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Ackermann-Gäumann R, Lang P, Zens KD. Defining the "Correlate(s) of Protection" to tick-borne encephalitis vaccination and infection - key points and outstanding questions. Front Immunol 2024; 15:1352720. [PMID: 38318179 PMCID: PMC10840404 DOI: 10.3389/fimmu.2024.1352720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 01/05/2024] [Indexed: 02/07/2024] Open
Abstract
Tick-borne Encephalitis (TBE) is a severe disease of the Central Nervous System (CNS) caused by the tick-borne encephalitis virus (TBEV). The generation of protective immunity after TBEV infection or TBE vaccination relies on the integrated responses of many distinct cell types at distinct physical locations. While long-lasting memory immune responses, in particular, form the basis for the correlates of protection against many diseases, these correlates of protection have not yet been clearly defined for TBE. This review addresses the immune control of TBEV infection and responses to TBE vaccination. Potential correlates of protection and the durability of protection against disease are discussed, along with outstanding questions in the field and possible areas for future research.
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Affiliation(s)
- Rahel Ackermann-Gäumann
- Microbiologie, ADMED Analyses et Diagnostics Médicaux, La Chaux-de-Fonds, Switzerland
- Swiss National Reference Center for Tick-transmitted Diseases, La Chaux-de-Fonds, Switzerland
| | - Phung Lang
- Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland
| | - Kyra D. Zens
- Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland
- Institute for Experimental Immunology, University of Zurich, Zurich, Switzerland
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Sycheva AL, Komech EA, Pogorelyy MV, Minervina AA, Urazbakhtin SZ, Salnikova MA, Vorovitch MF, Kopantzev EP, Zvyagin IV, Komkov AY, Mamedov IZ, Lebedev YB. Inactivated tick-borne encephalitis vaccine elicits several overlapping waves of T cell response. Front Immunol 2022; 13:970285. [PMID: 36091004 PMCID: PMC9449805 DOI: 10.3389/fimmu.2022.970285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 08/05/2022] [Indexed: 12/02/2022] Open
Abstract
The development and implementation of vaccines have been growing exponentially, remaining one of the major successes of healthcare over the last century. Nowadays, active regular immunizations prevent epidemics of many viral diseases, including tick-borne encephalitis (TBE). Along with the generation of virus-specific antibodies, a highly effective vaccine should induce T cell responses providing long-term immune defense. In this study, we performed longitudinal high-throughput T cell receptor (TCR) sequencing to characterize changes in individual T cell repertoires of 11 donors immunized with an inactivated TBE vaccine. After two-step immunization, we found significant clonal expansion of both CD4+ and CD8+ T cells, ranging from 302 to 1706 vaccine-associated TCRβ clonotypes in different donors. We detected several waves of T cell clonal expansion generated by distinct groups of vaccine-responding clones. Both CD4+ and CD8+ vaccine-responding T cell clones formed 17 motifs in TCRβ sequences shared by donors with identical HLA alleles. Our results indicate that TBE vaccination leads to a robust T cell response due to the production of a variety of T cell clones with a memory phenotype, which recognize a large set of epitopes.
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Affiliation(s)
- Anastasiia L. Sycheva
- Department of Genomics of Adaptive Immunity, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, Russia
- *Correspondence: Anastasiia L. Sycheva, ; Yuri B. Lebedev,
| | - Ekaterina A. Komech
- Department of Genomics of Adaptive Immunity, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, Russia
- Department of Molecular Technologies, Institute of Translational Medicine, Pirogov Russian National Research Medical University, Moscow, Russia
| | - Mikhail V. Pogorelyy
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, TN, United States
| | - Anastasia A. Minervina
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, TN, United States
| | - Shamil Z. Urazbakhtin
- Computational Systems Biochemistry Research Group, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Maria A. Salnikova
- Department of Genomics of Adaptive Immunity, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, Russia
- Department of Immunology, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Mikhail F. Vorovitch
- Laboratory of Tick-Borne Encephalitis and Other Encephalitis, Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of RAS (FSASI “Chumakov FSC R&D IBP RAS”), Moscow, Russia
- Department of Organization and Technology of Production of Immune-and-Biological Products, Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Eugene P. Kopantzev
- Department of Genomics and Postgenomic Technologies, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, Russia
| | - Ivan V. Zvyagin
- Department of Genomics of Adaptive Immunity, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, Russia
- Department of Molecular Technologies, Institute of Translational Medicine, Pirogov Russian National Research Medical University, Moscow, Russia
| | - Alexander Y. Komkov
- Department of Genomics of Adaptive Immunity, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, Russia
- Laboratory of Cytogenetics and Molecular Genetics, Dmitry Rogachev National Medical and Research Centre of Paediatric Haematology, Oncology and Immunology, Moscow, Russia
| | - Ilgar Z. Mamedov
- Department of Genomics of Adaptive Immunity, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, Russia
| | - Yuri B. Lebedev
- Department of Genomics of Adaptive Immunity, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, Moscow, Russia
- Department of Molecular Technologies, Institute of Translational Medicine, Pirogov Russian National Research Medical University, Moscow, Russia
- *Correspondence: Anastasiia L. Sycheva, ; Yuri B. Lebedev,
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Kubinski M, Beicht J, Gerlach T, Volz A, Sutter G, Rimmelzwaan GF. Tick-Borne Encephalitis Virus: A Quest for Better Vaccines against a Virus on the Rise. Vaccines (Basel) 2020; 8:E451. [PMID: 32806696 PMCID: PMC7564546 DOI: 10.3390/vaccines8030451] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/06/2020] [Accepted: 08/10/2020] [Indexed: 12/15/2022] Open
Abstract
Tick-borne encephalitis virus (TBEV), a member of the family Flaviviridae, is one of the most important tick-transmitted viruses in Europe and Asia. Being a neurotropic virus, TBEV causes infection of the central nervous system, leading to various (permanent) neurological disorders summarized as tick-borne encephalitis (TBE). The incidence of TBE cases has increased due to the expansion of TBEV and its vectors. Since antiviral treatment is lacking, vaccination against TBEV is the most important protective measure. However, vaccination coverage is relatively low and immunogenicity of the currently available vaccines is limited, which may account for the vaccine failures that are observed. Understanding the TBEV-specific correlates of protection is of pivotal importance for developing novel and improved TBEV vaccines. For affording robust protection against infection and development of TBE, vaccines should induce both humoral and cellular immunity. In this review, the adaptive immunity induced upon TBEV infection and vaccination as well as novel approaches to produce improved TBEV vaccines are discussed.
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Affiliation(s)
- Mareike Kubinski
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Foundation (TiHo), Buenteweg 17, 30559 Hannover, Germany; (M.K.); (J.B.); (T.G.)
| | - Jana Beicht
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Foundation (TiHo), Buenteweg 17, 30559 Hannover, Germany; (M.K.); (J.B.); (T.G.)
| | - Thomas Gerlach
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Foundation (TiHo), Buenteweg 17, 30559 Hannover, Germany; (M.K.); (J.B.); (T.G.)
| | - Asisa Volz
- Institute of Virology, University of Veterinary Medicine Hannover, Foundation (TiHo), Buenteweg 17, 30559 Hannover, Germany;
| | - Gerd Sutter
- Institute for Infectious Diseases and Zoonoses, Ludwig-Maximilians-University (LMU) Munich, Veterinaerstr. 13, 80539 Munich, Germany;
| | - Guus F. Rimmelzwaan
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Foundation (TiHo), Buenteweg 17, 30559 Hannover, Germany; (M.K.); (J.B.); (T.G.)
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Intrathecal expression of IL-5 and humoral response in patients with tick-borne encephalitis. Ticks Tick Borne Dis 2018; 9:896-911. [PMID: 29602685 DOI: 10.1016/j.ttbdis.2018.03.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 03/10/2018] [Accepted: 03/11/2018] [Indexed: 01/31/2023]
Abstract
AIM The aim of the study was to assess the role of an early specific humoral response in human infection with a tick-borne encephalitis virus (TBEV) and the role of IL-5 as its potential mediator and marker. MATERIALS AND METHODS The retrospective study involved a cohort of 199 patients diagnosed with TBE, in whom anti-TBEV IgM and IgG antibody titers were analyzed on admission and compared with clinical presentation and basic laboratory parameters. The prospective study included 50 TBE patients in whom IL-5 serum and CSF concentration was measured with ELISA on admission in the TBE neurologic phase and in selected patients before discharge, at follow-up or in samples obtained before the neurologic phase onset. RESULTS The serum anti-TBEV IgM correlated with good clinical outcome and the CSF anti-TBEV IgM with more pronounced CSF inflammation on admission, but also with its more complete resolution on follow-up. The serum anti-TBEV IgG correlated with milder presentation and better outcome. Concentration of IL-5 was increased in CSF but not in the serum of TBE patients. IL-5 concentration index on admission favored its intrathecal synthesis. IL-5 did not correlate significantly with clinical presentation and specific IgM and IgG titers. CONCLUSIONS Specific anti-TBEV IgM systemic and intrathecal response and IgG systemic response are protective, together favoring milder presentation, better outcome and resolution of central nervous system (CNS) inflammation. IL-5 is expressed intrathecally in TBE, but its pathogenetic role remains unclear.
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Ignatieva EV, Igoshin AV, Yudin NS. A database of human genes and a gene network involved in response to tick-borne encephalitis virus infection. BMC Evol Biol 2017; 17:259. [PMID: 29297316 PMCID: PMC5751789 DOI: 10.1186/s12862-017-1107-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
BACKGROUND Tick-borne encephalitis is caused by the neurotropic, positive-sense RNA virus, tick-borne encephalitis virus (TBEV). TBEV infection can lead to a variety of clinical manifestations ranging from slight fever to severe neurological illness. Very little is known about genetic factors predisposing to severe forms of disease caused by TBEV. The aims of the study were to compile a catalog of human genes involved in response to TBEV infection and to rank genes from the catalog based on the number of neighbors in the network of pairwise interactions involving these genes and TBEV RNA or proteins. RESULTS Based on manual review and curation of scientific publications a catalog comprising 140 human genes involved in response to TBEV infection was developed. To provide access to data on all genes, the TBEVhostDB web resource ( http://icg.nsc.ru/TBEVHostDB/ ) was created. We reconstructed a network formed by pairwise interactions between TBEV virion itself, viral RNA and viral proteins and 140 genes/proteins from TBEVHostDB. Genes were ranked according to the number of interactions in the network. Two genes/proteins (CCR5 and IFNAR1) that had maximal number of interactions were revealed. It was found that the subnetworks formed by CCR5 and IFNAR1 and their neighbors were a fragments of two key pathways functioning during the course of tick-borne encephalitis: (1) the attenuation of interferon-I signaling pathway by the TBEV NS5 protein that targeted peptidase D; (2) proinflammation and tissue damage pathway triggered by chemokine receptor CCR5 interacting with CD4, CCL3, CCL4, CCL2. Among nine genes associated with severe forms of TBEV infection, three genes/proteins (CCR5, IL10, ARID1B) were found to have protein-protein interactions within the network, and two genes/proteins (IFNL3 and the IL10, that was just mentioned) were up- or down-regulated in response to TBEV infection. Based on this finding, potential mechanisms for participation of CCR5, IL10, ARID1B, and IFNL3 in the host response to TBEV infection were suggested. CONCLUSIONS A database comprising 140 human genes involved in response to TBEV infection was compiled and the TBEVHostDB web resource, providing access to all genes was created. This is the first effort of integrating and unifying data on genetic factors that may predispose to severe forms of diseases caused by TBEV. The TBEVHostDB could potentially be used for assessment of risk factors for severe forms of tick-borne encephalitis and for the design of personalized pharmacological strategies for the treatment of TBEV infection.
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Affiliation(s)
- Elena V Ignatieva
- Laboratory of Evolutionary Bioinformatics and Theoretical Genetics, The Federal Research Center Institute of Cytology and Genetics of Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia. .,Center for Brain Neurobiology and Neurogenetics, The Federal Research Center Institute of Cytology and Genetics of Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia. .,Novosibirsk State University, Novosibirsk, 630090, Russia.
| | - Alexander V Igoshin
- Laboratory of Infectious Disease Genomics, The Federal Research Center Institute of Cytology and Genetics of Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - Nikolay S Yudin
- Laboratory of Infectious Disease Genomics, The Federal Research Center Institute of Cytology and Genetics of Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia.,Novosibirsk State University, Novosibirsk, 630090, Russia
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Computational prediction and analysis of potential antigenic CTL epitopes in Zika virus: A first step towards vaccine development. INFECTION GENETICS AND EVOLUTION 2016; 45:187-197. [DOI: 10.1016/j.meegid.2016.08.037] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 08/27/2016] [Accepted: 08/29/2016] [Indexed: 02/03/2023]
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Cox MMJ. Recombinant protein vaccines produced in insect cells. Vaccine 2012; 30:1759-66. [PMID: 22265860 PMCID: PMC7115678 DOI: 10.1016/j.vaccine.2012.01.016] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 01/02/2012] [Accepted: 01/05/2012] [Indexed: 11/15/2022]
Abstract
The baculovirus-insect cell expression system is a well known tool for the production of complex proteins. The technology is also used for commercial manufacture of various veterinary and human vaccines. This review paper provides an overview of how this technology can be applied to produce a multitude of vaccine candidates. The key advantage of this recombinant protein manufacturing platform is that a universal "plug and play" process may be used for producing a broad range of protein-based prophylactic and therapeutic vaccines for both human and veterinary use while offering the potential for low manufacturing costs. Large scale mammalian cell culture facilities previously established for the manufacturing of monoclonal antibodies that have now become obsolete due to yield improvement could be deployed for the manufacturing of these vaccines. Alternatively, manufacturing capacity could be established in geographic regions that do not have any vaccine production capability. Dependent on health care priorities, different vaccines could be manufactured while maintaining the ability to rapidly convert to producing pandemic influenza vaccine when the need arises.
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Affiliation(s)
- Manon M J Cox
- Protein Sciences Corporation, 1000 Research Parkway, Meriden, CT 06450, USA.
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Metz SW, Pijlman GP. Arbovirus vaccines; opportunities for the baculovirus-insect cell expression system. J Invertebr Pathol 2011; 107 Suppl:S16-30. [PMID: 21784227 DOI: 10.1016/j.jip.2011.05.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Revised: 02/08/2011] [Accepted: 02/08/2011] [Indexed: 02/06/2023]
Abstract
The baculovirus-insect cell expression system is a well-established technology for the production of heterologous viral (glyco)proteins in cultured cells, applicable for basic scientific research as well as for the development and production of vaccines and diagnostics. Arboviruses form an emerging group of medically important viral pathogens that are transmitted to humans and animals via arthropod vectors, mostly mosquitoes, ticks or midges. Few arboviral vaccines are currently available, but there is a growing need for safe and effective vaccines against some highly pathogenic arboviruses such as Chikungunya, dengue, West Nile, Rift Valley fever and Bluetongue viruses. This comprehensive review discusses the biology and current state of the art in vaccine development for arboviruses belonging to the families Togaviridae, Flaviviridae, Bunyaviridae and Reoviridae and the potential of the baculovirus-insect cell expression system for vaccine antigen production The members of three of these four arbovirus families have enveloped virions and display immunodominant glycoproteins with a complex structure at their surface. Baculovirus expression of viral antigens often leads to correctly folded and processed (glyco)proteins able to induce protective immunity in animal models and humans. As arboviruses occupy a unique position in the virosphere in that they also actively replicate in arthropod cells, the baculovirus-insect cell expression system is well suited to produce arboviral proteins with correct folding and post-translational processing. The opportunities for recombinant baculoviruses to aid in the development of safe and effective subunit and virus-like particle vaccines against arboviral diseases are discussed.
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Affiliation(s)
- Stefan W Metz
- Laboratory of Virology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
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Zlamy M, Würzner R, Holzmann H, Brandstätter A, Jeller V, Zimmerhackl LB, Prelog M. Antibody dynamics after tick-borne encephalitis and measles–mumps–rubella vaccination in children post early thymectomy. Vaccine 2010; 28:8053-60. [DOI: 10.1016/j.vaccine.2010.10.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 09/30/2010] [Accepted: 10/01/2010] [Indexed: 12/15/2022]
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Seidel MG, Grohmann E, Sadeghi K, Pollak A, Heitger A, Förster-Waldl E. Vaccination against tick-borne encephalitis virus tests specific IgG production ability in patients under immunoglobulin substitution therapy. Vaccine 2010; 28:6621-6. [DOI: 10.1016/j.vaccine.2010.07.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Revised: 06/16/2010] [Accepted: 07/12/2010] [Indexed: 12/30/2022]
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Diminished response to tick-borne encephalitis vaccination in thymectomized children. Vaccine 2007; 26:595-600. [PMID: 18178293 DOI: 10.1016/j.vaccine.2007.11.074] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Revised: 11/14/2007] [Accepted: 11/16/2007] [Indexed: 01/06/2023]
Abstract
In order to analyze the clinical impact of immunological alterations in thymectomized children after exposure to a new antigen (tick-borne encephalitis virus (TBEV) vaccine), 17 thymectomized children completed a three-dose immunization regimen. Thymectomized children showed significantly lower TBEV IgG antibody levels after the second vaccination when compared to healthy age-matched controls (n=30) (p=0.03), but a normal response after the third vaccination. Age at thymectomy correlated significantly with the TBEV IgG antibody levels (p=0.04). Thymectomized children also showed significantly lower total counts and percentages for naïve T cells correlating with time after thymectomy (p=0.02), than observed for controls. These changes in T cell subsets and the decreased ability to respond to new antigens in thymectomized children, as observed here, may precede more striking effects such as higher infection rates or autoimmune conditions as they age.
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Abstract
The baculovirus-insect cell expression system is an approved system for the production of viral antigens with vaccine potential for humans and animals and has been used for production of subunit vaccines against parasitic diseases as well. Many candidate subunit vaccines have been expressed in this system and immunization commonly led to protective immunity against pathogen challenge. The first vaccines produced in insect cells for animal use are now on the market. This chapter deals with the tailoring of the baculovirus-insect cell expression system for vaccine production in terms of expression levels, integrity and immunogenicity of recombinant proteins, and baculovirus genome stability. Various expression strategies are discussed including chimeric, virus-like particles, baculovirus display of foreign antigens on budded virions or in occlusion bodies, and specialized baculovirus vectors with mammalian promoters that express the antigen in the immunized individual. A historical overview shows the wide variety of viral (glyco)proteins that have successfully been expressed in this system for vaccine purposes. The potential of this expression system for antiparasite vaccines is illustrated. The combination of subunit vaccines and marker tests, both based on antigens expressed in insect cells, provides a powerful tool to combat disease and to monitor infectious agents.
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Affiliation(s)
- Monique M van Oers
- Laboratory of Virology, Wageningen University, Binnenhaven 11 6709 PD, Wageningen, The Netherlands
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Gomez I, Marx F, Gould EA, Grubeck-Loebenstein B. T cells from elderly persons respond to neoantigenic stimulation with an unimpaired IL-2 production and an enhanced differentiation into effector cells. Exp Gerontol 2004; 39:597-605. [PMID: 15050295 DOI: 10.1016/j.exger.2003.11.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2003] [Revised: 10/30/2003] [Accepted: 11/01/2003] [Indexed: 01/01/2023]
Abstract
We analysed the capacity of T cells from young and elderly persons to produce IL-2 and IFN-gamma after in vitro stimulation with two neoantigens, namely inactivated rabies virus and recombinant Etr protein of tick-borne encephalitis virus (TBEV). Soluble antigens should per definition primarly stimulate CD4(+) naïve T cells. Cytokine production was analysed by ELISPOT technology. T cells from elderly and young donors produced similar amounts of IL-2 after priming with both neoantigens. In contrast, IFN-gamma production was induced earlier and at lower antigenic concentrations in T cells from elderly persons than from young controls indicating an enhanced capacity of primed T cells to differentiate into effector cells. In both age groups the response pattern to neoantigenic stimulation was the same whether unfractionated blood mononuclear cells or purified CD4(+)CD45RA(+) T cells with autologous DC as APC were used. The magnitude of the response was, however slightly lower in isolated cells. Autologous DC still induced an MLR in purified CD4(+)CD45RA(+) cells, which was more pronounced in the young than in the elderly group. Our results demonstrate that the ability of CD4(+) T cells from elderly persons to respond to neoantigenic stimulation is intact and that their capacity to differentiate into effector cells is even enhanced. This is in good agreement with earlier reports on alterations in the homing receptor pattern of naïve T cells in old age. Rapid generation of effector cells from naïve cells may at least partly counterbalance the decreasing size of the naïve T cell pool in elderly persons.
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Affiliation(s)
- I Gomez
- Institute for Biomedical Ageing Research, Austrian Academy of Sciences, Rennweg 10, A-6020 Innsbruck, Austria
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