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Topic:Immunology
The equine immune system is a complex network of cells, tissues, and organs that work collaboratively to defend against pathogens and maintain homeostasis. It consists of innate and adaptive components, each with distinct functions and mechanisms. The innate immune system provides the first line of defense through physical barriers, phagocytic cells, and the complement system. The adaptive immune system involves lymphocytes, such as B cells and T cells, which generate specific responses to antigens and provide immunological memory. Research in equine immunology explores the interactions between these components, the impact of genetic and environmental factors on immune function, and the development of vaccines and therapeutics. This page gathers peer-reviewed studies and scholarly articles focusing on the mechanisms, regulation, and clinical applications of the equine immune system in health and disease.
Serum and uterine fluid extracellular vesicles and prostaglandin E metabolite concentrations during diestrus and early pregnancy in mares. Prostaglandins produced by endometrial and conceptus tissues have an established role in maintaining luteal function in early pregnancy and initiating luteolysis during diestrus in mares. The cellular mechanisms controlling the secretion and delivery of prostaglandins have not been fully elucidated. We hypothesized that nanosized lipid bilayer extracellular vesicles (EV) that carry a variety of biological molecules would be involved in these key regulatory processes. Serum and uterine fluid samples were collected from diestrus and pregnant mares on day (D) 10 and D14 post-ovulation, and concep...
Retrospective serological evidence of exposure to selected equine viruses in horses from Indigenous communities of Costa Rica, 2011. Horses are essential for transportation and livelihoods in Indigenous communities of Costa Rica. However, information on their exposure to viral pathogens remains scarce. We conducted a retrospective cross-sectional serosurvey using samples collected from horses from four Indigenous communities (Alto Pacuare, Amubre, Paso Marcos, and Vereh) sampled between March and October 2011 (n = 278). Sera were tested in 2014 using commercial immunodiffusion or ELISA assays for antibodies against West Nile virus (WNV), equine herpesviruses 1 and 4 (EHV-1 and EHV-4), influenza A virus, equine arteritis...
Ivermectin enhances the transcription of pro-inflammatory cytokines in equine leukocytes stimulated with LPS and nigericin. Ivermectin has been reported to exert immunomodulatory effects on the innate immune system; however, the available evidence is contradictory, with both anti-inflammatory and, paradoxically, pro-inflammatory effects described depending on species, dose, and experimental context, while data specific to horses remain scarce. We hypothesised that ivermectin would exert a context-dependent immunomodulatory effect on equine leucocytes. To test this, total leucocytes isolated from six healthy horses were incubated with ivermectin (2 and 4 µg/mL) before stimulation with lipopolysaccharide (LPS) and n...
Proof of Concept for Open Flow Microperfusion for Intratumoural Drug Administration in Equine Cutaneous Neoplasia. Intratumoural drug delivery can achieve high local therapeutic exposure while limiting systemic effects, but heterogeneous distribution may compromise treatment efficacy and precision. This proof-of-concept study investigated open flow microperfusion (OFM) as a novel platform for local delivery of tigilanol tiglate (TT), an intratumoural antineoplastic agent with immunomodulatory and vascular-disrupting effects. Four horses with histologically confirmed cutaneous neoplasia (three sarcoids and one squamous cell carcinoma) underwent OFM using TT concentrations of 0.01-0.04 mg/mL delivered at 9 ...
Equine viral arteritis in horses undergoing pre-export testing in Spain (2016-2023): Seroprevalence estimates and diagnostic performance of a commercial indirect ELISA. Equine viral arteritis (EVA) is a contagious disease that affects equine reproduction and international trade. Despite its importance, epidemiological data from Spain are limited. This study aimed to assess EVA seroprevalence and evaluate the diagnostic performance of a commercial ELISA in horses before export. Methods: From 2016 to 2023, 5000 serum samples from horses across 16 Spanish autonomous communities were tested using a commercial indirect ELISA. Samples with inconclusive results, or those submitted with specific requests, underwent virus neutralisation testing (VNT). Diagnostic perfo...
A single-cell RNA-seq dataset characterizing cellular diversity in healthy equine skin. The skin serves as the primary barrier tissue in horses and is frequently affected by immune-mediated dermatological conditions, most notably insect bite hypersensitivity (IBH). Yet, the cellular composition and transcriptional landscape of normal equine skin have never been characterized at single-cell resolution. Here, we present a single-cell RNA sequencing dataset of healthy equine skin comprising 85,574 high-quality transcriptomes from two horses, with one skin biopsy collected from each horse, divided into two portions for independent processing via manual or automated tissue dissociatio...
Etiological and immunological aspects of equine hoof canker. Chronic equine proliferative pododermatitis (canker) is a hypertrophic hoof disease characterized by excessive proliferation of horn-producing tissues resulting from dyskeratosis of keratinocytes. Since its etiology remains unknown, this study investigated potential etiological agents and evaluated biochemical and immunological profiles. Ten horses with hoof canker and ten healthy controls of the Norik of Muran breed were included. Dermatophytes and bovine papillomavirus 1 and 2 (BPV 1/2) were not detected. Candida glabrata was the most frequently identified species in both affected and health...
Association Between Matrix Metalloproteinase-9 (MMP-9) Immunohistochemical Expression and Clinicopathological Features in Equine Melanoma. Equine melanoma is one of the most important oncological diseases in horses and exhibits a distinct biological behavior compared with melanoma in other species. Matrix metalloproteinase-9 (MMP-9) has been associated with tumor aggressiveness and metastasis in human and canine melanoma, but its expression in equine melanoma remains unknown. Objective: Evaluate the immunohistochemical expression of MMP-9 in equine melanomas and investigate its association with clinicopathological features. Methods: 68 formalin-fixed, paraffin-embedded equine melanomas from 48 gray horses were evaluated immunohis...
Correction: First-time description of MHC diversity in Straight Egyptian Arabian horses using immune-linked microsatellite markers. [This corrects the article DOI: 10.3389/fimmu.2026.1859977.].
Evaluation of a lateral flow immunoassay for the quantitative measurement of immunoglobulin G in foals compared with radial immunodiffusion. Reliable point-of-care diagnostic tests are essential for diagnosing failure of transfer of passive immunity (FTPI) in foals. Quantitative lateral flow immunoassays (LFIAs) could reduce subjectivity but have not been well validated in foals. Objective: To validate the performance and diagnostic accuracy of a LFIA for quantifying immunoglobulin G (IgG) concentrations in foals, using radial immunodiffusion (RID) as the reference standard. Methods: Forty-two neonatal foals were sampled within 24 h of birth. Methods: This prospective exploratory diagnostic accuracy study evaluated the diagnostic ...
Correction: Development of an indirect ELISA for the detection of venezuelan equine encephalitis virus specific antibodies in horses. [This corrects the article DOI: 10.1371/journal.pone.0338819.].
Single-cell sequencing reveals synovial fluid γδ T-cell expansion in equine experimental osteoarthritis. Define temporal cellular changes following joint injury using single-cell RNA sequencing in experimental equine posttraumatic osteoarthritis (PTOA). Unassigned: PTOA was induced in 4 Quarter Horses (3 to 5 years) via carpal osteochondral fragmentation and high-speed treadmill exercise. Synovial fluid (SF) cells and synovium were sampled over 18 weeks (November 2023 to April 2024). Single-cell suspensions were processed (10x Genomics Chromium iX), then aligned to the equine genome (Cell Ranger). Downstream analysis was completed in the R Seurat package. Differential gene expression (log2[fold c...
Evaluation of tilapia skin (Oreochromis niloticus) frozen, frog skin (Rana catesbeiana), and tilapia skin (Oreochromis niloticus) sterilized with gamma rays dressings, in equine skin wound healing. Skin wounds are common in horses due to species-specific behavioral responses. Equine skin morphology, vascularization, and inflammatory responses to wounds are comparable to those in humans, supporting the translational relevance of equine wound-healing studies. Investigating biomaterials such as tilapia and frog skin may improve wound management. This study demonstrated that sterilized tilapia and frog skin exhibit promising wound-healing properties. Unassigned: Macroscopic, microscopic, and thermographic aspects of second-intention wound healing were compared in six horses with surgically i...
The effect of macrophage secretome on equine endometrial fibroblast transcriptomic and functional characteristics. Endometrial fibrosis is a main hallmark of endometrosis, a degenerative condition of the equine endometrium. Fibrosis, is characterized by the excessive accumulation of extracellular matrix (ECM) components. Current research highlights the crucial role of MΦ in activating fibroblasts in the development of fibrotic processes. However, the specific actions of distinct MΦ subpopulations on equine endometrial fibroblasts remain to be elucidated. Thus, this study aimed to investigate the long-term effect of the secretome of equine in vitro-generated monocyte-derived (eqMD)-MΦ (pro-inflammatory M...
Promises and Perspectives of Mesenchymal Stromal Cells in Companion and Farm Animals. Mesenchymal stromal cells (MSCs) are heterogeneous, multipotent cell populations that have become one of the most extensively investigated cell types in veterinary regenerative medicine. They can be isolated from a wide range of adult and perinatal tissues and have attracted considerable interest because of their immunomodulatory properties, broad secretory activity, and potential to promote tissue repair. However, increasing evidence indicates that MSCs should not be regarded as a uniform therapeutic product, as their biological behaviour is influenced by tissue source, donor characteristics,...
Transcriptome Sequencing and Differential Expression Analysis of Ovaries from Kazakh Mares During Seasonal Quiescence and Estrus Activation. Kazakh horses are typical seasonal breeders, and ovarian activity is markedly reduced during the non-breeding period. Hormonal stimulation can induce ovarian functional responses during seasonal anestrus; however, the early ovarian transcriptional changes associated with this response remain incompletely understood. In this study, ovarian transcriptome sequencing was performed in 12 Kazakh mares examined during the seasonal anestrous period. The mares were classified into a non-hormonally stimulated seasonal quiescent group (DB, = 6) and a hormone-induced ovarian activation group (DY, = 6) f...
Evaluation of a new immunoassay for measuring equine serum insulin and plasma adrenocorticotrophic hormone: A method comparison study. Insulin dysregulation (ID) and pituitary pars intermedia dysfunction (PPID) are common equine endocrinopathies detected by measurement of circulating insulin and adrenocorticotrophic hormone (ACTH) concentrations. Different assays may yield variable results, limiting comparability. Objective: To compare immunoassays developed specifically to measure equine insulin (VIDAS® Equine Insulin; enzyme-linked fluorescent assay [ELFA]) and equine ACTH (VIDAS® Equine ACTH; ELFA) with results obtained from a chemiluminescence immunoassay (CLIA) measured using IMMULITE 2000XPi, a chemiluminescence enzym...
Limited Antibodies to Henipaviruses Detected Among Nigerian Horses Using Pseudotyped Virus Neutralization Tests. The Hendra virus (HeV; ) and Nipah virus (NiV; ), members of the genus , are high-consequence pathogens that have caused multiple zoonotic outbreaks with high mortality. Frequently, pigs or horses have acted as bridging hosts between bats, the reservoir hosts, and people. We used pseudotyped viruses with the fusion (F) and glycoprotein (G) envelope proteins of the NiV and Ghana virus (GhV; ) in neutralization tests (PVNTs) to screen serum samples from 138 apparently healthy horses in northwest Nigeria. No antibodies to GhV were detected in the 138 samples tested. Two serum samples were positiv...
Ortholog-specific Spatial Expression of Vanins in the Respiratory Tract of Horses. Equine asthma (EA) is the most prevalent chronic respiratory disease in horses, but molecules thought to be relevant in its pathogenesis are not yet fully understood. Recently, increased Vanin-1 (VNN1) levels were found in bronchoalveolar lavage fluid from horses with severe EA. Human VNN1 is known as a pantetheinase, which is associated with respiratory diseases such as asthma, but the equine vanins (eVNNs) are uncharacterized. We identified the domain architecture of eVNN in silico and analyzed its tissue expression in healthy horses using RT-PCR (=5) and in situ hybridization (=3). Recombin...
Circulating Cell-Free RNA Reflects Immune-Associated and Airway Remodeling Signatures in Equine Asthma. Circulating cell-free RNA (cfRNA) has emerged as a promising minimally invasive biomarker capable of capturing transcripts originating from multiple tissues and cell types, but its utility in chronic inflammatory airway diseases remains poorly understood. Equine asthma (EA), a naturally occurring respiratory disease that shares key clinical and immunopathological features with human asthma, provides a valuable comparative model for evaluating plasma cfRNA in this context. We performed transcriptomic profiling of plasma cfRNA from horses with EA and healthy controls and compared these findings ...
No evidence of H5N1 avian influenza virus infection in Japanese horses in 2025. The global spillover of clade 2.3.4.4b H5N1 highly pathogenic avian influenza virus into mammalian hosts has become a concern for public health as well as for the equine industry. However, previous reports on H5N1 natural infection and the presence of specific antibodies in horses remain limited. Therefore, we conducted a serosurveillance study to assess the prevalence of H5N1 antibodies in serum samples collected from 400 horses in Japan. Samples were screened using competitive ELISA (cELISA) and hemagglutination inhibition (HI) tests against H5-recombinant protein and H5N1 viral antigen, res...
Selective oncolytic activity of newcastle disease virus in equine sarcoid primary cells: a preclinical investigation. Equine sarcoids are the most common skin tumors in horses and are characterized by local invasiveness, high recurrence rates, and inconsistent responses to current therapies. Oncolytic virotherapy represents a promising alternative approach that exploits defects in antiviral signaling pathways in tumor cells. Newcastle disease virus (NDV), an avian paramyxovirus that is nonpathogenic in mammals, has demonstrated tumor-selective activity in several species; however, its effects on equine sarcoids have not been previously investigated. In this study, primary cell cultures derived from equine sar...
Development and Evaluation of an Indirect ELISA for Strangles Based on an Untagged EQ8-SclF Fusion Protein. Strangles, caused by subsp. (), is a highly contagious respiratory disease that causes substantial economic losses to the horse industry worldwide. Serological diagnosis currently relies mainly on the imported IDvet dual-antigen sandwich ELISA kit, which shows good diagnostic performance but is expensive and lacks a domestic alternative in China, thereby limiting its routine use in primary veterinary settings. The aim of this study was to develop a domestic indirect ELISA based on novel antigen targets and an untagged antigen purification strategy. Using comparative bioinformatics analyses, ...
Genetic variants of EcPV2 E6 and E7 in equine genital and oronasal squamous cell carcinoma. Since its discovery in 2008, equine papillomavirus type 2 (EcPV2) has been detected in up to 100% of equine genital and up to 40% of equine oronasal squamous cell carcinomas (SCCs). Preliminary sequence data point to the existence of EcPV2 E6 and E7 oncogene variants compared to the British reference sequence from 2008. Objective: To Identify E6 and E7 sequence variations in EcPV2-positive tumours of horses from Continental Europe and Iceland. Methods: Cross-sectional study. Methods: EcPV2 E6 and E7 were amplified from DNA of 60 EcPV2-positive SCCs/SCC precursor lesions. Amplicons were gel-pur...
First-time description of MHC diversity in Straight Egyptian Arabian horses using immune-linked microsatellite markers. Understanding the immunogenetic structure of the major histocompatibility complex (MHC) in Arabian horses helps to clarify the population health structure-related phenotypes of this historically influential breed. Straight Egyptian (SE) Arabian horses, which fall under , are of global value but are limited in number, raising concerns about their distribution and the genetic diversity associated with immunity. In this study, we examined 57 Egyptian Arabian horses from two breeding programs: one in Germany (AR-DE) and the other in Qatar (AR-QA). Sixteen polymorphic intra-MHC microsatellite marke...
Administration of the Postbiotic Substance 412 to Slovak Warm-Blooded Horses: A Pilot Experiment. Antimicrobial proteinaceous postbiotic substances (PS) and/or bacteriocins can beneficially influence animal health, as previously shown with enterocins from non-autochthonous enterococcal strains. Therefore, the effectiveness of PS 412, produced by our beneficial autochthonous strain EF 412, was assessed in horses. In the pilot experiment, PS 412 was administered to 12 horses of various ages and breeds for 21 days via a small feed ball. Sampling was performed on days 0/1, 21, and 42 (after a 3-week cessation of PS 412). The horses served as their own controls. Although the number of horses w...
Equine Sarcoid: From BPV-Driven Oncogenesis to Host-Sustained Tumor Persistence. Equine sarcoid is the most common cutaneous neoplasm of equids and represents a distinctive model of virus-associated tumor persistence. Although bovine papillomaviruses, particularly BPV-1 and BPV-2, are recognized as the main etiological agents, viral infection alone does not fully explain the clinical heterogeneity, frequent recurrence, and limited spontaneous regression of these lesions. This review summarizes current evidence on the molecular and cellular mechanisms underlying equine sarcoid pathogenesis, with emphasis on the interaction between BPV infection, host signaling pathways, tum...
Evaluation of a commercial multiplex immunoassay for assessing uterine inflammation in mares susceptible to persistent breeding-induced endometritis. Persistent breeding-induced endometritis (PBIE) is characterized by a prolonged and dysregulated uterine inflammatory response following breeding. Although inflammatory cytokines are central to the post-breeding immune response, their assessment in the equine uterus has historically relied largely on gene expression analyses. Multiplex immunoassays provide an opportunity to simultaneously quantify multiple cytokine proteins within uterine secretions; however, the application of equine-specific multiplex immunoassays utilizing the Luminex platform to low-volume uterine lavage (LVL) fluid remain...
