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Yamamoto A, Toba M, Takahashi Y, Takakura Y. Pharmacokinetic Approach for the Elucidation of Elevated Plasma Small Extracellular Vesicle (sEV) Concentration in Cancer. J Pharm Sci 2023; 112:1967-1974. [PMID: 37001861 DOI: 10.1016/j.xphs.2023.03.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 03/24/2023] [Accepted: 03/24/2023] [Indexed: 04/03/2023]
Abstract
The abundance of circulating plasma small extracellular vesicles (sEVs) has been reported to be elevated in cancer; however, the underlying mechanism remains unclear. In this study, a pharmacokinetic approach was used to determine the factors contributing to elevated plasma sEV levels during cancer in a tumor-bearing mouse model. Mouse plasma-derived sEVs (MP-sEVs) isolated from tumor-bearing mice showed increased protein concentrations and physicochemical characteristics comparable to MP-sEVs isolated from healthy mice. The steady-state concentration of sEVs is determined by the balance between the MP-sEV production and clearance. Thus, to determine whether tumorigenesis influences sEV clearance, isolated MP-sEVs were intravenously administered to either tumor-bearing or healthy mice. The results showed minimal differences in sEV clearance rates, suggesting that sEV production is the driving force of elevated MP-sEV concentrations. Lastly, CD63-gLuc stably expressing B16BL6-bearing mice were used to estimate the contribution of tumor cell-derived sEVs in the plasma. The gLuc activity of the MP-sEVs isolated was below the limit of detection, and it was estimated that the tumor cell-derived sEVs comprised at most 0.5% of the total MP-sEVs. Taken together, these results suggest that cells other than tumor cells contribute to elevated plasma sEV levels in cancer.
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Affiliation(s)
- Aki Yamamoto
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Mihiro Toba
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yuki Takahashi
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yoshinobu Takakura
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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2
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Immunogenicity of HIV-1-Based Virus-Like Particles with Increased Incorporation and Stability of Membrane-Bound Env. Vaccines (Basel) 2021; 9:vaccines9030239. [PMID: 33801906 PMCID: PMC8002006 DOI: 10.3390/vaccines9030239] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/04/2021] [Accepted: 03/05/2021] [Indexed: 01/04/2023] Open
Abstract
An optimal prophylactic vaccine to prevent human immunodeficiency virus (HIV-1) transmission should elicit protective antibody responses against the HIV-1 envelope glycoprotein (Env). Replication-incompetent HIV-1 virus-like particles (VLPs) offer the opportunity to present virion-associated Env with a native-like structure during vaccination that closely resembles that encountered on infectious virus. Here, we optimized the incorporation of Env into previously designed mature-form VLPs (mVLPs) and assessed their immunogenicity in mice. The incorporation of Env into mVLPs was increased by replacing the Env transmembrane and cytoplasmic tail domains with those of influenza haemagglutinin (HA-TMCT). Furthermore, Env was stabilized on the VLP surface by introducing an interchain disulfide and proline substitution (SOSIP) mutations typically employed to stabilize soluble Env trimers. The resulting mVLPs efficiently presented neutralizing antibody epitopes while minimizing exposure of non-neutralizing antibody sites. Vaccination of mice with mVLPs elicited a broader range of Env-specific antibody isotypes than Env presented on immature VLPs or extracellular vesicles. The mVLPs bearing HA-TMCT-modified Env consistently induced anti-Env antibody responses that mediated modest neutralization activity. These mVLPs are potentially useful immunogens for eliciting neutralizing antibody responses that target native Env epitopes on infectious HIV-1 virions.
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Matsumoto A, Takahashi Y, Chang HY, Wu YW, Yamamoto A, Ishihama Y, Takakura Y. Blood concentrations of small extracellular vesicles are determined by a balance between abundant secretion and rapid clearance. J Extracell Vesicles 2019; 9:1696517. [PMID: 31807238 PMCID: PMC6882433 DOI: 10.1080/20013078.2019.1696517] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/13/2019] [Accepted: 11/15/2019] [Indexed: 12/19/2022] Open
Abstract
Small extracellular vesicles (sEVs) are important mediators of cell–cell communication with respect to diverse physiological processes. To further understand their physiological roles, understanding blood sEV homoeostasis in a quantitative manner is desired. In this study, we propose novel kinetic approaches to estimate the secretion and clearance of mouse plasma–derived sEVs (MP-sEVs) based on the hypothesis that blood sEV concentrations are determined by a balance between the secretion and clearance of sEVs. Using our specific and sensitive sEV labelling technology, we succeeded in analysing MP-sEV clearance from the blood after intravenous administration into mice. This revealed the rapid disappearance of MP-sEVs with a half-life of approximately 7 min. Moreover, the plasma sEV secretion rate, which is presently impossible to directly evaluate, was calculated as 18 μg/min in mice based on pharmacokinetic (PK) analysis. Next, macrophage-depleted mice were prepared as a model of disrupted sEV homoeostasis with retarded sEV clearance. MP-sEV concentrations were increased in macrophage-depleted mice, which probably reflected a shift in the balance of secretion and clearance. Moreover, the increased MP-sEV concentration in macrophage-depleted mice was successfully simulated using calculated clearance rate constant, secretion rate constant and volume of distribution, suggesting the validity of our PK approaches. These results demonstrate that blood sEV concentration homoeostasis can be explained by the dynamics of rapid secretion/clearance.
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Affiliation(s)
- Akihiro Matsumoto
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Yuki Takahashi
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Hsin-Yi Chang
- Department of Molecular and Cellular BioAnalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Yi-Wen Wu
- Department of Molecular and Cellular BioAnalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan.,Ph.D. Program for Cancer Molecular Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University and Academia Sinica, Taipei, Taiwan
| | - Aki Yamamoto
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Yasushi Ishihama
- Department of Molecular and Cellular BioAnalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Yoshinobu Takakura
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
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4
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Samer S, Namiyama G, Oshiro T, Arif MS, Cardoso da Silva W, Sucupira MCA, Janini LM, Diaz RS. Evidence of Noncompetent HIV after Ex Vivo Purging Among ART-Suppressed Individuals. AIDS Res Hum Retroviruses 2017. [PMID: 28632400 DOI: 10.1089/aid.2017.0036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Sadia Samer
- Retrovirology Laboratory, Infectious Diseases Division, Paulista School of Medicine, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Gislene Namiyama
- Institute of Adolf Lutz, University of Sao Paulo, Sao Paulo, Brazil
| | - Telma Oshiro
- Department of Dermatology, University of Sao Paulo, Sao Paulo, Brazil
| | - Muhammad Shoaib Arif
- Retrovirology Laboratory, Infectious Diseases Division, Paulista School of Medicine, Federal University of Sao Paulo, Sao Paulo, Brazil
| | | | - Maria Cecilia Araripe Sucupira
- Retrovirology Laboratory, Infectious Diseases Division, Paulista School of Medicine, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Luiz Mario Janini
- Retrovirology Laboratory, Infectious Diseases Division, Paulista School of Medicine, Federal University of Sao Paulo, Sao Paulo, Brazil
- Division of Microbiology, Immunology and Parasitology. Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Ricardo Sobhie Diaz
- Retrovirology Laboratory, Infectious Diseases Division, Paulista School of Medicine, Federal University of Sao Paulo, Sao Paulo, Brazil
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5
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Virion-incorporated alpha-enolase suppresses the early stage of HIV-1 reverse transcription. Biochem Biophys Res Commun 2017; 484:278-284. [DOI: 10.1016/j.bbrc.2017.01.096] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 01/19/2017] [Indexed: 11/22/2022]
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Abstract
The HIV genome encodes a small number of viral proteins (i.e., 16), invariably establishing cooperative associations among HIV proteins and between HIV and host proteins, to invade host cells and hijack their internal machineries. As a known example, the HIV envelope glycoprotein GP120 is closely associated with GP41 for viral entry. From a genome-wide perspective, a hypothesis can be worked out to determine whether 16 HIV proteins could develop 120 possible pairwise associations either by physical interactions or by functional associations mediated via HIV or host molecules. Here, we present the first systematic review of experimental evidence on HIV genome-wide protein associations using a large body of publications accumulated over the past 3 decades. Of 120 possible pairwise associations between 16 HIV proteins, at least 34 physical interactions and 17 functional associations have been identified. To achieve efficient viral replication and infection, HIV protein associations play essential roles (e.g., cleavage, inhibition, and activation) during the HIV life cycle. In either a dispensable or an indispensable manner, each HIV protein collaborates with another viral protein to accomplish specific activities that precisely take place at the proper stages of the HIV life cycle. In addition, HIV genome-wide protein associations have an impact on anti-HIV inhibitors due to the extensive cross talk between drug-inhibited proteins and other HIV proteins. Overall, this study presents for the first time a comprehensive overview of HIV genome-wide protein associations, highlighting meticulous collaborations between all viral proteins during the HIV life cycle.
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Affiliation(s)
- Guangdi Li
- Department of Metabolism and Endocrinology, Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China KU Leuven-University of Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Leuven, Belgium
| | - Erik De Clercq
- KU Leuven-University of Leuven, Rega Institute for Medical Research, Department of Microbiology and Immunology, Leuven, Belgium
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7
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HIV Genome-Wide Protein Associations: a Review of 30 Years of Research. Microbiol Mol Biol Rev 2016; 80:679-731. [PMID: 27357278 DOI: 10.1128/mmbr.00065-15] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The HIV genome encodes a small number of viral proteins (i.e., 16), invariably establishing cooperative associations among HIV proteins and between HIV and host proteins, to invade host cells and hijack their internal machineries. As a known example, the HIV envelope glycoprotein GP120 is closely associated with GP41 for viral entry. From a genome-wide perspective, a hypothesis can be worked out to determine whether 16 HIV proteins could develop 120 possible pairwise associations either by physical interactions or by functional associations mediated via HIV or host molecules. Here, we present the first systematic review of experimental evidence on HIV genome-wide protein associations using a large body of publications accumulated over the past 3 decades. Of 120 possible pairwise associations between 16 HIV proteins, at least 34 physical interactions and 17 functional associations have been identified. To achieve efficient viral replication and infection, HIV protein associations play essential roles (e.g., cleavage, inhibition, and activation) during the HIV life cycle. In either a dispensable or an indispensable manner, each HIV protein collaborates with another viral protein to accomplish specific activities that precisely take place at the proper stages of the HIV life cycle. In addition, HIV genome-wide protein associations have an impact on anti-HIV inhibitors due to the extensive cross talk between drug-inhibited proteins and other HIV proteins. Overall, this study presents for the first time a comprehensive overview of HIV genome-wide protein associations, highlighting meticulous collaborations between all viral proteins during the HIV life cycle.
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8
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Pang Y, Song H, Cheng W. Using optical trap to measure the refractive index of a single animal virus in culture fluid with high precision. BIOMEDICAL OPTICS EXPRESS 2016; 7:1672-89. [PMID: 27231613 PMCID: PMC4871073 DOI: 10.1364/boe.7.001672] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 03/20/2016] [Accepted: 03/29/2016] [Indexed: 05/22/2023]
Abstract
The refractive index (RI) is a fundamental parameter of materials that can be used to distinguish and sort materials of different nature. Although the RI of a virus is required for many optics-based biosensing applications, RIs of animal viruses have never been measured. Here we have developed a technique that can measure the RI of individual viruses in aqueous media with high precision. This technique is based on optical trapping of single virions and works by relating the size and RI of a single virus to the stiffness of an optical trap. We have derived an analytic expression to quantitatively describe the optical trapping of these particles. We have validated this equation using nanoparticles of known RI, and measured the RI of individual human immunodeficiency viruses type-1, which yielded a value of 1.42 at 830 nm with less than 2% coefficient of variation. This value is much lower than the RI typically assumed for viruses, but very close to that of 2.0 M sucrose solution in water. To the best of our knowledge, this is the first report on the experimental measurement of the RI for a single animal virus in aqueous media. This technique does not require prior knowledge on the diameter of the nanoparticles, and can be applied to other viruses or nanoparticles for accurate measurement of RI that is critical for the label-free detection of these particles in various settings.
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Affiliation(s)
- Yuanjie Pang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109, USA
| | - Hanna Song
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109, USA
| | - Wei Cheng
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109, USA
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, USA
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9
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Stieh DJ, King DF, Klein K, Aldon Y, McKay PF, Shattock RJ. Discrete partitioning of HIV-1 Env forms revealed by viral capture. Retrovirology 2015; 12:81. [PMID: 26399966 PMCID: PMC4581120 DOI: 10.1186/s12977-015-0207-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 09/15/2015] [Indexed: 11/25/2022] Open
Abstract
Background The structure of HIV-1 envelope glycoprotein (Env) is flexible and heterogeneous on whole virions. Although functional Env complexes are thought to require trimerization of cleaved gp41/gp120 heterodimers, variable processing can result in the potential incorporation of non-functional uncleaved proteins (gp160), non-trimeric arrangements of gp41/gp120 heterodimers, and gp120 depleted gp41 stumps. The potential distribution of functional and non-functional Env forms across replication-competent viral populations may have important implications for neutralizing and non-neutralizing antibody functions. This study applied an immuno-bead viral capture assay (VCA) to interrogate the potential distribution (heterologous vs homologous) of functional and non-functional forms of virion associated Env. Results The VCA revealed a significant association between depletion of infectious virions and virion Env incorporation, but not between infectivity and p24-gag. Three distinct subpopulations of virions were identified within pools of genetically homogenous viral particles. Critically, a significant subpopulation of infectious virions were exclusively captured by neutralizing antibodies (nAbs) indicative of a homologous distribution of functional trimeric Env forms. A second infectious subpopulation bound both neutralizing and non-neutralizing antibodies (nnAbs) representative of a heterologous distribution of Env forms, while a third non-infectious subpopulation was predominantly bound by nnAbs recognizing gp41 stumps. Conclusions The observation that a distinct and significant subpopulation of infectious virions is exclusively captured by neutralizing antibodies has important implications for understanding antibody binding and neutralization, as well as other antibody effector functions. Electronic supplementary material The online version of this article (doi:10.1186/s12977-015-0207-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daniel J Stieh
- Department of Cellular and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
| | - Deborah F King
- Mucosal Infection and Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
| | - Katja Klein
- Mucosal Infection and Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
| | - Yoann Aldon
- Mucosal Infection and Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
| | - Paul F McKay
- Mucosal Infection and Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
| | - Robin J Shattock
- Mucosal Infection and Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
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10
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Stieh DJ, King DF, Klein K, Liu P, Shen X, Hwang KK, Ferrari G, Montefiori DC, Haynes B, Pitisuttithum P, Kaewkungwal J, Nitayaphan S, Rerks-Ngarm S, Michael NL, Robb ML, Kim JH, Denny TN, Tomaras GD, Shattock RJ. Aggregate complexes of HIV-1 induced by multimeric antibodies. Retrovirology 2014; 11:78. [PMID: 25274446 PMCID: PMC4193994 DOI: 10.1186/s12977-014-0078-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 08/30/2014] [Indexed: 11/10/2022] Open
Abstract
Background Antibody mediated viral aggregation may impede viral transfer across mucosal surfaces by hindering viral movement in mucus, preventing transcytosis, or reducing inter-cellular penetration of epithelia thereby limiting access to susceptible mucosal CD4 T cells and dendritic cells. These functions may work together to provide effective immune exclusion of virus from mucosal tissue; however little is known about the antibody characteristics required to induce HIV aggregation. Such knowledge may be critical to the design of successful immunization strategies to facilitate viral immune exclusion at the mucosal portals of entry. Results The potential of neutralizing and non-neutralizing IgG and IgA monoclonals (mAbs) to induce HIV-1 aggregation was assessed by Dynamic light scattering (DLS). Although neutralizing and non-neutralizing IgG mAbs and polyclonal HIV-Ig efficiently aggregated soluble Env trimers, they were not capable of forming viral aggregates. In contrast, dimeric (but not monomeric) IgA mAbs induced stable viral aggregate populations that could be separated from uncomplexed virions. Epitope specificity influenced both the degree of aggregation and formation of higher order complexes by dIgA. IgA purified from serum of uninfected RV144 vaccine trial responders were able to efficiently opsonize viral particles in the absence of significant aggregation, reflective of monomeric IgA. Conclusions These results collectively demonstrate that dIgA is capable of forming stable viral aggregates providing a plausible basis for testing the effectiveness of aggregation as a potential protection mechanism at the mucosal portals of viral entry. Electronic supplementary material The online version of this article (doi:10.1186/s12977-014-0078-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daniel J Stieh
- Center for Infection, Department of Cellular and Molecular Medicine, St George's, University of London, London, SW17 0RE, UK. .,Current address: Department of Cellular and Molecular Biology, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA.
| | - Deborah F King
- Mucosal Infection & Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
| | - Katja Klein
- Mucosal Infection & Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
| | - Pinghuang Liu
- Duke Human Vaccine Center, Duke University Medical Center, Durham, NC, 27710, USA. .,Current address: Division of Swine Infectious Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China.
| | - Xiaoying Shen
- Duke Human Vaccine Center, Duke University Medical Center, Durham, NC, 27710, USA.
| | - Kwan Ki Hwang
- Duke Human Vaccine Center, Duke University Medical Center, Durham, NC, 27710, USA.
| | - Guido Ferrari
- Duke Human Vaccine Center, Duke University Medical Center, Durham, NC, 27710, USA.
| | - David C Montefiori
- Duke Human Vaccine Center, Duke University Medical Center, Durham, NC, 27710, USA.
| | - Barton Haynes
- Duke Human Vaccine Center, Duke University Medical Center, Durham, NC, 27710, USA.
| | | | | | | | | | - Nelson L Michael
- Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America.
| | - Merlin L Robb
- Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America.
| | - Jerome H Kim
- Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America.
| | - Thomas N Denny
- Duke Human Vaccine Center, Duke University Medical Center, Durham, NC, 27710, USA.
| | - Georgia D Tomaras
- Duke Human Vaccine Center, Duke University Medical Center, Durham, NC, 27710, USA.
| | - Robin J Shattock
- Mucosal Infection & Immunity Group, Section of Infectious Diseases, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
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11
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Dochi T, Nakano T, Inoue M, Takamune N, Shoji S, Sano K, Misumi S. Phosphorylation of human immunodeficiency virus type 1 capsid protein at serine 16, required for peptidyl-prolyl isomerase-dependent uncoating, is mediated by virion-incorporated extracellular signal-regulated kinase 2. J Gen Virol 2014; 95:1156-1166. [PMID: 24509437 DOI: 10.1099/vir.0.060053-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We reported previously that Pin1 facilitates human immunodeficiency virus type 1 (HIV-1) uncoating by interacting with the capsid core through the phosphorylated Ser(16)-Pro(17) motif. However, the specific kinase responsible for Ser(16) phosphorylation has remained unknown. Here, we showed that virion-associated extracellular signal-regulated kinase 2 (ERK2) phosphorylates Ser(16). The characterization of immature virions produced by exposing chronically HIV-1LAV-1-infected CEM/LAV-1 cells to 10 µM saquinavir indicated that Ser(16) is phosphorylated after the initiation of Pr55(Gag) processing. Furthermore, a mass spectrometry-based in vitro kinase assay demonstrated that ERK2 specifically phosphorylated the Ser(16) residue in the Ser(16)-Pro(17) motif-containing substrate. The treatment of CEM/LAV-1 cells with the ERK2 inhibitor sc-222229 decreased the Ser(16) phosphorylation level inside virions, and virus partially defective in Ser(16) phosphorylation showed impaired reverse transcription and attenuated replication owing to attenuated Pin1-dependent uncoating. Furthermore, the suppression of ERK2 expression by RNA interference in CEM/LAV-1 cells resulted in suppressed ERK2 packaging inside virions and decreased the Ser(16) phosphorylation level inside virions. Interestingly, the ERK2-packaging-defective virus showed impaired reverse transcription and attenuated HIV-1 replication. Taken together, these findings provide insights into the as-yet-obscure processes in Pin1-dependent HIV-1 uncoating.
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Affiliation(s)
- Takeo Dochi
- Department of Pharmaceutical Biochemistry, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Takashi Nakano
- Department of Microbiology and Infection Control, Osaka Medical College, Osaka 569-8686, Japan
| | - Mutsumi Inoue
- Department of Pharmaceutical Biochemistry, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Nobutoki Takamune
- Department of Pharmaceutical Biochemistry, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Shozo Shoji
- Department of Pharmaceutical Biochemistry, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Kouichi Sano
- Department of Microbiology and Infection Control, Osaka Medical College, Osaka 569-8686, Japan
| | - Shogo Misumi
- Department of Pharmaceutical Biochemistry, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
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12
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Mercier SK, Donaghy H, Botting RA, Turville SG, Harman AN, Nasr N, Ji H, Kusebauch U, Mendoza L, Shteynberg D, Sandgren K, Simpson RJ, Moritz RL, Cunningham AL. The microvesicle component of HIV-1 inocula modulates dendritic cell infection and maturation and enhances adhesion to and activation of T lymphocytes. PLoS Pathog 2013; 9:e1003700. [PMID: 24204260 PMCID: PMC3798598 DOI: 10.1371/journal.ppat.1003700] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 08/26/2013] [Indexed: 01/05/2023] Open
Abstract
HIV-1 is taken up by immature monocyte derived dendritic cells (iMDDCs) into tetraspanin rich caves from which the virus can either be transferred to T lymphocytes or enter into endosomes resulting in degradation. HIV-1 binding and fusion with the DC membrane results in low level de novo infection that can also be transferred to T lymphocytes at a later stage. We have previously reported that HIV-1 can induce partial maturation of iMDDCs at both stages of trafficking. Here we show that CD45⁺ microvesicles (MV) which contaminate purified HIV-1 inocula due to similar size and density, affect DC maturation, de novo HIV-1 infection and transfer to T lymphocytes. Comparing iMDDCs infected with CD45-depleted HIV-1BaL or matched non-depleted preparations, the presence of CD45⁺ MVs was shown to enhance DC maturation and ICAM-1 (CD54) expression, which is involved in DC∶T lymphocyte interactions, while restricting HIV-1 infection of MDDCs. Furthermore, in the DC culture HIV-1 infected (p24⁺) MDDCs were more mature than bystander cells. Depletion of MVs from the HIV-1 inoculum markedly inhibited DC∶T lymphocyte clustering and the induction of alloproliferation as well as limiting HIV-1 transfer from DCs to T lymphocytes. The effects of MV depletion on these functions were reversed by the re-addition of purified MVs from activated but not non-activated SUPT1.CCR5-CL.30 or primary T cells. Analysis of the protein complement of these MVs and of these HIV-1 inocula before and after MV depletion showed that Heat Shock Proteins (HSPs) and nef were the likely DC maturation candidates. Recombinant HSP90α and β and nef all induced DC maturation and ICAM-1 expression, greater when combined. These results suggest that MVs contaminating HIV-1 released from infected T lymphocytes may be biologically important, especially in enhancing T cell activation, during uptake by DCs in vitro and in vivo, particularly as MVs have been detected in the circulation of HIV-1 infected subjects.
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Affiliation(s)
- Sarah K. Mercier
- Centre for Virus Research, Westmead Millennium Institute, Westmead, New South Wales, Australia
- University of Sydney, Sydney, New South Wales, Australia
| | - Heather Donaghy
- Centre for Virus Research, Westmead Millennium Institute, Westmead, New South Wales, Australia
- * E-mail: (HD); (ALC)
| | - Rachel A. Botting
- Centre for Virus Research, Westmead Millennium Institute, Westmead, New South Wales, Australia
- University of Sydney, Sydney, New South Wales, Australia
| | - Stuart G. Turville
- Centre for Virus Research, Westmead Millennium Institute, Westmead, New South Wales, Australia
- University of Sydney, Sydney, New South Wales, Australia
| | - Andrew N. Harman
- Centre for Virus Research, Westmead Millennium Institute, Westmead, New South Wales, Australia
| | - Najla Nasr
- Centre for Virus Research, Westmead Millennium Institute, Westmead, New South Wales, Australia
| | - Hong Ji
- La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
| | - Ulrike Kusebauch
- Institute for Systems Biology, Seattle, Washington, United States of America
| | - Luis Mendoza
- Institute for Systems Biology, Seattle, Washington, United States of America
| | - David Shteynberg
- Institute for Systems Biology, Seattle, Washington, United States of America
| | - Kerrie Sandgren
- Centre for Virus Research, Westmead Millennium Institute, Westmead, New South Wales, Australia
| | - Richard J. Simpson
- La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
| | - Robert L. Moritz
- Institute for Systems Biology, Seattle, Washington, United States of America
| | - Anthony L. Cunningham
- Centre for Virus Research, Westmead Millennium Institute, Westmead, New South Wales, Australia
- University of Sydney, Sydney, New South Wales, Australia
- * E-mail: (HD); (ALC)
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13
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Arakelyan A, Fitzgerald W, Margolis L, Grivel JC. Nanoparticle-based flow virometry for the analysis of individual virions. J Clin Invest 2013; 123:3716-27. [PMID: 23925291 PMCID: PMC3754246 DOI: 10.1172/jci67042] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 06/06/2013] [Indexed: 11/17/2022] Open
Abstract
While flow cytometry has been used to analyze the antigenic composition of individual cells, the antigenic makeup of viral particles is still characterized predominantly in bulk. Here, we describe a technology, "flow virometry," that can be used for antigen detection on individual virions. The technology is based on binding magnetic nanoparticles to virions, staining the virions with monoclonal antibodies, separating the formed complexes with magnetic columns, and characterizing them with flow cytometers. We used this technology to study the distribution of two antigens (HLA-DR and LFA-1) that HIV-1 acquires from infected cells among individual HIV-1 virions. Flow virometry revealed that the antigenic makeup of virions from a single preparation is heterogeneous. This heterogeneity could not be detected with bulk analysis of viruses. Moreover, in two preparations of the same HIV-1 produced by different cells, the distribution of antigens among virions was different. In contrast, HIV-1 of two different HIV-1 genotypes replicating in the same cells became somewhat antigenically similar. This nanotechnology allows the study of virions in bodily fluids without virus propagation and in principle is not restricted to the analysis of HIV, but can be applied to the analysis of the individual surface antigenic makeup of any virus.
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Affiliation(s)
- Anush Arakelyan
- Program in Physical Biology, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, NIH, Bethesda, Maryland 20892, USA
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14
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Linde ME, Colquhoun DR, Ubaida Mohien C, Kole T, Aquino V, Cotter R, Edwards N, Hildreth JEK, Graham DR. The conserved set of host proteins incorporated into HIV-1 virions suggests a common egress pathway in multiple cell types. J Proteome Res 2013; 12:2045-54. [PMID: 23432411 DOI: 10.1021/pr300918r] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
HIV-1 incorporates a large array of host proteins into virions. Determining the host protein composition in HIV virions has technical difficulties, including copurification of microvesicles. We developed an alternative purification technique using cholesterol that differentially modulates the density of virions and microvesicles (density modification, DM) allowing for high-yield virion purification that is essential for tandem mass spectrometric and quantitative proteomic (iTRAQ) analysis. DM purified virions were analyzed using iTRAQ and validated against Optiprep (60% iodixanol) purified virions. We were able to characterize host protein incorporation in DM-purified HIV particles derived from CD4+ T-cell lines; we compared this data set to a reprocessed data set of monocyte-derived macrophages (MDM) derived HIV-1 using the same bioinformatics pipeline. Seventy-nine clustered proteins were shared between the MDM derived and T-cell derived data set. These clusters included an extensive collection of actin isoforms, HLA proteins, chaperones, and a handful of other proteins, many of which have previously been documented to interact with viral proteins. Other proteins of note were ERM proteins, the dynamin domain containing protein EH4, a phosphodiesterase, and cyclophilin A. As these proteins are incorporated in virions produced in both cell types, we hypothesize that these proteins may have direct interactions with viral proteins or may be important in the viral life cycle. Additionally, identified common set proteins are predicted to interact with >1000 related human proteins. Many of these secondary interacting proteins are reported to be incorporated into virions, including ERM proteins and adhesion molecules. Thus, only a few direct interactions between host and viral proteins may dictate the host protein composition in virions. Ultimately, interaction and expression differences in host proteins between cell types may drive virion phenotypic diversity, despite conserved viral protein-host protein interactions between cell types.
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Affiliation(s)
- Michael E Linde
- Graduate Program in Immunology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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15
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Stieh DJ, Phillips JL, Rogers PM, King DF, Cianci GC, Jeffs SA, Gnanakaran S, Shattock RJ. Dynamic electrophoretic fingerprinting of the HIV-1 envelope glycoprotein. Retrovirology 2013; 10:33. [PMID: 23514633 PMCID: PMC3648349 DOI: 10.1186/1742-4690-10-33] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 03/07/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Interactions between the HIV-1 envelope glycoprotein (Env) and its primary receptor CD4 are influenced by the physiological setting in which these events take place. In this study, we explored the surface chemistry of HIV-1 Env constructs at a range of pH and salinities relevant to mucosal and systemic compartments through electrophoretic mobility (EM) measurements. Sexual transmission events provide a more acidic environment for HIV-1 compared to dissemination and spread of infection occurring in blood or lymph node. We hypothesize functional, trimeric Env behaves differently than monomeric forms. RESULTS The dynamic electrophoretic fingerprint of trimeric gp140 revealed a change in EM from strongly negative to strongly positive as pH increased from that of the lower female genital tract (pHx) to that of the blood (pHy). Similar findings were observed using a trimeric influenza Haemagglutinin (HA) glycoprotein, indicating that this may be a general attribute of trimeric viral envelope glycoproteins. These findings were supported by computationally modeling the surface charge of various gp120 and HA crystal structures. To identify the behavior of the infectious agent and its target cells, EM measurements were made on purified whole HIV-1 virions and primary T-lymphocytes. Viral particles had a largely negative surface charge, and lacked the regions of positivity near neutral pH that were observed with trimeric Env. T cells changed their surface chemistry as a function of activation state, becoming more negative over a wider range of pH after activation. Soluble recombinant CD4 (sCD4) was found to be positively charged under a wide range of conditions. Binding studies between sCD4 and gp140 show that the affinity of CD4-gp140 interactions depends on pH. CONCLUSIONS Taken together, these findings allow a more complete model of the electrochemical forces involved in HIV-1 Env functionality. These results indicate that the influence of the localized environment on the interactions of HIV with target cells are more pronounced than previously appreciated. There is differential chemistry of trimeric, but not monomeric, Env under conditions which mimic the mucosa compared to those found systemically. This should be taken into consideration during design of immunogens which targets virus at mucosal portals of entry.
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Affiliation(s)
- Daniel J Stieh
- Center for Infection, Department of Cellular and Molecular Medicine, St. George's University of London, London SW17 0RE, UK
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16
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Kishimoto N, Onitsuka A, Kido K, Takamune N, Shoji S, Misumi S. Glyceraldehyde 3-phosphate dehydrogenase negatively regulates human immunodeficiency virus type 1 infection. Retrovirology 2012; 9:107. [PMID: 23237566 PMCID: PMC3531276 DOI: 10.1186/1742-4690-9-107] [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: 06/27/2012] [Accepted: 11/25/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Host proteins are incorporated inside human immunodeficiency virus type 1 (HIV-1) virions during assembly and can either positively or negatively regulate HIV-1 infection. Although the identification efficiency of host proteins is improved by mass spectrometry, how those host proteins affect HIV-1 replication has not yet been fully clarified. RESULTS In this study, we show that virion-associated glyceraldehyde 3-phosphate dehydrogenase (GAPDH) does not allosterically inactivate HIV-1 reverse transcriptase (RT) but decreases the efficiency of reverse transcription reactions by decreasing the packaging efficiency of lysyl-tRNA synthetase (LysRS) and tRNA(Lys3) into HIV-1 virions. Two-dimensional (2D) gel electrophoresis demonstrated that some isozymes of GAPDH with different isoelectric points were expressed in HIV-1-producing CEM/LAV-1 cells, and a proportion of GAPDH was selectively incorporated into the virions. Suppression of GAPDH expression by RNA interference in CEM/LAV-1 cells resulted in decreased GAPDH packaging inside the virions, and the GAPDH-packaging-defective virus maintained at least control levels of viral production but increased the infectivity. Quantitative analysis of reverse transcription products indicated that the levels of early cDNA products of the GAPDH-packaging-defective virus were higher than those of the control virus owing to the higher packaging efficiencies of LysRS and tRNA(Lys3) into the virions rather than the GAPDH-dependent negative allosteric modulation for RT. Furthermore, immunoprecipitation assay using an anti-GAPDH antibody showed that GAPDH directly interacted with Pr55(gag) and p160(gag)-pol and the overexpression of LysRS in HIV-1-producing cells resulted in a decrease in the efficiency of GAPDH packaging in HIV particles. In contrast, the viruses produced from cells expressing a high level of GAPDH showed decreased infectivity in TZM-bl cells and reverse transcription efficiency in TZM-bl cells and peripheral blood mononuclear cells (PBMCs). CONCLUSIONS These findings indicate that GAPDH negatively regulates HIV-1 infection and provide insights into a novel function of GAPDH in the HIV-1 life cycle and a new host defense mechanism against HIV-1 infection.
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Affiliation(s)
- Naoki Kishimoto
- Department of Pharmaceutical Biochemistry, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
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17
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Abstract
HIV entry involves binding of the trimeric viral envelope glycoprotein (Env) gp120/gp41 to cell surface receptors, which triggers conformational changes in Env that drive the membrane fusion reaction. The conformational landscape that the lipids and Env navigate en route to fusion has been examined by biophysical measurements on the microscale, whereas electron tomography, x-rays, and NMR have provided insights into the process on the nanoscale and atomic scale. However, the coupling between the lipid and protein pathways that give rise to fusion has not been resolved. Here, we discuss the known and unknown about the overall HIV Env-mediated fusion process.
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Affiliation(s)
| | - Stewart Durell
- Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, and
| | - Mathias Viard
- From the Nanobiology Program and
- the Basic Science Program, SAIC-Frederick, Inc., Center for Cancer Research Nanobiology Program (CCRNP), Frederick National Lab, Frederick, Maryland 21702
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18
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Santos S, Obukhov Y, Nekhai S, Bukrinsky M, Iordanskiy S. Virus-producing cells determine the host protein profiles of HIV-1 virion cores. Retrovirology 2012; 9:65. [PMID: 22889230 PMCID: PMC3432596 DOI: 10.1186/1742-4690-9-65] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 07/15/2012] [Indexed: 11/10/2022] Open
Abstract
Background Upon HIV entry into target cells, viral cores are released and rearranged into reverse transcription complexes (RTCs), which support reverse transcription and also protect and transport viral cDNA to the site of integration. RTCs are composed of viral and cellular proteins that originate from both target and producer cells, the latter entering the target cell within the viral core. However, the proteome of HIV-1 viral cores in the context of the type of producer cells has not yet been characterized. Results We examined the proteomic profiles of the cores purified from HIV-1 NL4-3 virions assembled in Sup-T1 cells (T lymphocytes), PMA and vitamin D3 activated THP1 (model of macrophages, mMΦ), and non-activated THP1 cells (model of monocytes, mMN) and assessed potential involvement of identified proteins in the early stages of infection using gene ontology information and data from genome-wide screens on proteins important for HIV-1 replication. We identified 202 cellular proteins incorporated in the viral cores (T cells: 125, mMΦ: 110, mMN: 90) with the overlap between these sets limited to 42 proteins. The groups of RNA binding (29), DNA binding (17), cytoskeleton (15), cytoskeleton regulation (21), chaperone (18), vesicular trafficking-associated (12) and ubiquitin-proteasome pathway-associated proteins (9) were most numerous. Cores of the virions from SupT1 cells contained twice as many RNA binding proteins as cores of THP1-derived virus, whereas cores of virions from mMΦ and mMN were enriched in components of cytoskeleton and vesicular transport machinery, most probably due to differences in virion assembly pathways between these cells. Spectra of chaperones, cytoskeletal proteins and ubiquitin-proteasome pathway components were similar between viral cores from different cell types, whereas DNA-binding and especially RNA-binding proteins were highly diverse. Western blot analysis showed that within the group of overlapping proteins, the level of incorporation of some RNA binding (RHA and HELIC2) and DNA binding proteins (MCM5 and Ku80) in the viral cores from T cells was higher than in the cores from both mMΦ and mMN and did not correlate with the abundance of these proteins in virus producing cells. Conclusions Profiles of host proteins packaged in the cores of HIV-1 virions depend on the type of virus producing cell. The pool of proteins present in the cores of all virions is likely to contain factors important for viral functions. Incorporation ratio of certain RNA- and DNA-binding proteins suggests their more efficient, non-random packaging into virions in T cells than in mMΦ and mMN.
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Affiliation(s)
- Steven Santos
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University School of Medicine and Health Sciences, 2300 I Street NW, Ross Hall, Washington, DC 20037, USA
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19
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An anti-phosphoinositide-specific monoclonal antibody that neutralizes HIV-1 infection of human monocyte-derived macrophages. Virology 2012; 430:110-9. [PMID: 22633000 DOI: 10.1016/j.virol.2012.04.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 04/12/2012] [Accepted: 04/24/2012] [Indexed: 11/20/2022]
Abstract
HIV-1 entry into cells requires the interaction of both HIV-1 envelope proteins and membrane lipids. We investigated the mechanism of neutralization of HIV-1 infection of primary monocyte-derived macrophages (MDM) by a murine monoclonal antibody (mAb) WR321. WR321 specifically binds phosphatidylinositol-4-phosphate and phosphatidylinositol-4,5-bisphosphate. These phosphoinositides are present not only on the inner surface of the plasma membranes of cells but also on the surface of virions. HIV-1 acquires these lipids during the budding process. Pre-incubation of WR321 with the virus but not with MDM neutralized HIV-1 infection of MDM. Our results demonstrate that WR321 was internalized only when it was bound to HIV-1. WR321 did not prevent the entry of HIV-1 into MDM. However, once WR321 was internalized along with HIV-1 the mAb acted intracellulary to prevent the release of virions from MDM and also triggered the release of β-chemokines.
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20
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Ammersbach M, Bienzle D. Methods for assessing feline immunodeficiency virus infection, infectivity and purification. Vet Immunol Immunopathol 2011; 143:202-14. [DOI: 10.1016/j.vetimm.2011.06.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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21
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Raymond A, Campbell-Sims T, Khan M, Lang M, Huang M, Bond V, Powell M. HIV Type 1 Nef is released from infected cells in CD45(+) microvesicles and is present in the plasma of HIV-infected individuals. AIDS Res Hum Retroviruses 2011; 27:167-78. [PMID: 20964480 DOI: 10.1089/aid.2009.0170] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
HIV-1 Nef has been demonstrated to be integral for viral persistence, infectivity, and the acceleration of disease pathogenesis (AIDS) in humans. Nef has also been detected in the plasma of HIV-infected individuals and is released from infected cells. The form in which Nef is released from infected cells is unknown. However, Nef is a myristoylated protein and has been shown to interact with the intracellular vesicular trafficking network. Here we show that Nef is released in CD45-containing microvesicles. This microvesicular Nef (mvNef) is detected in the plasma of HIV-infected individuals at relatively high concentrations (10 ng/ml). It is also present in tissue culture supernatants of Jurkat cells infected with HIV(MN). Interestingly, plasma mvNef levels in HIV(+) patients did not significantly correlate with viral load or CD4 count. Microvesicular Nef levels persisted in the plasma of HIV-infected individuals despite the use of antiretroviral therapy, even in individuals with undetectable viral loads. Using cell lines, we found Nef microvesicles induce apoptosis in Jurkat T-lymphocytes but had no observed effect on the U937 monocytic cell line. Given the large amount of mvNef present in the plasma of HIV-infected individuals, the apoptotic effect of mvNef on T cells, and the observed functions of extracellular soluble Nef in vitro, it seems likely that in vivo mvNef may play a significant role in the pathogenesis of AIDS.
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Affiliation(s)
| | | | - M. Khan
- Morehouse School of Medicine, Atlanta, Georgia
| | - M. Lang
- Morehouse School of Medicine, Atlanta, Georgia
| | - M.B. Huang
- Morehouse School of Medicine, Atlanta, Georgia
| | - V.C. Bond
- Morehouse School of Medicine, Atlanta, Georgia
| | - M.D. Powell
- Morehouse School of Medicine, Atlanta, Georgia
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22
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Segura MM, Kamen AA, Garnier A. Overview of current scalable methods for purification of viral vectors. Methods Mol Biol 2011; 737:89-116. [PMID: 21590394 DOI: 10.1007/978-1-61779-095-9_4] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
As a result of the growing interest in the use of viruses for gene therapy and vaccines, many virus-based products are being developed. The manufacturing of viruses poses new challenges for process developers and regulating authorities that need to be addressed to ensure quality, efficacy, and safety of the final product. The design of suitable purification strategies will depend on a multitude of variables including the vector production system and the nature of the virus. In this chapter, we provide an overview of the most commonly used purification methods for viral gene therapy vectors. Current chromatography options available for large-scale purification of γ-retrovirus, lentivirus, adenovirus, adeno-associated virus, herpes simplex virus, baculovirus, and poxvirus vectors are presented.
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Affiliation(s)
- María Mercedes Segura
- Department of Biochemistry and Molecular Biology, Center of Animal Biotechnology and Gene Therapy (CBATEG), Universitat Autònoma de Barcelona, Barcelona, Spain.
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23
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Stephenson ST, Bostik P, Song B, Rajan D, Bhimani S, Rehulka P, Mayne AE, Ansari AA. Distinct host cell proteins incorporated by SIV replicating in CD4+ T cells from natural disease resistant versus non-natural disease susceptible hosts. Retrovirology 2010; 7:107. [PMID: 21162735 PMCID: PMC3012658 DOI: 10.1186/1742-4690-7-107] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Accepted: 12/16/2010] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Enveloped viruses including the simian immunodeficiency virus (SIV) replicating within host cells acquire host proteins upon egress from the host cells. A number of studies have catalogued such host proteins, and a few have documented the potential positive and negative biological functions of such host proteins. The studies conducted herein utilized proteomic analysis to identify differences in the spectrum of host proteins acquired by a single source of SIV replicating within CD4+ T cells from disease resistant sooty mangabeys and disease susceptible rhesus macaques. RESULTS While a total of 202 host derived proteins were present in viral preparations from CD4+ T cells from both species, there were 4 host-derived proteins that consistently and uniquely associated with SIV replicating within CD4+ T cells from rhesus macaques but not sooty mangabeys; and, similarly, 28 host-derived proteins that uniquely associated with SIV replicating within CD4+ T cells from sooty mangabeys, but not rhesus macaques. Of interest was the finding that of the 4 proteins uniquely present in SIV preparations from rhesus macaques was a 26 S protease subunit 7 (MSS1) that was shown to enhance HIV-1 'tat' mediated transactivation. Among the 28 proteins found in SIV preparations from sooty mangabeys included several molecules associated with immune function such as CD2, CD3ε, TLR4, TLR9 and TNFR and a bioactive form of IL-13. CONCLUSIONS The finding of 4 host proteins that are uniquely associated with SIV replicating within CD4+ T cells from disease susceptible rhesus macaques and 28 host proteins that are uniquely associated with SIV replicating within CD4+ T cells from disease resistant sooty mangabeys provide the foundation for determining the potential role of each of these unique host-derived proteins in contributing to the polarized clinical outcome in these 2 species of nonhuman primates.
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Affiliation(s)
- Susan T Stephenson
- Department of Pathology & Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
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24
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HIV-1 and microvesicles from T cells share a common glycome, arguing for a common origin. Nat Chem Biol 2009; 5:244-50. [PMID: 19234452 PMCID: PMC2713040 DOI: 10.1038/nchembio.151] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Accepted: 02/03/2009] [Indexed: 01/17/2023]
Abstract
HIV-1 is a master at deceiving the immune system, usurping host biosynthetic machinery. Although HIV-1 is coated with host-derived glycoproteins only glycosylation of viral gp120 has been described. Herein we utilize lectin microarray technology to analyze the glycome of intact HIV-1 virions. We show that the glycan coat of human T-cell line-derived HIV-1 matches that of native immunomodulatory microvesicles. The carbohydrate composition of both virus and microvesicles is cell-line dependent, suggesting a mechanism to rapidly camouflage the virus within the host. In addition, binding of both virus and microvesicles to antiviral lectins is enriched over the host cell, raising concern about targeting these glycans for therapeutics. This work also sheds light on the binding of HIV-1 to galectin-1, an important human immune lectin. Overall, our work strongly supports the theory that HIV-1 co-opts the exocytic pathway of microvesicles, potentially explaining why eliciting a protective antiviral immune response is difficult.
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25
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Buffa V, Stieh D, Mamhood N, Hu Q, Fletcher P, Shattock RJ. Cyanovirin-N potently inhibits human immunodeficiency virus type 1 infection in cellular and cervical explant models. J Gen Virol 2009; 90:234-43. [PMID: 19088294 DOI: 10.1099/vir.0.004358-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In the absence of a protective vaccine against human immunodeficiency virus (HIV), there is an urgent need for the development of effective topical microbicides to prevent HIV infection. Candidate vaginal microbicides should provide protection against circulating strains, be cheap, stable on storage, safe and easy to use. Here we describe a detailed study of the safety and efficacy of Cyanovirin-N (CV-N) in vitro, and in an ex vivo model of female genital tissue explants. CV-N demonstrated potent activity in the low nanomolar range against laboratory and primary isolates. Activity was related to the affinity of CV-N for binding to whole virions as determined by acoustic resonance. Potent activity was also observed against cell-associated HIV-1, although slightly reduced. CV-N activity in the presence of whole semen was reduced by 7-10-fold, although it remained in the low nanomolar range and was minimally modified by the presence of Candida albicans. Furthermore, CV-N potently inhibited infection of ectocervical explants and virus dissemination by tissue-emigrating cells. In peripheral blood mononuclear cell (PBMC) assays, CV-N was shown to have some mitogenic activity following 3 days exposure to compound, and this was associated with a modest increase in expression of gamma interferon, stromal cell-derived factor 1beta and interleukin 4. However, 2 h exposure to CV-N had no effect on cytokine expression in PBMC or tissue explant culture over a 24 h period, suggesting that the potential for inflammation is low. Data presented here indicate that targeting HIV envelope glycoproteins may provide an effective strategy to prevent HIV-1 infection mediated by either cell-free virus or infected cells.
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Affiliation(s)
- Viviana Buffa
- Centre for Infection, Department of Cellular and Molecular Medicine, St George's Hospital, University of London, London SW17 0RE, UK
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26
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Abstract
VP40, the major matrix protein of Marburg virus, is the main driving force for viral budding. Additionally, cellular factors are likely to play an important role in the release of progeny virus. In the present study, we characterized the influence of the vacuolar protein sorting (VPS) pathway on the release of virus-like particles (VLPs), which are induced by Marburg virus VP40. In the supernatants of HEK 293 cells expressing VP40, different populations of VLPs with either a vesicular or a filamentous morphology were detected. While the filaments were almost completely composed of VP40, the vesicular particles additionally contained considerable amounts of cellular proteins. In contrast to that in the vesicles, the VP40 in the filaments was regularly organized, probably inducing the elimination of cellular proteins from the released VLPs. Vesicular particles were observed in the supernatants of cells even in the absence of VP40. Mutation of the late-domain motif in VP40 resulted in reduced release of filamentous particles, and likewise, inhibition of the VPS pathway by expression of a dominant-negative (DN) form of VPS4 inhibited the release of filamentous particles. In contrast, the release of vesicular particles did not respond significantly to the expression of DN VPS4. Like the budding of VLPs, the budding of Marburg virus particles was partially inhibited by the expression of DN VPS4. While the release of VLPs from VP40-expressing cells is a valuable tool with which to investigate the budding of Marburg virus particles, it is important to separate filamentous VLPs from vesicular particles, which contain many cellular proteins and use a different budding mechanism.
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27
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Retroviruses human immunodeficiency virus and murine leukemia virus are enriched in phosphoinositides. J Virol 2008; 82:11228-38. [PMID: 18799574 DOI: 10.1128/jvi.00981-08] [Citation(s) in RCA: 221] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Retroviruses acquire a lipid envelope during budding from the membrane of their hosts. Therefore, the composition of this envelope can provide important information about the budding process and its location. Here, we present mass spectrometry analysis of the lipid content of human immunodeficiency virus type 1 (HIV-1) and murine leukemia virus (MLV). The results of this comprehensive survey found that the overall lipid content of these viruses mostly matched that of the plasma membrane, which was considerably different from the total lipid content of the cells. However, several lipids are enriched in comparison to the composition of the plasma membrane: (i) cholesterol, ceramide, and GM3; and (ii) phosphoinositides, phosphorylated derivatives of phosphatidylinositol. Interestingly, microvesicles, which are similar in size to viruses and are also released from the cell periphery, lack phosphoinositides, suggesting a different budding mechanism/location for these particles than for retroviruses. One phosphoinositide, phosphatidylinositol 4,5-bisphosphate [PI(4,5)P(2)], has been implicated in membrane binding by HIV Gag. Consistent with this observation, we found that PI(4,5)P(2) was enriched in HIV-1 and that depleting this molecule in cells reduced HIV-1 budding. Analysis of mutant virions mapped the enrichment of PI(4,5)P(2) to the matrix domain of HIV Gag. Overall, these results suggest that HIV-1 and other retroviruses bud from cholesterol-rich regions of the plasma membrane and exploit matrix/PI(4,5)P(2) interactions for particle release from cells.
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28
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Abstract
It has been known for some time that HIV-1 virions contain cellular proteins in addition to proteins encoded by the viral genome. Recent studies have vastly increased the number of host proteins detected in HIV-1. This review summarises the current findings on several cellular proteins present in these virions, including some functional studies on their potential roles in the viral replication cycle and pathogenesis. Because retroviruses require extensive assistance from host proteins and pathways, the data from biochemical characterisations of HIV-1 serve as an important starting point for understanding the role of cellular proteins that act in or influence the biology of HIV-1. Additionally, a better understanding of the interactions between cellular proteins and viral components might provide more targets for anti-HIV therapeutic intervention and provide for a better understanding of how HIV-1 alters the immune system. The extensive study of HIV-1 has already brought new insights to the fields of immunology and vaccine science. In the same way, knowledge of viral--cellular protein interactions might assist our understanding of important cellular pathways.
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Affiliation(s)
- David E Ott
- AIDS Vaccine Program, SAIC-Frederick, Inc., National Cancer Institute at Frederick, Frederick, MD 21702-1201, USA.
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29
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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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Coren LV, Shatzer T, Ott DE. CD45 immunoaffinity depletion of vesicles from Jurkat T cells demonstrates that exosomes contain CD45: no evidence for a distinct exosome/HIV-1 budding pathway. Retrovirology 2008; 5:64. [PMID: 18631400 PMCID: PMC2490705 DOI: 10.1186/1742-4690-5-64] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Accepted: 07/16/2008] [Indexed: 11/10/2022] Open
Abstract
The presence of relatively high levels of cellular protein contamination in density-purified virion preparations is a confounding factor in biochemical analyses of HIV and SIV produced from hematopoietic cells. A major source of this contamination is from vesicles, either microvesicles or exosomes, that have similar physical properties as virions. Thus, these particles can not be removed by size or density fractionation. Although virions and vesicles have similar cellular protein compositions, CD45 is excluded from HIV-1 yet is present in vesicles produced from hematopoietic cells. By exploiting this finding, we have developed a CD45 immunoaffinity depletion procedure that removes vesicles from HIV-1 preparations. While this approach has been successfully applied to virion preparations from several different cell types, some groups have concluded that "exosomes" from certain T cell lines, specifically Jurkat, do not contain CD45. If this interpretation is correct, then these vesicles could not be removed by CD45 immunoaffinity depletion. Here we show that dense vesicles produced by Jurkat and SupT1/CCR5 cells contain CD45 and are efficiently removed from preparations by CD45-immunoaffinity depletion. Also, contaminating cellular proteins were removed from virion preparations produced by these lines. Previously, the absence of CD45 from both "exosomes" and virions has been used to support the so called Trojan exosome hypothesis, namely that HIV-1 is simply an exosome containing viral material. The presence of CD45 on vesicles, including exosomes, and its absence on virions argues against a specialized budding pathway that is shared by both exosomes and HIV-1.
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Affiliation(s)
- Lori V Coren
- AIDS and Cancer Virus Program, SAIC-Frederick, Inc,, National Cancer Institute at Frederick, Frederick, Maryland 21702-1201, USA.
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Harada S, Monde K, Tanaka Y, Kimura T, Maeda Y, Yusa K. Neutralizing antibodies decrease the envelope fluidity of HIV-1. Virology 2008; 370:142-50. [PMID: 17900650 DOI: 10.1016/j.virol.2007.08.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2007] [Revised: 08/06/2007] [Accepted: 08/17/2007] [Indexed: 11/28/2022]
Abstract
For successful penetration of HIV-1, the formation of a fusion pore may be required in order to accumulate critical numbers of fusion-activated gp41 with the help of fluidization of the plasma membrane and viral envelope. An increase in temperature to 40 degrees C after viral adsorption at 25 degrees C enhanced the infectivity by 1.4-fold. The enhanced infectivity was inhibited by an anti-CXCR4 peptide, T140, and anti-V3 monoclonal antibodies (0.5beta and 694/98-D) by post-attachment neutralization, but not by non-neutralizing antibodies (670-30D and 246-D) specific for the C5 of gp120 and cluster I of gp41, respectively. Anti-HLA-II and an anti-HTLV-I gp46 antibody, LAT27, neutralized the molecule-carrying HIV-1(C-2(MT-2)). The anti-V3 antibodies suppressed the fluidity of the HIV-1(C-2) envelope, whereas the non-neutralizing antibodies did not. The anti-HLA-II antibody decreased the envelope fluidity of HIV-1(C-2(MT-2)), but not that of HIV-1(C-2). Therefore, fluidity suppression by these antibodies represents an important neutralization mechanism, in addition to inhibition of viral attachment.
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Affiliation(s)
- Shinji Harada
- Department of Medical Virology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
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33
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Ott DE. Purification of HIV-1 virions by subtilisin digestion or CD45 immunoaffinity depletion for biochemical studies. Methods Mol Biol 2008; 485:15-25. [PMID: 19020815 DOI: 10.1007/978-1-59745-170-3_2] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The presence of cellular proteins outside and inside retroviruses can indicate the roles they play in viral biology. However, experiments examining retroviruses can be complicated by the contamination of even highly purified virion preparations with nonviral particles (either microvesicles or exosomes). Two useful methods have been developed that can remove contaminating particles from virus stocks to produce highly pure virus preparations. One approach, the subtilisin digestion procedure, enzymatically removes the proteins outside the virions. While this method is well suited for the analysis of the interior proteins in the virions, it removes the extracellular domains of the integral membrane proteins on the virion. To preserve the proteins on the exterior of the virion for biochemical studies, a CD45 immunoaffinity depletion procedure that removes vesicles by capture with antibody-linked microbeads is employed. These methods allow for the isolation of highly purified virion preparations that are suitable for a wide variety of experiments, including the biochemical characterization of cellular proteins both on and in HIV virions, examination of virion/cell interactions, and imaging of virions.
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Affiliation(s)
- David E Ott
- AIDS Vaccine Program, SAIC-Frederick, Inc., NCI-Frederick, Frederick, MD, USA
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Fang Y, Wu N, Gan X, Yan W, Morrell JC, Gould SJ. Higher-order oligomerization targets plasma membrane proteins and HIV gag to exosomes. PLoS Biol 2007; 5:e158. [PMID: 17550307 PMCID: PMC1885833 DOI: 10.1371/journal.pbio.0050158] [Citation(s) in RCA: 287] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Accepted: 04/10/2007] [Indexed: 11/19/2022] Open
Abstract
Exosomes are secreted organelles that have the same topology as the cell and bud outward (outward is defined as away from the cytoplasm) from endosome membranes or endosome-like domains of plasma membrane. Here we describe an exosomal protein-sorting pathway in Jurkat T cells that selects cargo proteins on the basis of both higher-order oligomerization (the oligomerization of oligomers) and plasma membrane association, acts on proteins seemingly without regard to their function, sequence, topology, or mechanism of membrane association, and appears to operate independently of class E vacuolar protein-sorting (VPS) function. We also show that higher-order oligomerization is sufficient to target plasma membrane proteins to HIV virus-like particles, that diverse Gag proteins possess exosomal-sorting information, and that higher-order oligomerization is a primary determinant of HIV Gag budding/exosomal sorting. In addition, we provide evidence that both the HIV late domain and class E VPS function promote HIV budding by unexpectedly complex, seemingly indirect mechanisms. These results support the hypothesis that HIV and other retroviruses are generated by a normal, nonviral pathway of exosome biogenesis.
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Affiliation(s)
- Yi Fang
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Ning Wu
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Xin Gan
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Wanhua Yan
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - James C Morrell
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Stephen J Gould
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * To whom correspondence should be addressed. E-mail:
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35
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Modulation of human immunodeficiency virus type 1 infectivity through incorporation of tetraspanin proteins. J Virol 2007; 82:1021-33. [PMID: 17989173 DOI: 10.1128/jvi.01044-07] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Accumulating evidence indicates that human immunodeficiency virus type 1 (HIV-1) acquires various cellular membrane proteins in the lipid bilayer of the viral envelope membrane. Although some virion-incorporated cellular membrane proteins are known to potently affect HIV-1 infectivity, the virological functions of most virion-incorporated membrane proteins remain unclear. Among these host proteins, we found that CD63 was eliminated from the plasma membranes of HIV-1-producing T cells after activation, followed by a decrease in the amount of virion-incorporated CD63, and in contrast, an increase in the infectivity of the released virions. On the other hand, we found that CD63 at the cell surface was preferentially embedded on the membrane of released virions in an HIV-1 envelope protein (Env)-independent manner and that virion-incorporated CD63 had the potential to inhibit HIV-1 Env-mediated infection in a strain-specific manner at the postattachment entry step(s). In addition, these behaviors were commonly observed in other tetraspanin proteins, such as CD9, CD81, CD82, and CD231. However, L6 protein, whose topology is similar to that of tetraspanins but which does not belong to the tetraspanin superfamily, did not have the potential to prevent HIV-1 infection, despite its successful incorporation into the released particles. Taken together, these results suggest that tetraspanin proteins have the unique potential to modulate HIV-1 infectivity through incorporation into released HIV-1 particles, and our findings may provide a clue to undiscovered aspects of HIV-1 entry.
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Quantitation of HLA proteins incorporated by human immunodeficiency virus type 1 and assessment of neutralizing activity of anti-HLA antibodies. J Virol 2007; 82:428-34. [PMID: 17942547 DOI: 10.1128/jvi.00638-07] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human anti-human leukocyte antigen (HLA) antibodies were assessed for neutralizing activity against human immunodeficiency virus type 1 (HIV-1) carrying HLA alleles with matching specificity. Multiparous women carrying anti-HLA antibodies were identified. Plasma samples from those women were confirmed as having antibodies that specifically bound to HLA proteins expressed on the peripheral blood mononuclear cells (PBMCs) of their husbands. A primary HIV-1 isolate was cultured in the husband's PBMCs so that the virus carried matching HLA alleles. To determine the HIV-1-neutralizing activity of anti-HLA antibodies, the infectivity of the virus for GHOST cells (which express green fluorescent protein after HIV infection) was investigated in the presence of a plasma sample positive for the respective anti-HLA antibody. A neutralization assay was also performed using purified immunoglobulin G (IgG) from two plasma samples, and two plasma samples were investigated in the presence of complement. The prerequisite for anti-HLA antibody-mediated neutralization is incorporation of HLA proteins by HIV-1. Therefore, the extent of incorporation of HLA proteins by the primary HIV-1 isolate was estimated. The ratios of HLA class I protein to HIV-1 capsid (p24) protein cultured in the PBMCs of two healthy individuals were 0.017 and 0.054. These ratios suggested that the HIV-1 strain used in the assay incorporated more HLA proteins than gp160 trimers. Anti-HLA antibody-positive plasma was found to contain antibodies that specifically reacted to HIV-1 carrying cognate HLA alleles. However, incubation of HIV-1 with anti-HLA antibody- positive plasma or purified IgG did not show a reduction in viral infectivity. HIV-1-neutralizing activity was also not detected in the presence of complement. This study shows that HIV-1 primary isolates cultured in PBMCs contain significant amounts of HLA proteins. However, the binding of antibodies to those HLA proteins does not mediate a reduction in viral infectivity.
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Bennett A, Liu J, Van Ryk D, Bliss D, Arthos J, Henderson RM, Subramaniam S. Cryoelectron Tomographic Analysis of an HIV-neutralizing Protein and Its Complex with Native Viral gp120. J Biol Chem 2007; 282:27754-9. [PMID: 17599917 DOI: 10.1074/jbc.m702025200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Identifying structural determinants of human immunodeficiency virus (HIV) neutralization is an important component of rational drug and vaccine design. We used cryoelectron tomography and atomic force microscopy to characterize the structure of an extremely potent HIV-neutralizing protein, D1D2-Ig alpha tp (abbreviated as D1D2-IgP), a polyvalent antibody construct that presents dodecameric CD4 in place of the Fab regions. We show that D1D2-IgP has a novel structure, displaying greater flexibility of its antibody arms than the closely related IgM. Using simian immunodeficiency virus in complex with D1D2-IgP, we present unequivocal evidence that D1D2-IgP can cross-link surface spikes on the same virus and on neighboring viruses. The observed binding to the viral envelope spikes is the result of specific CD4-gp120 interaction, because binding was not observed with MICA-IgP, a construct that is identical to D1D2-IgP except that major histocompatibility complex Class I-related Chain A (MICA) replaces the CD4 moiety. CD4-mediated binding was also associated with a significantly elevated proportion of ruptured viruses. The ratio of inactivated to CD4-liganded gp120-gp41 spikes can be much greater than 1:1, because all gp120-gp41 spikes on the closely apposed surfaces of cross-linked viruses should be incapable of accessing the target cell surface and mediating entry, as a result of inter-virus spike cross-linking. These results implicate flexibility rather than steric bulk or polyvalence per se as a structural explanation for the extreme potency of D1D2-IgP and thus suggest polyvalence presented on a flexible scaffold as a key design criterion for small molecule HIV entry inhibitors.
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Affiliation(s)
- Adam Bennett
- Laboratory of Cell Biology, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA
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38
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Sougrat R, Bartesaghi A, Lifson JD, Bennett AE, Bess JW, Zabransky DJ, Subramaniam S. Electron tomography of the contact between T cells and SIV/HIV-1: implications for viral entry. PLoS Pathog 2007; 3:e63. [PMID: 17480119 PMCID: PMC1864992 DOI: 10.1371/journal.ppat.0030063] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Accepted: 03/19/2007] [Indexed: 12/03/2022] Open
Abstract
The envelope glycoproteins of primate lentiviruses, including human and simian immunodeficiency viruses (HIV and SIV), are heterodimers of a transmembrane glycoprotein (usually gp41), and a surface glycoprotein (gp120), which binds CD4 on target cells to initiate viral entry. We have used electron tomography to determine the three-dimensional architectures of purified SIV virions in isolation and in contact with CD4+ target cells. The trimeric viral envelope glycoprotein surface spikes are heterogeneous in appearance and typically ∼120 Å long and ∼120 Å wide at the distal end. Docking of SIV or HIV-1 on the T cell surface occurs via a neck-shaped contact region that is ∼400 Å wide and consistently consists of a closely spaced cluster of five to seven rod-shaped features, each ∼100 Å long and ∼100 Å wide. This distinctive structure is not observed when viruses are incubated with T lymphocytes in the presence of anti-CD4 antibodies, the CCR5 antagonist TAK779, or the peptide entry inhibitor SIVmac251 C34. For virions bound to cells, few trimers were observed away from this cluster at the virion–cell interface, even in cases where virus preparations showing as many as 70 envelope glycoprotein trimers per virus particle were used. This contact zone, which we term the “entry claw”, provides a spatial context to understand the molecular mechanisms of viral entry. Determination of the molecular composition and structure of the entry claw may facilitate the identification of improved drugs for the inhibition of HIV-1 entry. Retroviruses such as simian immunodeficiency virus and HIV-1 enter target cells by exploiting the interaction between their surface glycoproteins and cell surface receptors. Knowledge of the structures of these glycoproteins and of the molecular details of their interaction with cell surface receptors is of fundamental interest in understanding viral entry mechanisms. Electron tomo-graphy is a powerful approach to determining the three-dimensional structures of large and heterogeneous sub-cellular assemblies such as virus–cell contact regions that cannot easily be analyzed by high-resolution structural methods such as X-ray crystallography. Here, we have used electron tomographic approaches to show that SIV and HIV-1 viruses make contact with T cells via a unique structure that we term the viral “entry claw”, which is typically composed of about six clustered rods of density that span the contact region. Investigation of the structure of the entry claw and the factors that promote its formation could lead to new insights into the design of more effective drugs to inhibit HIV entry.
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Affiliation(s)
- Rachid Sougrat
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Alberto Bartesaghi
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jeffrey D Lifson
- AIDS Vaccine Program, SAIC-Frederick, National Cancer Institue, Frederick, Maryland, United States of America
| | - Adam E Bennett
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Julian W Bess
- AIDS Vaccine Program, SAIC-Frederick, National Cancer Institue, Frederick, Maryland, United States of America
| | - Daniel J Zabransky
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sriram Subramaniam
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- * To whom correspondence should be addressed. E-mail:
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Segura MDLM, Kamen A, Lavoie MC, Garnier A. Exploiting heparin-binding properties of MoMLV-based retroviral vectors for affinity chromatography. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 846:124-31. [PMID: 16971193 DOI: 10.1016/j.jchromb.2006.08.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Revised: 08/10/2006] [Accepted: 08/21/2006] [Indexed: 12/22/2022]
Abstract
Chromatography is deemed the most promising technology for large-scale purification of viral vectors. The authors have previously shown that heparin affinity chromatography could be successfully employed for the purification of VSV-G pseudotyped Moloney murine leukemia virus (MoMLV)-derived vectors giving excellent results in terms of recovery of active particles, reproducibility and selectivity. In this study, the authors examined whether the ability of retrovirus particles to specifically bind to heparin ligands is restricted to VSV-G pseudotypes produced by 293-based packaging cells. It is shown that VSV-G deficient retrovirus particles are captured by a heparin chromatography column as efficiently as VSV-G containing particles. Most strikingly, RD114 pseudotyped retrovirus particles derived from a HT1080-based cell line were found to bind heparin with the same affinity as 293-derived VSV-G pseudotypes. RD114 pseudotyped retrovirus particles were successfully isolated using heparin affinity chromatography obtaining good recoveries of functional particles (43%). These results indicate that heparin affinity chromatography can be extended to the purification of retroviral vectors produced by different packaging cell lines independently of the Env-protein used for pseudotyping.
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Affiliation(s)
- María de las Mercedes Segura
- Department of Chemical Engineering and Centre de Recherche sur la Fonction, la Structure et l'Ingénierie des Protéines, Université Laval, Que., Canada G1K 7P4
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Harman AN, Wilkinson J, Bye CR, Bosnjak L, Stern JL, Nicholle M, Lai J, Cunningham AL. HIV induces maturation of monocyte-derived dendritic cells and Langerhans cells. THE JOURNAL OF IMMUNOLOGY 2007; 177:7103-13. [PMID: 17082627 DOI: 10.4049/jimmunol.177.10.7103] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In HIV infection, dendritic cells (DCs) may play multiple roles, probably including initial HIV uptake in the anogenital mucosa, transport to lymph nodes, and subsequent transfer to T cells. The effects of HIV-1 on DC maturation are controversial, with several recent conflicting reports in the literature. In this study, microarray studies, confirmed by real-time PCR, demonstrated that the genes encoding DC surface maturation markers were among the most differentially expressed in monocyte-derived dendritic cells (MDDCs), derived from human blood, treated with live or aldrithriol-2-inactivated HIV-1(BaL). These effects translated to enhanced cell surface expression of these proteins but differential expression of maturation markers was only partial compared with the effects of a conventional potent maturation stimulus. Such partially mature MDDCs can be converted to fully mature cells by this same potent stimulus. Furthermore, live HIV-1 stimulated greater changes in maturation marker surface expression than aldrithriol-2-inactivated HIV-1 and this enhanced stimulation by live HIV-1 was mediated via CCR5, thus suggesting both viral replication-dependent and -independent mechanisms. These partially mature MDDCs demonstrated enhanced CCR7-mediated migration and are also able to stimulate interacting T cells in a MLR, suggesting DCs harboring HIV-1 might prepare CD4 lymphocytes for transfer of HIV-1. Increased maturation marker surface expression was also demonstrated in native DCs, ex vivo Langerhans cells derived from human skin. Thus, HIV initiates maturation of DCs which could facilitate subsequent enhanced transfer to T cells.
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Affiliation(s)
- Andrew N Harman
- Centre for Virus Research, Westmead Millennium Institute, Sydney, Australia
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41
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Rodrigues T, Carrondo MJT, Alves PM, Cruz PE. Purification of retroviral vectors for clinical application: Biological implications and technological challenges. J Biotechnol 2007; 127:520-41. [PMID: 16950534 DOI: 10.1016/j.jbiotec.2006.07.028] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2006] [Revised: 07/12/2006] [Accepted: 07/25/2006] [Indexed: 11/16/2022]
Abstract
For centuries mankind led a difficult battle against viruses, the smallest infectious agents at the surface of the earth. Nowadays it is possible to use viruses for our benefit, both at a prophylactic level in the production of vaccines and at a therapeutic level in the promising field of gene therapy. Retroviruses were discovered at the end of the 19th century and constitute one of the most effective entities for gene transfer and insertion into the genome of mammalian cells. This attractive feature has intensified research in retroviral vectors development and production over the past years, mainly due to the expectations raised by the concept of gene therapy. The demand for high quality retroviral vectors that meet standard requisites from the regulatory agencies (FDA and EMEA) is therefore increasing, as the technology has moved into clinical trials. The development of safer producer cell lines that can be used in large-scale production will result in the production of large quantities of retroviral stocks. Cost-efficient and scalable purification processes are essential for production of injectable-grade preparations to achieve final implementation of these vectors as therapeutics. Several preparative purification steps already established for proteins can certainly be applied to retroviral vectors, in particular membrane filtration and chromatographic methods. Nevertheless, the special properties of these complex products require technological improvement of the existing purification steps and/or development of particular purification steps to increase productivity and throughput, while maintaining biological activity of the final product. This review focuses on downstream process development in relation to the retroviral vectors characteristics and quality assessment of retroviral stocks for intended use in gene therapy.
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Affiliation(s)
- Teresa Rodrigues
- IBET/ITQB, Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal
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42
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Xu H, Chertova E, Chen J, Ott DE, Roser JD, Hu WS, Pathak VK. Stoichiometry of the antiviral protein APOBEC3G in HIV-1 virions. Virology 2006; 360:247-56. [PMID: 17126871 DOI: 10.1016/j.virol.2006.10.036] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2006] [Revised: 05/01/2006] [Accepted: 10/17/2006] [Indexed: 10/23/2022]
Abstract
A host cytidine deaminase, APOBEC3G (A3G), inhibits replication of human immunodeficiency virus type 1 (HIV-1) by incorporating into virions in the absence of the virally encoded Vif protein (Deltavif virions), at least in part by causing G-to-A hypermutation. To gain insight into the antiretroviral function of A3G, we determined the quantities of A3G molecules that are incorporated in Deltavif virions. We combined three experimental approaches-reversed-phase high-pressure liquid chromatography (HPLC), scintillation proximity assay (SPA), and quantitative immunoblotting-to determine the molar ratio of A3G to HIV-1 capsid protein in Deltavif virions. Our studies revealed that the amount of the A3G incorporated into Deltavif virions was proportional to the level of its expression in the viral producing cells, and the ratio of the A3G to Gag in the Deltavif virions produced from activated human peripheral blood mononuclear cells (PBMC) was approximately 1:439. Based on previous estimates of the stoichiometry of HIV-1 Gag in virions (1400-5000), we conclude that approximately 7 (+/-4) molecules of A3G are incorporated into Deltavif virions produced from human PBMCs. These results indicate that virion incorporation of only a few molecules of A3G is sufficient to inhibit HIV-1 replication.
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Affiliation(s)
- Hongzhan Xu
- Viral Mutation Section, HIV Drug Resistance Program, Center for Cancer Research, National Cancer Institute-Frederick, P. O. Box B, Bldg. 535, Rm. 334, Frederick, MD 21702, USA
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Melar M, Ott DE, Hope TJ. Physiological levels of virion-associated human immunodeficiency virus type 1 envelope induce coreceptor-dependent calcium flux. J Virol 2006; 81:1773-85. [PMID: 17121788 PMCID: PMC1797554 DOI: 10.1128/jvi.01316-06] [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: 01/05/2023] Open
Abstract
Human immunodeficiency virus (HIV) entry into target cells requires the engagement of receptor and coreceptor by envelope glycoprotein (Env). Coreceptors CCR5 and CXCR4 are chemokine receptors that generate signals manifested as calcium fluxes in response to binding of the appropriate ligand. It has previously been shown that engagement of the coreceptors by HIV Env can also generate Ca(2+) fluxing. Since the sensitivity and therefore the physiological consequence of signaling activation in target cells is not well understood, we addressed it by using a microscopy-based approach to measure Ca(2+) levels in individual CD4(+) T cells in response to low Env concentrations. Monomeric Env subunit gp120 and virion-bound Env were able to activate a signaling cascade that is qualitatively different from the one induced by chemokines. Env-mediated Ca(2+) fluxing was coreceptor mediated, coreceptor specific, and CD4 dependent. Comparison of the observed virion-mediated Ca(2+) fluxing with the exact number of viral particles revealed that the viral threshold necessary for coreceptor activation of signaling in CD4(+) T cells was quite low, as few as two virions. These results indicate that the physiological levels of virion binding can activate signaling in CD4(+) T cells in vivo and therefore might contribute to HIV-induced pathogenesis.
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Affiliation(s)
- Marta Melar
- Northwestern University, Department of Cell and Molecular Biology, Feinberg School of Medicine, Ward 8-140, 303 E. Chicago Ave., Chicago, IL 60611, USA
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Pichlmair A, Diebold SS, Gschmeissner S, Takeuchi Y, Ikeda Y, Collins MK, Reis e Sousa C. Tubulovesicular structures within vesicular stomatitis virus G protein-pseudotyped lentiviral vector preparations carry DNA and stimulate antiviral responses via Toll-like receptor 9. J Virol 2006; 81:539-47. [PMID: 17079284 PMCID: PMC1797478 DOI: 10.1128/jvi.01818-06] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Recombinant lentiviral vectors (LVs) are commonly used as research tools and are being tested in the clinic as delivery agents for gene therapy. Here, we show that Vesicular stomatitis virus G protein (VSV-G)-pseudotyped LV preparations produced by transient transfection are heavily contaminated with tubulovesicular structures (TVS) of cellular origin, which carry nucleic acids, including the DNA plasmids originally used for LV generation. The DNA carried by TVS can act as a stimulus for innate antiviral responses, triggering Toll-like receptor 9 and inducing alpha/beta interferon production by plasmacytoid dendritic cells (pDC). Removal of TVS markedly reduces the ability of VSV-G-pseudotyped LV preparations to activate pDC. Conversely, virus-free TVS are sufficient to stimulate pDC and act as potent adjuvants in vivo, eliciting T- and B-cell responses to coadministered proteins. These results highlight the role of by-products of virus production in determining the immunostimulatory properties of recombinant virus preparations and suggest possible strategies for diminishing responses to LVs in gene therapy and in research use.
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Affiliation(s)
- Andreas Pichlmair
- Immunobiology Laboratory, Cancer Research UK, London Research Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London WC2A 3PX, United Kingdom
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Chertova E, Chertov O, Coren LV, Roser JD, Trubey CM, Bess JW, Sowder RC, Barsov E, Hood BL, Fisher RJ, Nagashima K, Conrads TP, Veenstra TD, Lifson JD, Ott DE. Proteomic and biochemical analysis of purified human immunodeficiency virus type 1 produced from infected monocyte-derived macrophages. J Virol 2006; 80:9039-52. [PMID: 16940516 PMCID: PMC1563931 DOI: 10.1128/jvi.01013-06] [Citation(s) in RCA: 354] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) infects CD4(+) T lymphocytes and monocytes/macrophages, incorporating host proteins in the process of assembly and budding. Analysis of the host cell proteins incorporated into virions can provide insights into viral biology. We characterized proteins in highly purified HIV-1 virions produced from human monocyte-derived macrophages (MDM), within which virus buds predominantly into intracytoplasmic vesicles, in contrast to the plasmalemmal budding of HIV-1 typically seen with infected T cells. Liquid chromatography-linked tandem mass spectrometry of highly purified virions identified many cellular proteins, including 33 previously described proteins in HIV-1 preparations from other cell types. Proteins involved in many different cellular structures and functions were present, including those from the cytoskeleton, adhesion, signaling, intracellular trafficking, chaperone, metabolic, ubiquitin/proteasomal, and immune response systems. We also identified annexins, annexin-binding proteins, Rab proteins, and other proteins involved in membrane organization, vesicular trafficking, and late endosomal function, as well as apolipoprotein E, which participates in cholesterol transport, immunoregulation, and modulation of cell growth and differentiation. Several tetraspanins, markers of the late endosomal compartment, were also identified. MDM-derived HIV contained 26 of 37 proteins previously found in exosomes, consistent with the idea that HIV uses the late endosome/multivesicular body pathway during virion budding from macrophages.
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Affiliation(s)
- Elena Chertova
- AIDS Vaccine Research Program, SAIC-Frederick, Inc., NCI-Frederick, Frederick, MD 21702, USA.
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Booth AM, Fang Y, Fallon JK, Yang JM, Hildreth JEK, Gould SJ. Exosomes and HIV Gag bud from endosome-like domains of the T cell plasma membrane. ACTA ACUST UNITED AC 2006; 172:923-35. [PMID: 16533950 PMCID: PMC2063735 DOI: 10.1083/jcb.200508014] [Citation(s) in RCA: 429] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Exosomes are secreted, single membrane organelles of approximately 100 nm diameter. Their biogenesis is typically thought to occur in a two-step process involving (1) outward vesicle budding at limiting membranes of endosomes (outward = away from the cytoplasm), which generates intralumenal vesicles, followed by (2) endosome-plasma membrane fusion, which releases these internal vesicles into the extracellular milieu as exosomes. In this study, we present evidence that certain cells, including Jurkat T cells, possess discrete domains of plasma membrane that are enriched for exosomal and endosomal proteins, retain the endosomal property of outward vesicle budding, and serve as sites of immediate exosome biogenesis. It has been hypothesized that retroviruses utilize the exosome biogenesis pathway for the formation of infectious particles. In support of this, we find that Jurkat T cells direct the key budding factor of HIV, HIV Gag, to these endosome-like domains of plasma membrane and secrete HIV Gag from the cell in exosomes.
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Affiliation(s)
- Amy M Booth
- Department of Biological Chemistry and 2Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Herrera C, Klasse PJ, Kibler CW, Michael E, Moore JP, Beddows S. Dominant-negative effect of hetero-oligomerization on the function of the human immunodeficiency virus type 1 envelope glycoprotein complex. Virology 2006; 351:121-32. [PMID: 16616288 DOI: 10.1016/j.virol.2006.03.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2006] [Revised: 02/23/2006] [Accepted: 03/03/2006] [Indexed: 11/29/2022]
Abstract
The human immunodeficiency virus type 1 (HIV-1) envelope (Env) glycoprotein forms trimers that mediate interactions with the CD4 receptor and a co-receptor on the target cell surface, thereby triggering viral fusion with the cell membrane. Cleavage of Env into its surface, gp120, and transmembrane, gp41, moieties is necessary for activation of its fusogenicity. Here, we produced pseudoviruses with phenotypically mixed wild-type (Wt) and mutant, cleavage-incompetent Env in order to quantify the effects of incorporating uncleaved Env on virion infectivity, antigenicity and neutralization sensitivity. We modeled the relative infectivity of three such phenotypically mixed viral strains, JR-FL, HXBc2 and a derivative of the latter, 3.2P, as a function of the relative amount of Wt Env. The data were fit very closely (R(2) > 0.99) by models which assumed that only Wt homotrimers were functional, with different approximate thresholds of critical numbers of functional trimers per virion for the three strains. We also produced 3.2P pseudoviruses containing both a cleavage-competent Env that is defective for binding the neutralizing monoclonal antibody (NAb) 2G12, and a cleavage-incompetent Env that binds 2G12. The 2G12 NAb was not able to reduce the infectivity of these pseudoviruses detectably. Their neutralization by the CD4-binding site-directed agents CD4-IgG2 and NAb b12 was also unaffected by 2G12 binding to uncleaved Env. These results further strengthen the conclusion that only homotrimers consisting of cleaved Env are functional. They also imply that the function of a trimer is unaffected sterically by the binding of an antibody to an adjacent trimer.
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Affiliation(s)
- Carolina Herrera
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY 10021, USA
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Segura MDLM, Kamen A, Garnier A. Downstream processing of oncoretroviral and lentiviral gene therapy vectors. Biotechnol Adv 2006; 24:321-37. [PMID: 16448798 DOI: 10.1016/j.biotechadv.2005.12.001] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2005] [Revised: 12/06/2005] [Accepted: 12/06/2005] [Indexed: 11/28/2022]
Abstract
Retroviral vectors from both oncoretroviral and lentiviral origins have a great potential as gene delivery vehicles. A number of research groups have devoted considerable effort to the development of large-scale production strategies for retroviral vectors. However, the manufacturing of clinical-grade vectors for gene therapy, especially for in vivo applications, additionally requires scaleable purification strategies to remove the contaminants present in the harvested supernatants while preserving the functionality of the vectors. In this article, we review recent advances made in the field of downstream processing of retroviral vectors. The methods currently described in the literature for clarification, concentration and purification of retroviral vectors will be presented, with special emphasis on novel chromatography methods that open up the possibility to selectively and efficiently purify retroviruses on a large-scale. Problems associated with stability and quantification of retroviral particles will be outlined and future challenges will be discussed.
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Affiliation(s)
- María de Las Mercedes Segura
- Department of Chemical Engineering, Centre de Recherche sur la fonction, la structure et l'ingénierie des protéines, Université Laval, Québec, Canada G1K 7P4
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Ye Z, Harmison GG, Ragheb JA, Schubert M. Targeted infection of HIV-1 Env expressing cells by HIV(CD4/CXCR4) vectors reveals a potential new rationale for HIV-1 mediated down-modulation of CD4. Retrovirology 2005; 2:80. [PMID: 16371160 PMCID: PMC1352389 DOI: 10.1186/1742-4690-2-80] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2005] [Accepted: 12/21/2005] [Indexed: 12/04/2022] Open
Abstract
Background Efficient targeted gene transfer and cell type specific transgene expression are important for the safe and effective expression of transgenes in vivo. Enveloped viral vectors allow insertion of exogenous membrane proteins into their envelopes, which could potentially aid in the targeted transduction of specific cell types. Our goal was to specifically target cells that express the T cell tropic HIV-1 envelope protein (Env) using the highly specific interaction of Env with its cellular receptor (CD4) inserted into the envelope of an HIV-1-based viral vector. Results To generate HIV-1-based vectors carrying the CD4 molecule in their envelope, the CD4 ectodomain was fused to diverse membrane anchors and inserted together with the HIV-1 coreceptor CXCR4 into the envelopes of HIV-1 vector particles. Independent of the type of CD4 anchor, all chimeric CD4 proteins inserted into HIV-1 vector envelopes and the resultant HIV(CD4/CXCR4) particles were able to selectively confer neomycin resistance to cells expressing the fusogenic T cell tropic HIV-1 Env protein. Unexpectedly, in the absence of Env on the target cells, all vector particles carrying the CD4 ectodomain anchored in their envelope adhered to various cell types without infecting these cells. This cell adhesion was very avid. It was independent of the presence of Env on the target cell, the type of CD4 anchor or the presence of CXCR4 on the particle. In mixed cell populations with defined ratios of Env+/Env- cells, the targeted transduction of Env+ cells by HIV(CD4/CXCR4) particles was diminished in proportion to the number of Env- cells. Conclusion Vector diversion caused by a strong, non-selective cell binding of CD4+-vector particles effectively prevents the targeted transduction of HIV-1 Env expressing cells in mixed cell populations. This Env-independent cell adhesion severely limits the effective use of targeted HIV(CD4/CXCR4) vectors designed to interfere with HIV-1 replication in vivo. Importantly, the existence of this newly described and remarkably strong CD4-dependent cell adhesion suggests that the multiple viral efforts to reduce CD4 cell surface expression may, in part, be to prevent cell adhesion to non-target cells and thereby to increase the infectivity of viral progeny. Preventing CD4 down-modulation by HIV-1 might be an effective component of a multi-faceted antiviral strategy.
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Affiliation(s)
- Zhiping Ye
- Molecular Virology and Neurogenetics Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Rm. 4S-18, 5625 Fishers Lane, Bethesda, MD 20892-9403, USA
- Laboratory of Pediatric and Respiratory Viral Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Bldg. 29A, 8800 Rockville Pike, Bethesda, MD 20892, USA
| | - George G Harmison
- Molecular Virology and Neurogenetics Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Rm. 4S-18, 5625 Fishers Lane, Bethesda, MD 20892-9403, USA
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bldg. 35, Rm. 2A1012, 35 Convent Drive, Bethesda, MD 20892-3705, USA
| | - Jack A Ragheb
- Clinical and Molecular Immunology Section, National Eye Institute, National Institutes of Health, Bldg. 10, Rm. 10N113A, 10 Center Drive, Bethesda, MD 20892-1857, USA
| | - Manfred Schubert
- Molecular Virology and Neurogenetics Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Rm. 4S-18, 5625 Fishers Lane, Bethesda, MD 20892-9403, USA
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Segura MDLM, Garnier A, Kamen A. Purification and characterization of retrovirus vector particles by rate zonal ultracentrifugation. J Virol Methods 2005; 133:82-91. [PMID: 16325928 DOI: 10.1016/j.jviromet.2005.10.030] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2005] [Revised: 10/23/2005] [Accepted: 10/25/2005] [Indexed: 11/28/2022]
Abstract
Sucrose equilibrium density ultracentrifugation remains the most widely used technique for retrovirus purification. However, purified virus preparations obtained by this routine method usually contain considerable amounts of contaminating cell membrane vesicles. In addition, sucrose solutions are highly viscous and hyperosmotic which jeopardizes the integrity and functionality of the retrovirus particle. In order to overcome these limitations, an alternative purification technique using rate zonal ultracentrifugation and iodixanol as gradient medium was developed. Recombinant retrovirus particles were produced by 293-GPG packaging cells grown in suspension in the presence of 10% FBS. Concentrated supernatants were purified by rate zonal sedimentation on a 10-30% continuous iodixanol gradient. Virus particles were recovered intact and active from the central fractions of the gradient. By using this strategy, high levels of purification were achieved, with no evident contamination with cell membrane vesicles as indicated by subtilisin treatment studies. The level of purity of the retrovirus preparation is over 95% as shown by SDS-PAGE analysis and size-exclusion chromatography. Purified particles appear homogenous in size and morphology according to negative stain electron microscopy. In addition, large amounts of defective retrovirus particles produced by 293-GPG packaging cells can be separated from functional retrovirus particles using this purification strategy.
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