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Kim T, Hearn C, Heidari M. Efficacy of Recombinant Marek's Disease Virus Vaccine 301B/1 Expressing Membrane-Anchored Chicken Interleukin-15. Avian Dis 2024; 68:117-128. [PMID: 38885053 DOI: 10.1637/aviandiseases-d-23-00068] [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: 09/12/2023] [Accepted: 05/25/2024] [Indexed: 06/20/2024]
Abstract
Cytokines are co-administrated with vaccines or co-expressed in the vaccine virus genome to improve protective efficacy by stimulating immune responses. Using glycosylphosphatidylinositol (GPI) anchoring by attachment to the target cytokine, we constructed recombinant Marek's disease virus (MDV) vaccine strain 301B/1 (v301B/1-rtg-IL-15) that expresses chicken interleukin-15 (IL-15) as the membrane-bound form at the cell surface. We evaluated the vaccine efficacy of v301B/1-rtg-IL-15 given as a bivalent Marek's disease (MD) vaccine in combination with turkey herpesvirus (HVT) against a very virulent plus MDV strain 648A challenge. The efficacy was compared with that of conventional bivalent MD vaccine, as a mixture with HVT plus parental v301B/1 or v301B/1-IL-15, which expresses a natural form of IL-15. The membrane-bound IL-15 expression did not interfere with the virus growth of recombinant v301B/1-rtg-IL-15. However, the MD incidence in birds vaccinated with v301B/1-rtg-IL-15 was higher than that of birds given the conventional bivalent MD vaccine containing parental v301B/1 virus, although the v301B/1-rtg-IL-15 vaccinated group showed increased natural killer cell activation at day 5 postvaccination, the same day as challenge. Overall, the protection of v301B/1-rtg-IL-15 was not improved from that of v301B/1 against very virulent plus MDV challenge.
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Affiliation(s)
- Taejoong Kim
- Southeast Poultry Research Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, United States Department of Agriculture, Athens, GA 30605,
| | - Cari Hearn
- Avian Diseases and Oncology Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, United States Department of Agriculture, East Lansing, MI 48823
| | - Mohammad Heidari
- Southeast Poultry Research Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, United States Department of Agriculture, Athens, GA 30605
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2
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Cortes-Galvez D, Dangerfield JA, Metzner C. Extracellular Vesicles and Their Membranes: Exosomes vs. Virus-Related Particles. MEMBRANES 2023; 13:397. [PMID: 37103824 PMCID: PMC10146078 DOI: 10.3390/membranes13040397] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/28/2023] [Accepted: 03/29/2023] [Indexed: 06/19/2023]
Abstract
Cells produce nanosized lipid membrane-enclosed vesicles which play important roles in intercellular communication. Interestingly, a certain type of extracellular vesicle, termed exosomes, share physical, chemical, and biological properties with enveloped virus particles. To date, most similarities have been discovered with lentiviral particles, however, other virus species also frequently interact with exosomes. In this review, we will take a closer look at the similarities and differences between exosomes and enveloped viral particles, with a focus on events taking place at the vesicle or virus membrane. Since these structures present an area with an opportunity for interaction with target cells, this is relevant for basic biology as well as any potential research or medical applications.
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Affiliation(s)
- Daniela Cortes-Galvez
- AG Histology and Embryology, Institute of Morphology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
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3
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Metzner C, Zaruba M. On the Relationship of Viral Particles and Extracellular Vesicles: Implications for Viral Vector Technology. Viruses 2021; 13:v13071238. [PMID: 34206771 PMCID: PMC8310354 DOI: 10.3390/v13071238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 06/20/2021] [Accepted: 06/22/2021] [Indexed: 12/15/2022] Open
Abstract
Gene therapy vectors derived from different viral species have become a fixture in biomedicine, both for direct therapeutic intervention and as tools to facilitate cell-based therapies, such as chimeric antigen receptor-based immunotherapies. On the contrary, extracellular vesicles have only recently gained a massive increase in interest and, concomitantly, knowledge in the field has drastically risen. Viral infections and extracellular vesicle biology overlap in many ways, both with pro- and antiviral outcomes. In this review, we take a closer look at these interactions for the most prominent groups of viral vectors (Adenoviral, Adeno-associated and Retro/Lentiviral vectors) and the possible implications of these overlaps for viral vector technology and its biomedical applications.
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4
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Zaruba M, Roschitz L, Sami H, Ogris M, Gerner W, Metzner C. Surface Modification of E. coli Outer Membrane Vesicles with Glycosylphosphatidylinositol-Anchored Proteins: Generating Pro/Eukaryote Chimera Constructs. MEMBRANES 2021; 11:membranes11060428. [PMID: 34199851 PMCID: PMC8228533 DOI: 10.3390/membranes11060428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 05/25/2021] [Accepted: 05/27/2021] [Indexed: 11/19/2022]
Abstract
Extracellular vesicles produced by different types of cells have recently attracted great attention, not only for their role in physiology and pathology, but also because of the emerging applications in gene therapy, vaccine production and diagnostics. Less well known than their eukaryotic counterpart, also bacteria produce extracellular vesicles, in the case of the Gram-negative E. coli the main species is termed outer membrane vesicles (OMVs). In this study, we show for the first time the functional surface modification of E. coli OMVs with glycosylphosphatidylinositol (GPI)-anchored protein, exploiting a process variably described as molecular painting or protein engineering in eukaryotic membranes, whereby the lipid part of the GPI anchor inserts in cell membranes. By transferring the process to bacterial vesicles, we can generate a hybrid of perfectly eukaryotic proteins (in terms of folding and post-translational modifications) on a prokaryotic platform. We could demonstrate that two different GPI proteins can be displayed on the same OMV. In addition to fluorescent marker proteins, cytokines, growth factors and antigens canb be potentially transferred, generating a versatile modular platform for a novel vaccine strategy.
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Affiliation(s)
- Marianne Zaruba
- Institute of Virology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria; (M.Z.); (L.R.)
| | - Lena Roschitz
- Institute of Virology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria; (M.Z.); (L.R.)
| | - Haider Sami
- Laboratory of Macromolecular Cancer Therapeutics MMCT, Department of Pharmaceutical Sciences, University of Vienna, 1090 Vienna, Austria; (H.S.); (M.O.)
| | - Manfred Ogris
- Laboratory of Macromolecular Cancer Therapeutics MMCT, Department of Pharmaceutical Sciences, University of Vienna, 1090 Vienna, Austria; (H.S.); (M.O.)
| | - Wilhelm Gerner
- Institute of Immunology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria;
| | - Christoph Metzner
- Institute of Virology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria; (M.Z.); (L.R.)
- Correspondence:
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5
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Hackl S, Ng XW, Lu D, Wohland T, Becker CFW. Cytoskeleton-dependent clustering of membrane-bound prion protein on the cell surface. J Biol Chem 2021; 296:100359. [PMID: 33539927 PMCID: PMC7988330 DOI: 10.1016/j.jbc.2021.100359] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 01/26/2021] [Accepted: 01/28/2021] [Indexed: 12/23/2022] Open
Abstract
Prion diseases are a group of neurodegenerative disorders that infect animals and humans with proteinaceous particles called prions. Prions consist of scrapie prion protein (PrPSc), a misfolded version of the cellular prion protein (PrPC). During disease progression, PrPSc replicates by interacting with PrPC and inducing its conversion to PrPSc. Attachment of PrPC to cellular membranes via a glycosylphosphatidylinositol (GPI) anchor is critical for the conversion of PrPC into PrPSc. However, the mechanisms governing PrPC conversion and replication on the membrane remain largely unclear. Here, a site-selectively modified PrP variant equipped with a fluorescent GPI anchor mimic (PrP-GPI) was employed to directly observe PrP at the cellular membrane in neuronal SH-SY5Y cells. PrP-GPI exhibits a cholesterol-dependent membrane accumulation and a cytoskeleton-dependent mobility. More specifically, inhibition of actin polymerization reduced the diffusion of PrP-GPI indicating protein clustering, which resembles the initial step of PrP aggregation and conversion into its pathogenic isoform. An intact actin cytoskeleton might therefore prevent conversion of PrPC into PrPSc and offer new therapeutic angles.
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Affiliation(s)
- Stefanie Hackl
- Institute of Biological Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Xue Wen Ng
- Departments of Biological Sciences and Chemistry and Centre for Bioimaging Sciences (CBIS), National University of Singapore (NUS), Singapore
| | - Danqin Lu
- Departments of Biological Sciences and Chemistry and Centre for Bioimaging Sciences (CBIS), National University of Singapore (NUS), Singapore; School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China
| | - Thorsten Wohland
- Departments of Biological Sciences and Chemistry and Centre for Bioimaging Sciences (CBIS), National University of Singapore (NUS), Singapore
| | - Christian F W Becker
- Institute of Biological Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria.
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Heider S, Muzard J, Zaruba M, Metzner C. Integrated Method for Purification and Single-Particle Characterization of Lentiviral Vector Systems by Size Exclusion Chromatography and Tunable Resistive Pulse Sensing. Mol Biotechnol 2018; 59:251-259. [PMID: 28567687 PMCID: PMC5486506 DOI: 10.1007/s12033-017-0009-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Elements derived from lentiviral particles such as viral vectors or virus-like particles are commonly used for biotechnological and biomedical applications, for example in mammalian protein expression, gene delivery or therapy, and vaccine development. Preparations of high purity are necessary in most cases, especially for clinical applications. For purification, a wide range of methods are available, from density gradient centrifugation to affinity chromatography. In this study we have employed size exclusion columns specifically designed for the easy purification of extracellular vesicles including exosomes. In addition to viral marker protein and total protein analysis, a well-established single-particle characterization technology, termed tunable resistive pulse sensing, was employed to analyze fractions of highest particle load and purity and characterize the preparations by size and surface charge/electrophoretic mobility. With this study, we propose an integrated platform combining size exclusion chromatography and tunable resistive pulse sensing for monitoring production and purification of viral particles.
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Affiliation(s)
- Susanne Heider
- Institute of Virology, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria.,Biological Physics, Department of Physics, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Julien Muzard
- Izon Science, 8C Homersham Place, PO Box 39168, Burnside, Christchurch, 8053, New Zealand
| | - Marianne Zaruba
- Institute of Virology, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria
| | - Christoph Metzner
- Institute of Virology, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria.
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7
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Real-time analysis of protein and protein mixture interaction with lipid bilayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:319-328. [DOI: 10.1016/j.bbamem.2017.10.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 10/25/2017] [Accepted: 10/25/2017] [Indexed: 02/04/2023]
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8
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Immune Protection of Retroviral Vectors Upon Molecular Painting with the Complement Regulatory Protein CD59. Mol Biotechnol 2017; 58:480-8. [PMID: 27170144 PMCID: PMC4899500 DOI: 10.1007/s12033-016-9944-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Glycosylphosphatidylinositol anchoring is a type of post-translational modification that allows proteins to be presented on the exterior side of the cell membrane. Purified glycosylphosphatidylinositol-anchored protein can spontaneously re-insert into lipid bilayer membranes in a process termed Molecular Painting. Here, we demonstrate the possibility of inserting purified, recombinant CD59 into virus particles produced from a murine retroviral producer cell line. CD59 is a regulator of the complement system that helps protect healthy cells from the lytic activity of the complement cascade. In this study, we could show that Molecular Painting confers protection from complement activity upon murine retroviral vector particles. Indeed, increased infectivity of CD59-modified virus particles was observed upon challenge with human serum, indicating that Molecular Painting is suitable for modulating the immune system in gene therapy or vaccination applications.
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9
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Heider S, Dangerfield JA, Metzner C. Biomedical applications of glycosylphosphatidylinositol-anchored proteins. J Lipid Res 2016; 57:1778-1788. [PMID: 27542385 PMCID: PMC5036375 DOI: 10.1194/jlr.r070201] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Indexed: 01/13/2023] Open
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) use a unique posttranslational modification to link proteins to lipid bilayer membranes. The anchoring structure consists of both a lipid and carbohydrate portion and is highly conserved in eukaryotic organisms regarding its basic characteristics, yet highly variable in its molecular details. The strong membrane targeting property has made the anchors an interesting tool for biotechnological modification of lipid membrane-covered entities from cells through extracellular vesicles to enveloped virus particles. In this review, we will take a closer look at the mechanisms and fields of application for GPI-APs in lipid bilayer membrane engineering and discuss their advantages and disadvantages for biomedicine.
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Affiliation(s)
- Susanne Heider
- Institute of Virology, University of Veterinary Medicine, 1210 Vienna, Austria
| | | | - Christoph Metzner
- Institute of Virology, University of Veterinary Medicine, 1210 Vienna, Austria.
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10
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Metzner C, Salmons B, Günzburg WH, Dangerfield JA. Comment on Patel et al; "Protein transfer-mediated surface engineering to adjuvantate virus-like nanoparticles for enhanced anti-viral immune responses" Nanomedicine, 2015. 11(5): p. 1097-107. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2015; 12:665-666. [PMID: 26593637 DOI: 10.1016/j.nano.2015.10.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 10/31/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Christoph Metzner
- Institute of Virology, University of Veterinary Medicine, Institute of Virology, Vienna, Austria.
| | | | - Walter H Günzburg
- Institute of Virology, University of Veterinary Medicine, Institute of Virology, Vienna, Austria
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11
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Ilyushina NA, Chernyy ES, Korchagina EY, Gambaryan AS, Henry SM, Bovin NV. Labeling of influenza viruses with synthetic fluorescent and biotin-labeled lipids. Virol Sin 2014; 29:199-210. [PMID: 25160755 DOI: 10.1007/s12250-014-3475-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Accepted: 07/17/2014] [Indexed: 10/24/2022] Open
Abstract
Direct labeling of virus particles is a powerful tool for the visualization of virus-cell interaction events. However, this technique involves the chemical modification of viral proteins that affects viral biological properties. Here we describe an alternative approach of influenza virus labeling that utilizes Function-Spacer-Lipid (FSL) constructs that can be gently inserted into the virus membrane. We assessed whether labeling with fluorescent (fluo-Ad-DOPE) or biotin-labeled (biot-CMG2-DOPE) probes has any deleterious effect on influenza virus hemagglutinin (HA) receptor specificity, neuraminidase (NA) activity, or replicative ability in vitro. Our data clearly show that neither construct significantly affected influenza virus infectivity or viral affinity to sialyl receptors. Neither construct influenced the NA activities of the influenza viruses tested, except the A/Puerto Rico/8/34 (H1N1) strain. Our data indicate that lipid labeling provides a powerful tool to analyze influenza virus infection in vitro.
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12
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Heider S, Metzner C. Quantitative real-time single particle analysis of virions. Virology 2014; 462-463:199-206. [PMID: 24999044 PMCID: PMC4139191 DOI: 10.1016/j.virol.2014.06.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 05/05/2014] [Accepted: 06/04/2014] [Indexed: 11/14/2022]
Abstract
Providing information about single virus particles has for a long time been mainly the domain of electron microscopy. More recently, technologies have been developed—or adapted from other fields, such as nanotechnology—to allow for the real-time quantification of physical virion particles, while supplying additional information such as particle diameter concomitantly. These technologies have progressed to the stage of commercialization increasing the speed of viral titer measurements from hours to minutes, thus providing a significant advantage for many aspects of virology research and biotechnology applications. Additional advantages lie in the broad spectrum of virus species that may be measured and the possibility to determine the ratio of infectious to total particles. A series of disadvantages remain associated with these technologies, such as a low specificity for viral particles. In this review we will discuss these technologies by comparing four systems for real-time single virus particle analysis and quantification. We introduce four methods for virus particle-based quantification of viruses. They allow for quantification of a wide range of samples in under an hour time. The additional measurement of size and zeta potential is possible for some.
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Affiliation(s)
- Susanne Heider
- Institute of Virology, University of Veterinary Medicine Vienna, Building AC, 3rd Floor, Veterinärplatz 1, 1210 Vienna, Austria
| | - Christoph Metzner
- Institute of Virology, University of Veterinary Medicine Vienna, Building AC, 3rd Floor, Veterinärplatz 1, 1210 Vienna, Austria.
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13
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Huang LL, Xie HY. Progress on the labeling and single-particle tracking technologies of viruses. Analyst 2014; 139:3336-46. [DOI: 10.1039/c4an00038b] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We review recent advances in virus labeling and the emerging fluorescence imaging technologies used in the imaging and tracking of viruses.
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Affiliation(s)
- Li-Li Huang
- School of Life Science
- Beijing Institute of Technology
- Beijing 100081, China
| | - Hai-Yan Xie
- School of Life Science
- Beijing Institute of Technology
- Beijing 100081, China
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14
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Schäfer B, Orbán E, Borics A, Huszár K, Nyeste A, Welker E, Tömböly C. Preparation of semisynthetic lipoproteins with fluorescent cholesterol anchor and their introduction to the cell membrane with minimal disruption of the membrane. Bioconjug Chem 2013; 24:1684-97. [PMID: 24020959 DOI: 10.1021/bc4002135] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The exogenous introduction of fluorescent lipoproteins into cell membranes is a method for visualizing the cellular traffic of membrane associated proteins, and also for altering the cell surface in a controlled manner. In order to achieve the cell membrane anchoring of proteins and their subsequent fluorescence based detection, a cholesterol derivative was designed. The headgroup of the novel cholesterol anchor contains a fluorescent reporter and a thiol reactive maleimide for protein conjugation. Protein conjugation was demonstrated by the addition of a green fluorescent maleimido anchor to the C-terminus of a Cys extended red fluorescent protein, mCherry. The resulting dual fluorescent cholesteryl lipoprotein was successfully separated from the micellar associates of the surplus fluorescent lipid anchor without denaturing the protein, and the lipoprotein containing only the covalently linked, stoichiometric fluorescent lipid was efficiently delivered to the plasma membrane of live cells. It was demonstrated that the membrane fluorescence could be directly assigned to the protein-anchor conjugate, because no excess of fluorescent lipid species were present during the imaging experiment and the protein and anchor fluorescence colocalized in the cell membrane. Molecular dynamics simulations and subsequent trajectory analysis suggest also the spontaneous and stable membrane association of the cholesterol anchor. Thus, the method could be beneficially applied for studying membrane associated proteins and for preparing mimetics of glycosylphosphatidylinositol (GPI)-anchored proteins to target cholesterol-rich membrane microdomains.
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Affiliation(s)
- Balázs Schäfer
- Laboratory of Chemical Biology and §Laboratory of Conformational Diseases, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences , Temesvári krt. 62., 6726 Szeged, Hungary
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15
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Heider S, Kochan F, Kleinberger S, Sperl E, Reimhult E, Metzner C. Investigating retroviral envelope proteome plasticity. Retrovirology 2013. [PMCID: PMC3847764 DOI: 10.1186/1742-4690-10-s1-p60] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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16
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Fluorosomes: fluorescent virus-like nanoparticles that represent a convenient tool to visualize receptor-ligand interactions. SENSORS 2013; 13:8722-49. [PMID: 23881135 PMCID: PMC3758619 DOI: 10.3390/s130708722] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 06/28/2013] [Accepted: 07/05/2013] [Indexed: 01/03/2023]
Abstract
Viruses are the smallest life forms and parasitize on many eukaryotic organisms, including humans. Consequently, the study of viruses and viral diseases has had an enormous impact on diverse fields of biology and medicine. Due to their often pathogenic properties, viruses have not only had a strong impact on the development of immune cells but also on shaping entire immune mechanisms in their hosts. In order to better characterize virus-specific surface receptors, pathways of virus entry and the mechanisms of virus assembly, diverse methods to visualize virus particles themselves have been developed in the past decades. Apart from characterization of virus-specific mechanisms, fluorescent virus particles also serve as valuable platforms to study receptor-ligand interactions. Along those lines the authors have developed non-infectious virus-like nanoparticles (VNP), which can be decorated with immune receptors of choice and used for probing receptor-ligand interactions, an especially interesting application in the field of basic but also applied immunology research. To be able to better trace receptor-decorated VNP the authors have developed technology to introduce fluorescent proteins into such particles and henceforth termed them fluorosomes (FS). Since VNP are assembled in a simple expression system relying on HEK-293 cells, gene-products of interest can be assembled in a simple and straightforward fashion—one of the reasons why the authors like to call fluorosomes ‘the poor-man's staining tool’. Within this review article an overview on virus particle assembly, chemical and recombinant methods of virus particle labeling and examples on how FS can be applied as sensors to monitor receptor-ligand interactions on leukocytes are given.
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17
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Postexit surface engineering of retroviral/lentiviral vectors. BIOMED RESEARCH INTERNATIONAL 2013; 2013:253521. [PMID: 23691494 PMCID: PMC3652111 DOI: 10.1155/2013/253521] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 03/15/2013] [Indexed: 11/25/2022]
Abstract
Gene delivery vectors based on retroviral or lentiviral particles are considered powerful tools for biomedicine and biotechnology applications. Such vectors require modification at the genomic level in the form of rearrangements to allow introduction of desired genes and regulatory elements (genotypic modification) as well as engineering of the physical virus particle (phenotypic modification) in order to mediate efficient and safe delivery of the genetic information to the target cell nucleus. Phenotypic modifications are typically introduced at the genomic level through genetic manipulation of the virus producing cells. However, this paper focuses on methods which allow modification of viral particle surfaces after they have exited the cell, that is, directly on the viral particles in suspension. These methods fall into three categories: (i) direct covalent chemical modification, (ii) membrane-topic reagents, and (iii) adaptor systems. Current applications of such techniques will be introduced and their advantages and disadvantages will be discussed.
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