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Keywords = modified vaccinia virus ankara

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21 pages, 1578 KiB  
Article
ISG15 as a Potent Immune Adjuvant in MVA-Based Vaccines Against Zika Virus and SARS-CoV-2
by Juan García-Arriaza, Michela Falqui, Patricia Pérez, Rocío Coloma, Beatriz Perdiguero, Enrique Álvarez, Laura Marcos-Villar, David Astorgano, Irene Campaña-Gómez, Carlos Óscar S. Sorzano, Mariano Esteban, Carmen Elena Gómez and Susana Guerra
Vaccines 2025, 13(7), 696; https://doi.org/10.3390/vaccines13070696 - 27 Jun 2025
Viewed by 619
Abstract
Background: Vaccines represent one of the most affordable and efficient tools for controlling infectious diseases; however, the development of efficacious vaccines against complex pathogens remains a major challenge. Adjuvants play a relevant role in enhancing vaccine-induced immune responses. One such molecule is interferon-stimulated [...] Read more.
Background: Vaccines represent one of the most affordable and efficient tools for controlling infectious diseases; however, the development of efficacious vaccines against complex pathogens remains a major challenge. Adjuvants play a relevant role in enhancing vaccine-induced immune responses. One such molecule is interferon-stimulated gene 15 (ISG15), a key modulator of antiviral immunity that acts both through ISGylation-dependent mechanisms and as a cytokine-like molecule. Methods: In this study, we assessed the immunostimulatory potential of ISG15 as an adjuvant in Modified Vaccinia virus Ankara (MVA)-based vaccine candidates targeting Zika virus (ZIKV) and Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Early innate responses and immune cell infiltration were analyzed in immunized mice by flow cytometry and cytokine profiling. To elucidate the underlying mechanism of action of ISG15, in vitro co-infection studies were performed in macrophages. Finally, we evaluated the magnitude and functional quality of the elicited antigen-specific cellular immune responses in vivo. Results: Analysis of early innate responses revealed both platform- and variant-specific effects. ISG15AA preferentially promoted natural killer (NK) cell recruitment at the injection site, whereas ISG15GG enhanced myeloid cell infiltration in draining lymph nodes (DLNs), particularly when delivered via MVA. Moreover, in vitro co-infection of macrophages with MVA-based vaccine vectors and the ISG15AA mutant led to a marked increase in proinflammatory cytokine production, highlighting a dominant role for the extracellular, ISGylation-independent functions of ISG15 in shaping vaccine-induced immunity. Notably, co-infection of ISG15 with MVA-ZIKV and MVA-SARS-CoV-2 vaccine candidates enhanced the magnitude of antigen-specific immune responses in both vaccine models. Conclusions: ISG15, particularly in its ISGylation-deficient form, acts as a promising immunomodulatory adjuvant for viral vaccines, enhancing both innate and adaptive immune responses. Consistent with previous findings in the context of Human Immunodeficiency virus type 1 (HIV-1) vaccines, this study further supports the potential of ISG15 as an effective adjuvant for vaccines targeting viral infections such as ZIKV and SARS-CoV-2. Full article
(This article belongs to the Special Issue Protective Immunity and Adjuvant Vaccines)
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20 pages, 986 KiB  
Review
Past, Present, and Future of Viral Vector Vaccine Platforms: A Comprehensive Review
by Justin Tang, Md Al Amin and Jian L. Campian
Vaccines 2025, 13(5), 524; https://doi.org/10.3390/vaccines13050524 - 15 May 2025
Viewed by 2599
Abstract
Over the past several decades, viral vector-based vaccines have emerged as some of the most versatile and potent platforms in modern vaccinology. Their capacity to deliver genetic material encoding target antigens directly into host cells enables strong cellular and humoral immune responses, often [...] Read more.
Over the past several decades, viral vector-based vaccines have emerged as some of the most versatile and potent platforms in modern vaccinology. Their capacity to deliver genetic material encoding target antigens directly into host cells enables strong cellular and humoral immune responses, often superior to what traditional inactivated or subunit vaccines can achieve. This has accelerated their application to a wide array of pathogens and disease targets, from well-established threats like HIV and malaria to emerging infections such as Ebola, Zika, and SARS-CoV-2. The COVID-19 pandemic further highlighted the agility of viral vector platforms, with several adenovirus-based vaccines quickly authorized and deployed on a global scale. Despite these advances, significant challenges remain. One major hurdle is pre-existing immunity against commonly used vector backbones, which can blunt vaccine immunogenicity. Rare but serious adverse events, including vector-associated inflammatory responses and conditions like vaccine-induced immune thrombotic thrombocytopenia (VITT), have raised important safety considerations. Additionally, scaling up manufacturing, ensuring consistency in large-scale production, meeting rigorous regulatory standards, and maintaining equitable global access to these vaccines present profound logistical and ethical dilemmas. In response to these challenges, the field is evolving rapidly. Sophisticated engineering strategies, such as integrase-defective lentiviral vectors, insect-specific flaviviruses, chimeric capsids to evade neutralizing antibodies, and plug-and-play self-amplifying RNA approaches, seek to bolster safety, enhance immunogenicity, circumvent pre-existing immunity, and streamline production. Lessons learned from the COVID-19 pandemic and prior outbreaks are guiding the development of platform-based approaches designed for rapid deployment during future public health emergencies. This review provides an exhaustive, in-depth examination of the historical evolution, immunobiological principles, current platforms, manufacturing complexities, regulatory frameworks, known safety issues, and future directions for viral vector-based vaccines. Full article
(This article belongs to the Special Issue Strategies of Viral Vectors for Vaccine Development)
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9 pages, 200 KiB  
Review
Vaccines and Antiviral Therapies for Mpox Virus in Pregnant and Breastfeeding Women: Efficacy and Maternal–Child Outcomes
by Maryum Imran, Myra Sohail, Javeria Kamran, Syeda Qaima Abbas, Khadija Azeem and Emmanuel Korir
Viruses 2025, 17(4), 456; https://doi.org/10.3390/v17040456 - 22 Mar 2025
Viewed by 672
Abstract
Mpox (formerly known as monkeypox), the major public health concern of 2022, has elicited much attention globally. In addition to the usual symptoms observed in smallpox virus infections, infected mothers were found to hold a possible risk of transmission to newborns during delivery. [...] Read more.
Mpox (formerly known as monkeypox), the major public health concern of 2022, has elicited much attention globally. In addition to the usual symptoms observed in smallpox virus infections, infected mothers were found to hold a possible risk of transmission to newborns during delivery. This review aimed to summarize recent clinical trials that involved antiviral therapy, vaccines, immunoglobulin therapy, and other pharmacological interventions specifically for treating infected pregnant women. A comprehensive search was performed using databases such as PubMed, Google Scholar, and Medline to find appropriate disease management strategies. Amongst the vaccines and antivirals being used for treatment, vaccines such as Modified Vaccinia Ankara (MVA/MVA-BN) and Lister clone 16-medium pocket size-8 (LC16m8), while prophylactically effective, have been deemed unsafe for pregnant and lactating females. Antivirals like Tecovirimat, on the other hand, are considered to be a better alternative, but they are not without risks that may outweigh the potential benefits. Additionally, efforts to reduce maternal and fetal complications include administering the MVA-BN vaccine and awareness campaigns regarding herd immunity. Therefore, necessary precautions, prophylactic vaccinations in high-risk outbreak regions, and symptomatic treatment in pregnant and lactating females currently appear to be more feasible approaches against the mpox virus. Full article
19 pages, 2598 KiB  
Article
Prime-Boost Vaccination Based on Nanospheres and MVA Encoding the Nucleoprotein of Crimean-Congo Hemorrhagic Fever Virus Elicits Broad Immune Responses
by Eva Calvo-Pinilla, Sandra Moreno, Natalia Barreiro-Piñeiro, Juana M. Sánchez-Puig, Rafael Blasco, José Martínez-Costas, Alejandro Brun and Gema Lorenzo
Vaccines 2025, 13(3), 291; https://doi.org/10.3390/vaccines13030291 - 10 Mar 2025
Cited by 1 | Viewed by 1285
Abstract
Background/Objectives: Crimean–Congo hemorrhagic fever virus (CCHFV) is an emerging, widely distributed zoonotic tick-borne pathogen. The virus causes severe disease in humans, and numerous wild and domestic animals act as reservoirs of it. Unfortunately, there are no effective therapies or safe vaccines commercialized [...] Read more.
Background/Objectives: Crimean–Congo hemorrhagic fever virus (CCHFV) is an emerging, widely distributed zoonotic tick-borne pathogen. The virus causes severe disease in humans, and numerous wild and domestic animals act as reservoirs of it. Unfortunately, there are no effective therapies or safe vaccines commercialized nowadays for this particular virus. As CCHF (Crimean–Congo hemorrhagic fever) is a serious threat to public health, there is an urgent need to investigate the development of safe and effective vaccination strategies further. Methods: In this work, we have employed two immunization platforms based on protein nanoparticles and a modified vaccinia Ankara (MVA) viral vector using the nucleoprotein (NP) as the target antigen. The humoral and cellular immune responses were characterized by ELISA, ICS, and cytokine measurement. Results: This work shows that a single dose of the vaccine candidates was not as immunogenic as the heterologous vaccination using nanoparticles and MVA. A prime with NP nanoparticles (NS-NP) and a boost with MVA-expressing NP were capable of triggering significant levels of humoral and cellular immune responses against CCHFV in mice. Conclusions: Our study shows that the NS-NP/MVA-NP vaccination strategy effectively elicits a robust humoral and cellular immune response in a mouse model, emphasizing its potential as a protective approach against CCHFV lineages. Full article
(This article belongs to the Special Issue Veterinary Vaccines and Host Immune Responses)
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15 pages, 1977 KiB  
Article
A Multi-Valent Hantavirus Vaccine Based on Recombinant Modified Vaccinia Ankara Reduces Viral Load in a Mouse Infection Model
by Marilyn Aram, Victoria Graham, Emma Kennedy, Emma Rayner, Roger Hewson and Stuart Dowall
Vaccines 2025, 13(3), 270; https://doi.org/10.3390/vaccines13030270 - 4 Mar 2025
Viewed by 1307
Abstract
Background: Old World orthohantaviruses are the aetiological agent of Haemorrhagic Fever with Renal Syndrome (HFRS) disease. Worldwide, the two most prominent pathogens of HFRS are Seoul orthohantavirus (SEOV) and Hantaan orthohantavirus (HTNV). There is currently no specific treatment nor widely licensed vaccine [...] Read more.
Background: Old World orthohantaviruses are the aetiological agent of Haemorrhagic Fever with Renal Syndrome (HFRS) disease. Worldwide, the two most prominent pathogens of HFRS are Seoul orthohantavirus (SEOV) and Hantaan orthohantavirus (HTNV). There is currently no specific treatment nor widely licensed vaccine form hantaviruses. Methods: This study developed a virus-vectored vaccine approach using modified vaccinia Ankara (MVA) incorporating a SEOV-HTNV chimeric nucleoprotein antigen. Results: The vaccine demonstrated the induction of humoral and cellular immunity. In the absence of a disease model, a reduction in the viral load of a susceptible mouse strain with type-I interferon receptor deficiency (A129) was used to ascertain protective effects after challenge with SEOV. Results demonstrated a significant reduction in and/or clearance of viral RNA in immunised animals. Conclusions: An MVA viral vector vaccine incorporating the nucleoprotein as antigen offers a promising approach for Hantavirus vaccine development. Full article
(This article belongs to the Special Issue Viral Vector-Based Vaccines and Therapeutics)
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13 pages, 627 KiB  
Review
Approaches to Next-Generation Capripoxvirus and Monkeypox Virus Vaccines
by Anna-Lise Williamson
Viruses 2025, 17(2), 186; https://doi.org/10.3390/v17020186 - 27 Jan 2025
Viewed by 1594
Abstract
Globally, there are two major poxvirus outbreaks: mpox, caused by the monkeypox virus, and lumpy skin disease, caused by the lumpy skin disease virus. While vaccines for both diseases exist, there is a need for improved vaccines. The original vaccines used to eradicate [...] Read more.
Globally, there are two major poxvirus outbreaks: mpox, caused by the monkeypox virus, and lumpy skin disease, caused by the lumpy skin disease virus. While vaccines for both diseases exist, there is a need for improved vaccines. The original vaccines used to eradicate smallpox, which also protect from the disease now known as mpox, are no longer acceptable. This is mainly due to the risk of serious adverse events, particularly in HIV-positive people. The next-generation vaccine for mpox prevention is modified vaccinia Ankara, which does not complete the viral replication cycle in humans and, therefore, has a better safety profile. However, two modified vaccinia Ankara immunizations are needed to give good but often incomplete protection, and there are indications that the immune response will wane over time. A better vaccine that induces a long-lived response with only one immunization is desirable. Another recently available smallpox vaccine is LC16m8. While LC16m8 contains replicating vaccinia virus, it is a more attenuated vaccine than the original vaccines and has limited side effects. The commonly used lumpy skin disease vaccines are based on attenuated lumpy skin disease virus. However, an inactivated or non-infectious vaccine is desirable as the disease spreads into new territories. This article reviews novel vaccine approaches, including mRNA and subunit vaccines, to protect from poxvirus infection. Full article
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15 pages, 6062 KiB  
Article
Specific Immune Responses and Oncolytic Effects Induced by EBV LMP2A-Armed Modified Ankara-Vaccinia Virus Vectored Vaccines in Nasopharyngeal Cancer
by Liying Sun, Chao Liu and Junping Peng
Pharmaceutics 2025, 17(1), 52; https://doi.org/10.3390/pharmaceutics17010052 - 3 Jan 2025
Cited by 1 | Viewed by 1311
Abstract
Background: The Epstein-Barr virus (EBV) is intricately linked to a range of human malignancies, with EBV latent membrane protein 2A (LMP2A) emerging as a potential target antigen for immunotherapeutic strategies in the treatment of nasopharyngeal carcinoma (NPC). Methods: The modified vaccinia virus Ankara [...] Read more.
Background: The Epstein-Barr virus (EBV) is intricately linked to a range of human malignancies, with EBV latent membrane protein 2A (LMP2A) emerging as a potential target antigen for immunotherapeutic strategies in the treatment of nasopharyngeal carcinoma (NPC). Methods: The modified vaccinia virus Ankara (MVA) is universally used in vector vaccine research because of its excellent safety profile and highly efficient recombinant gene expression. Here, we constructed a novel MVA-LMP2A recombinant virus and investigated its specific immune response induction and oncolytic effect. Results: An immunization dose of 2 × 107 PFU induced the highest specific immune response, which was no longer increased by boost injections after four doses. Three weeks post-final immunization, the specific immune response reached its peak. The MVA-LMP2A vaccine-induced LMP2A-specific cytotoxic T lymphocytes (CTLs), which exhibited substantial efficacy against target cells and effectively inhibited tumor growth. Conclusions: Thus, the MVA-LMP2A recombinant virus effectively induces strong LMP2A-specific cellular and humoral immune responses and anti-tumor activity. This work provides a promising therapeutic strategy for developing NPC candidate vaccines, as well as a reference for the treatment of EBV LMP2-associated malignancies. Full article
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19 pages, 682 KiB  
Article
Reactogenicity and Immunogenicity Against MPXV of the Intradermal Administration of Modified Vaccinia Ankara Compared to the Standard Subcutaneous Route
by Valentina Mazzotta, Pierluca Piselli, Alessandro Cozzi Lepri, Giulia Matusali, Eleonora Cimini, Rozenn Esvan, Francesca Colavita, Roberta Gagliardini, Stefania Notari, Alessandra Oliva, Silvia Meschi, Rita Casetti, Giulia Micheli, Licia Bordi, Alessandro Giacinta, Germana Grassi, Saba Gebremeskel Tekle, Claudia Cimaglia, Jessica Paulicelli, Alessandro Caioli, Paola Gallì, Giulia Del Duca, Miriam Lichtner, Loredana Sarmati, Enrica Tamburrini, Claudio Mastroianni, Alessandra Latini, Paolo Faccendini, Carla Fontana, Emanuele Nicastri, Andrea Siddu, Alessandra Barca, Francesco Vaia, Enrico Girardi, Fabrizio Maggi and Andrea Antinoriadd Show full author list remove Hide full author list
Vaccines 2025, 13(1), 32; https://doi.org/10.3390/vaccines13010032 - 31 Dec 2024
Cited by 1 | Viewed by 1405
Abstract
Background: The recent resurgence of mpox in central Africa has been declared a new public health emergency of international concern (PHEIC) requiring coordinated international responses. Vaccination is a priority to expand protection and enhance control strategies, but the vaccine’s need exceeds the currently [...] Read more.
Background: The recent resurgence of mpox in central Africa has been declared a new public health emergency of international concern (PHEIC) requiring coordinated international responses. Vaccination is a priority to expand protection and enhance control strategies, but the vaccine’s need exceeds the currently available doses. Intradermal (ID) administration of one-fifth of the standard modified vaccinia Ankara (MVA-BN) dose was temporarily authorized during the 2022 PHEIC. Studies conducted before 2022 provided evidence about the humoral response against the vaccinia virus (VACV) after vaccination but not against the mpox virus (MPXV). Moreover, no data are available on the T-cell response elicited by MVA-BN administered subcutaneously or intradermally. Methods: We compare the two vaccine administration routes according to reactogenicity (n = 943) and immunogenicity (n = 225) of vaccine recipients attending INMI Spallanzani hospital during the 2022 vaccination campaign in Rome, Italy. Results: We found that the ID route elicited higher titers of MPXV-specific IgG (mean difference of 0.26 log2, p = 0.05) and nAbs (0.24 log2, p = 0.08) than the subcutaneous (SC) route one month after the complete vaccination cycle. At the same time, no evidence for a difference in cellular response was found. Conclusions: MVA-BN was globally well tolerated despite higher reactogenicity for the ID than the SC route, especially for the reactions at the local injection site. The ID dose-sparing strategy was proven safe and immunogenic and would make vaccination available to more people. Our data support the current WHO recommendation of using the ID route in low–medium-income countries (LMIC), although response data in people infected with the new 1b clade are urgently needed. Full article
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14 pages, 1723 KiB  
Protocol
Optimizing Microneutralization and IFN-γ ELISPOT Assays to Evaluate Mpox Immunity
by Yinyi Yu, Krystal Meza, Chase Colbert, Daniel F. Hoft, Anna Jaunarajs, Azra Blazevic, Sharon E. Frey and Getahun Abate
Vaccines 2025, 13(1), 27; https://doi.org/10.3390/vaccines13010027 - 31 Dec 2024
Cited by 1 | Viewed by 1046
Abstract
Background: Available assays to measure pox virus neutralizing antibody titers are laborious and take up to 5 days. In addition, assays to measure T cell responses require the use of specific antigens, which may not be the same for all pox viruses. This [...] Read more.
Background: Available assays to measure pox virus neutralizing antibody titers are laborious and take up to 5 days. In addition, assays to measure T cell responses require the use of specific antigens, which may not be the same for all pox viruses. This study reports the development of robust assays for the measurement of mpox-specific neutralizing antibodies and IFN-γ-producing T-cell responses. Methods: Fourteen samples from 7 volunteers who received Modified Vaccinia Ankara-Bavarian Nordic (MVA-BN) were used. The focused reduction neutralization test (FRNT) was performed using the mpox-specific A29 monoclonal antibody. Optimization and further development of FRNT were conducted using the plaque reduction neutralization test (PRNT) as the gold standard. The mpox-specific IFN-γ ELISPOT assay was optimized using different mpox antigen preparations. Results with pre-vaccination samples were compared with post-vaccination samples using the Wilcoxon matched-pairs test. Results: Pre-vaccination and post-vaccination sera (n = 7) had FRNT50 (i.e., titers that inhibited at least 50% of the virus) of 109.1 ± 161.8 and 303.7 ± 402.8 (mean ± SD), respectively. Regression analysis of fold changes in FRNT50 and PRNT50 showed that the two assays closely agree (n = 25 tests on paired samples, R2 of 0.787). Using UV-inactivated mpox as an antigen, the number of IFN-γ spot-forming T cells (SFC) in pre-vaccination samples (16.13 ± 15.86, mean ± SD) was significantly lower than SFC in post-vaccination samples (172.9 ± 313.3, mean ± SD) with p = 0.0078. Conclusions: Our newly developed microneutralization test has a good correlation with PRNT. UV-inactivated mpox is an appropriate antigen for the ELISPOT assay that measures mpox cross-reactive T cells. These assays will be useful in future mpox vaccine studies. Full article
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20 pages, 15671 KiB  
Article
Expression of an Efficient Selection Marker Out of a Duplicated Site in the ITRs of a Modified Vaccinia Virus Ankara (MVA)
by Sirine Abidi, Aurora Elhazaz Fernandez, Nicole Seehase, Lina Hanisch, Alexander Karlas, Volker Sandig and Ingo Jordan
Vaccines 2024, 12(12), 1377; https://doi.org/10.3390/vaccines12121377 - 6 Dec 2024
Viewed by 1222
Abstract
Background/Objectives: Poxviruses are large DNA viruses that replicate in the host cytoplasm without a nuclear phase. As vaccine vectors, they can package and express large recombinant cassettes from different positions of their genomic core region. We present a comparison between wildtype modified [...] Read more.
Background/Objectives: Poxviruses are large DNA viruses that replicate in the host cytoplasm without a nuclear phase. As vaccine vectors, they can package and express large recombinant cassettes from different positions of their genomic core region. We present a comparison between wildtype modified vaccinia Ankara (MVA) and isolate CR19, which has significantly expanded inverted terminal repeats (ITRs). With this expansion, a site in wildtype MVA, called deletion site (DS) IV, has been duplicated at both ends of the genome and now occupies an almost central position in the newly formed ITRs. Methods: We inserted various reporter genes into this site and found that the ITRs can be used for transgene expression. However, ITRs are genomic structures that can rapidly adapt to selective pressure through transient duplication and contraction. To test the potential utility of insertions into viral telomers, we inserted a factor from the cellular innate immune system that interferes with viral replication as an example of a difficult transgene. Results: A site almost in the centre of the ITRs can be used for transgene expression, and both sides are mirrored into identical copies. The example of a challenging transgene, tetherin, proved to be surprisingly efficient in selecting candidate vectors against the large background of parental viruses. Conclusions: Insertion of transgenes into ITRs automatically doubles the gene doses. The functionalisation of viruses with tetherin may accelerate the identification and generation of recombinant vectors for personalised medicine and pandemic preparedness. Full article
(This article belongs to the Section Vaccine Design, Development, and Delivery)
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24 pages, 5421 KiB  
Article
Rapid Development of Modified Vaccinia Virus Ankara (MVA)-Based Vaccine Candidates Against Marburg Virus Suitable for Clinical Use in Humans
by Alina Tscherne, Georgia Kalodimou, Alexandra Kupke, Cornelius Rohde, Astrid Freudenstein, Sylvia Jany, Satendra Kumar, Gerd Sutter, Verena Krähling, Stephan Becker and Asisa Volz
Vaccines 2024, 12(12), 1316; https://doi.org/10.3390/vaccines12121316 - 24 Nov 2024
Cited by 1 | Viewed by 2318
Abstract
Background/Objectives: Marburg virus (MARV) is the etiological agent of Marburg Virus Disease (MVD), a rare but severe hemorrhagic fever disease with high case fatality rates in humans. Smaller outbreaks have frequently been reported in countries in Africa over the last few years, and [...] Read more.
Background/Objectives: Marburg virus (MARV) is the etiological agent of Marburg Virus Disease (MVD), a rare but severe hemorrhagic fever disease with high case fatality rates in humans. Smaller outbreaks have frequently been reported in countries in Africa over the last few years, and confirmed human cases outside Africa are, so far, exclusively imported by returning travelers. Over the previous years, MARV has also spread to non-endemic African countries, demonstrating its potential to cause epidemics. Although MARV-specific vaccines are evaluated in preclinical and clinical research, none have been approved for human use. Modified Vaccinia virus Ankara (MVA), a well-established viral vector used to generate vaccines against emerging pathogens, can deliver multiple antigens and has a remarkable clinical safety and immunogenicity record, further supporting its evaluation as a vaccine against MARV. The rapid availability of safe and effective MVA-MARV vaccine candidates would expand the possibilities of multi-factored intervention strategies in endemic countries. Methods: We have used an optimized methodology to rapidly generate and characterize recombinant MVA candidate vaccines that meet the quality requirements to proceed to human clinical trials. As a proof-of-concept for the optimized methodology, we generated two recombinant MVAs that deliver either the MARV glycoprotein (MVA-MARV-GP) or the MARV nucleoprotein (MVA-MARV-NP). Results: Infections of human cell cultures with recombinant MVA-MARV-GP and MVA-MARV-NP confirmed the efficient synthesis of MARV-GP and MARV-NP proteins in mammalian cells, which are non-permissive for MVA replication. Prime-boost immunizations in C57BL/6J mice readily induced circulating serum antibodies binding to recombinant MARV-GP and MARV-NP proteins. Moreover, the MVA-MARV-candidate vaccines elicited MARV-specific T-cell responses in C57BL/6J mice. Conclusions: We confirmed the suitability of our two backbone viruses MVA-mCherry and MVA-GFP in a proof-of-concept study to rapidly generate candidate vaccines against MARV. However, further studies are warranted to characterize the protective efficacy of these recombinant MVA-MARV vaccines in other preclinical models and to evaluate them as vaccine candidates in humans. Full article
(This article belongs to the Special Issue Strategies of Viral Vectors for Vaccine Development)
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33 pages, 62847 KiB  
Article
A Novel Monoclonal Antibody Against a Modified Vaccinia Ankara (MVA) Envelope Protein as a Tool for MVA Virus Titration by Flow Cytometry
by Simeon Cua, Brenda A. Tello, Mafalda A. Farelo, Esther Rodriguez, Gabriela M. Escalante, Lorraine Z. Mutsvunguma, Javier Gordon Ogembo and Ivana G. Reidel
Viruses 2024, 16(10), 1628; https://doi.org/10.3390/v16101628 - 17 Oct 2024
Viewed by 1974
Abstract
Modified vaccinia Ankara (MVA) virus is a widely used vaccine platform, making accurate titration essential for vaccination studies. However, the current plaque forming unit (PFU) assay, the standard for MVA titration, is prone to observer bias and other limitations that affect accuracy and [...] Read more.
Modified vaccinia Ankara (MVA) virus is a widely used vaccine platform, making accurate titration essential for vaccination studies. However, the current plaque forming unit (PFU) assay, the standard for MVA titration, is prone to observer bias and other limitations that affect accuracy and precision. To address these challenges, we developed a new flow cytometry-based quantification method using a highly specific monoclonal antibody (mAb) for the detection of MVA-infected cells, as a more accurate titration assay. Through previous work, we serendipitously identified three MVA-specific hybridoma antibody clones, which we characterized through ELISA, immunoblot, and flow cytometry, confirming their specificity for MVA. Sequencing confirmed that each antibody was monoclonal, and mass spectrometry results revealed that all mAbs target the MVA cell surface binding protein (CSBP, MVA105L). We next optimized the titration protocol using the most effective mAb, 33C7 by refining culture conditions and staining protocols to enhance sensitivity and minimize background. Our optimized method demonstrated superior sensitivity, reliability, and reduced processing time when compared with the traditional PFU assay, establishing it as a more accurate and efficient approach for MVA titration. Full article
(This article belongs to the Section Viral Immunology, Vaccines, and Antivirals)
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20 pages, 4410 KiB  
Article
Implementation of an Immunoassay Based on the MVA-T7pol-Expression System for Rapid Identification of Immunogenic SARS-CoV-2 Antigens: A Proof-of-Concept Study
by Satendra Kumar, Liangliang Nan, Georgia Kalodimou, Sylvia Jany, Astrid Freudenstein, Christine Brandmüller, Katharina Müller, Philipp Girl, Rosina Ehmann, Wolfgang Guggemos, Michael Seilmaier, Clemens-Martin Wendtner, Asisa Volz, Gerd Sutter, Robert Fux and Alina Tscherne
Int. J. Mol. Sci. 2024, 25(20), 10898; https://doi.org/10.3390/ijms252010898 - 10 Oct 2024
Cited by 1 | Viewed by 1706
Abstract
The emergence of hitherto unknown viral pathogens presents a great challenge for researchers to develop effective therapeutics and vaccines within a short time to avoid an uncontrolled global spread, as seen during the coronavirus disease 2019 (COVID-19) pandemic. Therefore, rapid and simple methods [...] Read more.
The emergence of hitherto unknown viral pathogens presents a great challenge for researchers to develop effective therapeutics and vaccines within a short time to avoid an uncontrolled global spread, as seen during the coronavirus disease 2019 (COVID-19) pandemic. Therefore, rapid and simple methods to identify immunogenic antigens as potential therapeutical targets are urgently needed for a better pandemic preparedness. To address this problem, we chose the well-characterized Modified Vaccinia virus Ankara (MVA)-T7pol expression system to establish a workflow to identify immunogens when a new pathogen emerges, generate candidate vaccines, and test their immunogenicity in an animal model. By using this system, we detected severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2) nucleoprotein (N)-, and spike (S)-specific antibodies in COVID-19 patient sera, which is in line with the current literature and our observations from previous immunogenicity studies. Furthermore, we detected antibodies directed against the SARS-CoV-2-membrane (M) and -ORF3a proteins in COVID-19 patient sera and aimed to generate recombinant MVA candidate vaccines expressing either the M or ORF3a protein. When testing our candidate vaccines in a prime-boost immunization regimen in humanized HLA-A2.1-/HLA-DR1-transgenic H-2 class I-/class II-knockout mice, we were able to demonstrate M- and ORF3a-specific cellular and humoral immune responses. Hence, the established workflow using the MVA-T7pol expression system represents a rapid and efficient tool to identify potential immunogenic antigens and provides a basis for future development of candidate vaccines. Full article
(This article belongs to the Special Issue Viral Infection and Virology Methods)
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22 pages, 3833 KiB  
Article
Viral Vector-Based Chlamydia trachomatis Vaccines Encoding CTH522 Induce Distinct Immune Responses in C57BL/6J and HLA Transgenic Mice
by Giuseppe Andreacchio, Ylenia Longo, Sara Moreno Mascaraque, Kartikan Anandasothy, Sarah Tofan, Esma Özün, Lena Wilschrey, Johannes Ptok, Dung T. Huynh, Joen Luirink and Ingo Drexler
Vaccines 2024, 12(8), 944; https://doi.org/10.3390/vaccines12080944 - 22 Aug 2024
Viewed by 1817
Abstract
Chlamydia trachomatis remains a major global health problem with increasing infection rates, requiring innovative vaccine solutions. Modified Vaccinia Virus Ankara (MVA) is a well-established, safe and highly immunogenic vaccine vector, making it a promising candidate for C. trachomatis vaccine development. In this study, [...] Read more.
Chlamydia trachomatis remains a major global health problem with increasing infection rates, requiring innovative vaccine solutions. Modified Vaccinia Virus Ankara (MVA) is a well-established, safe and highly immunogenic vaccine vector, making it a promising candidate for C. trachomatis vaccine development. In this study, we evaluated two novel MVA-based recombinant vaccines expressing spCTH522 and CTH522:B7 antigens. Our results show that while both vaccines induced CD4+ T-cell responses in C57BL/6J mice, they failed to generate antigen-specific systemic CD8+ T cells. Only the membrane-anchored CTH522 elicited strong IgG2b and IgG2c antibody responses. In an HLA transgenic mouse model, both recombinant MVAs induced Th1-directed CD4+ T cell and multifunctional CD8+ T cells, while only the CTH522:B7 vaccine generated antibody responses, underscoring the importance of antigen localization. Collectively, our data indicate that distinct antigen formulations can induce different immune responses depending on the mouse strain used. This research contributes to the development of effective vaccines by highlighting the importance of careful antigen design and the selection of appropriate animal models to study specific vaccine-induced immune responses. Future studies should investigate whether these immune responses provide protection in humans and should explore different routes of immunization, including mucosal and systemic immunization. Full article
(This article belongs to the Special Issue Strategies of Viral Vectors for Vaccine Development)
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17 pages, 6071 KiB  
Article
Vaccinia Virus Defective Particles Lacking the F17 Protein Do Not Inhibit Protein Synthesis: F17, a Double-Edged Sword for Protein Synthesis?
by Georges Beaud, Fleur Costa, Bernard Klonjkowski, François Piumi, Muriel Coulpier, Robert Drillien, Baptiste Monsion, Fauziah Mohd Jaafar and Houssam Attoui
Int. J. Mol. Sci. 2024, 25(3), 1382; https://doi.org/10.3390/ijms25031382 - 23 Jan 2024
Cited by 2 | Viewed by 1748
Abstract
Vaccinia virus (Orthopoxvirus) F17 protein is a major virion structural phosphoprotein having a molecular weight of 11 kDa. Recently, it was shown that F17 synthesised in infected cells interacts with mTOR subunits to evade cell immunity and stimulate late viral protein [...] Read more.
Vaccinia virus (Orthopoxvirus) F17 protein is a major virion structural phosphoprotein having a molecular weight of 11 kDa. Recently, it was shown that F17 synthesised in infected cells interacts with mTOR subunits to evade cell immunity and stimulate late viral protein synthesis. Several years back, we purified an 11 kDa protein that inhibited protein synthesis in reticulocyte lysate from virions, and that possesses all physico-chemical properties of F17 protein. To investigate this discrepancy, we used defective vaccinia virus particles devoid of the F17 protein (designated iF17 particles) to assess their ability to inhibit protein synthesis. To this aim, we purified iF17 particles from cells infected with a vaccinia virus mutant which expresses F17 only in the presence of IPTG. The SDS-PAGE protein profiles of iF17 particles or derived particles, obtained by solubilisation of the viral membrane, were similar to that of infectious iF17 particles. As expected, the profiles of full iF17 particles and those lacking the viral membrane were missing the 11 kDa F17 band. The iF17 particles did attach to cells and injected their viral DNA into the cytoplasm. Co-infection of the non-permissive BSC40 cells with a modified vaccinia Ankara (MVA) virus, expressing an mCherry protein, and iF17 particles, induced a strong mCherry fluorescence. Altogether, these experiments confirmed that the iF17 particles can inject their content into cells. We measured the rate of protein synthesis as a function of the multiplicity of infection (MOI), in the presence of puromycin as a label. We showed that iF17 particles did not inhibit protein synthesis at high MOI, by contrast to the infectious iF17 mutant. Furthermore, the measured efficiency to inhibit protein synthesis by the iF17 mutant virus generated in the presence of IPTG, was threefold to eightfold lower than that of the wild-type WR virus. The iF17 mutant contained about threefold less F17 protein than wild-type WR. Altogether these results strongly suggest that virion-associated F17 protein is essential to mediate a stoichiometric inhibition of protein synthesis, in contrast to the late synthesised F17. It is possible that this discrepancy is due to different phosphorylation states of the free and virion-associated F17 protein. Full article
(This article belongs to the Section Molecular Microbiology)
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