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Poria R, Kala D, Nagraik R, Dhir Y, Dhir S, Singh B, Kaushik NK, Noorani MS, Kaushal A, Gupta S. Vaccine development: Current trends and technologies. Life Sci 2024; 336:122331. [PMID: 38070863 DOI: 10.1016/j.lfs.2023.122331] [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: 09/21/2023] [Revised: 11/24/2023] [Accepted: 12/02/2023] [Indexed: 12/24/2023]
Abstract
Despite the effectiveness of vaccination in reducing or eradicating diseases caused by pathogens, there remain certain diseases and emerging infections for which developing effective vaccines is inherently challenging. Additionally, developing vaccines for individuals with compromised immune systems or underlying medical conditions presents significant difficulties. As well as traditional vaccine different methods such as inactivated or live attenuated vaccines, viral vector vaccines, and subunit vaccines, emerging non-viral vaccine technologies, including viral-like particle and nanoparticle vaccines, DNA/RNA vaccines, and rational vaccine design, offer new strategies to address the existing challenges in vaccine development. These advancements have also greatly enhanced our understanding of vaccine immunology, which will guide future vaccine development for a broad range of diseases, including rapidly emerging infectious diseases like COVID-19 and diseases that have historically proven resistant to vaccination. This review provides a comprehensive assessment of emerging non-viral vaccine production methods and their application in addressing the fundamental and current challenges in vaccine development.
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Affiliation(s)
- Renu Poria
- Department of Bio-Sciences and Technology, Maharishi Markandeshwar (Deemed to Be) University, Mullana, Ambala 134003, India
| | - Deepak Kala
- Centera Laboratories, Institute of High Pressure Physics PAS, 01-142 Warsaw, Poland
| | - Rupak Nagraik
- School of Bioengineering and Food Technology, Faculty of Applied Sciences and Biotechnology, Shoolini University, Solan, Himachal Pradesh, India
| | - Yashika Dhir
- Department of Bio-Sciences and Technology, Maharishi Markandeshwar (Deemed to Be) University, Mullana, Ambala 134003, India
| | - Sunny Dhir
- Department of Bio-Sciences and Technology, Maharishi Markandeshwar (Deemed to Be) University, Mullana, Ambala 134003, India
| | - Bharat Singh
- Department of Bio-Sciences and Technology, Maharishi Markandeshwar (Deemed to Be) University, Mullana, Ambala 134003, India
| | - Naveen Kumar Kaushik
- Amity Institute of Virology and Immunology, Amity University Uttar Pradesh, Sector-125, Noida, Uttar Pradesh, India
| | - Md Salik Noorani
- Department of Botany, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi 110062, India
| | - Ankur Kaushal
- Department of Bio-Sciences and Technology, Maharishi Markandeshwar (Deemed to Be) University, Mullana, Ambala 134003, India.
| | - Shagun Gupta
- Department of Bio-Sciences and Technology, Maharishi Markandeshwar (Deemed to Be) University, Mullana, Ambala 134003, India.
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Zhang L, Xu W, Ma X, Sun X, Fan J, Wang Y. Virus-like Particles as Antiviral Vaccine: Mechanism, Design, and Application. BIOTECHNOL BIOPROC E 2023; 28:1-16. [PMID: 36627930 PMCID: PMC9817464 DOI: 10.1007/s12257-022-0107-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/17/2022] [Accepted: 05/18/2022] [Indexed: 01/09/2023]
Abstract
Virus-like particles (VLPs) are viral structural protein that are noninfectious as they do not contain viral genetic materials. They are safe and effective immune stimulators and play important roles in vaccine development because of their intrinsic immunogenicity to induce cellular and humoral immune responses. In the design of antiviral vaccine, VLPs based vaccines are appealing multifunctional candidates with the advantages such as self-assembling nanoscaled structures, repetitive surface epitopes, ease of genetic and chemical modifications, versatility as antigen presenting platforms, intrinsic immunogenicity, higher safety profile in comparison with live-attenuated vaccines and inactivated vaccines. In this review, we discuss the mechanism of VLPs vaccine inducing cellular and humoral immune responses. We outline the impact of size, shape, surface charge, antigen presentation, genetic and chemical modification, and expression systems when constructing effective VLPs based vaccines. Recent applications of antiviral VLPs vaccines and their clinical trials are summarized.
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Affiliation(s)
- Lei Zhang
- Xi'an Key Laboratory of Pathogenic Microorganism and Tumor Immunity, Department of Basic Medicine, Xi'an Medical University, Xi'an, 710021, Shaanxi China
| | - Wen Xu
- Xi'an Key Laboratory of Pathogenic Microorganism and Tumor Immunity, Department of Basic Medicine, Xi'an Medical University, Xi'an, 710021, Shaanxi China
| | - Xi Ma
- Xi'an Key Laboratory of Pathogenic Microorganism and Tumor Immunity, Department of Basic Medicine, Xi'an Medical University, Xi'an, 710021, Shaanxi China
| | - XiaoJing Sun
- Xi'an Key Laboratory of Pathogenic Microorganism and Tumor Immunity, Department of Basic Medicine, Xi'an Medical University, Xi'an, 710021, Shaanxi China
| | - JinBo Fan
- Xi'an Key Laboratory of Pathogenic Microorganism and Tumor Immunity, Department of Basic Medicine, Xi'an Medical University, Xi'an, 710021, Shaanxi China
| | - Yang Wang
- Xi'an Key Laboratory of Pathogenic Microorganism and Tumor Immunity, Department of Basic Medicine, Xi'an Medical University, Xi'an, 710021, Shaanxi China
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Brisse M, Vrba SM, Kirk N, Liang Y, Ly H. Emerging Concepts and Technologies in Vaccine Development. Front Immunol 2020; 11:583077. [PMID: 33101309 PMCID: PMC7554600 DOI: 10.3389/fimmu.2020.583077] [Citation(s) in RCA: 142] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 09/14/2020] [Indexed: 01/05/2023] Open
Abstract
Despite the success of vaccination to greatly mitigate or eliminate threat of diseases caused by pathogens, there are still known diseases and emerging pathogens for which the development of successful vaccines against them is inherently difficult. In addition, vaccine development for people with compromised immunity and other pre-existing medical conditions has remained a major challenge. Besides the traditional inactivated or live attenuated, virus-vectored and subunit vaccines, emerging non-viral vaccine technologies, such as viral-like particle and nanoparticle vaccines, DNA/RNA vaccines, and rational vaccine design, offer innovative approaches to address existing challenges of vaccine development. They have also significantly advanced our understanding of vaccine immunology and can guide future vaccine development for many diseases, including rapidly emerging infectious diseases, such as COVID-19, and diseases that have not traditionally been addressed by vaccination, such as cancers and substance abuse. This review provides an integrative discussion of new non-viral vaccine development technologies and their use to address the most fundamental and ongoing challenges of vaccine development.
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Affiliation(s)
- Morgan Brisse
- Biochemistry, Molecular Biology, and Biophysics Graduate Program, University of Minnesota Twin Cities, St. Paul, MN, United States
- Department of Veterinary & Biomedical Sciences, University of Minnesota Twin Cities, St. Paul, MN, United States
| | - Sophia M. Vrba
- Department of Veterinary & Biomedical Sciences, University of Minnesota Twin Cities, St. Paul, MN, United States
| | - Natalie Kirk
- Department of Veterinary & Biomedical Sciences, University of Minnesota Twin Cities, St. Paul, MN, United States
- Comparative Molecular Biosciences Graduate Program, University of Minnesota Twin Cities, St. Paul, MN, United States
| | - Yuying Liang
- Department of Veterinary & Biomedical Sciences, University of Minnesota Twin Cities, St. Paul, MN, United States
| | - Hinh Ly
- Department of Veterinary & Biomedical Sciences, University of Minnesota Twin Cities, St. Paul, MN, United States
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Wu P, Lu J, Zhang X, Mei M, Feng L, Peng D, Hou J, Kang SM, Liu X, Tang Y. Single Dose of Consensus Hemagglutinin-Based Virus-Like Particles Vaccine Protects Chickens against Divergent H5 Subtype Influenza Viruses. Front Immunol 2017; 8:1649. [PMID: 29230222 PMCID: PMC5711813 DOI: 10.3389/fimmu.2017.01649] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 11/10/2017] [Indexed: 11/21/2022] Open
Abstract
The H5 subtype highly pathogenic avian influenza (HPAI) virus is one of the greatest threats to global poultry industry. To develop broadly protective H5 subunit vaccine, a recombinant consensus HA sequence (rHA) was constructed and expressed in virus-like particles (rHA VLPs) in the baculovirus-insect cell system. The efficacy of the rHA VLPs vaccine with or without immunopotentiator (CVCVA5) was assessed in chickens. Compared to the commercial Re6 or Re6-CVCVA5 vaccines, single dose immunization of chickens with rHA VLPs or rHA-CVCVA5 vaccines induced higher levels of serum hemagglutinin inhibition titers and neutralization titers, mucosal antibodies, IFN-γ and IL-4 cytokines in sera, and cytotoxic T lymphocyte responses. The rHA VLPs vaccine was superior to the commercial Re6 vaccine in conferring cross-protection against different clades of H5 subtype viruses. This study reports that H5 subtype consensus HA VLP single dose vaccination provides broad protection against HPAI virus in chickens.
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Affiliation(s)
- Peipei Wu
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonosis, Yangzhou, China
| | - Jihu Lu
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonosis, Yangzhou, China
| | - Xuehua Zhang
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonosis, Yangzhou, China
| | - Mei Mei
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonosis, Yangzhou, China
| | - Lei Feng
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonosis, Yangzhou, China
| | - Daxin Peng
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonosis, Yangzhou, China
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Jibo Hou
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonosis, Yangzhou, China
| | - Sang-Moo Kang
- Center for Inflammation, Immunity & Infection, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, United States
| | - Xiufan Liu
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonosis, Yangzhou, China
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Yinghua Tang
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonosis, Yangzhou, China
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Meador LR, Kessans SA, Kilbourne J, Kibler KV, Pantaleo G, Roderiguez ME, Blattman JN, Jacobs BL, Mor TS. A heterologous prime-boosting strategy with replicating Vaccinia virus vectors and plant-produced HIV-1 Gag/dgp41 virus-like particles. Virology 2017; 507:242-256. [PMID: 28458036 PMCID: PMC5529300 DOI: 10.1016/j.virol.2017.04.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 03/24/2017] [Accepted: 04/06/2017] [Indexed: 12/22/2022]
Abstract
Showing modest efficacy, the RV144 HIV-1 vaccine clinical trial utilized a non-replicating canarypox viral vector and a soluble gp120 protein boost. Here we built upon the RV144 strategy by developing a novel combination of a replicating, but highly-attenuated Vaccinia virus vector, NYVAC-KC, and plant-produced HIV-1 virus-like particles (VLPs). Both components contained the full-length Gag and a membrane anchored truncated gp41 presenting the membrane proximal external region with its conserved broadly neutralizing epitopes in the pre-fusion conformation. We tested different prime/boost combinations of these components in mice and showed that the group primed with NYVAC-KC and boosted with both the viral vectors and plant-produced VLPs have the most robust Gag-specific CD8 T cell responses, at 12.7% of CD8 T cells expressing IFN-γ in response to stimulation with five Gag epitopes. The same immunization group elicited the best systemic and mucosal antibody responses to Gag and dgp41 with a bias towards IgG1.
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Affiliation(s)
- Lydia R Meador
- Ira A. Fulton School of Engineering, Arizona State University, Tempe, AZ, USA; Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ, USA
| | - Sarah A Kessans
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ, USA; School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Jacquelyn Kilbourne
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ, USA
| | - Karen V Kibler
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ, USA
| | - Giuseppe Pantaleo
- Division of Immunology and Allergy, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Lausanne, Switzerland; Swiss Vaccine Research Institute, Lausanne, Switzerland
| | | | - Joseph N Blattman
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ, USA; School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Bertram L Jacobs
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ, USA; School of Life Sciences, Arizona State University, Tempe, AZ, USA.
| | - Tsafrir S Mor
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, AZ, USA; School of Life Sciences, Arizona State University, Tempe, AZ, USA.
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Williamson AL, Rybicki EP. Justification for the inclusion of Gag in HIV vaccine candidates. Expert Rev Vaccines 2015; 15:585-98. [PMID: 26645951 DOI: 10.1586/14760584.2016.1129904] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
It is widely accepted that effective human immunodeficiency virus (HIV) vaccines need to elicit a range of responses, including neutralising antibodies and T-cells. In natural HIV infections, immune responses to Gag are associated with lower viral load in infected individuals, and these responses can be measured against infected cells before the replication of HIV. Priming immune responses to Gag with DNA or recombinant Bacillus Calmette-Guérin (BCG) vaccines, and boosting with Gag virus-like particles as subunit vaccines or Gag produced in vivo by other vaccine vectors, elicits high-magnitude, broad polyfunctional responses, with memory T-cell responses appropriate for virus control. This review provides justification for the inclusion of HIV Gag in vaccine regimens, either as a transgene expressing protein that may assemble to form budded particles, or as purified virus-like particles. Possible benefits would include early control via CD8(+) T-cells at the site of infection, control of spread from the entry portal, and control of viraemia if infection is established.
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Affiliation(s)
- Anna-Lise Williamson
- a Institute of Infectious Disease and Molecular Medicine , University of Cape Town , Cape Town , South Africa.,b National Health Laboratory Service, Groote Schuur Hospital, Cape Town and Department of Pathology , University of Cape Town , Cape Town , South Africa
| | - Edward P Rybicki
- a Institute of Infectious Disease and Molecular Medicine , University of Cape Town , Cape Town , South Africa.,c Biopharming Research Unit, Department of Molecular and Cell Biology , University of Cape Town , Cape Town , South Africa
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Kushnir N, Streatfield SJ, Yusibov V. Virus-like particles as a highly efficient vaccine platform: diversity of targets and production systems and advances in clinical development. Vaccine 2012; 31:58-83. [PMID: 23142589 PMCID: PMC7115575 DOI: 10.1016/j.vaccine.2012.10.083] [Citation(s) in RCA: 401] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 10/13/2012] [Accepted: 10/25/2012] [Indexed: 12/16/2022]
Abstract
Virus-like particles (VLPs) are a class of subunit vaccines that differentiate themselves from soluble recombinant antigens by stronger protective immunogenicity associated with the VLP structure. Like parental viruses, VLPs can be either non-enveloped or enveloped, and they can form following expression of one or several viral structural proteins in a recombinant heterologous system. Depending on the complexity of the VLP, it can be produced in either a prokaryotic or eukaryotic expression system using target-encoding recombinant vectors, or in some cases can be assembled in cell-free conditions. To date, a wide variety of VLP-based candidate vaccines targeting various viral, bacterial, parasitic and fungal pathogens, as well as non-infectious diseases, have been produced in different expression systems. Some VLPs have entered clinical development and a few have been licensed and commercialized. This article reviews VLP-based vaccines produced in different systems, their immunogenicity in animal models and their status in clinical development.
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Affiliation(s)
- Natasha Kushnir
- Fraunhofer USA Center for Molecular Biotechnology, Newark, DE 19711, USA
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HIV-1 virus-like particles produced by stably transfected Drosophila S2 cells: a desirable vaccine component. J Virol 2012; 86:7662-76. [PMID: 22553333 DOI: 10.1128/jvi.07164-11] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The development of a successful vaccine against human immunodeficiency virus type 1 (HIV-1) likely requires immunogens that elicit both broadly neutralizing antibodies against envelope spikes and T cell responses that recognize multiple viral proteins. HIV-1 virus-like particles (VLP), because they display authentic envelope spikes on the particle surface, may be developed into such immunogens. However, in one way or the other current systems for HIV-1 VLP production have many limitations. To overcome these, in the present study we developed a novel strategy to produce HIV-1 VLP using stably transfected Drosophila S2 cells. We cotransfected S2 cells with plasmids encoding HIV-1 envelope, Gag, and Rev proteins and a selection marker. After stably transfected S2 clones were established, HIV-1 VLP and their immunogenicity in mice were carefully evaluated. Here, we report that HIV-1 envelope proteins are properly cleaved, glycosylated, and incorporated into VLP with Gag. The amount of VLP released into culture supernatants is comparable to those produced by insect cells infected with recombinant baculoviruses. Moreover, cryo-electron microscopy tomography revealed average 17 spikes per purified VLP, and antigenic epitopes on the spikes were recognized by the broadly neutralizing antibodies 2G12, b12, VRC01, and 4E10 but not by PG16. Finally, mice primed with DNA and boosted with VLP in the presence of CpG exhibited anti-envelope antibody responses, including ELISA-binding, neutralizing, antibody-dependent cell-mediated cytotoxicity and antibody-dependent cell-mediated viral inhibition, as well as envelope and Gag-specific CD8 T cell responses. Thus, we conclude that HIV-1 VLP produced by the S2 expression system has many desirable features to be developed into a vaccine component against HIV-1.
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Valley-Omar Z, Meyers AE, Shephard EG, Williamson AL, Rybicki EP. Abrogation of contaminating RNA activity in HIV-1 Gag VLPs. Virol J 2011; 8:462. [PMID: 21975161 PMCID: PMC3204299 DOI: 10.1186/1743-422x-8-462] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 10/06/2011] [Indexed: 11/25/2022] Open
Abstract
Background HIV-1 Gag virus like particles (VLPs) used as candidate vaccines are regarded as inert particles as they contain no replicative nucleic acid, although they do encapsidate cellular RNAs. During HIV-1 Gag VLP production in baculovirus-based expression systems, VLPs incorporate the baculovirus Gp64 envelope glycoprotein, which facilitates their entry into mammalian cells. This suggests that HIV-1 Gag VLPs produced using this system facilitate uptake and subsequent expression of encapsidated RNA in mammalian cells - an unfavourable characteristic for a vaccine. Methods HIV-1 Gag VLPs encapsidating reporter chloramphenicol acetyl transferase (CAT) RNA, were made in insect cells using the baculovirus expression system. The presence of Gp64 on the VLPs was verified by western blotting and RT-PCR used to detect and quantitate encapsidated CAT RNA. VLP samples were heated to inactivate CAT RNA. Unheated and heated VLPs incubated with selected mammalian cell lines and cell lysates tested for the presence of CAT protein by ELISA. Mice were inoculated with heated and unheated VLPs using a DNA prime VLP boost regimen. Results HIV-1 Gag VLPs produced had significantly high levels of Gp64 (~1650 Gp64 molecules/VLP) on their surfaces. The amount of encapsidated CAT RNA/μg Gag VLPs ranged between 0.1 to 7 ng. CAT protein was detected in 3 of the 4 mammalian cell lines incubated with VLPs. Incubation with heated VLPs resulted in BHK-21 and HeLa cell lysates showing reduced CAT protein levels compared with unheated VLPs and HEK-293 cells. Mice inoculated with a DNA prime VLP boost regimen developed Gag CD8 and CD4 T cell responses to GagCAT VLPs which also boosted a primary DNA response. Heating VLPs did not abrogate these immune responses but enhanced the Gag CD4 T cell responses by two-fold. Conclusions Baculovirus-produced HIV-1 Gag VLPs encapsidating CAT RNA were taken up by selected mammalian cell lines. The presence of CAT protein indicates that encapsidated RNA was expressed in the mammalian cells. Heat-treatment of the VLPs altered the ability of protein to be expressed in some cell lines tested but did not affect the ability of the VLPs to stimulate an immune response when inoculated into mice.
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Affiliation(s)
- Ziyaad Valley-Omar
- Department of Molecular and Cell Biology, Faculty of Science, University of Cape Town, University Ave, Rondebosch 7701, South Africa
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