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Hoornweg TE, Schaftenaar W, Rutten VPMG, de Haan CAM. Low gH/gL (Sub)Species-Specific Antibody Levels Indicate Elephants at Risk of Fatal Elephant Endotheliotropic Herpesvirus Hemorrhagic Disease. Viruses 2024; 16:268. [PMID: 38400043 PMCID: PMC10892434 DOI: 10.3390/v16020268] [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: 01/11/2024] [Revised: 02/02/2024] [Accepted: 02/03/2024] [Indexed: 02/25/2024] Open
Abstract
Elephant endotheliotropic herpesviruses (EEHVs), of which eleven (sub)species are currently distinguished, infect either Asian (Elephas maximus) or African elephants (Loxodonta species). While all adult elephants are latently infected with at least one EEHV (sub)species, young elephants, specifically those with low to non-detectable EEHV-specific antibody levels, may develop fatal hemorrhagic disease (EEHV-HD) upon infection. However, animals with high antibody levels against EEHV(1A) gB, an immunodominant antigen recognized by antibodies elicited against multiple (sub)species, may also occasionally succumb to EEHV-HD. To better define which animals are at risk of EEHV-HD, gB and gH/gL ELISAs were developed for each of the Asian elephant EEHV subspecies and assessed using 396 sera from 164 Asian elephants from European zoos. Antibody levels measured against gB of different (sub)species correlated strongly with one another, suggesting high cross-reactivity. Antibody levels against gH/gL of different subspecies were far less correlated and allowed differentiation between these (sub)species. Importantly, while high gB-specific antibody levels were detected in the sera of several EEHV-HD fatalities, all fatalities (n = 23) had low antibody levels against gH/gL of the subspecies causing disease. Overall, our data indicate that (sub)species-specific gH/gL ELISAs can be used to identify animals at risk of EEHV-HD when infected with a particular EEHV (sub)species.
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Affiliation(s)
- Tabitha E. Hoornweg
- Section of Virology, Division Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Department of Biomolecular Health Sciences, Utrecht University, 3584 CL Utrecht, The Netherlands
- Section of Immunology, Division Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Department of Biomolecular Health Sciences, Utrecht University, 3584 CL Utrecht, The Netherlands;
| | | | - Victor P. M. G. Rutten
- Section of Immunology, Division Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Department of Biomolecular Health Sciences, Utrecht University, 3584 CL Utrecht, The Netherlands;
- Faculty of Veterinary Science, Department of Veterinary Tropical Diseases, University of Pretoria, Onderstepoort 0110, South Africa
| | - Cornelis A. M. de Haan
- Section of Virology, Division Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Department of Biomolecular Health Sciences, Utrecht University, 3584 CL Utrecht, The Netherlands
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Sittisak T, Guntawang T, Srivorakul S, Photichai K, Boonprasert K, Khammesri S, Chuammitri P, Thitaram C, Hsu WL, Thanawongnuwech R, Pringproa K. Response of elephant peripheral blood mononuclear cells when stimulated with elephant endotheliotropic herpesvirus glycoprotein B (EEHV-gB). Vet Immunol Immunopathol 2023; 258:110577. [PMID: 36867998 DOI: 10.1016/j.vetimm.2023.110577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/10/2023] [Accepted: 02/26/2023] [Indexed: 03/05/2023]
Abstract
Elephant endotheliotropic herpesvirus-hemorrhagic disease (EEHV-HD) is the most highly fatal infectious disease among young Asian elephants. Despite the fact that antiviral therapy has been widely used, its therapeutic outcomes remain uncertain. Additionally, the virus has yet to be successfully cultivated in vitro in the process of develop viral envelope glycoproteins for vaccine design. The present study aims to investigate and evaluate EEHV1A glycoprotein B (gB) antigenic epitopes as potential candidates for further vaccine development. Epitopes of EEHV1A-gB were employed in in silico predictions and designed by using online antigenic predicting tools. Candidate genes were then constructed, transformed and expressed in the E. coli vectors prior to examine their potential for acceleration elephant immune responses in vitro. Elephant peripheral blood mononuclear cells (PBMCs) isolated from 16 healthy juvenile Asian elephants were investigated for their proliferative capability and cytokine responses after being stimulated with EEHV1A-gB epitopes. Exposure of elephant PBMCs to 20 µg/mL of gB for 72 h resulted in a significant proliferation of CD3 + cells when compared with the control group. Furthermore, proliferation of CD3 + cells was associated with a marked up-regulation of cytokine mRNA expression, involving IL-1β, IL-8, IL-12 and IFN-γ. It remains to be determined whether these candidate EEHV1A-gB epitopes could activate immune responses in animal models or elephants in vivo. Our potentially promising results demonstrate a degree of feasibility for the use of these gB epitopes in expanding EEHV vaccine development.
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Affiliation(s)
- Tidaratt Sittisak
- Department of Veterinary Biosciences and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Thunyamas Guntawang
- Department of Veterinary Biosciences and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Saralee Srivorakul
- Department of Veterinary Biosciences and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Kornravee Photichai
- Veterinary Diagnostic Center, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Khajohnpat Boonprasert
- Center of Excellence in Elephant and Wildlife Research, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Siripat Khammesri
- Center of Excellence in Elephant and Wildlife Research, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Phongsakorn Chuammitri
- Department of Veterinary Biosciences and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Chatchote Thitaram
- Center of Excellence in Elephant and Wildlife Research, Chiang Mai University, Chiang Mai 50100, Thailand; Department of Companion Animals and Wildlife Clinics, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Wei-Li Hsu
- Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, Taichung 402, Taiwan
| | - Roongroje Thanawongnuwech
- Department of Pathology, Faculty of Veterinary Sciences, Chulalongkorn University, Bangkok 10330, Thailand
| | - Kidsadagon Pringproa
- Department of Veterinary Biosciences and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand; Center of Excellence in Elephant and Wildlife Research, Chiang Mai University, Chiang Mai 50100, Thailand.
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Spencer Clinton JL, Hoornweg TE, Tan J, Peng R, Schaftenaar W, Rutten VPMG, de Haan CAM, Ling PD. EEHV1A glycoprotein B subunit vaccine elicits humoral and cell-mediated immune responses in mice. Vaccine 2022; 40:5131-5140. [PMID: 35879117 DOI: 10.1016/j.vaccine.2022.07.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 07/12/2022] [Accepted: 07/13/2022] [Indexed: 10/16/2022]
Abstract
Asian elephants are an endangered species facing many threats, including severe hemorrhagic disease (HD) caused by the elephant endotheliotropic herpesvirus (EEHV). EEHV-HD is the leading cause of death in captive juvenile Asian elephants in North America and Europe, and also affects elephants in their natural range countries. Significant challenges exist for successful treatment of EEHV-HD, which include timely recognition of disease onset and limited availability of highly effective treatment options. To address this problem, our goal is to prevent lethal disease in young elephants by developing a vaccine that elicits robust and durable humoral and cell-mediated immunity against EEHV. EEHV glycoprotein B (gB) is a major target for cellular and humoral immunity in elephants previously exposed to EEHV. Therefore, we generated a vaccine containing recombinant EEHV1A gB together with a liposome formulated TLR-4 and saponin combination adjuvant (SLA-LSQ). CD-1 mice that received one or two vaccinations with the vaccine elicited significant anti-gB antibody and polyfunctional CD4+ and CD8+ T cell responses, while no adverse effects of vaccination were observed. Overall, our findings demonstrate that an adjuvanted gB protein subunit vaccine stimulates robust humoral and cell-mediated immune responses and supports its potential use in elephants.
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Affiliation(s)
- Jennifer L Spencer Clinton
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, 1 Baylor Plaza, MS: BCM-385, Houston, TX 77030, USA.
| | - Tabitha E Hoornweg
- Department of Biomolecular Health Sciences, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands.
| | - Jie Tan
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, 1 Baylor Plaza, MS: BCM-385, Houston, TX 77030, USA.
| | - Rongsheng Peng
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, 1 Baylor Plaza, MS: BCM-385, Houston, TX 77030, USA.
| | - Willem Schaftenaar
- Veterinary Advisor EAZA Elephant TAG, Rotterdam Zoo, Blijdorplaan 8, 3041 JG Rotterdam, The Netherlands.
| | - Victor P M G Rutten
- Department of Biomolecular Health Sciences, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands; Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Pretoria, South Africa.
| | - Cornelis A M de Haan
- Department of Biomolecular Health Sciences, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands.
| | - Paul D Ling
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, 1 Baylor Plaza, MS: BCM-385, Houston, TX 77030, USA.
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