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Animals : an open access journal from MDPI2025; 15(16); 2352; doi: 10.3390/ani15162352

Cellular Immune Response in Horses After West Nile Neuroinvasive Disease.

Abstract: West Nile virus (WNV) is a mosquito-borne neurotropic virus that causes neurologic disease in both humans and horses. Yet the long-term cellular immune response following natural infection in horses remains poorly understood. This study aims to evaluate the WNV-specific T-cell response in horses recovered from West Nile neuroinvasive disease (WNND). Twelve client-owned horses (4 Hungarian sport horses, 2 Lippizaners, 1 KWPN, 1 Shagya Arabian, 1 Friesian, 1 Gidran, 1 Andalusian, and 1 draft cross horse) with confirmed clinical WNV infection were enrolled, and peripheral blood mononuclear cells (PBMCs) were collected approximately 290 days post infection. An equine interferon-gamma (IFNγ) Enzyme-Linked Immunospot (ELISpot) assay was performed using a WNV capsid peptide pool as an antigen to assess virus-specific cellular immunity. Results: Ten of twelve horses (83%) exhibited a significant IFNγ response. Statistical analyses revealed no association between ELISpot responses and clinical severity, age, sex, breed, or neutralizing antibody titers. These results demonstrate that naturally infected horses are capable of mounting robust WNV-specific T-cell responses independent of humoral immunity. The findings support a potentially important role for cellular immune memory in long-term protection against WNV reinfection and suggest that the capsid peptide-based ELISpot assay may serve as a useful diagnostic or research tool for the evaluation of orthoflavivirus immunity in equines.
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Publication Date: 2025-08-11 PubMed ID: 40867680PubMed Central: PMC12383191DOI: 10.3390/ani15162352Google Scholar: Lookup
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  • Journal Article

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 research investigates the long-term T-cell immune response in horses that have recovered from West Nile neuroinvasive disease (WNND), caused by the West Nile virus (WNV), focusing on how their cellular immunity persists approximately 290 days after natural infection.

Background

  • West Nile virus (WNV) is a mosquito-transmitted virus that affects the nervous system of humans and horses, often leading to neuroinvasive disease.
  • While antibody (humoral) responses to WNV in horses are somewhat understood, the long-term cellular immune response, specifically T-cell mediated immunity, has not been thoroughly explored.
  • Cellular immunity involves T cells that can recognize and respond to viral components, which may be important for lasting protection against reinfection.

Study Design and Methods

  • Twelve client-owned horses with naturally confirmed clinical WNV infection participated; these horses represented a variety of breeds including Hungarian sport horses, Lippizaners, KWPN, Shagya Arabian, Friesian, Gidran, Andalusian, and a draft cross horse.
  • Blood samples were taken approximately 290 days (about 9.5 months) post-infection to analyze the horses’ immune cells.
  • Peripheral blood mononuclear cells (PBMCs) were extracted from the blood samples. These include lymphocytes such as T cells and other immune cells.
  • An enzyme-linked immunospot (ELISpot) assay was used, which detects interferon-gamma (IFNγ) – a key cytokine produced by activated T cells.
  • The ELISpot assay used a pool of West Nile virus capsid peptides (small protein fragments) as antigens to stimulate the T cells and measure the virus-specific cellular immune response.

Key Findings

  • 10 out of the 12 horses (83%) showed a significant IFNγ response, indicating the presence of WNV-specific T-cell immunity long after recovery.
  • The study found no correlation between the strength of the T-cell response and factors such as:
    • Clinical severity of the initial WNV infection
    • Age of the horses
    • Sex of the horses
    • Breed
    • Neutralizing antibody titers (levels of circulating antibodies against WNV)
  • These results suggest that the cellular immune response operates independently of the humoral (antibody) immunity.

Implications of the Research

  • The presence of a robust, long-lasting WNV-specific T-cell response supports the idea that cellular immune memory is an important component of protection against potential WNV reinfection in horses.
  • The capsid peptide-based IFNγ ELISpot assay worked well as a tool to measure cellular immunity, showing promise for future diagnostic or research applications.
  • This assay could therefore aid in better understanding and monitoring protective immunity against WNV and possibly other related flaviviruses (orthoflavivirus family) in horses.
  • From a veterinary and epidemiological perspective, understanding cellular immunity can help improve vaccine strategies or immune monitoring after natural infection.

Conclusion

  • Horses naturally infected with WNV develop detectable and durable T-cell responses months after infection.
  • This cellular immunity appears to be maintained regardless of other clinical or demographic factors.
  • The study highlights the potential significance of T-cell-based assays for evaluating immune status against WNV in equine populations.

Cite This Article

APA
Tolnai C, O'Sullivan C, Lőrincz M, Karvouni M, Tenk M, Marosi A, Forgách P, Paszerbovics B, Wagenhoffer Z, Kutasi O. (2025). Cellular Immune Response in Horses After West Nile Neuroinvasive Disease. Animals (Basel), 15(16), 2352. https://doi.org/10.3390/ani15162352

Publication

Animals : an open access journal from MDPI
ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 15
Issue: 16
PII: 2352

Researcher Affiliations

Tolnai, Csenge
  • Department of Microbiology and Infectious Diseases, University of Veterinary Medicine Budapest, 1143 Budapest, Hungary.
  • Health Safety National Laboratory, 1078 Budapest, Hungary.
O'Sullivan, Ciara
  • Department of Microbiology and Infectious Diseases, University of Veterinary Medicine Budapest, 1143 Budapest, Hungary.
Lőrincz, Márta
  • Department of Microbiology and Infectious Diseases, University of Veterinary Medicine Budapest, 1143 Budapest, Hungary.
  • Health Safety National Laboratory, 1078 Budapest, Hungary.
Karvouni, Maria
  • MABTECH AB, SE-131 52 Nacka Strand, Sweden.
Tenk, Miklós
  • Department of Microbiology and Infectious Diseases, University of Veterinary Medicine Budapest, 1143 Budapest, Hungary.
  • Health Safety National Laboratory, 1078 Budapest, Hungary.
Marosi, András
  • Department of Microbiology and Infectious Diseases, University of Veterinary Medicine Budapest, 1143 Budapest, Hungary.
  • Health Safety National Laboratory, 1078 Budapest, Hungary.
Forgách, Petra
  • Department of Microbiology and Infectious Diseases, University of Veterinary Medicine Budapest, 1143 Budapest, Hungary.
  • Health Safety National Laboratory, 1078 Budapest, Hungary.
Paszerbovics, Bettina
  • Department of Biostatistics, University of Veterinary Medicine Budapest, 1078 Budapest, Hungary.
Wagenhoffer, Zsombor
  • Department of Animal Nutrition and Clinical Dietetics, Institute for Animal Breeding, Nutrition and Laboratory Animal Science, University of Veterinary Medicine Budapest, 1077 Budapest, Hungary.
Kutasi, Orsolya
  • Department of Animal Nutrition and Clinical Dietetics, Institute for Animal Breeding, Nutrition and Laboratory Animal Science, University of Veterinary Medicine Budapest, 1077 Budapest, Hungary.

Grant Funding

  • SRF-001. and SRF-002. / University of Veterinary Medicine Budapest
  • RRF 2.3.1-21-2021-00006. / National Research, Development and Innovation Office

Conflict of Interest Statement

Maria Karvouni was employed by MABTECH AB. All the authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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