped to the V2 region and were found to act by influencing early events of viral infection. By an assay of viral entry into macrophages, it was shown that viruses with the V2 region from the Ba-L strain of HIV-1 had >10-fold-higher entry efficiency than viruses with the V2 region derived from the NL4-3 strain. V1 region differences between these groups caused a twofold difference in entry. The known low expression of CD4 on macrophages appeared to be important in this process. In entry assays conducted with HeLa cell lines expressing various levels of CD4 and CCR5, low levels of CD4 influenced the efficiency of entry and fusion which were dependent on viral V1 and V2 envelope sequences. In contrast, no effect of V1 or V2 was seen in HeLa cells expressing high levels of CD4. Thus, the limited expression of CD4 on macrophages or other cell types could serve as a selective factor for V1 and V2 envelope sequences, and this selection could in turn influence many aspects of AIDS pathogenesis in vivo.
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Affiliation(s)
- Brandon L Walter
- Rocky Mountain Laboratories, 903 S. 4th St., Hamilton, MT 59840, USA
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46
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Centlivre M, Sommer P, Michel M, Ho Tsong Fang R, Gofflo S, Valladeau J, Schmitt N, Thierry F, Hurtrel B, Wain-Hobson S, Sala M. HIV-1 clade promoters strongly influence spatial and temporal dynamics of viral replication in vivo. J Clin Invest 2005; 115:348-58. [PMID: 15690084 PMCID: PMC546425 DOI: 10.1172/jci22873] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2004] [Accepted: 12/12/2004] [Indexed: 01/25/2023] Open
Abstract
Although the primary determinant of cell tropism is the interaction of viral envelope or capsid proteins with cellular receptors, other viral elements can strongly modulate viral replication. While the HIV-1 promoter is polymorphic for a variety of transcription factor binding sites, the impact of these polymorphisms on viral replication in vivo is not known. To address this issue, we engineered isogenic SIVmac239 chimeras harboring the core promoter/enhancer from HIV-1 clades B, C, and E. Here it is shown that the clade C and E core promoters/enhancers bear a noncanonical activator protein-1 (AP-1) binding site, absent from the corresponding clade B region. Relative ex vivo replication of chimeras was strongly dependent on the tissue culture system used. Notably, in thymic histocultures, replication of the clade C chimera was favored by IL-7 enrichment, which suggests that the clade C polymorphism in the AP-1 and NF-kappaB binding sites is involved. Simultaneous infection of rhesus macaques with the 3 chimeras revealed a strong predominance of the clade C chimera during primary infection. Thereafter, the B chimera dominated in all tissues. These data show that the clade C promoter is particularly adapted to sustain viral replication in primary viremia and that clade-specific promoter polymorphisms constitute a major determinant for viral replication.
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Affiliation(s)
- Mireille Centlivre
- Unité de Rétrovirologie Moléculaire, Unité de Biologie Cellulaire du Noyau, Institut Pasteur, Paris, France
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47
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Daecke J, Fackler OT, Dittmar MT, Kräusslich HG. Involvement of clathrin-mediated endocytosis in human immunodeficiency virus type 1 entry. J Virol 2005; 79:1581-94. [PMID: 15650184 PMCID: PMC544101 DOI: 10.1128/jvi.79.3.1581-1594.2005] [Citation(s) in RCA: 181] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Productive entry of human immunodeficiency virus (HIV) is believed to occur by direct fusion at the plasma membrane. Endocytic uptake of HIV particles has been observed in several studies but is considered to be nonproductive, leading to virus degradation in the lysosome. We show here that endocytosis contributes significantly to productive HIV entry in HeLa cells by using trans dominant-negative mutants of dynamin and Eps15. Inducible expression of a dominant-negative mutant of dynamin in a CD4-positive HeLa cell line reduced HIV infection by 40 to 80%. This effect was independent of the infectious dose and was observed for three different isolates. Analysis of reverse transcription products by real-time PCR and of virus entry by delivery of a virion-associated Vpr-beta-lactamase fusion protein revealed a similar reduction, indicating that the block occurred at the entry stage. A strong reduction of HIV entry was also observed upon transient transfection of a different trans dominant-negative variant of dynamin, and this reduction correlated with the relative inhibition of transferrin endocytosis. Expression of a dominant-negative variant of Eps15, which is specific for clathrin-dependent endocytosis, reduced HIV entry in HeLa cells by ca 95%, confirming the role of endocytosis for productive infection. In contrast, no effect was observed for a dominant-negative variant of caveolin. We conclude that dynamin-dependent, clathrin-mediated endocytosis can lead to productive entry of HIV in HeLa cells, suggesting this pathway as an alternative route of virus entry.
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Affiliation(s)
- Jessica Daecke
- Abteilung Virologie, Universitätsklinikum Heidelberg, D-69120 Heidelberg, Germany
| | - Oliver T. Fackler
- Abteilung Virologie, Universitätsklinikum Heidelberg, D-69120 Heidelberg, Germany
| | - Matthias T. Dittmar
- Abteilung Virologie, Universitätsklinikum Heidelberg, D-69120 Heidelberg, Germany
| | - Hans-Georg Kräusslich
- Abteilung Virologie, Universitätsklinikum Heidelberg, D-69120 Heidelberg, Germany
- Corresponding author. Mailing address: Abteilung Virologie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany. Phone: 49-6221-56-5001. Fax: 49-6221-56-5003. E-mail:
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48
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Centlivre M, Sommer P, Michel M, Fang RHT, Gofflo S, Valladeau J, Schmitt N, Thierry F, Hurtrel B, Wain-Hobson S, Sala M. HIV-1 clade promoters strongly influence spatial and temporal dynamics of viral replication in vivo. J Clin Invest 2005. [DOI: 10.1172/jci200522873] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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49
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Abstract
Cell-to-cell viral transmission facilitates the propagation of HIV-1 and human T cell leukemia virus type 1. Mechanisms of cell-to-cell transmission by retroviruses were not well understood until the recent description of virological synapses (VSs). VSs function as specialized sites of immune cell-to-cell contact that direct virus infection. Deciphering the molecular mechanisms of VS formation provides a fascinating insight into how pathogens subvert immune cell communication programs and achieve viral spread.
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Affiliation(s)
- Vincent Piguet
- Department of Dermatology and Venereology, University Hospital of Geneva, Geneva, Switzerland.
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50
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Narayan S, Young JAT. Reconstitution of retroviral fusion and uncoating in a cell-free system. Proc Natl Acad Sci U S A 2004; 101:7721-6. [PMID: 15128947 PMCID: PMC419673 DOI: 10.1073/pnas.0401312101] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The molecular events underlying the immediate steps of retroviral uncoating, occurring after membrane fusion and leading to the formation of an active reverse transcription complex, are not known. To better understand these processes, we have developed a cell-free system that recapitulates these early steps of retroviral replication by using avian sarcoma and leukosis virus as a model retrovirus. The substrates used in this system are viral particles that are trapped before completing membrane fusion. These virions are induced to fuse out of endosomes and the viral cores are released into solution where they are amenable to biochemical manipulation. This system revealed that membrane fusion is not sufficient to stimulate the formation of a reverse transcription complex. Instead, ATP hydrolysis and cellular factors >5 kDa in size are required. Furthermore, later steps of avian sarcoma and leukosis virus reverse transcription were stimulated by nuclear factors. The cell-free system should now allow for the definition of retroviral uncoating mechanisms and facilitate the identification and characterization of the cellular factors involved.
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Affiliation(s)
- Shakti Narayan
- Cell and Molecular Biology Program and Department of Oncology, McArdle Laboratory for Cancer Research, University of Wisconsin, 1400 University Avenue, Madison, WI 53706, USA
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