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Abbas MN, Jmel MA, Mekki I, Dijkgraaf I, Kotsyfakis M. Recent Advances in Tick Antigen Discovery and Anti-Tick Vaccine Development. Int J Mol Sci 2023; 24:4969. [PMID: 36902400 PMCID: PMC10003026 DOI: 10.3390/ijms24054969] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 03/08/2023] Open
Abstract
Ticks can seriously affect human and animal health around the globe, causing significant economic losses each year. Chemical acaricides are widely used to control ticks, which negatively impact the environment and result in the emergence of acaricide-resistant tick populations. A vaccine is considered as one of the best alternative approaches to control ticks and tick-borne diseases, as it is less expensive and more effective than chemical controls. Many antigen-based vaccines have been developed as a result of current advances in transcriptomics, genomics, and proteomic techniques. A few of these (e.g., Gavac® and TickGARD®) are commercially available and are commonly used in different countries. Furthermore, a significant number of novel antigens are being investigated with the perspective of developing new anti-tick vaccines. However, more research is required to develop new and more efficient antigen-based vaccines, including on assessing the efficiency of various epitopes against different tick species to confirm their cross-reactivity and their high immunogenicity. In this review, we discuss the recent advancements in the development of antigen-based vaccines (traditional and RNA-based) and provide a brief overview of recent discoveries of novel antigens, along with their sources, characteristics, and the methods used to test their efficiency.
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Affiliation(s)
- Muhammad Nadeem Abbas
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716, China
| | - Mohamed Amine Jmel
- Laboratory of Genomics and Proteomics of Disease Vectors, Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 Ceske Budejovice, Czech Republic
| | - Imen Mekki
- Laboratory of Genomics and Proteomics of Disease Vectors, Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 Ceske Budejovice, Czech Republic
| | - Ingrid Dijkgraaf
- Department of Biochemistry, CARIM, Maastricht University, 6229 ER Maastricht, The Netherlands
| | - Michail Kotsyfakis
- Laboratory of Genomics and Proteomics of Disease Vectors, Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005 Ceske Budejovice, Czech Republic
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Chen WH, Strych U, Bottazzi ME, Lin YP. Past, present, and future of Lyme disease vaccines: antigen engineering approaches and mechanistic insights. Expert Rev Vaccines 2022; 21:1405-1417. [PMID: 35836340 PMCID: PMC9529901 DOI: 10.1080/14760584.2022.2102484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 07/13/2022] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Transmitted by ticks, Lyme disease is the most common vector-borne disease in the Northern hemisphere. Despite the geographical expansion of human Lyme disease cases, no effective preventive strategies are currently available. Developing an efficacious and safe vaccine is therefore urgently needed. Efforts have previously been taken to identify vaccine targets in the causative pathogen (Borrelia burgdorferi sensu lato) and arthropod vector (Ixodes spp.). However, progress was impeded due to a lack of consumer confidence caused by the myth of undesired off-target responses, low immune responses, a limited breadth of immune reactivity, as well as by the complexities of the vaccine process development. AREA COVERED In this review, we summarize the antigen engineering approaches that have been applied to overcome those challenges and the underlying mechanisms that can be exploited to improve both safety and efficacy of future Lyme disease vaccines. EXPERT OPINION Over the past two decades, several new genetically redesigned Lyme disease vaccine candidates have shown success in both preclinical and clinical settings and built a solid foundation for further development. These studies have greatly informed the protective mechanisms of reducing Lyme disease burdens and ending the endemic of this disease.
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Affiliation(s)
- Wen-Hsiang Chen
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Hospital Center for Vaccine Development, Houston, TX, USA
| | - Ulrich Strych
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Hospital Center for Vaccine Development, Houston, TX, USA
| | - Maria Elena Bottazzi
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Hospital Center for Vaccine Development, Houston, TX, USA
- Department of Biology, Baylor University, Waco, TX, United States
| | - Yi-Pin Lin
- Division of Infectious Diseases, Wadsworth Center, NYSDOH, Albany, NY, USA
- Department of Biomedical Sciences, SUNY Albany, Albany, NY, USA
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van Oosterwijk JG, Wikel SK. Resistance to Ticks and the Path to Anti-Tick and Transmission Blocking Vaccines. Vaccines (Basel) 2021; 9:725. [PMID: 34358142 PMCID: PMC8310300 DOI: 10.3390/vaccines9070725] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/30/2021] [Accepted: 06/30/2021] [Indexed: 12/31/2022] Open
Abstract
The medical and veterinary public health importance of ticks and tick-borne pathogens is increasing due to the expansion of the geographic ranges of both ticks and pathogens, increasing tick populations, growing incidence of tick-borne diseases, emerging tick transmitted pathogens, and continued challenges of achieving effective and sustained tick control. The past decades show an increasing interest in the immune-mediated control of tick infestations and pathogen transmission through the use of vaccines. Bovine tick resistance induced by repeated infestations was reported over a century ago. This review addresses the phenomena and immunological underpinning of resistance to tick infestation by livestock and laboratory animals; the scope of tick countermeasures to host immune defenses; and the impact of genomics, functional genomics, and proteomics on dissecting complex tick-host-pathogen interactions. From early studies utilizing tick tissue extracts to salivary gland derived molecules and components of physiologically important pathways in tick gut and other tissues, an increased understanding of these relationships, over time, impacted the evolution of anti-tick vaccine antigen selection. Novel antigens continue to emerge, including increased interest in the tick microbiome. Anti-tick and transmission blocking vaccines targeting pathogen reservoirs have the potential to disrupt enzootic cycles and reduce human, companion, domestic animal, and wildlife exposure to infected ticks.
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Affiliation(s)
| | - Stephen K. Wikel
- US Biologic Inc., 20 Dudley Street, Memphis, TN 38103, USA;
- Department of Medical Sciences, School of Medicine, Quinnipiac University, Hamden, CT 06518, USA
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Shukla S, Wang C, Beiss V, Cai H, Washington T, Murray AA, Gong X, Zhao Z, Masarapu H, Zlotnick A, Fiering S, Steinmetz NF. The unique potency of Cowpea mosaic virus (CPMV) in situ cancer vaccine. Biomater Sci 2020; 8:5489-5503. [PMID: 32914796 PMCID: PMC8086234 DOI: 10.1039/d0bm01219j] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The immunosuppressive tumor microenvironment enables cancer to resist immunotherapies. We have established that intratumoral administration of plant-derived Cowpea mosaic virus (CPMV) nanoparticles as an in situ vaccine overcomes the local immunosuppression and stimulates a potent anti-tumor response in several mouse cancer models and canine patients. CPMV does not infect mammalian cells but acts as a danger signal that leads to the recruitment and activation of innate and subsequently, adaptive immune cells. In the present study we addressed whether other icosahedral viruses or virus-like particles (VLPs) of plant, bacteriophage and mammalian origin can be similarly employed as intratumoral immunotherapy. Our results indicate that CPMV in situ vaccine outperforms Cowpea chlorotic mottle virus (CCMV), Physalis mosaic virus (PhMV), Sesbania mosaic virus (SeMV), bacteriophage Qβ VLPs, or Hepatitis B virus capsids (HBVc). Furthermore, ex vivo and in vitro assays reveal unique features of CPMV that makes it an inherently stronger immune stimulant.
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Affiliation(s)
- Sourabh Shukla
- Department of NanoEngineering, University of California-San Diego, La Jolla, CA 92039, USA.
| | - Chao Wang
- Department of NanoEngineering, University of California-San Diego, La Jolla, CA 92039, USA.
| | - Veronique Beiss
- Department of NanoEngineering, University of California-San Diego, La Jolla, CA 92039, USA.
| | - Hui Cai
- Department of NanoEngineering, University of California-San Diego, La Jolla, CA 92039, USA.
| | - Torus Washington
- Department of NanoEngineering, University of California-San Diego, La Jolla, CA 92039, USA.
| | - Abner A Murray
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Xingjian Gong
- Department of Bioengineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Zhongchao Zhao
- Molecular and Cellular Biochemistry Department, Indiana University Bloomington, IN 47405, USA
| | - Hema Masarapu
- Department of Virology, Sri Venkateswara University, Tirupati 517502, India
| | - Adam Zlotnick
- Molecular and Cellular Biochemistry Department, Indiana University Bloomington, IN 47405, USA
| | - Steven Fiering
- Geisel School of Medicine, Dartmouth College, Lebanon, NH 03756, USA
| | - Nicole F Steinmetz
- Department of NanoEngineering, University of California-San Diego, La Jolla, CA 92039, USA. and Department of Bioengineering, University of California-San Diego, La Jolla, CA 92039, USA and Department of Radiology, University of California-San Diego, La Jolla, CA 92039, USA and Moores Cancer Center, University of California-San Diego, La Jolla, CA 92039, USA and Center for Nano-ImmunoEngineering, University of California-San Diego, La Jolla, CA 92039, USA
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5
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Wen S, Wang F, Ji Z, Pan Y, Jian M, Bi Y, Zhou G, Luo L, Chen T, Li L, Ding Z, Abi ME, Liu A, Bao F. Salp15, a Multifunctional Protein From Tick Saliva With Potential Pharmaceutical Effects. Front Immunol 2020; 10:3067. [PMID: 31998324 PMCID: PMC6968165 DOI: 10.3389/fimmu.2019.03067] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 12/16/2019] [Indexed: 12/30/2022] Open
Abstract
Ixodes ticks are the main vectors for a number of zoonotic diseases, including Lyme disease. Ticks secrete saliva directly into a mammalian host while feeding on the host's blood. This action serves to modulate host immunity and coagulation, thus allowing ticks to attach and feed upon their host. One of the most extensively studied components of tick saliva is Salp15. Research has shown that this protein binds specifically to CD4 molecules on the surface of T lymphocytes, interferes with TCR-mediated signaling transduction, inhibits CD4+ T cell activation and proliferation, and impedes the secretion of interleukin 2 (IL-2). Salp15 also binds specifically to dendritic cell dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) to up-regulate the expression of CD73 in regulatory T cells. Collectively, these findings render this salivary protein a potential candidate for a range of therapeutic applications. Here, we discuss our current understanding of Salp15 and the mechanisms that might be used to treat disease.
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Affiliation(s)
- Shiyuan Wen
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, China.,The Center of Tropical Diseases, The Institute for Tropical Medicine, Kunming Medical University, Kunming, China.,Yunnan Demonstration Base of International Science and Technology Cooperation for Tropical Diseases, Kunming, China.,The First People's Hospital of Yunnan Province, The Affiliated Hospital of Kunming University of Science and Technology, Kunming, China
| | - Feng Wang
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, China.,The Center of Tropical Diseases, The Institute for Tropical Medicine, Kunming Medical University, Kunming, China.,Yunnan Demonstration Base of International Science and Technology Cooperation for Tropical Diseases, Kunming, China
| | - Zhenhua Ji
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, China
| | - YingYi Pan
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, China
| | - Miaomiao Jian
- The Center of Tropical Diseases, The Institute for Tropical Medicine, Kunming Medical University, Kunming, China.,Department of Biochemistry and Molecular Biology, Kunming Medical University, Kunming, China
| | - YunFeng Bi
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, China.,The Center of Tropical Diseases, The Institute for Tropical Medicine, Kunming Medical University, Kunming, China.,Yunnan Demonstration Base of International Science and Technology Cooperation for Tropical Diseases, Kunming, China
| | - Guozhong Zhou
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, China.,The Center of Tropical Diseases, The Institute for Tropical Medicine, Kunming Medical University, Kunming, China.,Yunnan Demonstration Base of International Science and Technology Cooperation for Tropical Diseases, Kunming, China
| | - Lisha Luo
- The Center of Tropical Diseases, The Institute for Tropical Medicine, Kunming Medical University, Kunming, China.,Department of Biochemistry and Molecular Biology, Kunming Medical University, Kunming, China
| | - Taigui Chen
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, China
| | - Lianbao Li
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, China
| | - Zhe Ding
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, China
| | - Manzama-Esso Abi
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, China
| | - Aihua Liu
- The Center of Tropical Diseases, The Institute for Tropical Medicine, Kunming Medical University, Kunming, China.,Yunnan Demonstration Base of International Science and Technology Cooperation for Tropical Diseases, Kunming, China.,Department of Biochemistry and Molecular Biology, Kunming Medical University, Kunming, China
| | - Fukai Bao
- Department of Microbiology and Immunology, Kunming Medical University, Kunming, China.,The Center of Tropical Diseases, The Institute for Tropical Medicine, Kunming Medical University, Kunming, China.,Yunnan Demonstration Base of International Science and Technology Cooperation for Tropical Diseases, Kunming, China
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Federizon J, Lin YP, Lovell JF. Antigen Engineering Approaches for Lyme Disease Vaccines. Bioconjug Chem 2019; 30:1259-1272. [PMID: 30987418 DOI: 10.1021/acs.bioconjchem.9b00167] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Increasing rates of Lyme disease necessitate preventive measures such as immunization to mitigate the risk of contracting the disease. At present, there is no human Lyme disease vaccine available on the market. Since the withdrawal of the first and only licensed Lyme disease vaccine based on lipidated recombinant OspA, vaccine and antigen research has aimed to overcome its risks and shortcomings. Replacement of the putative cross-reactive T-cell epitope in OspA via mutation or chimerism addresses the potential risk of autoimmunity. Multivalent approaches in Lyme disease vaccines have been pursued to address sequence heterogeneity of Lyme borreliae antigens and to induce a repertoire of functional antibodies necessary for efficient heterologous protection. This Review summarizes recent antigen engineering strategies that have paved the way for the development of next generation vaccines against Lyme disease, some of which have reached clinical testing. Bioconjugation methods that incorporate antigens to self-assembling nanoparticles for immune response potentiation are also discussed.
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Affiliation(s)
- Jasmin Federizon
- Department of Biomedical Engineering , University at Buffalo, State University of New York , Buffalo , New York 14260 , United States
| | - Yi-Pin Lin
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health , Albany , New York 12208 , United States.,Department of Biomedical Sciences , State University of New York at Albany , Albany , New York 12222 , United States
| | - Jonathan F Lovell
- Department of Biomedical Engineering , University at Buffalo, State University of New York , Buffalo , New York 14260 , United States
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7
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Boulanger N. [Immunomodulatory effect of tick saliva in pathogen transmission]. Biol Aujourdhui 2019; 212:107-117. [PMID: 30973140 DOI: 10.1051/jbio/2019001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Indexed: 12/29/2022]
Abstract
Ticks are the most important vectors of pathogens in human and veterinary medicine. These strictly haematophagous acarines produce a saliva containing a variety of bioactive molecules affecting host pharmacology and immunity. This process is vital for hard ticks to prevent rejection by the host during the blood meal that lasts several days. All actors involved in the immunity interplay are impacted by this saliva, the innate immunity being represented by resident and migrating immune cells, as well as the T and B lymphocytes of the adaptive immune system. The skin plays a key role in vector-borne diseases. During the long co-evolution with the tick, the infectious agents benefit from this favorable environment to be transmitted efficiently into the skin and to multiply in the vertebrate host. Therefore, the saliva is an important virulence booster, which enhances substantially their pathogenicity.
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Affiliation(s)
- Nathalie Boulanger
- EA7290, Virulence Bactérienne Précoce, Groupe Borrelia, Facultés de Pharmacie et Médecine, Université de Strasbourg, Institut de bactériologie, 3 rue Koeberlé, 67000 Strasbourg, France - Centre National de Référence Borrelia, Plateau technique de Microbiologie, CHRU Strasbourg, 1 rue Koeberlé, 67000 Strasbourg, France
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8
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Charlton Hume HK, Vidigal J, Carrondo MJT, Middelberg APJ, Roldão A, Lua LHL. Synthetic biology for bioengineering virus-like particle vaccines. Biotechnol Bioeng 2019; 116:919-935. [PMID: 30597533 PMCID: PMC7161758 DOI: 10.1002/bit.26890] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 11/08/2018] [Accepted: 11/29/2018] [Indexed: 12/13/2022]
Abstract
Vaccination is the most effective method of disease prevention and control. Many viruses and bacteria that once caused catastrophic pandemics (e.g., smallpox, poliomyelitis, measles, and diphtheria) are either eradicated or effectively controlled through routine vaccination programs. Nonetheless, vaccine manufacturing remains incredibly challenging. Viruses exhibiting high antigenic diversity and high mutation rates cannot be fairly contested using traditional vaccine production methods and complexities surrounding the manufacturing processes, which impose significant limitations. Virus-like particles (VLPs) are recombinantly produced viral structures that exhibit immunoprotective traits of native viruses but are noninfectious. Several VLPs that compositionally match a given natural virus have been developed and licensed as vaccines. Expansively, a plethora of studies now confirms that VLPs can be designed to safely present heterologous antigens from a variety of pathogens unrelated to the chosen carrier VLPs. Owing to this design versatility, VLPs offer technological opportunities to modernize vaccine supply and disease response through rational bioengineering. These opportunities are greatly enhanced with the application of synthetic biology, the redesign and construction of novel biological entities. This review outlines how synthetic biology is currently applied to engineer VLP functions and manufacturing process. Current and developing technologies for the identification of novel target-specific antigens and their usefulness for rational engineering of VLP functions (e.g., presentation of structurally diverse antigens, enhanced antigen immunogenicity, and improved vaccine stability) are described. When applied to manufacturing processes, synthetic biology approaches can also overcome specific challenges in VLP vaccine production. Finally, we address several challenges and benefits associated with the translation of VLP vaccine development into the industry.
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Affiliation(s)
- Hayley K. Charlton Hume
- The University of Queensland, Australian Institute of Bioengineering and NanotechnologySt LuciaQueenslandAustralia
| | - João Vidigal
- Health & Pharma Division, Animal Cell Technology Unit, Instituto de Biologia Experimental e Tecnológica (iBET)OeirasPortugal
- Health & Pharma Division, Animal Cell Technology Unit, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da RepúblicaOeirasPortugal
| | - Manuel J. T. Carrondo
- Health & Pharma Division, Animal Cell Technology Unit, Instituto de Biologia Experimental e Tecnológica (iBET)OeirasPortugal
| | - Anton P. J. Middelberg
- Faculty of Engineering, Computer and Mathematical Sciences, The University of AdelaideAdelaideSouth AustraliaAustralia
| | - António Roldão
- Health & Pharma Division, Animal Cell Technology Unit, Instituto de Biologia Experimental e Tecnológica (iBET)OeirasPortugal
- Health & Pharma Division, Animal Cell Technology Unit, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da RepúblicaOeirasPortugal
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Abstract
The highly immunogenic icosahedral capsid of hepatitis B virus (HBV) can be exploited as a nanoparticulate display platform for heterologous molecules. Its constituent core protein (HBc) of only ~180 amino acids spontaneously forms capsid-like particles (CLPs) even in E. coli. The immunodominant c/e1 epitope in the center of the HBc primary sequence comprises a solvent-exposed loop that tolerates insertions of flexible peptide sequences yet also of selected whole proteins as long as their 3D structures fit into the two acceptor sites. This constraint is largely overcome in the SplitCore system, where the sequences flanking the loop are expressed as two separate but self-complementing entities, with the foreign sequence fixed to the carrier at one end only. Both the contiguous and the split type of CLP strongly enhance immunogenicity of the displayed sequence but also nonvaccine applications can easily be envisaged. After a brief survey of the basic features of the two HBc carrier forms, we provide conceptual guidelines concerning which foreign proteins are likely to be presentable, or not, on either carrier type. We describe generally applicable protocols for CLP expression in E. coli, cell lysis and CLP enrichment by sucrose gradient velocity sedimentation, plus a simple but meaningful gel electrophoretic assay to assess proper particle formation.
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Heger-Stevic J, Zimmermann P, Lecoq L, Böttcher B, Nassal M. Hepatitis B virus core protein phosphorylation: Identification of the SRPK1 target sites and impact of their occupancy on RNA binding and capsid structure. PLoS Pathog 2018; 14:e1007488. [PMID: 30566530 PMCID: PMC6317823 DOI: 10.1371/journal.ppat.1007488] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 01/03/2019] [Accepted: 11/27/2018] [Indexed: 12/19/2022] Open
Abstract
Hepatitis B virus (HBV) replicates its 3 kb DNA genome through capsid-internal reverse transcription, initiated by assembly of 120 core protein (HBc) dimers around a complex of viral pregenomic (pg) RNA and polymerase. Following synthesis of relaxed circular (RC) DNA capsids can be enveloped and secreted as stable virions. Upon infection of a new cell, however, the capsid disintegrates to release the RC-DNA into the nucleus for conversion into covalently closed circular (ccc) DNA. HBc´s interactions with nucleic acids are mediated by an arginine-rich C terminal domain (CTD) with intrinsically strong non-specific RNA binding activity. Adaptation to the changing demands for nucleic acid binding during the viral life cycle is thought to involve dynamic phosphorylation / dephosphorylation events. However, neither the relevant enzymes nor their target sites in HBc are firmly established. Here we developed a bacterial coexpression system enabling access to definably phosphorylated HBc. Combining Phos-tag gel electrophoresis, mass spectrometry and mutagenesis we identified seven of the eight hydroxy amino acids in the CTD as target sites for serine-arginine rich protein kinase 1 (SRPK1); fewer sites were phosphorylated by PKA and PKC. Phosphorylation of all seven sites reduced nonspecific RNA encapsidation as drastically as deletion of the entire CTD and altered CTD surface accessibility, without major structure changes in the capsid shell. The bulk of capsids from human hepatoma cells was similarly highly, yet non-identically, phosphorylated as by SRPK1. While not proving SRPK1 as the infection-relevant HBc kinase the data suggest a mechanism whereby high-level HBc phosphorylation principally suppresses RNA binding whereas one or few strategic dephosphorylation events enable selective packaging of the pgRNA/polymerase complex. The tools developed in this study should greatly facilitate the further deciphering of the role of HBc phosphorylation in HBV infection and its evaluation as a potential new therapeutic target.
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Affiliation(s)
- Julia Heger-Stevic
- University Hospital Freiburg, Department of Medicine II / Molecular Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Biological Faculty, University of Freiburg, Freiburg, Germany
| | - Peter Zimmermann
- University Hospital Freiburg, Department of Medicine II / Molecular Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Biological Faculty, University of Freiburg, Freiburg, Germany
| | - Lauriane Lecoq
- Institut de Biologie et Chimie des Protéines, University of Lyon1, Lyon, France
| | - Bettina Böttcher
- Department of Biochemistry, Biocenter, University of Würzburg, Würzburg, Germany
| | - Michael Nassal
- University Hospital Freiburg, Department of Medicine II / Molecular Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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11
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Pumpens P, Grens E. The true story and advantages of the famous Hepatitis B virus core particles: Outlook 2016. Mol Biol 2016. [DOI: 10.1134/s0026893316040099] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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