Increase in Virus-Specific Mucosal Antibodies in the Upper Respiratory Tract Following Intramuscular Vaccination of Previously Exposed Horses Against Equine Herpesvirus Type-1/4.
Abstract: Equine herpesvirus type-1 (EHV-1) enters through the upper respiratory tract (URT) and causes respiratory disease, abortions, and myeloencephalopathy in equids. Pre-existing immunity at the viral entry site, especially mucosal IgG4/7 antibodies, has recently been shown to correlate with protection from disease and incomplete viral replication at the URT. Here, we tested whether intramuscular (i.m.) vaccination with a commercial inactivated EHV-1/4 vaccine can induce mucosal antibodies (mucAbs) at the URT. Methods: Adult horses with complete EHV-1 vaccination and/or exposure histories were vaccinated i.m. six times within eight months. Before and after each vaccination, blood and nasal swab samples were obtained. Serum and mucAbs were measured in fluorescent bead-based EHV-1 assays. Results: All horses still had existing EHV-1 specific serum and mucAbs prior to vaccination, which were mainly composed of IgG4/7 antibody isotypes. Serum IgG4/7 significantly increased after the first vaccination and stayed high until the end of the study. An additional short-lasting serum IgG1 response was only induced by the first vaccine application. At the URT, mucAbs increased after five out of six i.m. vaccine injections. Like the systemic antibody response, mucAbs were dominated by IgG4/7 and a small IgG1 increase after the first vaccination. Conclusions: Our data emphasize that robust EHV-1 specific mucAb levels are obtained after i.m. vaccination with the inactivated EHV-1/4 vaccine used here. The findings have important implications for evaluating EHV-1/4 vaccines for their ability to induce and maintain protective mucosal IgG4/7 antibodies.
Publication Date: 2025-03-10 PubMed ID: 40266191PubMed Central: PMC11946061DOI: 10.3390/vaccines13030290Google Scholar: Lookup
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- Journal Article
Summary
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Overview
- This study investigated whether intramuscular vaccination with an inactivated Equine Herpesvirus type-1/4 (EHV-1/4) vaccine can boost mucosal antibodies in the upper respiratory tract (URT) of horses previously exposed to the virus.
- The research found that repeated intramuscular vaccinations increased virus-specific mucosal IgG4/7 antibodies in the URT, which are important for protection against EHV-1 infection.
Background
- Equine herpesvirus type-1 (EHV-1) infects horses primarily through the URT, causing respiratory illness, abortions, and neurological symptoms.
- Protection against the virus is linked to immunity at the entry site, particularly mucosal antibodies of the IgG4/7 isotype, which can prevent or limit viral replication.
- It was unclear whether intramuscular (i.m.) vaccination, which typically induces systemic immunity, could also stimulate mucosal antibody responses in the URT, especially in horses already exposed or vaccinated previously.
Study Methods
- Adult horses with known histories of EHV-1 exposure or vaccination were enrolled.
- Each horse received six intramuscular doses of a commercial inactivated EHV-1/4 vaccine over an eight-month period.
- Samples of blood and nasal swabs were collected before and after each vaccination to measure antibody levels.
- Antibody concentrations in serum and mucosal samples were quantified using fluorescent bead-based assays specific to EHV-1.
Key Findings
- Before vaccination, horses already had measurable serum and mucosal antibodies against EHV-1, predominantly of the IgG4/7 subtype, likely from prior exposure or vaccination.
- After the first vaccination:
- The serum IgG4/7 antibody levels increased significantly and remained elevated throughout the study.
- An additional, short-lived increase in serum IgG1 antibodies was observed.
- In the upper respiratory tract mucosa:
- Mucosal antibody levels increased after five of the six vaccine doses.
- Similar to serum, mucosal antibodies were mostly IgG4/7, with a small IgG1 rise after the first vaccination.
Implications of the Results
- The study demonstrates that intramuscular vaccination can effectively boost mucosal IgG4/7 antibodies in the URT despite prior immunity, which is important because mucosal antibodies at the viral entry site help block infection.
- This challenges the common expectation that inactivated vaccines given intramuscularly mainly stimulate systemic immunity but not mucosal responses.
- The persistence of mucosal antibody increases after multiple doses suggests that repeated vaccination may be necessary to maintain protective immunity in the URT.
- These findings could inform vaccine evaluation and development, highlighting the importance of measuring mucosal IgG4/7 levels as a marker of vaccine-induced protection against EHV-1/4.
Conclusion
- Intramuscular administration of an inactivated EHV-1/4 vaccine in horses with prior exposure leads to a robust and sustained increase in virus-specific mucosal IgG4/7 antibodies in the upper respiratory tract.
- This mucosal antibody response is critical for protection against EHV-1 infection and provides a relevant endpoint to assess vaccine effectiveness.
- The study supports the use of such vaccination protocols to maintain protective mucosal immunity in equine populations at risk of EHV-1/4 infection.
Cite This Article
APA
Wagner B, Schnabel CL, Rollins A.
(2025).
Increase in Virus-Specific Mucosal Antibodies in the Upper Respiratory Tract Following Intramuscular Vaccination of Previously Exposed Horses Against Equine Herpesvirus Type-1/4.
Vaccines (Basel), 13(3), 290.
https://doi.org/10.3390/vaccines13030290 Publication
Researcher Affiliations
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Grant Funding
- NA / This work was supported by the Harry M. Zweig Memorial Fund for Equine Research at Cornell University.
Conflict of Interest Statement
B.W. is the inventor on US patent No. 10/10132 entitled “Enhancing serological assays via fusion proteins”, a technology that is used for the “EHV-1 Risk Evaluation assay” described in this article.
References
This article includes 42 references
- Afify AF, Hassanien RT, El Naggar RF, Rohaim MA, Munir M. Unmasking the ongoing challenge of equid herpesvirus-1 (EHV-1): A comprehensive review. Microb. Pathog. 2024;193:106755.
- Lunn DP, Burgess BA, Dorman DC, Goehring LS, Gross P, Osterrieder K, Pusterla N, Hussey GS. Updated ACVIM consensus statement on equine herpesvirus-1. J. Vet.-Intern. Med. 2024;38:1290–1299.
- Gilkerson J, Whalley J, Drummer H, Studdert M, Love D. Epidemiological studies of equine herpesvirus 1 (EHV-1) in Thoroughbred foals: A review of studies conducted in the Hunter Valley of New South Wales between 1995 and 1997. Vet.-Microbiol. 1999;68:15–25.
- Carvelli A, Nielsen SS, Paillot R, Broglia A, Kohnle L. Clinical impact, diagnosis and control of Equine Herpesvirus-1 infection in Europe. EFSA J. 2022;20:e07230.
- Schulman ML, Becker A, van der Merwe BD, Guthrie AJ, Stout TAE. Epidemiology and reproductive outcomes of EHV-1 abortion epizootics in unvaccinated Thoroughbred mares in South Africa. Equine Vet.-J. 2015;47:155–159.
- Öhrmalm J, Cholleti H, Theelke A-K, Berg M, Gröndahl G. Divergent strains of EHV-1 in Swedish outbreaks during 2012 to 2021. BMC Vet.-Res. 2024;20:270.
- Gilkerson JR, Bailey KE, Diaz-Méndez A, Hartley CA. Update on Viral Diseases of the Equine Respiratory Tract. Vet.-Clin. N. Am. Equine Pract. 2015;31:91–104.
- Kydd JH, Smith KC, Hannant D, Livesay GJ, Mumford JA. Distribution of Equid herpesvirus-1 (EHV-1) in respiratory tract associated lymphoid tissue: Implications for cellular immunity. Equine Vet.-J. 1994;26:470–473.
- Patel J, Heldens J. Equine herpesviruses 1 (EHV-1) and 4 (EHV-4)—Epidemiology, disease and immunoprophylaxis: A brief review. Vet.-J. 2005;170:14–23.
- Goehring LS, van Winden SC, van Maanen C, Sloet van Oldruitenborgh-Oosterbaan MM. Equine herpesvirus type 1-associated myeloencephalopathy in The Netherlands: A four-year retrospective study (1999–2003). J. Vet. Intern. Med. 2006;20:601–607.
- Perkins GA, Goodman LB, Tsujimura K, Van de Walle GR, Kim SG, Dubovi EJ, Osterrieder N. Investigation of the prevalence of neurologic equine herpes virus type 1 (EHV-1) in a 23-year retrospective analysis (1984–2007). Vet.-Microbiol. 2009;139:375–378.
- Oladunni FS, Horohov DW, Chambers TM. EHV-1: A Constant Threat to the Horse Industry. Front. Microbiol. 2019;10:2668.
- Allen GP, Bolin DC, Bryant U, Carter CN, Giles RC, Harrison LR, Hong CB, Jackson CB, Poonacha K, Wharton R. Prevalence of latent, neuropathogenic equine herpesvirus-1 in the Thoroughbred broodmare population of central Kentucky. Equine Vet. J. 2008;40:105–110.
- Foote CE, Love DN, Gilkerson JR, Whalley JM. Detection of EHV-1 and EHV-4 DNA in unweaned Thoroughbred foals from vaccinated mares on a large stud farm. Equine Vet.-J. 2004;36:341–345.
- Schnabel CL, Wimer CL, Perkins G, Babasyan S, Freer H, Watts C, Rollins A, Osterrieder N, Wagner B. Deletion of the ORF2 gene of the neuropathogenic equine herpesvirus type 1 strain Ab4 reduces virulence while maintaining strong immunogenicity. BMC Vet.-Res. 2018;14:245.
- Wimer CL, Schnabel CL, Perkins G, Babasyan S, Freer H, Stout AE, Rollins A, Osterrieder N, Goodman LB, Glaser A. The deletion of the ORF1 and ORF71 genes reduces virulence of the neuropathogenic EHV-1 strain Ab4 without compromising host immunity in horses.. PLoS ONE 2018;13:e0206679.
- Soboll-Hussey G, Dorman DC, Burgess BA, Goehring L, Gross P, Neinast C, Osterrieder K, Pusterla N, Lunn DP. Relationship between equine herpesvirus-1 viremia and abortion or equine herpesvirus myeloencephalopathy in domesticated horses: A systematic review.. J. Vet.-Intern. Med. 2024;38:1872–1891.
- Slater JD, Borchers K, Thackray AM, Field HJ. The trigeminal ganglion is a location for equine herpesvirus 1 latency and reactivation in the horse.. J. Gen. Virol. 1994;75:2007–2016.
- Baxi MK, Efstathiou S, Lawrence G, Whalley JM, Slater JD, Field HJ. The detection of latency-associated transcripts of equine herpesvirus 1 in ganglionic neurons.. J. Gen. Virol. 1995;76:3113–3118.
- Chesters PM, Allsop R, Purewal A, Edington N. Detection of latency-associated transcripts of equid herpesvirus 1 in equine leukocytes but not in trigeminal ganglia.. J. Virol. 1997;71:3437–3443.
- Samoilowa S, Giessler KS, Torres CEM, Hussey GS, Allum A, Fux R, Jerke C, Kiupel M, Matiasek K, Sledge DG. Equid herpesvirus-1 Distribution in Equine Lymphoid and Neural Tissues 70 Days Post Infection.. Pathogens 2021;10:707.
- Edington N, Smyth B, Griffiths L. The role of endothelial cell infection in the endometrium, placenta and foetus of equid herpesvirus 1 (EHV-1) Abortions.. J. Comp. Pathol. 1991;104:379–387.
- Kydd JH, Townsend HG, Hannant D. The equine immune response to equine herpesvirus-1: The virus and its vaccines.. Vet.-Immunol. Immunopathol. 2006;111:15–30.
- Goehring L, Wagner B, Bigbie R, Hussey S, Rao S, Morley P, Lunn D. Control of EHV-1 viremia and nasal shedding by commercial vaccines.. Vaccine 2010;28:5203–5211.
- . AAEP Vaccination Guidelines.. 2024.
- . AAEP Vaccination for Foals.. 2024.
- . AAEP Horse Vaccination.. 2024.
- Perkins G, Babasyan S, Stout AE, Freer H, Rollins A, Wimer CL, Wagner B. Intranasal IgG4/7 antibody responses protect horses against equid herpesvirus-1 (EHV-1) infection including nasal virus shedding and cell-associated viremia.. Virology 2019;531:219–232.
- Schnabel CL, Babasyan S, Rollins A, Freer H, Wimer CL, Perkins GA, Raza F, Osterrieder N, Wagner B. An equine herpesvirus type 1 (EHV-1) Ab4 open reading frame (ORF)2 deletion mutant provides immunity and protection from EHV-1 infection and disease.. J. Virol. 2019;93:e01011-19.
- Allen GP. Risk factors for development of neurologic disease after experimental exposure to equine herpesvirus-1 in horses.. Am. J. Vet.-Res. 2008;69:1595–1600.
- Kydd J, Wattrang E, Hannant D. Pre-infection frequencies of equine herpesvirus-1 specific, cytotoxic T lymphocytes correlate with protection against abortion following experimental infection of pregnant mares.. Vet.-Immunol. Immunopathol. 2003;96:207–217.
- Breathnach C, Soboll G, Suresh M, Lunn D. Equine herpesvirus-1 infection induces IFN-γ production by equine T lymphocyte subsets.. Vet.-Immunol. Immunopathol. 2005;103:207–215.
- Paillot R, Daly J, Juillard V, Minke J, Hannant D, Kydd J. Equine interferon gamma synthesis in lymphocytes after in vivo infection and in vitro stimulation with EHV-1.. Vaccine 2005;23:4541–4551.
- Paillot R, Daly JM, Luce R, Montesso F, Davis-Poynter N, Hannant D, Kydd JH. Frequency and phenotype of EHV-1 specific, IFN-γ synthesising lymphocytes in ponies: The effects of age, pregnancy and infection.. Dev. Comp. Immunol. 2007;31:202–214.
- Wagner B, Goodman L, Babasyan S, Freer H, Torsteinsdóttir S, Svansson V, Björnsdóttir S, Perkins G. Antibody and cellular immune responses of naïve mares to repeated vaccination with an inactivated equine herpesvirus vaccine.. Vaccine 2015;33:5588–5597.
- Eady NA, Holmes C, Schnabel C, Babasyan S, Wagner B. Equine herpesvirus type 1 (EHV-1) replication at the upper respiratory entry site is inhibited by neutralizing EHV-1-specific IgG1 and IgG4/7 mucosal antibodies.. J. Virol. 2024;98:e0025024.
- Holmes CM, Babasyan S, Eady N, Schnabel CL, Wagner B. Immune horses rapidly increase antileukoproteinase and lack type I interferon secretion during mucosal innate immune responses against equine herpesvirus type 1.. Microbiol. Spectr. 2024;12:e0109224.
- Sheoran AS, Lunn D, Holmes MA. Monoclonal antibodies to subclass-specific antigenic determinants on equine immunoglobulin gamma chains and their characterization.. Vet.-Immunol. Immunopathol. 1998;62:153–165.
- Keggan A, Freer H, Rollins A, Wagner B. Production of seven monoclonal equine immunoglobulins isotyped by multiplex analysis.. Vet.-Immunol. Immunopathol. 2013;153:187–193.
- Lunn D, Holmes M, Antczak D, Agerwal N, Baker J, Bendali-Ahcene S, Blanchard-Channell M, Byrne KM, Cannizzo K, Davis W. Report of the Second Equine Leucocyte Antigen Workshop, Squaw Valley, California, July 1995.. Vet.-Immunol. Immunopathol. 1998;62:101–143.
- Sheoran AS, Timoney JF, Holmes MA, Karzenski SS, Crisman MV. Immunoglobulin isotypes in sera and nasal mucosal secretions and their neonatal transfer and distribution in horses.. Am. J. Vet.-Res. 2000;61:1099–1105.
- Kydd JH, Smith KC, Hannant D, Livesay GJ, Mumford JA. Distribution of Equid herpesvirus-1 (EHV-1) in the respiratory tract of ponies: Implications for vaccination strategies.. Equine Vet.-J. 1994;26:466–469.
Citations
This article has been cited 2 times.- Matsuyama-Kato A, Abdul-Careem MF. Closing Editorial-Special Issue on Veterinary Vaccines and Host Immune Responses.. Vaccines (Basel) 2026 Jan 20;14(1).
- Eman S, Mohai Ud Din R, Zafar MH, Zhang M, Wen X, Ma J, Saleh AA, Husien HM, Wang M, Guo X. Technologies in Biomarker Discovery for Animal Diseases: Mechanisms, Classification, and Diagnostic Applications.. Animals (Basel) 2025 Oct 29;15(21).
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