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Veterinary research2026; doi: 10.1186/s13567-026-01741-x

Mucosal T cell activation pathways are upregulated by equine herpesvirus type 1 infection.

Abstract: Equine herpesvirus type 1 (EHV-1) is a high morbidity and mortality virus that impacts horse populations worldwide. As a respiratory virus, it enters through the upper respiratory tract (URT), where mucosal immunity plays a crucial role in preventing severe disease. In this study, flow cytometry was used to characterize the nasal leukocyte population during EHV-1 infection, and RNA sequencing of nasal secretions was employed to assess transcriptional markers of the mucosal immune response. Horses with distinct immune statuses were compared at four stages: pre-infection, early (day 1 and 3 post-infection [pi]), mid (days 8 and 10 pi) and late (day 18 pi) infection. Non-immune horses (n = 4), developed clinical signs, shed virus, and established viremia, whereas, immune horses (n = 4), possessing pre-existing immunity, showed no disease or detectable virus after EHV-1 infection. This comparison revealed differential expression of various T cell associated markers based on pre-existing immunity. In immune horses, upregulation of fewer genes occurred during early infection only, while in non-immune horses, a large number of genes were upregulated during mid and late infection. Collectively, these findings highlight a key role for mucosal T cells in mediating viral clearance and restoring homeostasis.
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Publication Date: 2026-04-06 PubMed ID: 41937208DOI: 10.1186/s13567-026-01741-xGoogle Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

Overview

  • This study investigated how equine herpesvirus type 1 (EHV-1), a respiratory virus affecting horses, impacts mucosal T cell activation in the upper respiratory tract.
  • Researchers compared immune and non-immune horses to understand how T cell responses differ during the course of infection and contribute to viral clearance.

Background and Importance

  • Equine herpesvirus type 1 (EHV-1): A viral pathogen that causes significant illness and death among horse populations globally, primarily invading the respiratory tract.
  • Mucosal immunity: The immune response localized at mucosal surfaces (e.g., the nasal passages) plays a critical role in preventing viral infections from becoming severe.
  • T cells: A type of white blood cell important in recognizing and eliminating infected cells, crucial for viral clearance and immune regulation.

Study Objective

  • To characterize changes in nasal immune cells, particularly T cells, over the course of EHV-1 infection.
  • To compare these immune responses between horses previously exposed to the virus (immune) and those not previously exposed (non-immune).

Methods

  • Subjects: Eight horses divided into two groups—four non-immune and four immune to EHV-1.
  • Sampling timeline: Samples collected at four distinct infection stages:
    • Pre-infection (baseline)
    • Early infection (day 1 and 3 post-infection)
    • Mid infection (day 8 and 10 post-infection)
    • Late infection (day 18 post-infection)
  • Techniques:
    • Flow cytometry to analyze cell types and activation states in nasal leukocytes.
    • RNA sequencing of nasal secretions to examine gene expression profiles related to immune responses.

Key Findings

  • Clinical outcomes:
    • Non-immune horses developed clinical signs of disease, shed virus, and had viremia (virus in bloodstream).
    • Immune horses showed no clinical disease and no detectable virus, indicating protective immunity.
  • Gene expression differences:
    • Immune horses showed upregulation of fewer immune-related genes early after infection, suggesting a rapid and contained mucosal T cell response.
    • Non-immune horses exhibited upregulation of a large number of genes during mid and late infection stages, reflecting prolonged and intensified immune activation due to active infection.
    • The genes upregulated were primarily associated with T cell activation pathways, emphasizing the role of T cells in responding to and clearing the virus.
  • Implications for mucosal immunity:
    • The study highlights that mucosal T cells are crucial for controlling EHV-1 infection and restoring the immune balance after infection.
    • Pre-existing immunity enables a more efficient and potentially less damaging immune response at the mucosal surface.

Conclusions and Significance

  • This research provides evidence that mucosal T cell activation is a key factor in the immune response against EHV-1 in horses.
  • Understanding these mechanisms can inform strategies for vaccines or therapies aimed at enhancing mucosal immunity to prevent or mitigate EHV-1 infection.
  • The study establishes a framework to better understand viral respiratory infections and their control at the mucosal level in horses, with potential relevance to other species and viruses.

Cite This Article

APA
Holmes CM, Babasyan S, Wagner B. (2026). Mucosal T cell activation pathways are upregulated by equine herpesvirus type 1 infection. Vet Res. https://doi.org/10.1186/s13567-026-01741-x

Publication

Veterinary research
ISSN: 1297-9716
NlmUniqueID: 9309551
Country: England
Language: English

Researcher Affiliations

Holmes, Camille M
  • Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
Babasyan, Susanna
  • Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
Wagner, Bettina
  • Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA. bw73@cornell.edu.

Conflict of Interest Statement

Declarations. Ethics approval and consent to participate: Not applicable. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.

References

This article includes 60 references
  1. Khalil AM, Martinez-Sobrido L, Mostafa A. Zoonosis and zooanthroponosis of emerging respiratory viruses. Front Cell Infect Microbiol 13:1232772.
    doi: 10.3389/fcimb.2023.1232772google scholar: lookup
  2. Ariel E. Viruses in reptiles. Vet Res 42:100.
    doi: 10.1186/1297-9716-42-100google scholar: lookup
  3. Marschang RE, Salzmann E, Pees M. Diagnostics of infectious respiratory pathogens in reptiles. Vet Clin North Am Exot Anim Pract 24:369–395.
    doi: 10.1016/j.cvex.2021.01.007google scholar: lookup
  4. Gray GC, Robie ER, Studstill CJ, Nunn CL. Mitigating future respiratory virus pandemics: New threats and approaches to consider. Viruses 13:637.
    doi: 10.3390/v13040637google scholar: lookup
  5. Proctor DF. Airborne disease and the upper respiratory tract. Bacteriol Rev 30:498–513.
    doi: 10.1128/br.30.3.498-513.1966google scholar: lookup
  6. Jain N, Lodha R, Kabra SK. Upper respiratory tract infections. Indian J Pediatr 68:1135–1138.
    doi: 10.1007/bf02722930google scholar: lookup
  7. Bosch AATM, Biesbroek G, Trzcinski K, Sanders EAM, Bogaert D. Viral and bacterial interactions in the upper respiratory tract. PLoS Pathog 9:e1003057.
    doi: 10.1371/journal.ppat.1003057google scholar: lookup
  8. Kutter JS, Spronken MI, Fraaij PL, Fouchier RA, Herfst S. Transmission routes of respiratory viruses among humans. Curr Opin Virol 28:142–151.
    doi: 10.1016/j.coviro.2018.01.001google scholar: lookup
  9. Thomas RJ. Particle size and pathogenicity in the respiratory tract. Virulence 4:847–858.
    doi: 10.4161/viru.27172google scholar: lookup
  10. Bellanti JA, Artenstein MS, Buescher EL. Characterization of virus neutralizing antibodies in human serum and nasal secretions. J Immunol 94:344–351.
    doi: 10.4049/jimmunol.94.3.344google scholar: lookup
  11. Renegar KB, Small PA, Boykins LG, Wright PF. Role of IgA versus IgG in the control of influenza viral infection in the Murine respiratory tract. J Immunol 173:1978–1986.
    doi: 10.4049/jimmunol.173.3.1978google scholar: lookup
  12. Spiekermann GM, Finn PW, Ward ES, Dumont J, Dickinson BL, Blumberg RS, Lencer WI. Receptor-mediated immunoglobulin G transport across mucosal barriers in adult life: functional expression of FcRn in the mammalian lung. J Exp Med 196:303–310.
    doi: 10.1084/jem.20020400google scholar: lookup
  13. Heidl S, Ellinger I, Niederberger V, Waltl EE, Fuchs R. Localization of the human neonatal Fc receptor (FcRn) in human nasal epithelium. Protoplasma 253:1557–1564.
    doi: 10.1007/s00709-015-0918-ygoogle scholar: lookup
  14. Apodaca G, Bomsel M, Arden J, Breitfeld PP, Tang K, Mostov KE. The polymeric immunoglobulin receptor. A model protein to study transcytosis. J Clin Invest 87:1877–1882.
    doi: 10.1172/jci115211google scholar: lookup
  15. Pausder A, Fricke J, Schughart K, Schreiber J, Strowig T, Bruder D, Boehme JD. Exogenous and endogenous triggers differentially stimulate Pigr expression and antibacterial secretory immunity in the Murine respiratory tract. Lung 200:119–128.
    doi: 10.1007/s00408-021-00498-8google scholar: lookup
  16. Hupin C, Rombaux P, Bowen H, Gould H, Lecocq M, Pilette C (2013) Downregulation of polymeric immunoglobulin receptor and secretory IgA antibodies in eosinophilic upper airway diseases. Allergy 68:1589–1597. https://doi.org/10.1111/all.12274
  17. Fournier M, Lebargy F, Ladurie FLR, Lenormand E, Pariente R (1989) Intraepithelial T-lymphocyte subsets in the airways of normal subjects and of patients with chronic bronchitis. Am Rev Respir Dis 140:737–742. https://doi.org/10.1164/ajrccm/140.3.737
  18. Gilkerson JR, Bailey KE, Diaz-Méndez A, Hartley CA (2015) Update on viral diseases of the Equine respiratory tract. Vet Clin North Am Equine Pract 31:91–104. https://doi.org/10.1016/j.cveq.2014.11.007
  19. Paillot R, Case R, Ross J, Newton R, Nugent J (2008) Equine Herpes Virus-1: virus, immunity and vaccines. Open Vet Sci J. https://doi.org/10.2174/1874318808002010068
  20. Laval K, Van Cleemput J, Poelaert KC, Brown IK, Nauwynck HJ (2017) Replication of neurovirulent equine herpesvirus type 1 (EHV-1) in CD172a+ monocytic cells. Comp Immunol Microbiol Infect Dis 50:58–62. https://doi.org/10.1016/j.cimid.2016.11.006
  21. Zhao J, Poelaert KCK, Van Cleemput J, Nauwynck HJ (2017) CCL2 and CCL5 driven attraction of CD172a+ monocytic cells during an equine herpesvirus type 1 (EHV-1) infection in equine nasal mucosa and the impact of two migration inhibitors, rosiglitazone (RSG) and quinacrine (QC). Vet Res 48:14. https://doi.org/10.1186/s13567-017-0419-4
  22. Poelaert KCK, Van Cleemput J, Laval K, Favoreel HW, Couck L, Van den Broeck W, Azab W, Nauwynck HJ (2019) Equine herpesvirus 1 bridles T lymphocytes to reach its target organs. J Virol 93:e02098. https://doi.org/10.1128/JVI.02098-18
  23. Baghi HB, Nauwynck HJ (2014) Impact of equine herpesvirus type 1 (EHV-1) infection on the migration of monocytic cells through equine nasal mucosa. Comp Immunol Microbiol Infect Dis 37:321–329. https://doi.org/10.1016/j.cimid.2014.09.004
  24. Kydd JH, Smith KC, Hannant D, Livesay GJ, Mumford JA (1994) Distribution of equid herpesvirus-1 (EHV-1) in the respiratory tract of ponies: implications for vaccination strategies. Equine Vet J 26:466–469. https://doi.org/10.1111/j.2042-3306.1994.tb04051.x
  25. Edington N, Bridges CG, Patel JR (1986) Endothelial cell infection and thrombosis in paralysis caused by equid herpesvirus-1: equine stroke. Arch Virol 90:111–124. https://doi.org/10.1007/BF01314149
  26. Smith KC, Mumford JA, Lakhani K (1996) A comparison of equid herpesvirus-1 (EHV-1) vascular lesions in the early versus late pregnant equine uterus. J Comp Pathol 114:231–247. https://doi.org/10.1016/S0021-9975(96)80045-4
  27. Eady NA, Holmes C, Schnabel C, Babasyan S, Wagner B (2024) 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 98:e00250. https://doi.org/10.1128/jvi.00250-24
  28. Schnabel CL, Babasyan S, Rollins A, Freer H, Wimer CL, Perkins GA, Raza F, Osterrieder N, Wagner B (2019) An equine herpesvirus type 1 (EHV-1) Ab4 open reading frame 2 deletion mutant provides immunity and protection from EHV-1 infection and disease. J Virol 93:e01011-19. https://doi.org/10.1128/JVI.01011-19
  29. Perkins G, Babasyan S, Stout AE, Freer H, Rollins A, Wimer CL, Wagner B (2019) Intranasal IgG4/7 antibody responses protect horses against equid herpesvirus-1 (EHV-1) infection including nasal virus shedding and cell-associated viremia. Virology 531:219–232. https://doi.org/10.1016/j.virol.2019.03.014
  30. Bridges CG, Edington N (1987) Genetic restriction of cytolysis during equid herpesvirus 1 subtype 2 infection. Clin Exp Immunol 70:276–282
  31. Allen G, Yeargan M, Costa LR, Cross R (1995) Major histocompatibility complex class I-restricted cytotoxic T-lymphocyte responses in horses infected with equine herpesvirus 1. J Virol 69:606–612. https://doi.org/10.1128/jvi.69.1.606-612.1995
  32. O’Neill T, Kydd JH, Allen GP, Wattrang E, Mumford JA, Hannant D (1999) Determination of equid herpesvirus 1-specific, CD8+, cytotoxic T lymphocyte precursor frequencies in ponies. Vet Immunol Immunopathol 70:43–54. https://doi.org/10.1016/S0165-2427(99)00037-9
  33. Kydd JH, Wattrang E, Hannant D (2003) 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 96:207–217. https://doi.org/10.1016/j.vetimm.2003.08.004
  34. Breathnach CC, Soboll G, Suresh M, Lunn DP (2005) Equine herpesvirus-1 infection induces IFN-γ production by equine T lymphocyte subsets. Vet Immunol Immunopathol 103:207–215. https://doi.org/10.1016/j.vetimm.2004.09.024
  35. Paillot R, Daly JM, Juillard V, Minke JM, Hannant D, Kydd JH (2005) Equine interferon gamma synthesis in lymphocytes after in vivo infection and in vitro stimulation with EHV-1. Vaccine 23:4541–4551. https://doi.org/10.1016/j.vaccine.2005.03.048
  36. Breathnach CC, Yeargan MR, Sheoran AS, Allen GP (2010) The mucosal humoral immune response of the horse to infective challenge and vaccination with equine herpesvirus-1 antigens. Equine Vet J 33:651–657. https://doi.org/10.2746/042516401776249318
  37. Holmes CM, Wagner B (2024) Characterization of nasal mucosal T cells in horses and their response to equine herpesvirus type 1. Viruses 16:1514. https://doi.org/10.3390/v16101514
  38. Mair TS, Batten EH, Stokes CR, Bourne FJ (1987) The histological features of the immune system of the equine respiratory tract. J Comp Pathol 97:575–586. https://doi.org/10.1016/0021-9975(87)90008-9
  39. Kumar P, Timoney JF (2001) Light and electron microscope studies on the nasopharynx and nasopharyngeal tonsil of the horse. Anat Histol Embryol 30:77–84. https://doi.org/10.1111/j.1439-0264.2001.00299.x
  40. Wimer CL, Schnabel CL, Perkins G, Babasyan S, Freer H, Stout AE, Rollins A, Osterrieder N, Goodman LB, Glaser A, Wagner B (2018) 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 13:e0206679. https://doi.org/10.1371/journal.pone.0206679
  41. Schnabel CL, Wimer CL, Perkins G, Babasyan S, Freer H, Watts C, Rollins A, Osterrieder N, Wagner B (2018) Deletion of the ORF2 gene of the neuropathogenic equine herpesvirus type 1 strain Ab4 reduces virulence while maintaining strong immunogenicity. BMC Vet Res 14:245. https://doi.org/10.1186/s12917-018-1563-4
  42. 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 13:290. https://doi.org/10.3390/vaccines13030290
  43. Perkins GA, Wagner B, Rollins A, Sfraga H, Pearson E, Cercone M (2025) Serum and mucosal antibody testing to detect viral exposure in contact horses during an equine herpesvirus myeloencephalopathy outbreak. Am J Vet Res. https://doi.org/10.2460/ajvr.25.03.0106
  44. Ge SX, Son EW, Yao R (2018) iDEP: an integrated web application for differential expression and pathway analysis of RNA-Seq data. BMC Bioinform 19:534. https://doi.org/10.1186/s12859-018-2486-6
  45. Love MI, Huber W, Anders S (2014) Moderated estimation of fold change and dispersion for RNA-seq data with DESeq2. Genome Biol 15:550. https://doi.org/10.1186/s13059-014-0550-8
  46. Raudvere U, Kolberg L, Kuzmin I, Arak T, Adler P, Peterson H, Vilo J (2019) g:Profiler: a web server for functional enrichment analysis and conversions of gene lists (2019 update). Nucleic Acids Res 47:W191–W198. https://doi.org/10.1093/nar/gkz369
  47. Holmes CM, Babasyan S, Eady N, Schnabel CL, Wagner B (2024) Immune horses rapidly increase antileukoproteinase and lack type I interferon secretion during mucosal innate immune responses against equine herpesvirus type 1. Microbiol Spectr. https://doi.org/10.1128/spectrum.01092-24
  48. Sun C, Mezzadra R, Schumacher TN (2018) Regulation and function of the PD-L1 checkpoint. Immunity 48:434–452.https://doi.org/10.1016/S0165-2427(97)00163-3
  49. Sharpe AH, Pauken KE (2018) The diverse functions of the PD1 inhibitory pathway. Nat Rev Immunol 18:153–167. https://doi.org/10.1016/0165-2427(94)90088-4
  50. Freeman GJ, Long AJ, Iwai Y, Bourque K, Chernova T, Nishimura H, Fitz LJ, Malenkovich N, Okazaki T, Byrne MC, Horton HF, Fouser L, Carter L, Ling V, Bowman MR, Carreno BM, Collins M, Wood CR, Honjo T (2000) Engagement of the Pd-1 immunoinhibitory receptor by a novel B7 family member leads to negative regulation of lymphocyte activation. J Exp Med 192:1027–1034. https://doi.org/10.1016/S0165-2427(97)00160-8
  51. Butte MJ, Keir ME, Phamduy TB, Sharpe AH, Freeman GJ (2007) Programmed Death-1 Ligand 1 interacts specifically with the B7–1 costimulatory molecule to inhibit T cell responses. Immunity 27:111–122. https://doi.org/10.1016/j.immuni.2007.05.016
  52. Keir ME, Liang SC, Guleria I, Latchman YE, Qipo A, Albacker LA, Koulmanda M, Freeman GJ, Sayegh MH, Sharpe AH (2006) Tissue expression of PD-L1 mediates peripheral T cell tolerance. J Exp Med 203:883–895. https://doi.org/10.1084/jem.20051776
  53. Hendriks J, Xiao Y, Borst J (2003) CD27 promotes survival of activated T cells and complements CD28 in generation and establishment of the effector T cell pool. J Exp Med 198:1369–1380. https://doi.org/10.1084/jem.20030916
  54. Walch M, Dotiwala F, Mulik S, Thiery J, Kirchhausen T, Clayberger C, Krensky AM, Martinvalet D, Lieberman J (2014) Cytotoxic cells kill intracellular bacteria through granulysin-mediated delivery of granzymes. Cell 157:1309–1323. https://doi.org/10.1016/j.cell.2014.03.062
  55. Krensky AM, Clayberger C (2009) Biology and clinical relevance of granulysin. Tissue Antigens 73:193–198. https://doi.org/10.1111/j.1399-0039.2008.01218.x
  56. Lieberman J (2003) The ABCs of granule-mediated cytotoxicity: new weapons in the arsenal. Nat Rev Immunol 3:361–370. https://doi.org/10.1038/nri1083
  57. Ma LL, Spurrell JCL, Wang JF, Neely GG, Epelman S, Krensky AM, Mody CH (2002) CD8 T cell-mediated killing of Cryptococcus neoformans requires granulysin and is dependent on CD4 T cells and IL-15. J Immunol 169:5787–5795. https://doi.org/10.4049/jimmunol.169.10.5787
  58. Ochoa M-T, Stenger S, Sieling PA, Thoma-Uszynski S, Sabet S, Cho S, Krensky AM, Rollinghoff M, Nunes Sarno E, Burdick AE, Rea TH, Modlin RL (2001) T-cell release of granulysin contributes to host defense in leprosy. Nat Med 7:174–179. https://doi.org/10.1038/84620
  59. Andersson M, Gunne H, Agerberth B, Boman A, Bergman T, Sillard R, Jörnvall H, Mutt V, Olsson B, Wigzell H (1995) NK-lysin, a novel effector peptide of cytotoxic T and NK cells. Structure and cDNA cloning of the porcine form, induction by interleukin 2, antibacterial and antitumour activity. EMBO J 14:1615–1625. https://doi.org/10.1002/j.1460-2075.1995.tb07150.x
  60. Dotiwala F, Lieberman J (2019) Granulysin: killer lymphocyte safeguard against microbes. Curr Opin Immunol 60:19–29. https://doi.org/10.1016/j.coi.2019.04.013

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