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Topic:Immune Response
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.
Sevoflurane inhibits equine myeloperoxidase release and activity in vitro. To investigate the effects of the volatile anaesthetic sevoflurane on the release of total and active myeloperoxidase (MPO) by non-stimulated and stimulated polymorphonuclear neutrophils (PMNs) in whole blood from healthy horses. Methods: In vitro experimental study. Methods: Adult healthy horses. Methods: Samples of whole venous blood were collected and incubated in air or in air plus 2.3% or 4.6% sevoflurane for 1 hour. PMNs were stimulated with N-formyl-methionyl-leucyl-phenylalanine (fMLP), with a combination of cytochalasin B (CB) and fMLP or with phorbol myristate acetate (PMA). Total an...
Assessment of oxidative stress biomarkers in exhaled breath condensate and blood of Thoroughbred foals. This study reports preliminary data on systemic and local biomarkers of oxidative stress (OS) in Thoroughbred foals. Blood and exhaled breath condensate (EBC) were sampled from 13 foals on two farms. Values of reactive oxygen metabolites (d-ROMs), biological antioxidant potential (BAP), antioxidant barrier (OXY-ads), thiol antioxidant barrier (SHp) and advanced oxidation protein products (AOPPs) were determined in blood, while EBC samples were assayed for hydrogen peroxide (H(2)O(2)) levels. Systemic and local OS biomarkers did not differ between farms and gender. Increased oxidative stress in...
Effects of oxytocin, lipopolysaccharide (LPS), and polyunsaturated fatty acids on prostaglandin secretion and gene expression in equine endometrial explant cultures. Increased secretion of prostaglandin F(2)α (PGF(2)α) within the uterus because of uterine inflammation can cause luteolysis and result in early embryonic loss. Supplementation with polyunsaturated fatty acids (PUFAs) has been shown to influence PG production in many species, although the effects on the mare remain unknown. The present study aimed to determine fatty acid uptake in equine endometrial explants and evaluate their influence on PG secretion and expression of enzymes involved in PG synthesis in vitro. Equine endometrial explants were treated with 100 μM arachidonic acid, eicosapen...
An in vitro whole blood model to test the effects of different stimuli conditions on the release of myeloperoxidase and elastase by equine neutrophils. Horses are particularly sensitive and exposed to excessive inflammatory responses evolving toward an important stimulation of polymorphonuclear neutrophils (PMNs). The aim of this work was to stimulate equine neutrophils in whole blood and to evaluate their response by measuring the release of total and active myeloperoxidase (MPO) and total elastase, considered as markers of neutrophil stimulation and degranulation. Because of the critical importance of the concomitant presence of LPS and TNF-α in equine pathological situations, we combined these two natural mediators to stimulate PMN and co...
Enhanced protocol for CD14+ cell enrichment from equine peripheral blood via anti-human CD14 mAb and automated magnetic activated cell sorting. CD14 positive (CD14+) cells are the precursor cells of monocyte-derived dendritic cells (DCs). In horses their potent antigen-presenting capacity and ability to induce an effective immune response classify these cells suitable for several therapeutic approaches such as for equine sarcoid. However, in horses, the generation efficiency of DCs from adherent peripheral blood mononuclear cells (PBMCs) is currently still poor. Objective: Establishment of a simple short protocol to enhance DC generation in horses by using a human CD14 monoclonal antibody (mAb) and an automated magnetic activated cell...
Effect of training status on immune defence related gene expression in Thoroughbred: are genes ready for the sprint? Athletic performance is both a stress factor and an adaptive response to exercise that may be modulated by training, reduce inflammation and help prevent disease. Studies on the endocrinology of exercise and training have demonstrated the existence of an integrated metabolic network of hormone and cytokine regulation. Subsequent molecular studies have shown that repeated bouts of exercise may establish new basal levels of gene expression at rest. The Thoroughbred horse may be a useful 'exercise model' for inter-individual comparisons between subjects with homogeneous genetic and environmental ...
Expression of tlr4, md2 and cd14 in equine blood leukocytes during endotoxin infusion and in intestinal tissues from healthy horses. The expression of tlr4, md2 and cd14 was studied in equine blood leukocytes and in intestinal samples using real time PCR. The stability of three commonly used reference genes, glyceraldehyde-3P-dehydrogenase (GAPDH), hypoxantine ribosyltransferase (HPRT) and succinate dehydrogenase complex subunit A (SDHA), was evaluated using qbase(PLUS). The equine peripheral blood mononuclear cells (eqPBMC) examined were either stimulated in vitro with Phorbol 12-myristate 13-acetate (PMA) and ionomycin or with the CpG oligodeoxynuclotide 2216 (CpG-ODN 2216) or obtained from horses before, during and after...
Non-genomic action of beclomethasone dipropionate on bronchoconstriction caused by leukotriene C4 in precision cut lung slices in the horse. Glucocorticoids have been proven to be effective in the therapy of recurrent airway obstruction (RAO) in horses via systemic as well as local (inhalative) administration. Elective analysis of the effects of this drug on bronchoconstriction in viable lung tissue offers an insight into the mechanism of action of the inflammatory cascade occurring during RAO which is still unclear. The mechanism of action of steroids in treatment of RAO is thought to be induced through classical genomic pathways. We aimed at electively studying the effects of the glucocorticoid beclomethasone dipropionate on equi...
Persistence of an immunoreactive MUC1 protein at the feto-maternal interface throughout pregnancy in the mare. A polyclonal human mucin-1 (MUC1) antibody was used to stain immunohistochemically for the presence of MUC1 on the endometrium and fetal membranes in mares between 20 and 309 days of gestation. Western blot analysis demonstrated the presence of a protein equivalent in size to a human MUC1 isoform, MUC1/Y, in equine endometrium, allantochorion and amnion. At all stages of gestation examined immunoreactivity to the MUC1 antibody was detected on the apical surface of the lumenal epithelium of the endometrium and the epithelium lining the mouths and apical regions of the endometrial glands. Furthe...
Accelerated vaccination schedule provides protective levels of antibody and complete herd immunity to equine influenza. During the 2007 Australian equine influenza (EI) outbreak, an accelerated primary course 14 day intervaccination schedule was proposed, but not widely implemented. Expert opinion was divided as to the efficacy of such a schedule given the lack of published data. This study determined the level and duration of humoral immunity following administration of a recombinant canarypox-vectored vaccine (ALVAC-EIV) with a primary intervaccination interval of 14 days and booster at 105 days. Objective: To examine whether protective levels of immunity of adequate duration were achieved following a primary...
Ethyl pyruvate diminishes the inflammatory response to lipopolysaccharide infusion in horses. Endotoxaemia contributes to morbidity and mortality in horses with colic due to inflammatory cascade activation. Effective therapeutic interventions are limited for these horses. Ethyl pyruvate (EP), an anti-inflammatory agent that alters the expression of proinflammatory cytokines, improved survival and organ function in sepsis and gastrointestinal injury in rodents and swine. Therapeutic efficacy of EP is unknown in endotoxaemic horses. Objective: Determine the effects of EP on signs of endotoxaemia and expression of proinflammatory cytokines following administration of lipopolysaccharide (L...
Expression of interleukin-1β, interleukin-8, and interferon-γ in blood samples obtained from healthy and sick neonatal foals. To evaluate and compare the gene expression of interleukin(IL)-1β, IL-8, and interferon-γ during the first 72 hours after birth in healthy foals and during the first 72 hours after hospitalization in sick neonatal foals and investigate correlations of clinicopathologic variables with cytokine expressions in healthy and sick neonatal foals. Methods: 33 foals < 7 days old (10 healthy foals, 7 foals with sepsis, 6 foals with peripartum asphyxia syndrome, and 12 foals with other diseases [2 with failure of passive transfer of immunity only were not further evaluated]). Methods: A blood sample...
Post-mating inflammatory responses of the uterus. This review attempts to summarize the current knowledge on uterine inflammatory response after mating in horses, pigs and cattle. Post-mating endometritis has been extensively studied in horses as it has been considered to cause infertility. The inflammation is known to occur also in cattle, but it has not been investigated to a similar extent. There are a number of publications about mechanisms of post-mating uterine inflammation in pigs, which seem to resemble those in horses. The major focus of this review is the horse, but relevant literature is presented also on swine and cattle. Spermato...
Markers of systemic inflammation in horses with heaves. Systemic inflammation in horses with heaves is poorly characterized. Objective: To assess acute phase proteins (APP) and inflammatory cytokine profiles in serum of healthy horses and horses with heaves. Methods: Six healthy horses and 6 heaves-affected horses belonging to the University of Montreal. Methods: Prospective, observational study. Healthy and heaves-affected control horses were exposed to a 30-day natural challenge with hay and straw to induce clinical exacerbation of heaves. Serum samples were obtained by venipuncture before (T0) as well as after 7 (T7) and 30 days (T30) of stablin...
Snake venomics and antivenomics of Protobothrops mucrosquamatus and Viridovipera stejnegeri from Taiwan: keys to understand the variable immune response in horses. The proteomes of the venoms of the snakes Viridovipera stejnegeri and Protobothrops mucrosquamatus from Taiwan were characterized by N-terminal sequencing, MALDI-TOF mass fingerprinting, and collision-induced dissociation tandem mass spectrometry of in-gel generated tryptic peptides. Proteins belonging to the following toxin classes were identified: metalloproteinase, phospholipase A(2) (PLA(2)), serine proteinase, C-type lectin-like, CRISP, l-amino acid oxidase, disintegrin, and peptides (vasoactive and inhibitors of SVMPs). Nine horses were immunized with a mixture of these venoms. All horse...
Biomarkers of antioxidant status, inflammation, and cartilage metabolism are affected by acute intense exercise but not superoxide dismutase supplementation in horses. Objectives were to evaluate effects of (1) repetitive arthrocentesis on biomarkers of inflammation (prostaglandin E(2), PGE(2)) and aggrecan synthesis (chondroitin sulfate-846; CS) in synovial fluid (SF); (2) exercise and superoxide dismutase (SOD) supplementation on biomarkers of inflammation, antioxidant status, and aggrecan synthesis, in horses. Preliminary trial. Standardbreds underwent four arthrocentesis procedures within 48 h and exhibited elevated CS and no changes in PGE(2). Exercise trial. this randomized crossover design used twelve Standardbred mares which received either treatment...
Rhodococcus equi’s extreme resistance to hydrogen peroxide is mainly conferred by one of its four catalase genes. Rhodococcus equi is one of the most widespread causes of disease in foals aged from 1 to 6 months. R. equi possesses antioxidant defense mechanisms to protect it from reactive oxygen metabolites such as hydrogen peroxide (H(2)O(2)) generated during the respiratory burst of phagocytic cells. These defense mechanisms include enzymes such as catalase, which detoxify hydrogen peroxide. Recently, an analysis of the R. equi 103 genome sequence revealed the presence of four potential catalase genes. We first constructed ΔkatA-, ΔkatB-, ΔkatC-and ΔkatD-deficient mutants to study the ability of R. ...
Effects of age and R848 stimulation on expression of Toll-like receptor 8 mRNA by foal neutrophils. The innate immune system plays a critical role in protecting neonates against infections early in life and Toll-like receptors (TLRs) are key components of innate immune recognition of pathogens. This study examined the effects of age and stimulation with a TLR 7/8 agonist (R848) on TLR8 mRNA expression by foal neutrophils during the first month of life. We also examined the effects of R848 stimulation on mRNA expression of interleukin (IL)-6 and IL-8 at 1 and 14 days of life. We observed that TLR8 mRNA was constitutively expressed (P<0.05) at all ages examined, and its expression did not c...
Effects of extracellular lactate on production of reactive oxygen species by equine polymorphonuclear leukocytes in vitro. To evaluate effects of extracellular lactate on viability, shape change, lactate metabolism, and reactive oxygen species (ROS) production in equine polymorphonuclear leukocytes (PMNs). Methods: PMNs isolated from equine venous blood samples. Methods: PMNs were incubated with 0 to 300mM lactate for 30 minutes before each experiment. Viability was assessed via trypan blue exclusion. Shape change was assessed via flow cytometry and light microscopy. Relative quantification of monocarboxylic acid transporter and lactate dehydrogenase lactate dehydrogenase (LDH) isotype mRNAs was performed with a r...
T-cell tolerance to the developing equine conceptus. One of the most intriguing and dramatic examples of immunological tolerance is displayed by the mammalian foetal-placental unit, which thrives as a semi-allograft in the mother's uterus during pregnancy. The success of the so-called foetal allograft stands in stark contrast to the failure of most tissue and organ grafts to survive without genetic matching of donor and recipient or drastic immunosuppression of the recipient's immune system. Experiments conducted over the past 60 years have revealed multiple mechanisms that enable the conceptus to avoid immunological detection or destruction. Ma...
Development of a novel mucosal vaccine against strangles by supercritical enhanced atomization spray-drying of Streptococcus equi extracts and evaluation in a mouse model. Strangles is an extremely contagious and sometimes deadly disease of the Equidae. The development of an effective vaccine should constitute an important asset to eradicate this worldwide infectious disease. In this work, we address the development of a mucosal vaccine by using a Supercritical Enhanced Atomization (SEA) spray-drying technique. Aqueous solutions containing the Streptococcus equi extracts and chitosan were converted into nanospheres with no use of organic solvents. The immune response in a mouse model showed that the nanospheres induced a well-balanced Th1 and Th2 response charac...
Effects of oral treatment with N-acetylcysteine on the viscosity of intrauterine mucus and endometrial function in estrous mares. Persistent breeding-induced endometritis is ranked as the third most common medical problem in the adult mare and leads to enormous economic loss in horse breeding. In mares suffering from persistent breeding-induced endometritis, increased amounts of intrauterine (i.u.) fluid or viscous mucus in estrus or after breeding may act as a barrier for sperm and can contribute to low fertility. Current therapies of these mares aim to eliminate i.u. fluid and mucus by uterine lavage and/or administration of ecbolic drugs. Recently, i.u. administration of N-acetylcysteine (NAC) has been shown to suppor...
Inhalant horse allergens and allergies: a review of the literature. A wealth of literature exists regarding common allergies to household pets such as cat or dog. Allergy to horse, however, is infrequently discussed in the medical literature despite significant sensitization rates among urban-dwelling subjects without direct exposure to horses. A literature search was conducted in PubMed and additional references were collected from surveying the references of the pulled articles. This review summarizes aspects of IgE-mediated horse allergy including the prevalence and mechanisms for sensitization, clinical presentation, molecular characterization of the major...
Autologous point-of-care cellular therapies variably induce equine mesenchymal stem cell migration, proliferation and cytokine expression. Autologous cellular therapy products including adipose-derived stromal vascular fraction (SVF), bone marrow mononuclear cells (BMMNs), cord blood mononuclear cells (CBMNs) and platelet rich plasma are options for treatment of acute orthopaedic lesions while mesenchymal stem cells (MSCs) are culture expanded. These products may contribute to healing by secreting matrix proteins or growth factors, but they may also act on endogenous MSCs to facilitate healing. Objective: To determine the effects of cell therapy products on MSCs function in vitro. The hypothesis was that cell therapy products pro...
Serum iron parameters and acute experimental EHV-1 infection in horses. Research in humans has demonstrated that high serum iron (sFe) concentration can predispose to infection, and many infections subsequently result in alterations of host sFe. A decrease in sFe concentration is an early and sensitive indicator of systemic inflammation caused by tissue necrosis, bacterial infections, or endotoxemia in horses. Serum iron parameters in acute equine herpesvirus type 1 (EHV-1) infection have not been evaluated previously. Objective: To document the sFe response to EHV-1 infection and to determine whether or not significant differences in sFe concentration exist betwe...
Effects of a single dose of enrofloxacin on body temperature and tracheobronchial neutrophil count in healthy Thoroughbreds premedicated with interferon-α and undergoing long-distance transportation. To evaluate effects of a single dose of enrofloxacin (5 mg/kg, IV) on body temperature and tracheobronchial neutrophil count in healthy Thoroughbreds premedicated with interferon-α and undergoing long-distance transportation. Methods: 32 healthy Thoroughbreds. Methods: All horses received interferon-α (0.5 U/kg, sublingually, q 24 h) as an immunologic stimulant for 2 days before transportation and on the day of transportation. Horses were randomly assigned to receive enrofloxacin (5 mg/kg, IV, once; enrofloxacin group) or saline (0.9% NaCl) solution (50 mL, IV, once; control group) ≤ 1 hou...
Modeling within-host dynamics of influenza virus infection including immune responses. Influenza virus infection remains a public health problem worldwide. The mechanisms underlying viral control during an uncomplicated influenza virus infection are not fully understood. Here, we developed a mathematical model including both innate and adaptive immune responses to study the within-host dynamics of equine influenza virus infection in horses. By comparing modeling predictions with both interferon and viral kinetic data, we examined the relative roles of target cell availability, and innate and adaptive immune responses in controlling the virus. Our results show that the rapid and ...
Experimental infection with equid herpesvirus 3 in seronegative and seropositive mares. Equine coital exanthema (ECE), caused by equid herpesvirus 3 (EHV-3), has been recognized as an economically significant venereal disease for years. However, no infection models on the natural host have been established. In order to set up an experimental infection protocol, seronegative and seropositive mares were topically inoculated in the perineal region with 4 × 10(6)TCID(50)/ml of EHV-3. Clinical signs were then evaluated by means of a designed scoring system, and body temperature was recorded daily. Virological, and serological studies were also performed. Typical ECE lesions, with cli...
The determination of in vivo envelope-specific cell-mediated immune responses in equine infectious anemia virus-infected ponies. Distinct from human lentivirus infection, equine infectious anemia virus (EIAV)-infected horses will eventually enter an inapparent carrier state in which virus replication is apparently controlled by adaptive immune responses. Although recrudescence of disease can occur after immune suppression, the actual immune correlate associated with protection has yet to be determined. Therefore, EIAV provides a model for investigating immune-mediated protective mechanisms against lentivirus infection. Here, we have developed a method to monitor EIAV-envelope specific cellular immunity in vivo. An EIA c...
Corticosteroids and antigen avoidance decrease airway smooth muscle mass in an equine asthma model. Recent studies suggest that airway smooth muscle remodeling is an early event in the course of asthma. Little is known of the effects of long-term antigen avoidance and inhaled corticosteroids on chronically established airway remodeling. We sought to measure the effects of inhaled corticosteroids and antigen avoidance on airway remodeling in the peripheral airways of horses with heaves, a naturally occurring asthma-like disease. Heaves-affected adult horses with ongoing airway inflammation and bronchoconstriction were treated with fluticasone propionate (with and without concurrent antigen av...
