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Topic:T Cells
T cells are a type of lymphocyte that play a significant role in the adaptive immune system of horses. They are involved in identifying and responding to pathogens, such as viruses and bacteria, by recognizing specific antigens. T cells can be categorized into various subsets, including helper T cells (CD4+), cytotoxic T cells (CD8+), and regulatory T cells, each with specific functions in immune regulation and response. The study of T cells in horses encompasses their development, activation, and the mechanisms by which they mediate immune responses. This research area includes investigations into how T cells contribute to equine health, their response to vaccinations, and their involvement in immune-mediated diseases. This page compiles peer-reviewed research studies and scholarly articles that explore the biology, function, and clinical relevance of T cells in equine immunology.
Central nervous system lymphoma and neurolymphomatosis in equids. Lymphoma affecting the central and peripheral nervous systems in equids is rarely reported. Objective: To describe the clinical presentation, neuroanatomical localization, laboratory and pathologic features, type of lymphoma, and outcome to further current knowledge. Methods: Fourteen equids (13 horses, 1 mule). Methods: Retrospective study. Medical records from a veterinary teaching hospital were reviewed (1993-2025). The inclusion criteria consisted of a definitive diagnosis of lymphoma of the nervous system. Data collected included signalment, neurologic findings, laboratory results, imagin...
Cell-Type Deconvolution of Equine BALF RNA-Seq: A Critical Comparison with Matched Single-Cell Data. Bulk RNA sequencing (RNA-seq) averages signals across heterogeneous cell populations. Computational deconvolution methods aim to infer cell type composition and cell type-specific gene expression from bulk data, but their performance in equine samples has not been evaluated. In this study, we assessed the ability of computational deconvolution to recover cellular composition and differential expression signals in bronchoalveolar lavage fluid (BALF) from horses with severe equine asthma (SEA) and controls (CTL). Cryopreserved BALF samples from six SEA and five CTL horses previously analyzed b...
Dendritic-cell diversity in equine blood revealed by single-cell transcriptomics. 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...
Intra-articular 2.5% polyacrylamide hydrogel alters synovial immune pathways in equine experimental osteoarthritis. To determine differential gene expression in synovial tissues following injection of IA 2.5% polyacrylamide hydrogel (2.5% iPAAG), a biocompatible nondegradable synthetic polymer, to treat osteoarthritis (OA). Unassigned: Osteoarthritis was induced in 1 middle carpal joint of 16, 2- to 5-year-old horses (7 mares and 9 geldings) via surgical osteochondral fragment creation in combination with exercise on a high-speed treadmill; the contralateral limb underwent a sham operation. Horses were exercised 5 days per week, beginning on day 16 postoperatively. The osteochondral fragment joint was injec...
Short-interval longitudinal analysis of immune cell dynamics in heavy draft foals after colostrum intake. Maternal cells and antibodies are present in equine colostrum, but their relationship with immune cells in foals after colostrum ingestion remains unclear. This study longitudinally analyzed immune cells in the peripheral blood of neonatal foals at short intervals and investigated their relationship with colostral immune cells. Eleven clinically healthy draft mares and their foals were examined. Foal blood was collected before colostrum intake (0 hr) and at 2-3, 6, 12, 36-48 hr, and 3 and 7 days after ingestion. Mare blood and milk (0, 36-48 hr; 0 hr milk defined as colostrum) were also collec...
CD8+ T-cells, CD86+ macrophages and TNF-α signalling pathways are correlated with fetlock osteoarthritis in racehorses. There is emerging evidence for the role of the immune system in osteoarthritis (OA) pathophysiology; however, little is known about how immune cells and the synovial transcriptome are altered in naturally occurring equine OA. Objective: To evaluate synovial fluid (SF) and synovial membrane (SM) immune cell populations and the SM transcriptome in racehorses with fetlock OA. Methods: Cross-sectional cadaver study. Methods: Fetlock joints from racehorses euthanised at NY racetracks were considered for inclusion. SF and SM were analysed by flow cytometry using T-cell (CD3, CD4, CD8) and macrophage...
Mucosal T cell activation pathways are upregulated by equine herpesvirus type 1 infection. 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...
In Vitro Characterization of an Equinized Anti-PD-L1 Antibody for Cancer Immunotherapy in Horses. Horses develop spontaneous tumors, typically in old age. Although local tumor control can be achieved using conventional therapies, systemic therapies are required to treat recurrent and/or metastatic tumors. Immune checkpoint inhibitors, such as anti-PD-L1 antibodies, have been approved for the treatment of various tumor types in humans; however, little is known about the immunosuppressive roles of the PD-1/PD-L1 pathway in horses, and the therapeutic potential of these inhibitors remains to be elucidated. Previously, we reported that the rat monoclonal anti-PD-L1 antibody 6C11-3A11 cross-rea...
Association between ultraviolet-related TP53 mutations and immune microenvironment in equine ocular squamous cell carcinoma. This study investigates the molecular and immune characteristics of equine ocular squamous cell carcinoma (eoSCC). Immunohistochemistry (IHC) and next-generation sequencing (NGS) were used to detect protein expression and TP53 mutations, respectively. T lymphocytes (CD3+), regulatory T cells (FoxP3+), B lymphocytes (CD20+), and macrophages (IBA-1+) were quantified. A total of 29 cases of eoSCC were evaluated, consisting of 3/29 carcinomas in situ (CISs) and 26/29 squamous cell carcinomas (SCCs). p53 positivity by IHC was detected in 19/29 cases while by NGS, 21 TP53 mutations were found in 13/...
Senescence-associated gene pathways are differentially expressed in equine aging-related osteoarthritis. Osteoarthritis (OA) is a aging-associated degenerative joint disease. The objective was to determine relative senescence gene expression in joints and leukocytes of OA horses toward considering senotherapeutics to manage OA. Unassigned: To define local (joint) and systemic (peripheral blood mononuclear cells [PBMCs]) senescence burden, synovial fluid cell single-cell RNA sequencing and PBMC mRNA sequencing datasets (n = 65 samples) were examined. Differential analyses were conducted using limma to compare OA versus control. A custom 3,043-gene senescence set curated from published metadata was...
Beneath the surface: gut microbes, cyathostomins and resident immune cells – Characterising the baseline. Cyathostomins are the most prevalent and currently considered the most pathogenic gastrointestinal nematodes in horses. Their life cycle includes an encystment phase within the large intestinal mucosa, where up to 90 % of the total worm burden resides. Clinical disease ranges from chronic protein-losing enteropathy to acute, sometimes fatal, typhlocolitis. Despite their significance, the ecological interplay between cyathostomins, the host immune response, and the gut microbiota remains poorly understood. To our knowledge, this is the first study to investigate these interactions at the mucos...
Cannabinoid and cannabinoid related receptors in fibroblasts, inflammatory and endothelial cells of the equine hoof with and without laminitis: novel pharmacological target. Evidence suggests that the endocannabinoid system (ECS) is crucial for regulating inflammation, cell proliferation and pain. The ECS is composed of cannabinoid receptors such as type 1 (CBR1), type 2 (CBR2) and GPR55, endocannabinoids and enzymes. Proteins of ECS have previously been localized in the epidermal cells of the horse hooves. Given the physio-pathological role and cellular distribution of the ECS across species, the authors hypothesized that cannabinoid receptors are expressed within the inflammatory cells, fibroblasts and endothelial cells of the equine hoof laminae, going beyond t...
Associations between immunological and hormonal parameters during healthy pregnancy in mares. Associations between the immune and endocrine systems during equine pregnancy remain poorly understood. Based on the hypothesis that distinct phases of the equine healthy gestation are characterized by specific associations between circulating immunological and hormonal parameters, contributing to pregnancy maintenance, this investigation aimed to: (i) evaluate how circulating immunological and hormonal parameters change across different phases of pregnancy; (ii) investigate associations between changes in circulating immunological and hormonal parameters; and (iii) propose potential hormonal ...
Identification of Antibodies to Chondrocyte and Synoviocyte Antigens in Equine Osteoarthritis. Innate immune responses within the joint are now known to play a key role in osteoarthritis (OA) pathogenesis. However, comparatively little is known regarding the role of adaptive immune responses in OA, and whether they may be important for initiating and sustaining progressive low-level joint inflammation. Therefore, we evaluated spontaneous osteoarthritis in horses to investigate whether antibodies recognizing live joint cells (chondrocytes, synoviocytes) were present in blood or synovial fluid, and to identify possible cellular target antigens. We found that horses with advanced OA had an...
Th1 and Th2 cells in equine endometrosis and their interactions with endometrial fibroblasts. Mare endometrosis is a chronic degenerative condition of the endometrium, primarily characterized by fibrosis, involving interactions among fibroblasts, immune cells, and epithelial cells regulated by cytokines and growth factors. T helper (Th)1 and Th2 cells seem to play a pivotal role in fibrosis. However, their roles in equine endometrial fibrosis remain unknown. This study explores Th1 and Th2 cell distribution across different stages of endometrium histopathological Kenney and Doig categories; and evaluated their secretome effects on non-fibrotic endometrium derived fibroblast functional ...
Abnormal Fetuin-A levels in obese horses are associated with activated TLR4/NF-ƙB/MAPK axis and depleted FBXW7 E3 ubiquitin ligase. Fetuin-A (FetA) is a multifactorial glycoprotein primarily synthesized by the liver with additional expression in adipose tissue, the abundance of which is tightly regulated by the FBXW7 E3 ubiquitin ligase. Recently, FetA has been implicated in the pathogenesis of insulin resistance and associated metabolic failures in humans through its potent and selective inhibition of insulin receptor tyrosine kinase activity, however, no studies have yet directly investigated its role in the development and progression of equine obesity. In this investigation, FetA levels were measured in serum, liver, a...
BCG Immunotherapy in Equine Sarcoid Treatment: Mechanisms, Clinical Efficacy, and Challenges in Veterinary Oncology. Equine sarcoids are the most common dermatological neoplasm in horses worldwide, associated with bovine papillomavirus (BPV) infection and characterized by high recurrence rates after conventional therapies. Bacillus Calmette-Guérin (BCG) immunotherapy has historically been used for sarcoid treatment, yet its role in contemporary veterinary oncology remains debated. This narrative review critically examines the immunological mechanisms, clinical efficacy, and limitations of BCG in equine sarcoid therapy, while integrating insights from comparative oncology and One Health perspectives. A syste...
Autologous Cancer Vaccines: A Precision Immunotherapy Strategy for Veterinary Cancer Patients. Precision medicine is a therapeutic strategy to provide treatment that is tailored to a specific patient based on factors unique to that individual, such as the genetic makeup or the environment. Autologous cancer vaccines (ACVs) are ideal for a precision medicine approach because they incorporate antigens specific to the patient's tumor and provide an elegant solution to identifying and selecting relevant immunogenic neoantigens. ACVs are an appealing option for veterinary medicine because they are cancer-type and species agnostic. Over the past 50 years, many innovative ACVs have been evalua...
Adjuvant combination enhances immune response of equine influenza virus vaccine in horses. Despite routine vaccination, equine influenza outbreaks occur due to disparities of virus strains between vaccine and field, and immunity gaps between vaccinations. Objective: To evaluate whether a combination of adjuvants can enhance immune responses to equine influenza virus (EIV) vaccines. Methods: In vivo experimental study. Methods: Eight mixed-breed horses were immunised intramuscularly with a recombinant canarypox-based EIV vaccine, either alone or in combination with monophosphoryl lipid A (MPL) and polyinosinic-polycytidylic acid (poly I:C). A single vaccine dose was administered, and...
Comparative analysis of blood whole transcriptome profiles in Yili horses pre- and post-5000-meter racing. This study employed Yili horses participating in a 5000-meter race as a model to investigate exercise-induced gene expression alterations in peripheral blood using whole transcriptome sequencing. Jugular vein blood samples from the three leading horses were collected pre- and immediately post-race, yielding 2,171 differentially expressed mRNAs (2,080 upregulated, 91 downregulated), 4,375 differentially expressed LncRNAs (4,354 upregulated), and 68 differentially expressed circRNAs (64 upregulated). GO/KEGG analyses demonstrated significant enrichment of differential mRNAs in transmembrane tran...
Anti-IL-5 Vaccination Dampens Allergen-Specific IgE Levels and Modulates IL-4 and IL-5 Th2 Cytokines in Skin Allergy of Mice and Horses. Skin allergies are among the most frequent types of allergies, where continuous investigation of the pathological immune mechanisms is required for a better understanding and a more effective treatment of the disease. In this study, we aimed to investigate the effect of interleukin (IL)-5 vaccination on allergen-specific IgE antibodies as well as T cell cytokine modulation in skin allergy using a mouse model and a naturally occurring disease in horses. Methods: Ovalbumin (OVA)-sensitized mice, as well as horses affected by equine insect bite hypersensitivity (IBH) were administered an anti-IL-...
Cellular Immune Response in Horses After West Nile Neuroinvasive Disease. 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 ...
Equine influenza antigen-based particle vaccine protects mice against homologous and heterosubtypic viral challenges. Influenza virus is a common source of respiratory illness and poses a major public health burden globally. Significant efforts have been dedicated towards developing and deploying effective vaccines. However, since being licensed in 1945, influenza vaccines have made limited progress and still suffer from several limitations, including suboptimal efficacy against variants. In this work, we report on two influenza A polyanhydride particle- and pentablock copolymer-based vaccine formulations intended for intranasal or subcutaneous administration. These nanovaccines are based on a newly discovere...
CD81 is a receptor for equine arteritis virus (family: Arteriviridae). Arteriviruses are a family of single-stranded, positive-sense RNA (+ssRNA) viruses that infect diverse animal hosts. Many arteriviruses are macrophage-tropic, consistent with their utilization of the macrophage-specific molecule CD163 as a receptor. However, the horse arterivirus (equine arteritis virus, EAV), which infects additional cell types beyond macrophages, does not utilize CD163 in its entry mechanism. Here, we use a genome-wide CRISPR knockout screen to identify alternative receptors that could explain this discrepancy in arterivirus receptor utilization and tropism, identifying the ...
Immune cell analysis in equine penile papilloma, in situ squamous cell carcinoma and invasive squamous cell carcinoma: FoxP3+ T regulatory lymphocytes differ according to equine papillomavirus 2 status. Equine penile tumors are common in horses and are often related to infection with equine papillomavirus type 2 (EcPV2). This study investigated the immune cell infiltrate (ICI) of these tumors in horses, focusing on the role of EcPV2. Using multiplex immunohistochemistry (mIHC) for CD3, CD20, and IBA-1 and immunohistochemistry (IHC) for FoxP3, 27 horses with papillomas (5/27), in situ carcinomas (CISs) (3/27), and squamous cell carcinomas (SCCs) (19/27) were evaluated. Eighteen cases tested positive for EcPV2 by either or both in situ hybridization (ISH) and polymerase chain reaction (PCR) (18...
Immunological Responses to Tetanus and Influenza Vaccination in Donkeys. Donkeys are routinely vaccinated with protocols developed for horses, yet species-specific data on their immune responses are limited. Objective: We hypothesized that donkeys exhibit robust T-cell-mediated immunity and regulatory adaptation after vaccination, comparable to horses. Methods: Thirty-six healthy, seronegative donkeys (34 mares, 2 stallions), aged 0.5-23 years (median 8 years), from two farms with similar housing and management conditions. Methods: Prospective study. Animals were selected based on clinical health assessment and confirmed seronegativity for tetanus and equine in...
Enteral immunization with live bacteria reprograms innate immune cells and protects neonatal foals from pneumonia. Using a horse foal model, we show that enteral immunization of newborn foals with Rhodococcus equi overcomes neonatal vaccination challenges by reprogramming innate immune responses, inducing R. equi-specific adaptive humoral and cell-mediated immune responses and protecting foals against experimental pneumonia challenge. Foals were immunized twice via gavage of R. equi (immunized group) or saline (control group) at ages 1 and 3 days. At age 28 days, all foals were challenged intrabronchially with R. equi. Post-challenge, all 5 immunized foals remained healthy, whereas 67% (4/6) of control foa...
Astaxanthin supplementation in Arabian racing horses mitigates oxidative stress and inflammation in peripheral blood mononuclear cells through enhanced mitophagy. Astaxanthin, a strong antioxidant carotenoid, has shown promising features in mitigating inflammation and oxidative stress and so that has been considered as a supplement for high-performance animals. In this study, we aimed to evaluate the effects of astaxanthin on oxidative stress, inflammation, and mitochondrial health in peripheral blood mononuclear cells (PBMC) isolated from Arabian racehorses. Horse-derived peripheral blood mononuclear cells exposed to hydrogen peroxide (H₂O₂) presented increased reactive oxygen species (ROS) accumulation and overexpression of pro-inflammatory cytoki...
Circadian Oscillation of Leukocyte Subpopulations and Inflammatory Cytokines over a 24-H Period in Horses. The objective of the present study was to investigate the influence of daily rhythms on the immune and inflammatory systems in horses, considering white blood cell count (WBCs), leukocyte subpopulations (neutrophils, basophils, eosinophils, lymphocytes, and monocytes), CD4+, and CD8+ lymphocyte populations, interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). Ten Italian Saddle horses (7-12 years old, body weight 480 ± 30 kg) underwent blood sampling every 4 h over a 24-h period. The COSINOR method was used to identify rhythms and their parameters. A one-way ...
Exploration of the Differential Expression Patterns of Immunoglobulin Heavy Chain Genes in Horses and Donkeys. This study investigated the immunoglobulins (IG) gene locus structure and expression diversity in local Chinese horse and donkey breeds, including Ningqiang, Guanzhong horses, and varieties such as Guanzhong, Jiami, and Northern Shaanxi donkey using genome alignment and high-throughput sequencing. The aim was to expand understanding of IG expression patterns in horses, donkeys, and their different breeds. The results revealed that the donkey IGH locus contains 117 VH genes (23 functional), 44 DH genes, and 8 JH genes, arranged in a VH-DH-JH sequence on chromosome 7, spanning approximately 1189...
