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Discovery immunology2026; 5(1); kyag012; doi: 10.1093/discim/kyag012

Dendritic-cell diversity in equine blood revealed by single-cell transcriptomics.

Abstract: Detailed classification of equine dendritic cells (DC) is necessary to address various research questions, such as the role of DC subsets in immune-mediated diseases of horses. Unassigned: We applied single-cell RNA sequencing (scRNA-seq) on DC enriched from the blood of two horses. Unassigned: All main DC subsets were detected by key gene expression, including conventional DC type 1 (cDC1; ) and type 2 (cDC2; , ), as well as plasmacytoid DC (pDC; ). In addition, we detected a small cluster of hematopoietic progenitors, as well as transitional DC (tDC; , ) and putative DC type 3 (DC3; , ). Our data confirms the previously reported phenotype of equine pDC (Flt3MHC-IICADM1CD172a), cDC1 (Flt3MHC-IICADM1CD172a), and cDC2 (Flt3MHC-IICADM1CD172a), while also highlighting considerable CD14 expression for cDC2. Two subclusters of equine cDC2 were found to be enriched in or transcripts (cDC2.1 and cDC2.2, respectively), with suggested enhanced extravasation and T-cell stimulatory capacities of the latter. Conservation of DC subsets across species (horse, pig, human, mouse) was illustrated by enrichment analyses with subset-specific gene signatures and by cross-species data integration with publicly available scRNA-seq datasets. Unassigned: Our atlas of equine blood DC is a valuable resource for comparative analyses, and it forms the foundation for understanding the involvement of distinct DC subsets in infections and immune-mediated pathologies.
© The Author(s) 2026. Published by Oxford University Press on behalf of the British Society of Immunology.
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Publication Date: 2026-06-26 PubMed ID: 42453898PubMed Central: PMC13367329DOI: 10.1093/discim/kyag012Google 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 research used single-cell RNA sequencing to identify and classify different types of dendritic cells (DCs) in horse blood.
  • The study characterized known DC subsets and discovered new subtypes, contributing important data for understanding immune responses and diseases in horses.

Introduction to Dendritic Cells and Research Importance

  • Dendritic cells (DCs) are a crucial type of immune cell responsible for detecting pathogens and activating other immune cells.
  • Classifying DC subsets in horses is important for studying their role in immune-mediated diseases and infections.
  • Prior to this study, detailed classification of equine DCs was limited.

Methods: Single-Cell RNA Sequencing Approach

  • The researchers enriched dendritic cells from the blood of two horses to focus on this cell population.
  • Single-cell RNA sequencing (scRNA-seq) was applied, allowing for gene expression profiling at the individual cell level.
  • This technique helps identify distinct cell types and states based on their unique gene expression signatures.

Main Findings: Identification of DC Subsets

  • All major known DC subsets were identified by key gene expression markers:
    • Conventional DC type 1 (cDC1)
    • Conventional DC type 2 (cDC2)
    • Plasmacytoid DC (pDC)
  • Additional cell populations found include:
    • Hematopoietic progenitors (precursor blood cells)
    • Transitional DCs (tDCs), which represent an intermediate state
    • Putative DC type 3 (DC3), a newly suggested subset in horses
  • Confirmed phenotypes of equine DC types based on previous markers, specifically indicating the expression of Flt3, MHC-II, CADM1, and CD172a.
  • Highlighted notable CD14 expression on cDC2 cells, which was not previously emphasized.

Subclassification of cDC2 and Functional Insights

  • Two distinct subclusters of cDC2 were identified, termed cDC2.1 and cDC2.2.
  • These subclusters differ in their gene expression related to:
    • cDC2.1 enriched in one transcript set (unspecified in abstract)
    • cDC2.2 enriched in another transcript set, suggesting enhanced capabilities in:
      • Extravasation – the ability to move out of blood vessels into tissues
      • T-cell stimulation – activating T cells to mount an immune response

Comparative Analysis Across Species

  • The study compared equine DC subset gene signatures to those of pigs, humans, and mice.
  • Conservation of DC subsets was observed across these different species, supporting the relevance of the findings beyond horses.
  • Cross-species data integration with publicly available scRNA-seq datasets reinforced these conclusions.

Significance and Future Applications

  • The generated atlas of equine blood DCs serves as a valuable resource for veterinary and immunological research.
  • This detailed classification helps provide a foundation for studying how specific DC subsets participate in infections and immune-mediated diseases in horses.
  • The data may support comparative immunology approaches and improve understanding of immune function across species.

Cite This Article

APA
Baillou A, Botos M, Oberhaensli S, Cvitas I, Jonsdottir S, Ziegler A, Brito F, Summerfield A, Marti E, Talker SC. (2026). Dendritic-cell diversity in equine blood revealed by single-cell transcriptomics. Discov Immunol, 5(1), kyag012. https://doi.org/10.1093/discim/kyag012

Publication

Discovery immunology
ISSN: 2754-2483
NlmUniqueID: 9918486782306676
Country: England
Language: English
Volume: 5
Issue: 1
Pages: kyag012
PII: kyag012

Researcher Affiliations

Baillou, Ambre
  • Institute of Virology and Immunology, Bern, Switzerland.
  • Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Botos, Marius
  • Institute of Virology and Immunology, Bern, Switzerland.
  • Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Oberhaensli, Simone
  • Interfaculty Bioinformatics Unit and Swiss Institute of Bioinformatics, University of Bern, Bern, Switzerland.
Cvitas, Iva
  • Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Jonsdottir, Sigridur
  • Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Ziegler, Anja
  • Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Brito, Francisco
  • Institute of Virology and Immunology, Bern, Switzerland.
  • Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Summerfield, Artur
  • Institute of Virology and Immunology, Bern, Switzerland.
  • Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Marti, Eliane
  • Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Talker, Stephanie C
  • Institute of Virology and Immunology, Bern, Switzerland.
  • Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.

Conflict of Interest Statement

Conflicts of interest: 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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