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Persaud AT, Khela J, Fernandes C, Chaphekar D, Burnie J, Tang VA, Colpitts CC, Guzzo C. Virion-incorporated CD14 enables HIV-1 to bind LPS and initiate TLR4 signaling in immune cells. J Virol 2024; 98:e0036324. [PMID: 38661384 PMCID: PMC11092368 DOI: 10.1128/jvi.00363-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 04/01/2024] [Indexed: 04/26/2024] Open
Abstract
HIV-1 has a broad range of nuanced interactions with the immune system, and the incorporation of cellular proteins by nascent virions continues to redefine our understanding of the virus-host relationship. Proteins located at the sites of viral egress can be selectively incorporated into the HIV-1 envelope, imparting new functions and phenotypes onto virions, and impacting viral spread and disease. Using virion capture assays and western blot, we show that HIV-1 can incorporate the myeloid antigen CD14 into its viral envelope. Virion-incorporated CD14 remained biologically active and able to bind its natural ligand, bacterial lipopolysaccharide (LPS), as demonstrated by flow virometry and immunoprecipitation assays. Using a Toll-like receptor 4 (TLR4) reporter cell line, we also demonstrated that virions with bound LPS can trigger TLR4 signaling to activate transcription factors that regulate inflammatory gene expression. Complementary assays with THP-1 monocytes demonstrated enhanced secretion of inflammatory cytokines like tumor necrosis factor alpha (TNF-α) and the C-C chemokine ligand 5 (CCL5), when exposed to LPS-loaded virus. These data highlight a new type of interplay between HIV-1 and the myeloid cell compartment, a previously well-established cellular contributor to HIV-1 pathogenesis and inflammation. Persistent gut inflammation is a hallmark of chronic HIV-1 infection, and contributing to this effect is the translocation of microbes across the gut epithelium. Our data herein provide proof of principle that virion-incorporated CD14 could be a novel mechanism through which HIV-1 can drive chronic inflammation, facilitated by HIV-1 particles binding bacterial LPS and initiating inflammatory signaling in TLR4-expressing cells.IMPORTANCEHIV-1 establishes a lifelong infection accompanied by numerous immunological changes. Inflammation of the gut epithelia, exacerbated by the loss of mucosal T cells and cytokine dysregulation, persists during HIV-1 infection. Feeding back into this loop of inflammation is the translocation of intestinal microbes across the gut epithelia, resulting in the systemic dissemination of bacterial antigens, like lipopolysaccharide (LPS). Our group previously demonstrated that the LPS receptor, CD14, can be readily incorporated by HIV-1 particles, supporting previous clinical observations of viruses derived from patient plasma. We now show that CD14 can be incorporated by several primary HIV-1 isolates and that this virion-incorporated CD14 can remain functional, enabling HIV-1 to bind to LPS. This subsequently allowed CD14+ virions to transfer LPS to monocytic cells, eliciting pro-inflammatory signaling and cytokine secretion. We posit here that virion-incorporated CD14 is a potential contributor to the dysregulated immune responses present in the setting of HIV-1 infection.
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Affiliation(s)
- Arvin T. Persaud
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Jasmin Khela
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Claire Fernandes
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Deepa Chaphekar
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Jonathan Burnie
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Vera A. Tang
- Flow Cytometry and Virometry Core Facility, Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Canada
| | - Che C. Colpitts
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Christina Guzzo
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
- Department of Immunology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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2
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Burnie J, Persaud AT, Thaya L, Liu Q, Miao H, Grabinsky S, Norouzi V, Lusso P, Tang VA, Guzzo C. P-selectin glycoprotein ligand-1 (PSGL-1/CD162) is incorporated into clinical HIV-1 isolates and can mediate virus capture and subsequent transfer to permissive cells. Retrovirology 2022; 19:9. [PMID: 35597982 PMCID: PMC9123692 DOI: 10.1186/s12977-022-00593-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 04/21/2022] [Indexed: 11/16/2022] Open
Abstract
Background P-selectin glycoprotein ligand-1 (PSGL-1/CD162) has been studied extensively for its role in mediating leukocyte rolling through interactions with its cognate receptor, P-selectin. Recently, PSGL-1 was identified as a novel HIV-1 host restriction factor, particularly when expressed at high levels in the HIV envelope. Importantly, while the potent antiviral activity of PSGL-1 has been clearly demonstrated in various complementary model systems, the breadth of PSGL-1 incorporation across genetically diverse viral isolates and clinical isolates has yet to be described. Additionally, the biological activity of virion-incorporated PSGL-1 has also yet to be shown. Results Herein we assessed the levels of PSGL-1 on viruses produced through transfection with various amounts of PSGL-1 plasmid DNA (0–250 ng), compared to levels of PSGL-1 on viruses produced through infection of T cell lines and primary PBMC. We found that very low levels of PSGL-1 plasmid DNA (< 2.5 ng/well) were necessary to generate virus models that could closely mirror the phenotype of viruses produced via infection of T cells and PBMC. Unique to this study, we show that PSGL-1 is incorporated in a broad range of HIV-1 and SIV isolates and that virions with incorporated PSGL-1 are detectable in plasma from viremic HIV-1-infected individuals, corroborating the relevance of PSGL-1 in natural infection. Additionally, we show that PSGL-1 on viruses can bind its cognate selectin receptors, P-, E-, and L-selectins. Finally, we show viruses with endogenous levels of PSGL-1 can be captured by P-selectin and transferred to HIV-permissive bystander cells, highlighting a novel role for PSGL-1 in HIV-1 infection. Notably, viruses which contained high levels of PSGL-1 were noninfectious in our hands, in line with previous findings reporting the potent antiviral activity of PSGL-1. Conclusions Our results indicate that levels of PSGL-1 incorporation into virions can vary widely among model systems tested, and that careful tailoring of plasmid levels is required to recapitulate physiological systems when using pseudovirus models. Taken together, our data suggest that PSGL-1 may play diverse roles in the physiology of HIV-1 infection, particularly due to the functionally active state of PSGL-1 on virion surfaces and the breadth of PSGL-1 incorporation among a wide range of viral isolates. Supplementary Information The online version contains supplementary material available at 10.1186/s12977-022-00593-5.
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Affiliation(s)
- Jonathan Burnie
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, Canada.,Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, Canada
| | - Arvin Tejnarine Persaud
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, Canada.,Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, Canada
| | - Laxshaginee Thaya
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, Canada.,Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, Canada
| | - Qingbo Liu
- Viral Pathogenesis Section, Laboratory of Immunoregulation (LIR), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Huiyi Miao
- Viral Pathogenesis Section, Laboratory of Immunoregulation (LIR), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Stephen Grabinsky
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, Canada
| | - Vanessa Norouzi
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, Canada
| | - Paolo Lusso
- Viral Pathogenesis Section, Laboratory of Immunoregulation (LIR), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Vera A Tang
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, Flow Cytometry and Virometry Core Facility, University of Ottawa, Ottawa, ON, Canada
| | - Christina Guzzo
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, Canada. .,Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, Canada.
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3
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Burnie J, Tang VA, Welsh JA, Persaud AT, Thaya L, Jones JC, Guzzo C. Flow Virometry Quantification of Host Proteins on the Surface of HIV-1 Pseudovirus Particles. Viruses 2020; 12:v12111296. [PMID: 33198254 PMCID: PMC7697180 DOI: 10.3390/v12111296] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/04/2020] [Accepted: 11/09/2020] [Indexed: 12/20/2022] Open
Abstract
The HIV-1 glycoprotein spike (gp120) is typically the first viral antigen that cells encounter before initiating immune responses, and is often the sole target in vaccine designs. Thus, characterizing the presence of cellular antigens on the surfaces of HIV particles may help identify new antiviral targets or impact targeting of gp120. Despite the importance of characterizing proteins on the virion surface, current techniques available for this purpose do not support high-throughput analysis of viruses, and typically only offer a semi-quantitative assessment of virus-associated proteins. Traditional bulk techniques often assess averages of viral preparations, which may mask subtle but important differences in viral subsets. On the other hand, microscopy techniques, which provide detail on individual virions, are difficult to use in a high-throughput manner and have low levels of sensitivity for antigen detection. Flow cytometry is a technique that traditionally has been used for rapid, high-sensitivity characterization of single cells, with limited use in detecting viruses, since the small size of viral particles hinders their detection. Herein, we report the detection and surface antigen characterization of HIV-1 pseudovirus particles by light scattering and fluorescence with flow cytometry, termed flow virometry for its specific application to viruses. We quantified three cellular proteins (integrin α4β7, CD14, and CD162/PSGL-1) in the viral envelope by directly staining virion-containing cell supernatants without the requirement of additional processing steps to distinguish virus particles or specific virus purification techniques. We also show that two antigens can be simultaneously detected on the surface of individual HIV virions, probing for the tetraspanin marker, CD81, in addition to α4β7, CD14, and CD162/PSGL-1. This study demonstrates new advances in calibrated flow virometry as a tool to provide sensitive, high-throughput characterization of the viral envelope in a more efficient, quantitative manner than previously reported techniques.
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Affiliation(s)
- Jonathan Burnie
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada; (J.B.); (A.T.P.); (L.T.)
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada
| | - Vera A. Tang
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Flow Cytometry and Virometry Core Facility, Ottawa, ON K1H 8M5, Canada;
| | - Joshua A. Welsh
- Translational Nanobiology Section, Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA; (J.A.W.); (J.C.J.)
| | - Arvin T. Persaud
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada; (J.B.); (A.T.P.); (L.T.)
| | - Laxshaginee Thaya
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada; (J.B.); (A.T.P.); (L.T.)
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada
| | - Jennifer C. Jones
- Translational Nanobiology Section, Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA; (J.A.W.); (J.C.J.)
| | - Christina Guzzo
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada; (J.B.); (A.T.P.); (L.T.)
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada
- Correspondence: ; Tel.: +1-(416)-287-7436
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Yu X, Shang H, Jiang Y. ICAM-1 in HIV infection and underlying mechanisms. Cytokine 2019; 125:154830. [PMID: 31491723 DOI: 10.1016/j.cyto.2019.154830] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/29/2019] [Accepted: 08/24/2019] [Indexed: 02/07/2023]
Abstract
Intercellular adhesion molecule 1 (ICAM-1) is a glycoprotein that participates in inflammatory and immune responses. Both cell surface and soluble ICAM-1 are significantly increased during human immunodeficiency virus (HIV) infection, and ICAM-1 has important functions in promoting inflammatory responses and enhancing HIV infectivity; however, a comprehensive summary these roles has yet to be elaborated. In this review we describe the general biological characteristics of ICAM-1, its association with HIV disease progression and promotion of HIV production, mechanisms inducing upregulation of ICAM-1, and possible intervention strategies, representing important insights in the context of HIV treatment.
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Affiliation(s)
- Xiaowen Yu
- NHC Key Laboratory of AIDS Immunology (China Medical University), Department of Laboratory Medicine, The First Affiliated Hospital of China Medical University, Shenyang 110001, China; National Clinical Research Center for Laboratory Medicine, The First Affiliated Hospital of China Medical University, Shenyang 110001, China; Key Laboratory of AIDS Immunology of Liaoning Province, The First Affiliated Hospital of China Medical University, Shenyang 110001, China; Key Laboratory of AIDS Immunology, Chinese Academy of Medical Sciences, Shenyang 110001, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, 79 Qingchun Street, Hangzhou 310003, China
| | - Hong Shang
- NHC Key Laboratory of AIDS Immunology (China Medical University), Department of Laboratory Medicine, The First Affiliated Hospital of China Medical University, Shenyang 110001, China; National Clinical Research Center for Laboratory Medicine, The First Affiliated Hospital of China Medical University, Shenyang 110001, China; Key Laboratory of AIDS Immunology of Liaoning Province, The First Affiliated Hospital of China Medical University, Shenyang 110001, China; Key Laboratory of AIDS Immunology, Chinese Academy of Medical Sciences, Shenyang 110001, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, 79 Qingchun Street, Hangzhou 310003, China.
| | - Yongjun Jiang
- NHC Key Laboratory of AIDS Immunology (China Medical University), Department of Laboratory Medicine, The First Affiliated Hospital of China Medical University, Shenyang 110001, China; National Clinical Research Center for Laboratory Medicine, The First Affiliated Hospital of China Medical University, Shenyang 110001, China; Key Laboratory of AIDS Immunology of Liaoning Province, The First Affiliated Hospital of China Medical University, Shenyang 110001, China; Key Laboratory of AIDS Immunology, Chinese Academy of Medical Sciences, Shenyang 110001, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, 79 Qingchun Street, Hangzhou 310003, China.
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5
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Burnie J, Guzzo C. The Incorporation of Host Proteins into the External HIV-1 Envelope. Viruses 2019; 11:v11010085. [PMID: 30669528 PMCID: PMC6356245 DOI: 10.3390/v11010085] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 01/15/2019] [Accepted: 01/16/2019] [Indexed: 02/07/2023] Open
Abstract
The incorporation of biologically active host proteins into HIV-1 is a well-established phenomenon, particularly due to the budding mechanism of viral egress in which viruses acquire their external lipid membrane directly from the host cell. While this mechanism might seemingly imply that host protein incorporation is a passive uptake of all cellular antigens associated with the plasma membrane at the site of budding, this is not the case. Herein, we review the evidence indicating that host protein incorporation can be a selective and conserved process. We discuss how HIV-1 virions displaying host proteins on their surface can exhibit a myriad of altered phenotypes, with notable impacts on infectivity, homing, neutralization, and pathogenesis. This review describes the canonical and emerging methods to detect host protein incorporation, highlights the well-established host proteins that have been identified on HIV-1 virions, and reflects on the role of these incorporated proteins in viral pathogenesis and therapeutic targeting. Despite many advances in HIV treatment and prevention, there remains a global effort to develop increasingly effective anti-HIV therapies. Given the broad range of biologically active host proteins acquired on the surface of HIV-1, additional studies on the mechanisms and impacts of these incorporated host proteins may inform the development of novel treatments and vaccine designs.
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Affiliation(s)
- Jonathan Burnie
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada.
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada.
| | - Christina Guzzo
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S 3G5, Canada.
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada.
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6
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Dufloo J, Bruel T, Schwartz O. HIV-1 cell-to-cell transmission and broadly neutralizing antibodies. Retrovirology 2018; 15:51. [PMID: 30055632 PMCID: PMC6064125 DOI: 10.1186/s12977-018-0434-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Accepted: 07/23/2018] [Indexed: 12/19/2022] Open
Abstract
HIV-1 spreads through contacts between infected and target cells. Polarized viral budding at the contact site forms the virological synapse. Additional cellular processes, such as nanotubes, filopodia, virus accumulation in endocytic or phagocytic compartments promote efficient viral propagation. Cell-to-cell transmission allows immune evasion and likely contributes to HIV-1 spread in vivo. Anti-HIV-1 broadly neutralizing antibodies (bNAbs) defeat the majority of circulating viral strains by binding to the viral envelope glycoprotein (Env). Several bNAbs have entered clinical evaluation during the last years. It is thus important to understand their mechanism of action and to determine how they interact with infected cells. In experimental models, HIV-1 cell-to-cell transmission is sensitive to neutralization, but the effect of antibodies is often less marked than during cell-free infection. This may be due to differences in the conformation or accessibility of Env at the surface of virions and cells. In this review, we summarize the current knowledge on HIV-1 cell-to-cell transmission and discuss the role of bNAbs during this process.
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Affiliation(s)
- Jérémy Dufloo
- Virus and Immunity Unit, Department of Virology, Institut Pasteur, Paris, France.,CNRS-UMR3569, Paris, France
| | - Timothée Bruel
- Virus and Immunity Unit, Department of Virology, Institut Pasteur, Paris, France.,CNRS-UMR3569, Paris, France.,Vaccine Research Institute, Créteil, France
| | - Olivier Schwartz
- Virus and Immunity Unit, Department of Virology, Institut Pasteur, Paris, France. .,CNRS-UMR3569, Paris, France. .,Vaccine Research Institute, Créteil, France.
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7
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IL-2 Inducible Kinase ITK is Critical for HIV-1 Infection of Jurkat T-cells. Sci Rep 2018; 8:3217. [PMID: 29453458 PMCID: PMC5816632 DOI: 10.1038/s41598-018-21344-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 01/15/2018] [Indexed: 01/04/2023] Open
Abstract
Successful replication of Human immunodeficiency virus (HIV)-1 depends on the expression of various cellular host factors, such as the interleukin-2 inducible T-cell kinase (ITK), a member of the protein family of TEC-tyrosine kinases. ITK is selectively expressed in T-cells and coordinates signaling pathways downstream of the T-cell receptor and chemokine receptors, including PLC-1 activation, Ca2+-release, transcription factor mobilization, and actin rearrangements. The exact role of ITK during HIV-1 infection is still unknown. We analyzed the function of ITK during HIV-1 replication and showed that attachment, fusion of virions with the cell membrane and entry into Jurkat T-cells was inhibited when ITK was knocked down. In contrast, reverse transcription and provirus expression were not affected by ITK deficiency. Inhibited ITK expression did not affect the CXCR4 receptor on the cell surface, whereas CD4 and LFA-1 integrin levels were slightly enhanced in ITK knockdown cells and heparan sulfate (HS) expression was completely abolished in ITK depleted T-cells. However, neither HS expression nor other attachment factors could explain the impaired HIV-1 binding to ITK-deficient cells, which suggests that a more complex cellular process is influenced by ITK or that not yet discovered molecules contribute to restriction of HIV-1 binding and entry.
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8
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Moerdyk-Schauwecker M, Hwang SI, Grdzelishvili VZ. Cellular proteins associated with the interior and exterior of vesicular stomatitis virus virions. PLoS One 2014; 9:e104688. [PMID: 25105980 PMCID: PMC4126742 DOI: 10.1371/journal.pone.0104688] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 07/15/2014] [Indexed: 01/18/2023] Open
Abstract
Virus particles (virions) often contain not only virus-encoded but also host-encoded proteins. Some of these host proteins are enclosed within the virion structure, while others, in the case of enveloped viruses, are embedded in the host-derived membrane. While many of these host protein incorporations are likely accidental, some may play a role in virus infectivity, replication and/or immunoreactivity in the next host. Host protein incorporations may be especially important in therapeutic applications where large numbers of virus particles are administered. Vesicular stomatitis virus (VSV) is the prototypic rhabdovirus and a candidate vaccine, gene therapy and oncolytic vector. Using mass spectrometry, we previously examined cell type dependent host protein content of VSV virions using intact (“whole”) virions purified from three cell lines originating from different species. Here we aimed to determine the localization of host proteins within the VSV virions by analyzing: i) whole VSV virions; and ii) whole VSV virions treated with Proteinase K to remove all proteins outside the viral envelope. A total of 257 proteins were identified, with 181 identified in whole virions and 183 identified in Proteinase K treated virions. Most of these proteins have not been previously shown to be associated with VSV. Functional enrichment analysis indicated the most overrepresented categories were proteins associated with vesicles, vesicle-mediated transport and protein localization. Using western blotting, the presence of several host proteins, including some not previously shown in association with VSV (such as Yes1, Prl1 and Ddx3y), was confirmed and their relative quantities in various virion fractions determined. Our study provides a valuable inventory of virion-associated host proteins for further investigation of their roles in the replication cycle, pathogenesis and immunoreactivity of VSV.
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Affiliation(s)
- Megan Moerdyk-Schauwecker
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, United States of America
- Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, Charlotte, North Carolina, United States of America
| | - Sun-Il Hwang
- Proteomics Laboratory for Clinical and Translational Research, Carolinas HealthCare System, Charlotte, North Carolina, United States of America
| | - Valery Z. Grdzelishvili
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, United States of America
- Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, Charlotte, North Carolina, United States of America
- * E-mail:
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9
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Kondo N, Melikyan GB. Intercellular adhesion molecule 1 promotes HIV-1 attachment but not fusion to target cells. PLoS One 2012; 7:e44827. [PMID: 22970312 PMCID: PMC3435301 DOI: 10.1371/journal.pone.0044827] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 08/07/2012] [Indexed: 12/24/2022] Open
Abstract
Incorporation of intercellular adhesion molecule 1 (ICAM-1) into HIV-1 particles is known to markedly enhance the virus binding and infection of cells expressing lymphocyte function-associated antigen-1 (LFA-1). At the same time, ICAM-1 has been reported to exert a less pronounced effect on HIV-1 fusion with lymphoid cells. Here we examined the role of ICAM-1/LFA-1 interactions in productive HIV-1 entry into lymphoid cells using a direct virus-cell fusion assay. ICAM-1 promoted HIV-1 attachment to cells in a temperature-dependent manner. It exerted a marginal effect on virus binding in the cold, but enhanced binding up to 4-fold at physiological temperature. ICAM-1-independent attachment in the cold was readily reversible upon subsequent incubation at elevated temperature, whereas ICAM-1-bearing particles were largely retained by cells. The better virus retention resulted in a proportional increase in HIV-1 internalization and fusion, suggesting that ICAM-1 did not specifically accelerate endocytosis or fusion steps. We also measured the rates of CD4 engagement, productive endocytosis and HIV-endosome fusion using specific fusion inhibitors. These rates were virtually independent of the presence of ICAM-1 in viral particles. Importantly, irrespective of the presence of ICAM-1, HIV-1 escaped from the low temperature block, which stopped virus endocytosis and fusion, much later than from a membrane-impermeant fusion inhibitor targeting surface-accessible particles. This result, along with the complete inhibition of HIV-1 fusion by a small molecule dynamin inhibitor, implies this virus enters lymphoid cells used in this study via endocytosis and that this pathway is not altered by the viral ICAM-1. Our data highlight the role of ICAM-1 in stabilizing the HIV-1 attachment to LFA-1 expressing cells, which leads to a proportional enhancement of the receptor-mediated uptake and fusion with endosomes.
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Affiliation(s)
- Naoyuki Kondo
- Division of Pediatric Infectious Diseases, Emory Children's Center, Atlanta, Georgia, United States of America
| | - Gregory B. Melikyan
- Division of Pediatric Infectious Diseases, Emory Children's Center, Atlanta, Georgia, United States of America
- Children's Healthcare of Atlanta, Atlanta, Georgia, United States of America
- * E-mail:
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10
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Hioe CE, Tuen M, Vasiliver-Shamis G, Alvarez Y, Prins KC, Banerjee S, Nádas A, Cho MW, Dustin ML, Kachlany SC. HIV envelope gp120 activates LFA-1 on CD4 T-lymphocytes and increases cell susceptibility to LFA-1-targeting leukotoxin (LtxA). PLoS One 2011; 6:e23202. [PMID: 21850260 PMCID: PMC3151267 DOI: 10.1371/journal.pone.0023202] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 07/08/2011] [Indexed: 11/18/2022] Open
Abstract
The cellular adhesion molecule LFA-1 and its ICAM-1 ligand play an important role in promoting HIV-1 infectivity and transmission. These molecules are present on the envelope of HIV-1 virions and are integral components of the HIV virological synapse. However, cellular activation is required to convert LFA-1 to the active conformation that has high affinity binding for ICAM-1. This study evaluates whether such activation can be induced by HIV itself. The data show that HIV-1 gp120 was sufficient to trigger LFA-1 activation in fully quiescent naïve CD4 T cells in a CD4-dependent manner, and these CD4 T cells became more susceptible to killing by LtxA, a bacterial leukotoxin that preferentially targets leukocytes expressing high levels of the active LFA-1. Moreover, virus p24-expressing CD4 T cells in the peripheral blood of HIV-infected subjects were found to have higher levels of surface LFA-1, and LtxA treatment led to significant reduction of the viral DNA burden. These results demonstrate for the first time the ability of HIV to directly induce LFA-1 activation on CD4 T cells. Although LFA-1 activation may enhance HIV infectivity and transmission, it also renders the cells more susceptible to an LFA-1-targeting bacterial toxin, which may be harnessed as a novel therapeutic strategy to deplete virus reservoir in HIV-infected individuals.
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Affiliation(s)
- Catarina E Hioe
- Department of Pathology, New York University School of Medicine, and Veterans Affairs New York Harbor Healthcare System, Manhattan Campus, New York, New York, United States of America.
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11
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Imbeault M, Ouellet M, Tremblay MJ. Microarray study reveals that HIV-1 induces rapid type-I interferon-dependent p53 mRNA up-regulation in human primary CD4+ T cells. Retrovirology 2009; 6:5. [PMID: 19146679 PMCID: PMC2637825 DOI: 10.1186/1742-4690-6-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Accepted: 01/15/2009] [Indexed: 11/10/2022] Open
Abstract
Background Infection with HIV-1 has been shown to alter expression of a large array of host cell genes. However, previous studies aimed at investigating the putative HIV-1-induced modulation of host gene expression have been mostly performed in established human cell lines. To better approximate natural conditions, we monitored gene expression changes in a cell population highly enriched in human primary CD4+ T lymphocytes exposed to HIV-1 using commercial oligonucleotide microarrays from Affymetrix. Results We report here that HIV-1 influences expression of genes related to many important biological processes such as DNA repair, cellular cycle, RNA metabolism and apoptosis. Notably, expression of the p53 tumor suppressor and genes involved in p53 homeostasis such as GADD34 were up-regulated by HIV-1 at the mRNA level. This observation is distinct from the previously reported p53 phosphorylation and stabilization at the protein level, which precedes HIV-1-induced apoptosis. We present evidence that the HIV-1-mediated increase in p53 gene expression is associated with virus-mediated induction of type-I interferon (i.e. IFN-α and IFN-β). Conclusion These observations have important implications for our understanding of HIV-1 pathogenesis, particularly in respect to the virus-induced depletion of CD4+ T cells.
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Affiliation(s)
- Michaël Imbeault
- Centre de Recherche en Infectiologie, Centre Hospitalier de l'Université Laval, and Faculté de Médecine, Université Laval, Québec, Canada.
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12
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Bingle CD, Vyakarnam A. Novel innate immune functions of the whey acidic protein family. Trends Immunol 2008; 29:444-53. [PMID: 18676177 DOI: 10.1016/j.it.2008.07.001] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Revised: 07/01/2008] [Accepted: 07/01/2008] [Indexed: 10/21/2022]
Abstract
Studies on the interaction of HIV with host factors have recently highlighted a potential role in the pathogenesis of AIDS for three distinct members of the whey acidic protein (WAP) family, secretory leukocyte protease inhibitor, Elafin, and ps20. Identified by an evolutionarily conserved canonical four-disulphide structural domain [whey four disulphide core domain (WFDC)], WAP proteins are increasingly being shown to display functions beyond both protease inhibition and anti-infective activity, to which they were originally ascribed. We propose novel mechanisms on why this might be the case based on an analysis of the structure-function of its human members. Our analysis suggests that the interaction of HIV with WAP proteins might unravel unknown functions of the ancient WFDC and inform novel immunotherapies for the treatment of HIV and broader virus infections.
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Affiliation(s)
- Colin D Bingle
- Academic Unit of Respiratory Medicine, University of Sheffield Medical School, Sheffield S10 2JF, UK
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13
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Cantin R, Diou J, Bélanger D, Tremblay AM, Gilbert C. Discrimination between exosomes and HIV-1: purification of both vesicles from cell-free supernatants. J Immunol Methods 2008; 338:21-30. [PMID: 18675270 DOI: 10.1016/j.jim.2008.07.007] [Citation(s) in RCA: 236] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Revised: 06/02/2008] [Accepted: 07/01/2008] [Indexed: 01/02/2023]
Abstract
Although enveloped retroviruses bud from the cell surface of T lymphocytes, they use the endocytic pathway and the internal membrane of multivesicular bodies for their assembly and release from macrophages and dendritic cells (DCs). Exosomes, physiological nanoparticles produced by hematopoietic cells, egress from this same pathway and are similar to retroviruses in terms of size, density, the molecules they incorporate and their ability to activate immune cells. Retroviruses are therefore likely to contaminate in vitro preparations of exosomes and vice versa and sucrose gradients are inefficient at separating them. However, we have found that their sedimentation velocities in an iodixanol (Optiprep) velocity gradient are sufficiently different to allow separation and purification of both vesicles. Using acetylcholinesterase as an exosome marker, we demonstrate that Optiprep velocity gradients are very efficient in separating exosomes from HIV-1 particles produced on 293T cells, primary CD4(+) T cells, macrophages or DCs, with exosomes collecting at 8.4-12% iodixanol and HIV-1 at 15.6%. We also show that immunodepletion with an anti-acetylcholinesterase antibody rapidly produces highly purified preparations of HIV-1 or exosomes. These findings have applications in fundamental research on exosomes and/or AIDS, as well as in clinical applications where exosomes are involved, more specifically in tumour therapy or in gene therapy using exosomes generated from DCs genetically modified by transfection with virus.
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Affiliation(s)
- Réjean Cantin
- Centre de recherche en infectiologie, Faculty of Medicine, Laval University, Québec, Canada
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14
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Jolly C, Mitar I, Sattentau QJ. Adhesion molecule interactions facilitate human immunodeficiency virus type 1-induced virological synapse formation between T cells. J Virol 2007; 81:13916-21. [PMID: 17913807 PMCID: PMC2168851 DOI: 10.1128/jvi.01585-07] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.2] [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) can spread between CD4+ T cells by using a virological synapse (VS). The VS assembly is a cytoskeleton-driven process dependent on HIV-1 envelope glycoprotein (Env)-receptor engagement and is hypothesized to require adhesion molecule interactions. Here we demonstrate that leukocyte function-associated antigen 1 (LFA-1), intercellular adhesion molecule 1 (ICAM-1), and ICAM-3 are enriched at the VS and that inhibition of these interactions influences conjugate formation and reduces VS assembly. Moreover, CD4+ T cells deficient in LFA-1 or with modified LFA-1 function were less able to support VS assembly and cell-cell transfer of HIV-1. Thus, cognate adhesion molecule interactions at the VS are important for HIV-1 spread between T cells.
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Affiliation(s)
- Clare Jolly
- The Sir William Dunn School of Pathology, The University of Oxford, South Parks Road, Oxford OX1 3RE, United Kingdom.
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15
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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: 97] [Impact Index Per Article: 5.7] [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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16
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Gilbert C, Cantin R, Barat C, Tremblay MJ. Human immunodeficiency virus type 1 replication in dendritic cell-T-cell cocultures is increased upon incorporation of host LFA-1 due to higher levels of virus production in immature dendritic cells. J Virol 2007; 81:7672-82. [PMID: 17494076 PMCID: PMC1933380 DOI: 10.1128/jvi.02810-06] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Dendritic cells (DCs) act as a portal for invasion by human immunodeficiency virus type-1 (HIV-1). Here, we investigated whether virion-incorporated host cell membrane proteins can affect virus replication in DC-T-cell cocultures. Using isogenic viruses either devoid of or bearing host-derived leukocyte function-associated antigen 1 (LFA-1), we showed that HIV-1 production is augmented when LFA-1-bearing virions are used compared to that for viral entities lacking this adhesion molecule. This phenomenon was observed in immature monocyte-derived DCs (IM-MDDCs) only and not in DCs displaying a mature phenotype. The increase is not due to higher virus production in responder CD4(+) T cells but rather is linked with a more important productive infection of IM-MDDCs. We provided evidence that virus-associated host LFA-1 molecules do not affect a late event in the HIV-1 life cycle but rather exert an effect on an early step in virus replication. We demonstrated that the enhancement of productive infection of IM-MDDCs that is conferred by virus-anchored host LFA-1 involves the protein kinase A (PKA) and PKC signal transduction pathways. The biological significance of this phenomenon was established by performing experiments with virus stocks produced in primary human cells and anti-LFA-1 antibodies. Together, our results indicate that the association between some virus-bound host proteins and their natural cognate ligands can modulate de novo HIV-1 production by IM-MDDCs. Therefore, the additional interactions between virus-bound host cell membrane constituents and counter receptors on the surfaces of DCs can influence HIV-1 replication in IM-MDDC-T-cell cocultures.
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Affiliation(s)
- Caroline Gilbert
- Research Center in Infectious Diseases, Laval Univeristy, Quebec, Canada
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17
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Pöhlmann S, Tremblay MJ. Attachment of human immunodeficiency virus to cells and its inhibition. ENTRY INHIBITORS IN HIV THERAPY 2007. [PMCID: PMC7123856 DOI: 10.1007/978-3-7643-7783-0_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The entry of enveloped viruses involves virus adsorption followed by close apposition of the viral and plasma membranes. This multistep process is initiated by specific binding interactions between glycoproteins in the viral envelope and appropriate receptors on the cell surface. In the case of HIV-1, attachment of virions to the cell surface is attributed to a high affinity interaction between envelope spike glycoproteins (Env, composed of the surface protein gp120 and the transmembrane protein gp41) and a complex made of the primary CD4 receptor and a seven-transmembrane co-receptor (e.g., CXCR4 or CCR5) (reviewed in [1]). Then a chain of dynamic events take place that enable the viral nucleocapsid to penetrate within the target cell following the destabilization of membrane microenvironment and the formation of a fusion pore.
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18
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Tardif MR, Tremblay MJ. Regulation of LFA-1 activity through cytoskeleton remodeling and signaling components modulates the efficiency of HIV type-1 entry in activated CD4+ T lymphocytes. THE JOURNAL OF IMMUNOLOGY 2005; 175:926-35. [PMID: 16002691 DOI: 10.4049/jimmunol.175.2.926] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Besides interactions between the viral envelope glycoproteins with cell surface receptors, interactions between cell-derived molecules incorporated onto virions and their ligand could also modulate HIV type-1 (HIV-1) entry inside CD4(+) T lymphocytes. Although incorporation of host ICAM-1 within HIV-1 increases both virus attachment and fusion, the precise mechanism through which this phenomenon is occurring is still unclear. We demonstrate in this study that activation of primary human CD4(+) T lymphocytes increases LFA-1 affinity and avidity states, two events promoting the early events of the HIV-1 replication cycle through interactions between virus-embedded host ICAM-1 and LFA-1 clusters. Confocal analyses suggest that HIV-1 is concentrated in microdomains rich in LFA-1 clusters that also contain CD4 and CXCR4 molecules. Experiments performed with specific inhibitors revealed that entry of HIV-1 in activated CD4(+) T cells is regulated by LFA-1-dependent ZAP70, phospholipase Cgamma1, and calpain enzymatic activities. By using laboratory and clinical strains of HIV-1 produced in primary human cells, we demonstrate the importance of the LFA-1 activation state and cluster formation in the initial step of the virus life cycle. Overall, these data provide new insights into the complex molecular events involved in HIV-1 binding and entry.
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Affiliation(s)
- Mélanie R Tardif
- Research Center in Infectious Diseases, Centre Hospitalier de l'Université Laval (CHUL) Research Center, and Faculty of Medicine, Laval University, 2705 Laurier Boulevard, Quebec, Canada G1V 4G2
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19
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Li M, Gao F, Mascola JR, Stamatatos L, Polonis VR, Koutsoukos M, Voss G, Goepfert P, Gilbert P, Greene KM, Bilska M, Kothe DL, Salazar-Gonzalez JF, Wei X, Decker JM, Hahn BH, Montefiori DC. Human immunodeficiency virus type 1 env clones from acute and early subtype B infections for standardized assessments of vaccine-elicited neutralizing antibodies. J Virol 2005; 79:10108-25. [PMID: 16051804 PMCID: PMC1182643 DOI: 10.1128/jvi.79.16.10108-10125.2005] [Citation(s) in RCA: 946] [Impact Index Per Article: 49.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2005] [Accepted: 05/09/2005] [Indexed: 01/16/2023] Open
Abstract
Induction of broadly cross-reactive neutralizing antibodies is a high priority for AIDS vaccine development but one that has proven difficult to be achieved. While most immunogens generate antibodies that neutralize a subset of T-cell-line-adapted strains of human immunodeficiency virus type 1 (HIV-1), none so far have generated a potent, broadly cross-reactive response against primary isolates of the virus. Even small increments in immunogen improvement leading to increases in neutralizing antibody titers and cross-neutralizing activity would accelerate vaccine development; however, a lack of uniformity in target strains used by different investigators to assess cross-neutralization has made the comparison of vaccine-induced antibody responses difficult. Thus, there is an urgent need to establish standard panels of HIV-1 reference strains for wide distribution. To facilitate this, full-length gp160 genes were cloned from acute and early subtype B infections and characterized for use as reference reagents to assess neutralizing antibodies against clade B HIV-1. Individual gp160 clones were screened for infectivity as Env-pseudotyped viruses in a luciferase reporter gene assay in JC53-BL (TZM-bl) cells. Functional env clones were sequenced and their neutralization phenotypes characterized by using soluble CD4, monoclonal antibodies, and serum samples from infected individuals and noninfected recipients of a recombinant gp120 vaccine. Env clones from 12 R5 primary HIV-1 isolates were selected that were not unusually sensitive or resistant to neutralization and comprised a wide spectrum of genetic, antigenic, and geographic diversity. These reference reagents will facilitate proficiency testing and other validation efforts aimed at improving assay performance across laboratories and can be used for standardized assessments of vaccine-elicited neutralizing antibodies.
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Affiliation(s)
- Ming Li
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
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20
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Cantin R, Méthot S, Tremblay MJ. Plunder and stowaways: incorporation of cellular proteins by enveloped viruses. J Virol 2005; 79:6577-87. [PMID: 15890896 PMCID: PMC1112128 DOI: 10.1128/jvi.79.11.6577-6587.2005] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Affiliation(s)
- Réjean Cantin
- Laboratory of Human Immuno-Retrovirology, Research Center in Infectious Diseases, CHUL Research Center, Quebec (QC), Canada
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21
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Ouellet M, Mercier S, Pelletier I, Bounou S, Roy J, Hirabayashi J, Sato S, Tremblay MJ. Galectin-1 Acts as a Soluble Host Factor That Promotes HIV-1 Infectivity through Stabilization of Virus Attachment to Host Cells. THE JOURNAL OF IMMUNOLOGY 2005; 174:4120-6. [PMID: 15778371 DOI: 10.4049/jimmunol.174.7.4120] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The establishment of HIV type 1 (HIV-1) infection is initiated by the stable attachment of the virion to the target cell surface. Although this process relies primarily upon interaction between virus-encoded gp120 and cell surface CD4, a number of distinct interactions influence binding of HIV-1 to host cells. In this study, we report that galectin-1, a dimeric beta-galactoside-binding protein, promotes infection with R5, X4, and R5X4 variants. Galectin-1 acts as a soluble adhesion molecule by facilitating attachment of HIV-1 to the cell surface. This postulate is based on experiments where galectin-1 rendered HIV-1 particles more refractory to various agents that block HIV-1 adsorption and coreceptor binding (i.e., a blocking anti-CD4, soluble CD4, human anti-HIV-1 polyclonal Abs; stromal cell-derived factor-1alpha; RANTES). Experiments performed with the fusion inhibitor T-20 confirmed that galectin-1 is primarily affecting HIV-1 attachment. The relevance of the present findings for the pathogenesis of HIV-1 infection is provided by the fact that galectin-1 is abundantly expressed in the thymus and lymph nodes, organs that represent major reservoirs for HIV-1. Moreover, galectin-1 is secreted by activated CD8(+) T lymphocytes, which are found in high numbers in HIV-1-positive patients. Therefore, it is proposed that galectin-1, which is released in an exocrine fashion at HIV-1 replication sites, can cross-link HIV-1 and target cells and promote a firmer adhesion of the virus to the cell surface, thereby augmenting the efficiency of the infection process. Overall, our findings suggest that galectin-1 might affect the pathogenesis of HIV-1 infection.
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Affiliation(s)
- Michel Ouellet
- Laboratory of Human Immuno-Retrovirology, Research Center in Infectious Diseases, Centre Hospitalier de l'Université Laval, and Faculty of Medicine, Laval University, Quebec, Canada
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22
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Abstract
The third variable region, V3, of the gp120 surface envelope glycoprotein is an approximately 35-residue-long, frequently glycosylated, highly variable, disulfide-bonded structure that has a major influence on HIV-1 tropism. Thus the sequence of V3, directly or indirectly, can determine which coreceptor (CCR5 or CXCR4) is used to trigger the fusion potential of the Env complex, and hence which cells the virus can infect. V3 also influences HIV-1's sensitivity to, and ability to escape from, entry inhibitors that are being developed as antiviral drugs. For some strains, V3 is a prominent target for HIV-1 neutralizing antibodies (NAbs); indeed, for many years it was considered to be the "principal neutralization determinant" (PND). Some efforts to use V3 as a vaccine target continue to this day, despite disappointing progress over more than a decade. Recent findings on the structure, function, antigenicity, and immunogenicity of V3 cast new doubts on the value of this vaccine approach. Here, we review recent advances in the understanding of V3 as a determinant of viral tropism, and discuss how this new knowledge may inform the development of HIV-1 drugs and vaccines.
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Affiliation(s)
- Oliver Hartley
- Department of Structural Biology and Bioinformatics, Centre Medical Universitaire, Geneva, Switzerland
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23
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Beauséjour Y, Tremblay MJ. Interaction between the cytoplasmic domain of ICAM-1 and Pr55Gag leads to acquisition of host ICAM-1 by human immunodeficiency virus type 1. J Virol 2004; 78:11916-25. [PMID: 15479832 PMCID: PMC523275 DOI: 10.1128/jvi.78.21.11916-11925.2004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have examined the molecular basis for the selective incorporation of the adhesion molecule ICAM-1 within human immunodeficiency virus type 1 (HIV-1). The process of ICAM-1 incorporation was investigated by using different ICAM-1 constructs in combination with virus capture and immunoprecipitation studies, Western blot and confocal microscopy analyses, and infectivity assays. Experiments conducted with viruses bearing a truncated version of ICAM-1 revealed that the cytoplasmic domain of ICAM-1 governs insertion of this adhesion molecule into HIV-1. Further experiments suggested that there is an association between ICAM-1 and the virus-encoded Pr55(Gag) polyprotein. This study represents the first demonstration that structural Gag polyproteins play a key role in the uptake of a host-derived cell surface by the virus entity. Taken together, our results indicate that interactions between viral and cellular proteins are responsible for the selective uptake of host ICAM-1 by HIV-1. This observation describes a new strategy by which HIV-1 can modulate its replicative cycle, considering that insertion of ICAM-1 within nascent virions has been shown to increase virus infectivity.
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Affiliation(s)
- Yannick Beauséjour
- Research Center in Infectious Diseases, RC709, CHUL Research Center, Faculty of Medicine, Laval University, Quebec, Canada
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24
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Martin G, Tremblay MJ. HLA-DR, ICAM-1, CD40, CD40L, and CD86 are incorporated to a similar degree into clinical human immunodeficiency virus type 1 variants expanded in natural reservoirs such as peripheral blood mononuclear cells and human lymphoid tissue cultured ex vivo. Clin Immunol 2004; 111:275-85. [PMID: 15183148 DOI: 10.1016/j.clim.2004.02.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2003] [Accepted: 02/17/2004] [Indexed: 12/19/2022]
Abstract
To provide additional information on the acquisition of host cell membrane proteins by human immunodeficiency virus type 1 (HIV-1) produced by natural cellular reservoirs, two different field isolates were used to infect ex vivo expanded peripheral blood mononuclear cells (PBMCs) and human lymphoid tissue histocultures. The insertion of host-derived HLA-DR, intercellular adhesion molecule-1 (ICAM-1), CD40, CD40L, and CD86 within HIV-1 particles was evaluated by using specific antibodies linked to a solid matrix to capture ultrafiltrated viral progeny. Overall, our data indicate that neither the HIV-1 co-receptor usage (i.e., T-tropic or macrophage-tropic) nor the cellular source of HIV-1 has an impact on the incorporation process but it was found to be under the influence of the donor source. Given that most viral replication is thought to occur in lymphoid tissues and previous works have shown that HIV-1 life cycle is affected by several virus-anchored host proteins, our results suggest that this phenomenon is likely to contribute to the pathogenesis of this retroviral infection.
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Affiliation(s)
- Geneviève Martin
- Research Center in Infectious Diseases, CHUL Research Center, and Faculty of Medicine, Laval University, Quebec, Canada G1V 4G2
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25
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Beauséjour Y, Tremblay MJ. Envelope glycoproteins are not required for insertion of host ICAM-1 into human immunodeficiency virus type 1 and ICAM-1-bearing viruses are still infectious despite a suboptimal level of trimeric envelope proteins. Virology 2004; 324:165-72. [PMID: 15183063 DOI: 10.1016/j.virol.2004.03.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2003] [Revised: 02/10/2004] [Accepted: 03/10/2004] [Indexed: 11/19/2022]
Abstract
Previous works have indicated that incorporation of surface glycoprotein into retroviruses such as the human immunodeficiency virus type 1 (HIV-1) is not a highly specific process because several cellular glycoproteins can be inserted within the mature viral particle. The mechanism(s) that govern the acquisition of such host constituents have remained so far elusive. In this study, we have investigated the role played by the viral envelope (Env) of HIV-1 in the acquisition of host intercellular adhesion molecule type I (ICAM-1). ICAM-1 proteins were still present on viruses carrying much lower levels of gp120/gp41 due to a mutation in the matrix (MA) domain or on Env-deficient viruses when produced in immortalized and primary human cell lines. Interestingly, infectivity of an HIV-1 MA mutant that carry a suboptimal amount of Env proteins was restored to a certain degree by the presence of ICAM-1 when infection was performed in cells expressing an activated form of its natural counter-ligand, LFA-1.
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Affiliation(s)
- Yannick Beauséjour
- Research Center in Infectious Diseases, CHUL Research Center, and Faculty of Medicine, Laval University, Quebec, Canada
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26
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Ouellet M, Barbeau B, Tremblay MJ. Protein tyrosyl phosphatases in T cell activation: implication for human immunodeficiency virus transcriptional activity. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2004; 73:69-105. [PMID: 12882515 DOI: 10.1016/s0079-6603(03)01003-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The protein tyrosine phosphatases (PTPs) superfamily is a large group of enzymes showing a wide diversity of structure and biological functions. Their implication in the regulation of signal transduction processes is critical for homeostasis and efficient cellular activation. Disturbance of the delicate balance between protein tyrosine kinase and protein tyrosine phosphatase activities is at the heart of a large number of diseases. Control of cellular activation is especially important for human immunodeficiency virus type 1 (HIV-1) since this retrovirus requires activated T cells in order to replicate efficiently. Identification of PTPs implicated in signaling pathways leading to upregulation of HIV-1 gene transcription therefore contributes to the general understanding of cellular factors needed for strong HIV-1 replication and progression to AIDS. The use of bisperoxovanadium compounds as potent, specific, and highly purified PTP inhibitors releases HIV-1 from PTP control and strongly increases HIV-1 gene expression. These inhibitors can thus be used to study signal transduction mechanisms regulated by PTP activity that are important for HIV-1 replication and provide new and interesting therapeutic avenues for the efficient control of this debilitating retroviral infection.
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Affiliation(s)
- Michel Ouellet
- Centre de Recherche en Infectiologie, Hôpital CHUL, Centre Hospitalier Universitaire de Québec, Canada, G1V 4G2
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27
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Abstract
Retroviral vectors capable of efficient in vivo gene delivery to specific target cell types or to specific locations of disease pathology would greatly facilitate many gene therapy applications. The surface glycoproteins of membrane-enveloped viruses stand among the choice candidates to control the target cell receptor recognition and host range of retroviral vectors onto which they are incorporated. This can be achieved in many ways, such as the exchange of glycoprotein by pseudotyping, their biochemical modifications, their conjugation with virus-cell bridging agents or their structural modifications. Understanding the fundamental properties of the viral glycoproteins and the molecular mechanism of virus entry into cells has been instrumental in the functional alteration of their tropism. Here we briefly review the current state of our understanding of the structure and function of viral envelope glycoproteins and we discuss the emerging targeting strategies based on retroviral and lentiviral vector systems.
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Affiliation(s)
- V Sandrin
- Laboratoire de Vectorologie Rétrovirale et Thérapie Génique, Unité de Virologie Humaine, INSERM U412, Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon Cedex 07, France
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28
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Abstract
Defining the mechanisms of HIV-1 entry has enabled the rational design of strategies aimed at interfering with the process. This article delineates what is currently understood about HIV-1 entry, as a window through which to understand what will likely be the next major group of antiretroviral therapeutics. These exciting new approaches offer the promise of adding viral entry to reverse transcription and protein processing as steps to block in the viral life cycle. Several principles learned with other antiretroviral drugs are sure to be valid for entry antagonists, whereas other considerations may be unique to this group of agents. There is no agent to which HIV-1 has not been able to acquire resistance and this is likely to remain the case. Multiple rounds of viral replication are required to generate the genetic diversity that forms the basis of resistance. Combination therapy in which replication is maximally suppressed will remain a cornerstone of treatment with entry inhibitors, as with other agents. Furthermore, the coreceptor specificity of some entry and fusion inhibitors argues that combinations will likely be needed to broaden the effective range of susceptible viral variants. Finally, the targeting of multiple steps within the entry process has the potential for synergy. The fusion inhibitor T20 and CXCR4 antagonist AMD3100 are synergistic in vitro at blocking infection of PBMC with clinical isolates [115] and T20 combined with the CD4 inhibitor PRO 542 have synergistic in vitro effects, with more than 10-fold greater inhibition of R5, X4, and R5X4 strains than either agent alone [116]. Entry antagonists raise other, unique issues. As discussed previously, the theoretic concern exists that blocking CCR5 could enhance the emergence of CXCR4-using variants and possibly accelerate disease. So far, in vitro selection for variants resistant to the CCR5 antagonist SCH-C in PBMC (which express both CCR5 and CXCR4) has resulted in mutants that were resistant to the blocker but still used CCR5. Alternatively, because many HIV-1 strains have the capacity to use several other chemokine or orphan receptors for entry, blocking both CCR5 and CXCR could lead to a variant that uses one of these other molecules in place of the principal coreceptors, although data in vitro so far suggest that this is unlikely [13,14]. This new class of antiviral drugs offers great promise but also novel concerns, and careful analysis of viruses that arise with their use in vivo is essential.
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Affiliation(s)
- Linda D Starr-Spires
- Pulmonary, Allergy and Critical Care Division, University of Pennsylvania School of Medicine, 522 Johnson Pavilion, 36th and Hamilton Walk, Philadelphia, PA 19104-6060, USA
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29
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Xiao Y, Dong X, Chen YH. Neutralizing antibodies mechanism of neutralization and protective activity against HIV-1. Immunol Res 2002; 25:193-200. [PMID: 12018459 DOI: 10.1385/ir:25:3:193] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The role of the humoral immune response in prevention against HIV-1 infection is still incompletely understood. However, neutralizing antibodies to certain epitopes on HIV-1 envelope glycoproteins inhibit HIV-1 infection in vitro and in vivo. Passive administration of these antibodies by themselves or in combination completely protected hu-PBL-SCID mice or macaques from intravenous, vaginal, as well as maternal-fetal mucosal transmission. All these studies provide direct experimental evidence that neutralizing antibodies are potent enough to prevent HIV infection, and strongly suggest that neutralizing-antibody-based vaccines could provide effective protection against HIV-1, despite the potent action of CTLs. Some neutralizing epitopes have been defined in vitro and in vivo. Unfortunately, none of the neutralizing-antibody-based candidate vaccines has been demonstrated to induce enough protective activity. Weak antigenicity and immunogenicity of neutralizing epitopes on native or recombinant proteins and other factors made it difficult to induce neutralizing-epitope-specific antibody responses in vivo enough to prevent against primary isolates. Recent studies indicated that HIV-1 variations resulted in escape from neutralization or the CTL responses, which may be the principal challenge for HIV-1 prevention. Epitope vaccine as a new strategy activating both arms of the immune system, namely, using the "principal neutralizing epitopes" and the CTL epitopes in combination, should provide new hope for developing an effective vaccine to halt the HIV-1 epidemic.
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Affiliation(s)
- Yi Xiao
- Research Centre for Medical Science, Department of Biology, Tsinghua University, Beijing, P.R. China
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30
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Abstract
Human immunodeficiency virus type-1 particles contain host proteins, both on their surface and interior. This review summarises the cellular proteins found in these virions and covers some of their potential roles in the viral life cycle and pathogenesis. For most proteins studied, their role and function are either unknown or in the hypothesis stage. This reflects the relatively recent emphasis given to these proteins by the HIV-1 field as well as the incomplete understanding of their function in the cell. The study of cellular proteins in HIV-1 promises to help us better understand the interaction of this virus with the cell, the immune system, and the whole human host as well as to shed light on the nature of AIDS and suggest more targets for therapeutic intervention. Finally, many of the cell systems themselves are still poorly understood. The extensive study of HIV-1 has already brought increased attention to the fields of immunology and vaccine science and, in the same way, might assist our understanding of the cellular pathways themselves.
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Affiliation(s)
- David E Ott
- AIDS Vaccine Program, SAIC-Frederick, Inc., National Cancer Institute at Frederick, Frederick, Maryland 21702-1201, USA.
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Lavillette D, Ruggieri A, Boson B, Maurice M, Cosset FL. Relationship between SU subdomains that regulate the receptor-mediated transition from the native (fusion-inhibited) to the fusion-active conformation of the murine leukemia virus glycoprotein. J Virol 2002; 76:9673-85. [PMID: 12208946 PMCID: PMC136517 DOI: 10.1128/jvi.76.19.9673-9685.2002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Envelope glycoproteins (Env) of retroviruses are trimers of SU (surface) and TM (transmembrane) heterodimers and are expressed on virions in fusion-competent forms that are likely to be metastable. Activation of the viral receptor-binding domain (RBD) via its interaction with a cell surface receptor is thought to initiate a cascade of events that lead to refolding of the Env glycoprotein into its stable fusion-active conformation. While the fusion-active conformation of the TM subunit has been described in detail for several retroviruses, little is known about the fusion-competent structure of the retroviral glycoproteins or the molecular events that mediate the transition between the two conformations. By characterizing Env chimeras between the ecotropic and amphotropic murine leukemia virus (MLV) SUs as well as a set of point mutants, we show that alterations of the conformation of the SU glycoprotein strongly elevate Env fusogenicity by disrupting the stability of the Env complex. Compensatory mutations that restored both Env stability and fusion control were also identified, allowing definition of interactions within the Env complex that maintain the stability of the native Env complex. We show that, in the receptor-unbound form, structural interactions between the N terminus of the viral RBD (NTR domain), the proline-rich region (PRR), and the distal part of the C-terminal domain of the SU subunit maintain a conformation of the glycoprotein that is fusion inhibitory. Additionally, we identified mutations that disrupt this fusion-inhibitory conformation and allow fusion activation in the absence of viral receptors, provided that receptor-activated RBD fragments are added in trans during infection. Other mutations were identified that allow fusion activation in the absence of receptors for both the viral glycoprotein and the trans-acting RBD. Finally, we found mutations of the SU that bypass in cis the requirement for the NTR domain in fusion activation. All these different mutations call for a critical role of the PRR in mediating conformational changes of the Env glycoprotein during fusion activation. Our results suggest a model of MLV Env fusion activation in which unlocking of the fusion-inhibitory conformation is initiated by receptor binding of the viral RBD, which, upon disruption of the PRR, allows the NTR domain to promote further events in Env fusion activation. This involves a second type of interaction, in cis or in trans, between the receptor-activated RBD and a median segment of the freed C-terminal domain.
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Affiliation(s)
- Dimitri Lavillette
- Laboratoire de Vectorologie Rétrovirale et Thérapie Génique, INSERM U412, IFR 74, Ecole Normale Supérieure de Lyon, Lyon, France
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32
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Yusuf-Makagiansar H, Anderson ME, Yakovleva TV, Murray JS, Siahaan TJ. Inhibition of LFA-1/ICAM-1 and VLA-4/VCAM-1 as a therapeutic approach to inflammation and autoimmune diseases. Med Res Rev 2002; 22:146-67. [PMID: 11857637 DOI: 10.1002/med.10001] [Citation(s) in RCA: 289] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This review focuses on providing insights into the structural basis and clinical relevance of LFA-1 and VLA-4 inhibition by peptides and small molecules as adhesion-based therapeutic strategies for inflammation and autoimmune diseases. Interactions of cell adhesion molecules (CAM) play central roles in mediating immune and inflammatory responses. Leukocyte function-associated antigen (LFA-1, alpha(L)beta(2), and CD11a/CD18) and very late antigen (VLA-4, alpha(4)beta(1), and CD49d/CD29) are members of integrin-type CAM that are predominantly involved in leukocyte trafficking and extravasation. LFA-1 is exclusively expressed on leukocytes and interacts with its ligands ICAM-1, -2, and -3 to promote a variety of homotypic and heterotypic cell adhesion events required for normal and pathologic functions of the immune systems. VLA-4 is expressed mainly on lymphocyte, monocytes, and eosinophils, but is not found on neutrophils. VLA-4 interacts with its ligands VCAM-1 and fibronectin (FN) CS1 during chronic inflammatory diseases, such as rheumatoid arthritis, asthma, psoriasis, transplant-rejection, and allergy. Blockade of LFA-1 and VLA-4 interactions with their ligands is a potential target for immunosuppression. LFA-1 and VLA-4 antagonists (antibodies, peptides, and small molecules) are being developed for controlling inflammation and autoimmune diseases. The therapeutic intervention of mostly mAb-based has been extensively studied. However, due to the challenging relative efficacy/safety ratio of mAb-based therapy application, especially in terms of systemic administration and immunogenic potential, strategic alternatives in the forms of peptide, peptide mimetic inhibitors, and small molecule non-peptide antagonists are being sought. Linear and cyclic peptides derived from the sequences of LFA-1, ICAM-1, ICAM-2, VCAM-1, and FN C1 have been shown to have inhibitory effects in vitro and in vivo. Finally, understanding the mechanism of LFA-1 and VLA-4 binding to their ligands has become a fundamental basis in developing therapeutic agents for inflammation and autoimmune diseases.
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Affiliation(s)
- Helena Yusuf-Makagiansar
- Department of Pharmaceutical Chemistry, The University of Kansas, Simons Research Laboratory, 2095 Constant Avenue, Lawrence, Kansas 66047, USA
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Baribaud F, Pöhlmann S, Sparwasser T, Kimata MT, Choi YK, Haggarty BS, Ahmad N, Macfarlan T, Edwards TG, Leslie GJ, Arnason J, Reinhart TA, Kimata JT, Littman DR, Hoxie JA, Doms RW. Functional and antigenic characterization of human, rhesus macaque, pigtailed macaque, and murine DC-SIGN. J Virol 2001; 75:10281-9. [PMID: 11581396 PMCID: PMC114602 DOI: 10.1128/jvi.75.21.10281-10289.2001] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
DC-SIGN, a type II membrane protein with a C-type lectin binding domain that is highly expressed on mucosal dendritic cells (DCs) and certain macrophages in vivo, binds to ICAM-3, ICAM-2, and human and simian immunodeficiency viruses (HIV and SIV). Virus captured by DC-SIGN can be presented to T cells, resulting in efficient virus infection, perhaps representing a mechanism by which virus can be ferried via normal DC trafficking from mucosal tissues to lymphoid organs in vivo. To develop reagents needed to characterize the expression and in vivo functions of DC-SIGN, we cloned, expressed, and analyzed rhesus macaque, pigtailed macaque, and murine DC-SIGN and made a panel of monoclonal antibodies (MAbs) to human DC-SIGN. Rhesus and pigtailed macaque DC-SIGN proteins were highly similar to human DC-SIGN and bound and transmitted HIV type 1 (HIV-1), HIV-2, and SIV to receptor-positive cells. In contrast, while competent to bind virus, murine DC-SIGN did not transmit virus to receptor-positive cells under the conditions tested. Thus, mere binding of virus to a C-type lectin does not necessarily mean that transmission will occur. The murine and macaque DC-SIGN molecules all bound ICAM-3. We mapped the determinants recognized by a panel of 16 MAbs to the repeat region, the lectin binding domain, and the extreme C terminus of DC-SIGN. One MAb was specific for DC-SIGN, failing to cross-react with DC-SIGNR. Most MAbs cross-reacted with rhesus and pigtailed macaque DC-SIGN, although none recognized murine DC-SIGN. Fifteen of the MAbs recognized DC-SIGN on DCs, with MAbs to the repeat region generally reacting most strongly. We conclude that rhesus and pigtailed macaque DC-SIGN proteins are structurally and functionally similar to human DC-SIGN and that the reagents that we have developed will make it possible to study the expression and function of this molecule in vivo.
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Affiliation(s)
- F Baribaud
- Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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34
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Spenlehauer C, Kirn A, Aubertin AM, Moog C. Antibody-mediated neutralization of primary human immunodeficiency virus type 1 isolates: investigation of the mechanism of inhibition. J Virol 2001; 75:2235-45. [PMID: 11160727 PMCID: PMC114807 DOI: 10.1128/jvi.75.5.2235-2245.2001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) neutralization occurs when specific antibodies, mainly those directed against the envelope glycoproteins, inhibit infection, most frequently by preventing the entry of the virus into target cells. However, the precise mechanisms of neutralization remain unclear. Previous studies, mostly with cell lines, have produced conflicting results involving either the inhibition of virus attachment or interference with postbinding events. In this study, we investigated the mechanisms of neutralization by immune sera and compared the inhibition of peripheral blood mononuclear cells (PBMC) infection by HIV-1 primary isolates (PI) with the inhibition of T-cell line infection by T-cell line-adapted (TCLA) strains. We followed the kinetics of neutralization to determine at which step of the viral cycle the antibodies act. We found that neutralization of the TCLA strain HIV-1MN/MT-4 required an interaction between antibodies and cell-free virions before the addition of MT-4 cells, whereas PI were neutralized even after adsorption onto PBMC. In addition, the dose-dependent inhibition of HIV-1MN binding to MT-4 cells was strongly correlated with serum-induced neutralization. In contrast, neutralizing sera did not reduce the adhesion of PI to PBMC. Postbinding inhibition was also detected for HIV-1MN produced by and infecting PBMC, demonstrating that the mechanism of neutralization depends on the target cell used in the assay. Finally, we considered whether the different mechanisms of neutralization may reflect the recognition of qualitatively different epitopes on the surface of PI and HIV-1MN or whether they reflect differences in virus attachment to PBMC and MT-4 cells.
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Affiliation(s)
- C Spenlehauer
- INSERM U74, Institut de Virologie, 67000 Strasbourg, France
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35
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Pöhlmann S, Soilleux EJ, Baribaud F, Leslie GJ, Morris LS, Trowsdale J, Lee B, Coleman N, Doms RW. DC-SIGNR, a DC-SIGN homologue expressed in endothelial cells, binds to human and simian immunodeficiency viruses and activates infection in trans. Proc Natl Acad Sci U S A 2001; 98:2670-5. [PMID: 11226297 PMCID: PMC30196 DOI: 10.1073/pnas.051631398] [Citation(s) in RCA: 253] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2000] [Accepted: 12/29/2000] [Indexed: 12/16/2022] Open
Abstract
DC-SIGN, a C-type lectin expressed on the surface of dendritic cells (DCs), efficiently binds and transmits HIVs and simian immunodeficiency viruses to susceptible cells in trans. A DC-SIGN homologue, termed DC-SIGNR, has recently been described. Herein we show that DC-SIGNR, like DC-SIGN, can bind to multiple strains of HIV-1, HIV-2, and simian immunodeficiency virus and transmit these viruses to both T cell lines and human peripheral blood mononuclear cells. Binding of virus to DC-SIGNR was dependent on carbohydrate recognition. Immunostaining with a DC-SIGNR-specific antiserum showed that DC-SIGNR was expressed on sinusoidal endothelial cells in the liver and on endothelial cells in lymph node sinuses and placental villi. The presence of this efficient virus attachment factor on multiple endothelial cell types indicates that DC-SIGNR could play a role in the vertical transmission of primate lentiviruses, in the enabling of HIV to traverse the capillary endothelium in some organs, and in the presentation of virus to CD4-positive cells in multiple locations including lymph nodes.
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Affiliation(s)
- S Pöhlmann
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, 806 Abramson, Philadelphia, PA 19104, USA
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Hioe CE, Chien PC, Lu C, Springer TA, Wang XH, Bandres J, Tuen M. LFA-1 expression on target cells promotes human immunodeficiency virus type 1 infection and transmission. J Virol 2001; 75:1077-82. [PMID: 11134324 PMCID: PMC114007 DOI: 10.1128/jvi.75.2.1077-1082.2001] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
While CD4 and the chemokine receptors are the principal receptors for human immunodeficiency virus (HIV), other cellular proteins, such as LFA-1, are also involved in HIV infection. LFA-1 and its ligands, ICAM-1, ICAM-2, and ICAM-3, can be expressed on the cells infected by HIV, as well as on the HIV virions themselves. To examine the role of LFA-1 expressed on target cells in HIV infection, Jurkat-derived Jbeta2.7 T-cell lines that express either wild-type LFA-1, a constitutively active mutant LFA-1, or no LFA-1 were used. The presence of wild-type LFA-1 enhanced the initial processes of HIV infection, as well as the subsequent replication and transmission from cell to cell. In contrast, the constitutively active LFA-1 mutant failed to promote virus replication and spread, even though this mutant could help HIV enter cells and establish the initial infection. This study clearly demonstrates the contribution of LFA-1 in the different stages of HIV infection. Moreover, not only is LFA-1 expression important for initial HIV-cell interaction, subsequent replication, and transmission, but its activity must also be properly regulated.
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Affiliation(s)
- C E Hioe
- New York University School of Medicine and Manhattan VA Medical Center, New York, New York 10010, USA.
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37
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Popik W, Pitha PM. Exploitation of cellular signaling by HIV-1: unwelcome guests with master keys that signal their entry. Virology 2000; 276:1-6. [PMID: 11021988 DOI: 10.1006/viro.2000.0581] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- W Popik
- Oncology Center, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, USA.
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