The immune response in horses involves a complex network of cells, tissues, and molecules that work together to protect the animal from pathogens and other harmful agents. This process includes both innate and adaptive immune mechanisms. Innate immunity provides the first line of defense and involves components such as physical barriers, phagocytic cells, and the complement system. Adaptive immunity, on the other hand, is characterized by the activation of lymphocytes and the production of antibodies, which provide a targeted response to specific antigens. Key components of the equine immune system include T cells, B cells, and various cytokines that facilitate communication between immune cells. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, regulation, and implications of immune responses in equine health.
Ozawa Y, Bahrami S.Formalized African horse-sickness (AHS) type 9 virus cultivated in monkey kidney stable (MS) cell cultures was experimentally used for immunizing horses. Inactivated vaccines prepared either from viscerotropic or neurotropic type 9 AHS virus produced antibodies in vaccinated horses. Immunity developed in all horses vaccinated with various amounts of the vaccine, and protected them from infection, when challenged 5 weeks after vaccination.
Goebel WF, Staub AM.1. The immunization of horses with the colicinogenic bacillus E. coli K235 L + O(m) stimulates antibodies which precipitate and neutralize colicine K and neutralize the heterologous colicine I as well. 2. Unlike rabbits, horses evoke predpitating antibodies for the sialic acid-containing polysaccharide colominic acid.
INGRAM DG.A method is described for the quantitative measurement of the reactions between sensitized cells and horse complement and between alexinated cells and conglutinin. The method is laborious but its application has allowed the determination of the optimal times of the reactions at various temperatures. The results obtained in these experiments indicate that the alexinated configuration with which conglutinin and immuno-conglutinin react is not one of the recognized intermediates formed during the process of immune haemolysis.
REBERS PA, HURWITZ E, HEIDELBERGER M.Rebers, Paul A. (Rutgers University, New Brunswick, N. J.), Esther Hurwitz, and Michael Heidelberger. Immunochemistry of pneumococcal types II, V, and VI. II. Inhibition tests in the type VI precipitating system. J. Bacteriol. 82:920-926. 1961.-As in other immune systems involving polysaccharides, rabbit antibodies but not those engendered in the horse were found sensitive to degradation of type VI pneumococcal (Pn) polysaccharide (SVI), and were readily inhibited by fragments of SVI. Large amounts, 30 to 111 mumoles, of most sugars gave up to 15% inhibition, while sugar and polyol phosphates ...
HETRICK FM, YANCEY FS, HANSEN PA, BYRNE RJ. Four horses inoculated with EEE virus remained asymptomatic following injection but did develop measurable HI and neutralizing antibodies as a result of infection. HI antibodies were detectable earlier than neutralizing antibodies but the levels tended to drop more rapidly. 2. Of 14 horses and ponies having significant levels of neutralizing antibody, 5 to 9 had measurable HI antibody depending on number of units of antigen employed in the test. 3. Sera from 3 clinical cases of EEE were positive on the HI test while only one of these animals had a significant neutralizing antibody level.
Feijo LS, Ledeck J, Wolfsdorf K, Ponthier J, Parry S, Felippe MJB.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 ...
Wang T, Yang X, Wang C, Wang J, Meng J, Yao X, Zeng Y, Ren W.Studying the genetic characteristics and molecular mechanisms of immune regulation in horses is of great significance for protecting their genetic resources, improving breeding strategies, and enhancing their disease resistance, thereby ensuring their healthy performance in both sports and production. Objective: This study investigates the genetic characteristics and molecular mechanisms underlying immune regulation in Yili horses, comparing them with Thoroughbreds and Kazakh horses. Methods: Blood samples from each breed were analyzed for physiological, biochemical, and immune indices alongsi...
Monteiro MM, de Castro ELA, Pereira AJM, Thiesen R, Thiesen RMC, Salvarani FM.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...
The aim of the study was to identify proteomic signatures from the serum of horses affected by simple obstructive intestinal colic to characterize the pathological process and to assess potential biomarkers for early diagnosis. Seven horses with obstructive colic received venous blood samples for determination of standard hematobiochemical, inflammatory, and lipid profiles at the time of initial clinical examination and after conservative therapy upon recovery. Proteomic profiling was also performed on all samples by means of a within-group analysis (sick horses at discharge vs. sick horses at...
Salinas-Varas C, Espinosa G, Muñoz-Caro T, Conejeros I, Gärtner U, Fey K, Arnhold S, Taubert A, Hermosilla C.Neutrophil extracellular trap (NET) are thin and long web-like structures composed of DNA and antimicrobial proteins released by activated polymorphonuclear neutrophils (PMN) as part of the innate immune response. Adipose-derived stem cells (ADSCs) represent an accessible, abundant and minimal invasive source of mesenchymal stem cells (MSCs), with high regenerative potential, immunomodulatory and anti-inflammatory properties. Although recognized immunomodulatory properties of ADSCs, their interaction with PMN and their role on NET formation remains poorly characterized. The present study aimed...
Piecuch A, Szterk A.This review highlights the role of β-glucans-specifically β(1 → 3), β(1 → 6), and β(1 → 4)-glucans-as water-soluble dietary fibres in animal nutrition and health. Sourced from yeast, plants, seaweed, and mushrooms, β-glucans differ in structure depending on origin, which affects their solubility and biological activity. Recent studies emphasize their therapeutic potential in horses, particularly for managing gastric ulcers, viral infections, immune dysfunction, and poor performance. The review summarizes data on effective dosages, formulations, and sources of β-glucans tailor...
Mitlyng N, Hobbs KJ, Cooper BL, Sheats MK.Lipopolysaccharide (LPS) is frequently used in equine research to model clinical endotoxemia; however, there is no standardized protocol for inducing cytokine production in equine whole blood. To address this knowledge gap, the goal of this study was to compare the cytokine responses elicited by three different LPS stimulation protocols. Whole blood was collected from six healthy horses (aged 5-30 years; mixed breeds and genders) from the North Carolina State University teaching herd (IACUC #23-412). Sixty milliliters of heparinized blood were aseptically drawn and divided into 15 mL aliquots....
Clark KF, Lemcke RA, Gasiorowski JC, Wagner B.Lyme arthritis, a well-documented subtype of arthritis in humans and dogs, is caused by Borrelia burgdorferi and spread primarily through ticks (Ixodes spp.). While Lyme disease in horses is known to cause a variety of clinical signs, its involvement in the development of equine arthritis is controversial. As climate change enables tick populations to expand, more horses could be exposed to B. burgdorferi; therefore, a greater understanding of how Lyme disease affects joints is critical to preserving soundness. Objective: To determine if systemic, naturally occurring Lyme disease had a discern...
Meng C, Wang J, Zeng Y, Yao X, Meng J.This study investigated the effects of varying proline supplementation doses in weaned foals. Twenty-eight weaned foals (approximately 5 months of age; body weight: 54.45 ± 11.33 kg; with an equal number of males and females) were randomly assigned to one of four groups-a control group, a low-dose group (20 mg/kg·d), a medium-dose group (40 mg/kg·d), and a high-dose group (60 mg/kg·d)- receiving continuous supplementation for 60 days. Blood samples were collected periodically for the analysis of hormones, antioxidants, immune parameters, and plasma amino acids. Concurrently, fecal 16S rRNA...
Costa VMD, de Aguiar Filho RN, Braz GF, Paz CFR, Drumond BP, Teixeira BM, Kroon EG.Equine infectious anemia (EIA) is a chronic disease caused by the equine infectious anemia virus (EIAV), a member of the Retroviridae family and the Lentivirus genus. Most infected animals are asymptomatic carriers, which makes clinical diagnosis challenging. This study aimed to conduct a clinical and laboratory evaluation of EIA in equids used for equestrian tourism in Jericoacoara National Park, Ceará, Brazil. A total of 112 equids (104 horses and 8 mules) underwent clinical, hematological, biochemical, serological, and molecular assessments. The EIAV seropositivity rates were 11.6% by AGID...
Bhat S, Karunakaran S, Frossard JP, Choudhury B, Steinbach F.Equine arteritis virus (EAV) is the causative agent of equine viral arteritis, a notifiable respiratory and reproductive disease of equids that causes significant losses to the equine industry. This study presents a comprehensive analysis of two EAV outbreaks in the UK in 2019, combining virus isolation, sequencing and phylogenetic analysis to provide a holistic understanding of EAV dynamics in these outbreaks. Genetic characterization revealed that all outbreak strains were similar to viruses detected in the UK and Europe from 2004 to 2011, belonging to phylogroup D and clustering in two grou...
Jandová V, Huber N, AlMheiri FG, Bábor K, Trachsel DS.Stress represents a serious health and welfare concern; however, its objective assessment remains difficult. The equine gastric ulcer syndrome (EGUS) and orthopedic diseases that cause pain are among stress associated diseases in equine medicine. The leukocyte coping capacity (LCC) quantifies oxygen radical generation of neutrophil granulocytes which is altered under stress. Therefore, LCC could be a novel biomarker for stress in horses and we hypothesized that horses with stress associated diseases would have lower LCC values in comparison to horses without these diseases. Methods: In this ob...
Schank N, Cottone A, Wulf M, Seiter K, Thomas B, Miller LMJ, Anderson SL, Sahyoun A, Abidi AH, Kassan M, Verma A.Equine colic remains a prevalent and potentially life-threatening condition with multifactorial origins, including dietary imbalances, stress, and microbial dysbiosis. Central to equine gut health is the production of short-chain fatty acids (SCFAs), primarily acetate, propionate, and butyrate, generated through microbial fermentation of dietary fibers in the hindgut. These metabolites not only serve as vital energy sources but also play crucial roles in maintaining intestinal barrier integrity, modulating motility, and suppressing inflammation. This review explores the role of SCFAs in equine...
Cooper BL, Hobbs KJ, Bayless R, Stinson-Miller A, Gruber E, Hepworth-Warren K, Lavoie JP, Sheats MK.Severe equine asthma (sEA) is characterized by increased lower airway neutrophils that contribute to dysregulated inflammation through the release of cytokines, reactive oxygen species and neutrophil extracellular traps (NETs). NETs are composed of cell-free DNA (cfDNA) intercalated with enzymatic proteins and are known to be increased in the lower airway of asthmatic horses. The objectives of this study were two-fold: 1. Determine if cfDNA can be accurately measured in equine bronchoalveolar lavage fluid (BALF) and tracheal wash (TW) with a Qubit 4 fluorometer. 2. Determine whether Qubit-meas...
Jager MC, Luethy D, Shallop S, Cathcart J, Divers TJ, Tan JY, Beasley EM, Johnson P, Leduc L, Smith C, Jamieson CA, Magdesian KG, Van de Walle GR....Equine hepacivirus (EqHV) is closely related to hepatitis C virus (HCV), which causes persistent infection and chronic hepatitis in people. Information on persistent EqHV infection and hepatitis is limited. Objective: To report 19 cases of chronic hepatitis and persistent EqHV infection. Methods: Mixed retrospective and prospective case series. Methods: Inclusion criteria were: (1) chronic hepatitis, defined as persistently increased serum liver biomarkers, increased serum liver biomarkers accompanied by histopathological evidence of chronicity, for example, fibrosis, or both; (2) positive ser...
Eskandari G, Ahmadi Sheikhsarmast S, Ghasemi S, Mohri M.Neutrophil gelatinase-associated lipocalin (NGAL) is a glycoprotein involved in immune responses and inflammation, with established diagnostic utility in acute kidney injury (AKI) and systemic diseases. However, reference values for NGAL in healthy horses, particularly the Turkmen breed, remain poorly defined. Objective: This study aimed to establish reference values for serum NGAL concentrations in healthy Turkmen horses and to evaluate the influence of age, sex, pregnancy status and physical activity on its levels, as well as its correlations with haematological and serum biochemical variabl...
Deniz Ö, Erol HS, van den Hoven R, Onmaz AC, Aragona F, Fazio F.Weaning represents a major developmental milestone for foals, especially when 4- to 7-month-old foals are abruptly separated from their dams. Studies have shown that the post-weaning period is associated with physiological and psychological stress, which may affect immune function. The present study aimed to describe and analyze the pattern of blood inflammatory biomarkers related to the innate immune system. A gradual foal-dam separation procedure was chosen, which included post-weaning social buffering by a familiar adult horse. Twelve Thoroughbred foals (six fillies, six colts) aged 4-6 mon...
Rask E, Righetti F, Ruiz A, Bjerketorp J, Frosth S, Frykberg L, Jacobsson K, Guss B, Flock JI, Henriques-Normark B, Hartman E, Gustafsson A....Infection of susceptible horses with subspecies (), the causative agent of strangles, is associated with commingling. Exposure may occur among horses at equestrian events, sales, or horses moved among different equine stabling environments. Strangles can affect all horses on a farm, leading to the death of up to 10% of cases depending on their immunity status at the time of infection, the development of complications, the success of biosecurity measures, and the use of vaccination. The current retrospective study used ELISAs to measure the exposure of horses to at a farm that experienced an...
Rodrigues MF, Neves AP, Ferreira R, Pessoa GA, Araujo DN, de Souza GV.Melatonin has demonstrated beneficial effects in regulating inflammatory processes in various tissues, but its role in mare uterine physiology remains unclear. Objective: To investigate the effects of melatonin on the gene expression of cytokines (IL-1β, IL-6, IL-8, IL-10, and TNF-α) in equine uterine explants cultured for 6, 12, or 24 hours. Methods: The study was divided into two experiments. Part 1 aimed to evaluate the cytotoxicity of melatonin at concentrations of 0, 0.5, 1, 2, 4, and 8 mM on endometrial cells. Part 2 aimed to determine the expression of inflammatory cytokines in uterin...
Sfraga H, Demeter EA, Pinn-Woodcock T, Guarino C, Young R, Cronk B, Cercone M.To investigate the presence of subclinical cranial nuchal bursitis and characterize its histopathologic features and association with Borrelia burgdorferi. Unassigned: This was a prospective descriptive cadaver study on a convenience population of horses in a B burgdorferi-endemic region (15 horses: 5 geldings and 10 mares of various breeds; 4 to 29 years old). Horses without history or clinical signs of cranial nuchal bursitis underwent euthanasia and tissue donation. Cranial nuchal bursa, synovial fluid, and nuchal ligament were collected postmortem. The bursa and ligament were evaluated via...
Conrad NL, Mazzoleni I, Abreu MC, Costa AV, Di Giácomo CP, Zorzi VSG, Leite FPL.Equine proliferative enteropathy (EPE), caused by Lawsonia intracellularis induces intestinal epithelial hyperplasia, resulting in malabsorption, weight loss, colic, and diarrhea. Despite its clinical and economic importance, no equine-specific vaccine is commercially available. Recombinant subunit vaccines are a safe and scalable alternative; however, their immunogenicity often requires improvement. Probiotic supplementation with Bacillus toyonensis may act as an immunomodulatory strategy to potentiate vaccine efficacy. This study aimed to evaluate the immunogenicity of a recombinant protein ...
Aucoin AA, Zhidkov V, Legere RM, Borba KER, Landrock KK, Parker LE, Bray JM, Bordin AI, Cohen ND.To characterize age-related trajectories of the relative concentrations of anti-virulence-associated protein A (VapA) immunoglobulin (Ig)-G1, IgG3/5, IgG4/7, and IgA in serum and bronchoalveolar lavage fluid (BALF) as indicators of systemic and intrapulmonary immune responses in foals naturally exposed to Rhodococcus equi. Unassigned: Blood and BALF samples were collected at ages 4, 14, 28, and 56 days from healthy Quarter Horse foals (n = 19) naturally exposed to R equi. Samples were tested via ELISA for relative concentration of IgG1, IgG3/5, IgG4/7, and IgA recognizing the VapA of R equi. D...
Epizootic lymphangitis (EEL), caused by Histoplasma capsulatum var. farciminosum (HCF), is a neglected equine fungal disease lacking effective vaccines. The newly developed inactivated '8ZH' vaccine requires safety validation in the target species. Objective: To evaluate the biochemical, haematological and clinical safety of the inactivated HCF '8ZH' vaccine in foals. Methods: A controlled, single-blinded study was conducted on 30 clinically healthy foals (4-6 months), randomized into vaccinated (n = 15) and control (n = 15) groups. Vaccinated animals received a 5 mL intramuscular dose (...
Wang C, Wang J, Ma B, Liu T, Yuan X, Meng J, Zeng Y.: This study investigated the effects of dietary bamboo leaf extract (BLE) on milk parameters and intestinal microbiota in lactating mares. : Twenty-four mares of similar age (10 ± 2 years), weight (360.62 ± 15.23 kg) and body condition were selected for this study and randomly divided into four groups of six mares each: an untreated control group (CG) and three experimental groups (EG1, EG2, EG3) were fed a basal diet supplemented with 0, 10, 20, or 30 g/day of BLE, respectively, for 60 days. Then, horse milk composition, antioxidant activity, and immunoglobulin levels along with the rela...
Sadowska A, Molcan T, Słyszewska M, Skarzynski DJ, Ferreira-Dias G, Szóstek-Mioduchowska A.Equine endometrosis is a chronic degenerative condition of the endometrium. A hallmark feature of endometrosis is endometrial fibrosis accompanied by degenerative changes in the adjacent tissue structure. Tumor necrosis factor α (TNFα), a pleiotropic cytokine produced by various immune cells, plays a dual role in coordinating immune responses and regulating cell/tissue homeostasis, making it an important regulator of fibrotic-related disorders. However, the exact role of TNFα in the development of equine endometrial fibrosis remains to be discovered and explained. Therefore, the main aim of...
Beaumont RE, Flood C, Guest DJ.Interleukin 1 beta (IL-1β) is upregulated following a tendon injury and in vitro studies have shown that it leads to numerous negative effects on tendon cell function and gene expression. IL-1β activates nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and we hypothesised that inhibiting NF-κB activation would mediate the negative effects of IL-1β on equine tendon cells in 3-dimensional (3D) cultures. Results: Here, we tested three inhibitors of NF-κB signalling (Bortezomib, BAY11-7082 and Wedelolactone) along withTJ-M2010-5, an inhibitor of MyD88, which is a critic...
Sprenzel CJ, Amann B, Deeg CA, Degroote RL.Glycosylation of surface proteins is a crucial post-translational modification that reflects the activation status of neutrophils, the predominant leukocyte subset in humans and horses. Neutrophils have emerged as active contributors to diseases mediated by the adaptive immune system, such as equine recurrent uveitis (ERU), a sight-threatening disease in horses and a unique model for studying the pathogenesis of autoimmune uveitis in humans. Since changes in surface glycosylation can impact neutrophil function, we were interested in the surface glycosylation landscape on neutrophils from healt...
Boakari Y, El-Sheikh Ali H, Almeida GHDR, Scoggin KE, Fernandes CB, Marchio SP, Troedsson MHT, Carreira ACO.Equine placental dysfunction impairs fetal growth and disrupts pregnancy outcomes. Despite many advances in diagnosis, the molecular pathophysiology of equine placentitis and premature placental separation remains poorly understood. However, the hypoxia-inducible factor (HIF-α) pathway is related to placental hypoxia, and its modulation in placental diseases has been shown in other species. Therefore, we hypothesized that in conditions marked by equine placental dysfunction, oxygen deprivation in the chorioallantois membrane triggers the activation of the HIF-α pathway, which is related to m...
Wójtowicz A, Sadowska A, Molcan T, Słyszewska M, Drzewiecka EM, Tobolski D, Ferreira-Dias G, Szóstek-Mioduchowska A.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 ...
Pipitpornsirikul P, Thangthamniyom N, Laikul A, Songkasupa T, Pathomsakulwong W, Apichaimongkonkun T, Kasemsuwan S, E-Kobon T, Lekcharoensuk P.African horse sickness (AHS), a life-threatening disease caused by African horse sickness virus serotype 1 (AHSV-1), emerged in Thailand in February 2020 with 607 cases and a 93% fatality rate. The outbreak was mitigated by vector control and a live attenuated virus (LAV) vaccine. Information regarding viremia and immunity after infection and vaccination during outbreaks are essential for controlling disease transmission. This study evaluated these parameters in 15 infected naïve horses and 11 vaccinated horses during the 2020 outbreak. Whole blood was collected and subjected to RT real-time ...
