White blood cells (WBCs) are integral components of the equine immune system, responsible for protecting horses against infections and foreign invaders. These cells circulate in the bloodstream and are produced in the bone marrow. The primary types of white blood cells in horses include neutrophils, lymphocytes, monocytes, eosinophils, and basophils, each with distinct functions in immune defense. Neutrophils are involved in the immediate response to infections, while lymphocytes play a role in adaptive immunity. Monocytes are involved in phagocytosis and the regulation of immune responses. Eosinophils and basophils are associated with allergic reactions and parasitic infections. Variations in white blood cell counts can indicate health conditions, making them valuable in veterinary diagnostics. This page compiles peer-reviewed research studies and scholarly articles that explore the function, regulation, and clinical relevance of white blood cells in equine health.
Laroche N, Grimm P, Julliand S, Sorci G.The use of anthelminthic drugs has several drawbacks, including the selection of resistant parasite strains. Alternative avenues to mitigate the negative effects of helminth infection involve dietary interventions that might affect resistance and/or tolerance by improving host immunity, modulating the microbiota, or exerting direct anthelmintic effects. The aim of this study was to assess the impact of diet on strongyle infection in horses, specifically through immune-mediated, microbiota-mediated, or direct anthelmintic effects. Horses that were naturally infected with strongyles were fed eit...
Carvalho Seabra J, Martinez do Vale M, Spercoski KM, Hess T, Patricio Viviani de Moura P, Dittrich JR.Keeping horses in single stalls can lead to the development of abnormal and stereotypic behaviors (ASB). Opportunities for social interactions and stall architecture can influence behavior. The current study aimed to identify how three different stall architectures influenced time-budget and physiological parameters in horses. Stall types included: (1) 3.2 × 3.7 m with tactile contact between horses (B1); (2) 2.6 × 3.5 m with visual contact between horses and outside view (B2); (3) 2.3 × 3.4 m with visual contact and outside view (B3). Ten horses from B1 and B3, and nine from B2 were ...
Köhne M, Kirch F, Tönissen A, Martinsson G, Rabe U, Sieme H, Schuberth HJ.To improve accuracy in evaluating stallion ejaculates, an antibody-based, flow cytometric assay for the detection and identification of leukocyte subpopulations (CD4-, CD8-, CD21-, CD172a-positive cells) in stallion semen (n = 12) was established. For establishment of the assay, native semen was supplemented with blood leukocytes (control: 20% leukocytes, 80% sperm cells) and analysed by flow cytometry. Adding antioxidants (ascorbic acid and butylated hydroxytoluol) to semen immediately after collection inhibited rapid death of lymphoid cells in sperm leukocyte mixtures. In control set-ups...
This study aimed to evaluate the change of white blood cell count, serum concentration of cortisol, C-reactive protein, albumin and globulin fractions in horse after road transport, and to assess the linkage among hypothalamic-pituitary-adrenal axis (HPA) and inflammatory reaction. From 10 horses blood samples were collected at rest, before road transport (218 km) (BT); after unloaded (AT), 30 and 60 min after unloaded (AT30 and AT60) in order to assess white blood cell count (WBC), serum cortisol, C-reactive protein (CRP), total proteins, albumin, α1-, α-2, β1-, β2- and γ-globulins. WB...
The aim of our study was to analyze circadian rhythm of the hematological profile of horses housed in a loose box and paddock during the different seasons (spring, summer, autumn, and winter). Blood samples were performed every 4 h for 48 consecutive hours. Red blood cells (RBCs), hemoglobin (HGB), hematocrit (HCT), white blood cells (WBCs), platelets (PLTs), and leukocyte subpopulations (neutrophils, basophils, eosinophils, lymphocytes, and monocytes) were analyzed, and, at the same time, environmental conditions were recorded. A statistically significant effect of housing conditions ( < 0...
Aboashia FA, Alatrag F, Elmarimi A.Hematological and biochemical values are widely used in veterinary clinics for disease prognosis, nutritional and therapeutic monitoring, as well as in understanding the disease process in farm animals, including equines. This study aims to assess the alterations in hematological and biochemical parameters in pure Arabian horses infested with internal parasites. Samples of feces and blood were collected from 20 adult mares. Fecal samples were proceeded by flotation test. The blood samples were analyzed for hematological and biochemical parameters to determine their means ± standard error (M Â...
Simonin EM, Babasyan S, Tarsillo J, Wagner B.IgE+ plasmablasts develop following allergen exposure and B cell activation. They secrete IgE and therefore are directly linked to maintain the mechanisms of IgE-mediated allergies. Here, we show that the presence of IgE+ plasmablasts in peripheral blood not only coincides with clinical allergy, but also predicts the upcoming development of clinical disease. Using an equine model of naturally occurring allergy, we compared the timing of allergen exposure, arrival of IgE+ plasmablasts in peripheral blood, and onset of clinical disease. We found that IgE+ plasmablasts predict the development of ...
MartÃn-Cuervo M, Gracia-Calvo LA, MacÃas-GarcÃa B, Ezquerra LJ, Barrera R.Systemic inflammatory response syndrome (SIRS) is a very common finding in critically ill patients. To accurately identify patients with SIRS and those who need intensive care, several markers have been evaluated, including cortisol, WBC or lactate. It is widely known that a stress leukogram includes eosinopenia as one of its main markers (neutrophilia, eosinopenia, lymphopenia and mild monocytes). It is known that cortisol concentration in plasma is the main stress biomarker and is strongly correlated with the severity of disease in horses. However, it is not possible to measure this paramete...
Cocco R, Rizzo M, Carta C, Arfuso F, Piccione G, Luridiana S, Crovace A, Passino ES, Sechi S.Among infection diseases transmitted by arthropods, the equine vector-borne diseases transmitted by ticks represent an emerging problem worldwide due to their morbidity and mortality and, in some cases, to their zoonotic relevance. Understanding the host immune/inflammatory response to the pathogens is crucial to develop effective methods of diagnosis, control and treatment. This study aimed to evaluate red blood cells (RBC), hematocrit (Hct), hemoglobin concentration (Hb), mean cell volume (MCV), mean cell hemoglobin content (MCH), mean cell hemoglobin (MCHC), platelets (PLT), white blood cel...
Coelho CS, Silva ASBA, Santos CMR, Santos AMR, Vintem CMBL, Leite AG, Fonseca JMC, Prazeres JMCS, Souza VRC, Siqueira RF, Manso Filho HC, Simões JSA.The purpose of this study was to investigate stressful responses during a 6-week training protocol in young Lusitano horses used for dressage. The hypothesis was that the proposed training protocol would improve fitness and ensure the welfare of the animals by reducing stress predictors. Nine 4-year-old horses were evaluated before (M1) and six weeks after (M2) beginning a training protocol. The training program was performed six times per week and included 40−80 min of individually intensity-adjusted preparatory exercises for dressage. For both moments, the horses were examined before (T0) ...
Dória RGS, Reginato GM, Hayasaka YB, Fantinato Neto P, Passarelli D, Arantes JA.Percutaneous decompression of the cecum is a procedure that could be considered for horses with cecal gas distension. The aim of this study was to identify complications such as peritonitis and clinically relevant peritonitis (CRP) after transabdominal cecal trocarization in healthy horses using a cattle trocar and a cecal needle. Mixed breed horses were assigned to three groups (n = 6): horses that underwent trocarization with a cecal needle (G1) or a cattle trocar (G2), and a control group (CG) without cecal trocarization. The same horses were used in each group, respecting a three-month was...
Jacobsen S.Serum amyloid A (SAA) has become an indispensable part of the management of equine patients in general practice and specialized hospital settings. Although several proteins possess acute phase properties in horses, the usefulness of SAA exceeds that of other acute phase proteins. This is due to the highly desirable kinetics of the equine SAA response. SAA concentrations exhibit a rapid and pronounced increase in response to inflammation and a rapid decline after the resolution of inflammation. This facilitates the detection of inflammatory disease and real-time monitoring of inflammatory activ...
Schmucker S, Preisler V, Marr I, Krüger K, Stefanski V.Domestic horses are currently often subject to management practices that can entail social stressors, which in turn can negatively influence immunocompetence and disease susceptibility. The present study therefore aimed to characterize the number of various blood leukocyte subsets in horses, focusing on two potentially stressful housing environments: changes in group composition and relocation to individual stabling. Immune measurements were conducted before as well as one and eight days after changes were made. They were complemented by an assessment of plasma cortisol concentrations as well ...
Dias De Castro LL, Oliveira Júnior GA, Perez BC, Carvalho ME, De Souza Ramos EA, Ferraz JBS, Molento MB.Cyathostomins are considered one of the most important parasites of horses. A group of horses within a herd can be responsible for eliminating the majority of parasite eggs. This phenotype might be explained by genetic factors. This study aimed to identify genomic regions associated with fecal egg count (FEC) and hematological parameters by performing a genomic-wide association study (GWAS) in Thoroughbred horses naturally infected with cyathostomins. Packed cell volume (PCV), differential leukocyte, and FEC were determined from 90 horses. All animals were genotyped using the Illumina Equine 7...
Salinas C, Espinosa G, Morales N, HenrÃquez C, Morán G, Gajardo G, Burgos RA, Uberti B.Obesity and insulin dysregulation (ID) are increasingly prevalent conditions in equid populations worldwide. Immune impairment is well described in humans with metabolic dysfunction and is reported but still incompletely understood in horses. This study evaluated the effect of acute induced transient hyperglycemia on apoptosis, phagocytosis and oxidative burst activity of peripheral blood polymorphonuclear cells (PMN) of lean and obese adult horses with or without insulin dysregulation. Seventeen adult horses were allocated into three groups based on their body condition score (BCS) and metabo...
Seabaugh KA, Barrett MF, Rao S, McIlwraith CW, Frisbie DD.Osteoarthritis (OA) is a common problem in horses. Several oral supplements have been proposed as treatments for horses with OA. The object of this study was to evaluate the use of the oil extract from the seeds of (BO) for the treatment of experimentally induced OA in horses. OA was induced in 16, 2-5 year old horses in one middle carpal joint on Day 0; the other limb underwent a sham operation. Once daily oral treatment with BO or placebo was initiated on Day 0 and continued to Day 70. All horses were exercised 5 days a week starting on Day 14 through Day 70. The horses were evaluated every...
Lizarraga I, Beeler-Marfisi J, Marshall DL, Hassan M, Castillo-Alcala F, Simon BT, Fraites T, Thrall MA.There is a large population of donkeys in Saint Kitts; however, hematological and biochemical reference intervals (RIs) are lacking. This study addressed this deficiency by following the American Society for Veterinary Clinical Pathology RI guidelines. Sixty-six healthy, gelding standard donkeys with a median and interquartile range age of 5 years (3.5 - 8 years) and a mean ± standard deviation body weighed of 156 ± 16.7 kg were used to produce a five-part differential complete blood count using an impedance-based analyzer. Clinical chemistry analytes were quantified using a photometric-base...
Arfuso F, Giudice E, Panzera M, Rizzo M, Fazio F, Piccione G, Giannetto C.The monitoring of endocrine and immunologic markers during exercise is of paramount importance to assess and/or maintain the physical well-being of athletes as well as to optimize the athletic performance. This study aimed to investigate the linkage between acute stress response and immune status in Thoroughbred horses competing in an official 1300-m race. From 10 horses blood was collected 1 week before the day of the race (1W-BEFORE), before (REST) and immediately after the race to assess the cortisol, Interleukin-1 receptor antagonist (IL-1Ra), total proteins, white blood cells (WBC), red b...
Kamm JL, Riley CB, Parlane NA, Gee EK, McIlwraith CW.Mesenchymal stromal cells (MSCs) are believed to be hypoimmunogeneic with potential use for allogeneic administration. Bone marrow was harvested from Connemara (n = 1), Standardbred (n = 6), and Thoroughbred (n = 3) horses. MSCs were grouped by their level of expression of major histocompatibility factor II (MHC II). MSCs were then sub-grouped by those MSCs derived from universal blood donor horses. MSCs were isolated and cultured using media containing fetal bovine serum until adequate numbers were acquired. The MSCs were cultured in xenogen-free media for 48 h prior to use and d...
Giannetto C, Fazio F, Nava V, Arfuso F, Piccione G, Coelho C, Gugliandolo E, Licata P.The objective of this study was to evaluate the biomarkers of exposure to boron, nickel, arsenic, and antimony in an industrial region, evaluating the bioaccumulation in biological substrates and the correlation with biomarkers such as hematological parameters. Through indication of the accumulation of some minerals in the horse's biological substrates reflects environmental pollution. Moreover, an additional aim of the study was to show whether these contaminants have an influence on the hematological parameters in horses. Blood, serum, mane, and tail samples from 20 horses from an industrial...
Leeth C, Adkins J, Hay A, Bogers S, Potter A, Witonsky S, Zhu J.Immunological studies in the horse are frequently hampered by lack of environmental control, complicated study design, and ethical concerns when performing high risk studies. The purpose of the current study was to investigate the utility of a xenograft model for studying acute equine immune responses. Immunocompromised non obese diabetic (NOD). sudden combined immunodeficiency (scid).gamma-/- (NSG) mice were engrafted with either equine peripheral blood lymphocytes (PBLs) or equine bone marrow to determine an optimal protocol for equine lymphocyte engraftment. We found that both PBL and bone ...
Müller AC, Büttner K, Röcken M.Synovial structure involvement secondary to limb injury is a common emergency in equine practice, requiring an accurate initial diagnosis for immediate treatment. This study aimed to investigate the clinical usefulness of Serum amyloid A (SAA) in the initial diagnosis of synovial structure involvement caused by acute (<24 h) penetrating limb injuries in horses and to correlate SAA with standard diagnostic parameters. Fifty-five horses with acute limb injuries were divided into two groups: Group 1 (G1, n = 26) with a diagnosis of penetrating synovial trauma and Group 2 (G2, n = 29) without s...
Lucassen A, Finkler-Schade C, Schuberth HJ. () fermentation products (SCFP) are used in animal husbandry as pre- and postbiotic feed supplements. A variety of immunomodulatory effects are noted in many species. The purpose of this study was to test the hypothesis that horses fed with SCFP containing feed additive Olimond BB display a modulated early immune response after influenza vaccination. Six horses received Olimond BB pellets (OLI) and five horses were fed placebo pellets (PLA) for 56 days. On day 40 all horses were vaccinated with a recombinant influenza A/equi-2 vaccine. At the day of vaccination, the groups did not differ in t...
Russell A, Shost N, Burch M, Salazara LL, Fikes K, Bechelli J, Suagee-Bedore J.Anaplasmosis is a disease caused by the bacterium Anaplasma phagocytophilum, which is spread by infected ticks. In horses, A. phagocytophilum generally causes transient infection characterized by fever, lethargy, inappetence, ventral edema, petechiae, icterus, ataxia, recumbency, muscle stiffness, and, in severe cases, death. Following natural infection, horses retain antibodies for approximately 2 years, which can be detected through an immunofluorescence antibody assay. Current infections are determined through PCR assay of white blood cell DNA. For this study, whole blood was collected from...
Rocchigiani G, Ricci E, Navarro MA, Samol MA, Uzal FA.Healthy horses and other animals have large numbers of resident leukocytes in the intestinal wall, but there is scant information regarding which and how many leukocytes are normally present in the equine intestinal wall. Our aim was to provide a reference range of leukocytes in the intestinal mucosal and submucosal propria of normal horses. We included in our study intestinal tissues from 22 Thoroughbred racehorses with no clinical intestinal disease, which had been euthanized because of catastrophic musculoskeletal injuries. Neutrophils, lymphocytes, eosinophils, macrophages, and plasma cell...
Bowlby C, Mudge M, Schroeder E, Godman J, Hurcombe S.To investigate the, equine inflammatory response to ventral midline celiotomy in the absence of gastrointestinal disease in horses of varying body condition scores primarily using serial measurements of serum amyloid A (SAA). Methods: Experimental clinical study. Methods: University teaching hospital. Methods: Ten adult light breed horses free of any clinical disease, 5 with body condition score (BCS) 3-4/9 and 5 with BCS 7-8/9. Methods: Horses had a ventral midline celiotomy performed under general anesthesia, including manual decompression of the small intestine. SAA, semiquantitative fibrin...
Schnabel CL, Babasyan S, Freer H, Larson EM, Wagner B.Tumor necrosis factor-α (TNF-α) is a pleiotropic cytokine, that is involved in acute inflammation and is employed as a biomarker of inflammatory diseases in several species for which reliable quantification is available. We aimed to develop suitable tools to quantify TNF-α in equine samples. We generated two new mAbs against equine TNF-α (clones 48 and 292), evaluated their specificity for this cytokine, and confirmed detection of native TNF-α in stimulated equine PBMC. The TNF-α mAbs were paired in a fluorescent bead-based assay for quantification of equine TNF-α. The TNF-α assay had ...
Hammond SA, Cook SJ, Lichtenstein DL, Issel CJ, Montelaro RC.Equine infectious anemia virus (EIAV) provides a natural model system by which immunological control of lentivirus infections may be studied. To date, no detailed study addressing in parallel both the humoral and cellular immune responses induced in horses upon infection by EIAV has been conducted. Therefore, we initiated the first comprehensive characterization of the cellular and humoral immune responses during clinical progression from chronic disease to inapparent stages of EIAV infection. Using new analyses of antibody avidity and antibody epitope conformation dependence that had not been...
Carrade DD, Affolter VK, Outerbridge CA, Watson JL, Galuppo LD, Buerchler S, Kumar V, Walker NJ, Borjesson DL.BACKGROUND AIMS. The use of allogeneic mesenchymal stem cells (MSC) to treat acute equine lesions would greatly expand equine cellular therapy options; however, the safety and antigenicity of these cells have not been well-studied. We hypothesized that equine allogeneic umbilical cord tissue (UCT)-derived MSC would not elicit acute graft rejection or a delayed-type hypersensitivity response when injected intradermally. METHODS. Six Quarterhorse yearlings received 12 intradermal injections (autologous MSC, allogeneic MSC, positive control and negative control, in triplicate) followed by the sam...
Afable MG, Shaik M, Sugimoto Y, Elson P, Clemente M, Makishima H, Sekeres MA, Lichtin A, Advani A, Kalaycio M, Tiu RV, O'Keefe CL, Maciejewski JP.A combination of horse anti-thymocyte globulin and cyclosporine produces responses in 60-70% of patients with severe aplastic anemia. We performed a phase II study of rabbit anti-thymocyte globulin and cyclosporine as first-line therapy for severe aplastic anemia. Methods: Twenty patients with severe aplastic anemia treated with rabbit anti-thymocyte globulin were compared to 67 historical control cases with matched clinical characteristics treated with horse anti-thymocyte globulin. Results: Response rates at 3, 6 and 12 months were similar for patients treated with rabbit anti-thymocyte glob...
Bertone AL, Palmer JL, Jones J.To evaluate the value of various synovial fluid cytokines and eicosanoids to diagnose joint disease or categories of joint disease. Methods: Prospective acquisition of clinicopathologic data. Methods: Client-owned or donated horses: 50 joints with no evidence of disease; 28 joints with acute disease; 32 joints with chronic disease; 9 joints with cartilage damage and no other signs of joint disease. Methods: Concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), interleukin-6 (IL-6), prostaglandin E(2) (PGE(2)), thromboxane B(2) (TXB(2)), prostaglandin F1-alpha...
Breathnach CC, Sturgill-Wright T, Stiltner JL, Adams AA, Lunn DP, Horohov DW.The increased vulnerability of foals to specific pathogens such as Rhodococcus equi is believed to reflect an innate immunodeficiency, the nature of which remains poorly understood. Previous studies have demonstrated that neonates of many species fail to mount potent Th1 responses. The current research investigates the ability of circulating and pulmonary lymphocytes of developing foals to produce interferon gamma (IFNgamma). Peripheral blood mononuclear cells (PBMC) were prepared from up to 10 horse foals at regular intervals throughout the first 6 months of life. Bronchoalveolar lavage (BAL)...
Jacobsen S, Nielsen JV, Kjelgaard-Hansen M, Toelboell T, Fjeldborg J, Halling-Thomsen M, Martinussen T, Thoefner MB.To evaluate the postoperative inflammatory response of horses to elective surgery of varying intensity. Methods: Prospective longitudinal study. Methods: Horses referred to 2 hospitals for either arthroscopic removal of a unilateral osteochondritic lesion in the tibiotarsal joint (minimal surgical trauma, n=11), correction of recurrent laryngeal neuropathy by laryngoplasty and ventriculectomy (intermediate surgical trauma, n=10) or removal of an ovarian tumor by laparotomy (major surgical trauma, n=5). Methods: Horses had a thorough clinical examination every day. White blood cell (WBC) counts...
Kol A, Wood JA, Carrade Holt DD, Gillette JA, Bohannon-Worsley LK, Puchalski SM, Walker NJ, Clark KC, Watson JL, Borjesson DL.Intravenous (IV) injection of mesenchymal stem cells (MSCs) is used to treat systemic human diseases and disorders but is not routinely used in equine therapy. In horses, MSCs are isolated primarily from adipose tissue (AT) or bone marrow (BM) and used for treatment of orthopedic injuries through one or more local injections. The objective of this study was to determine the safety and lymphocyte response to multiple allogeneic IV injections of either AT-derived MSCs (AT-MSCs) or BM-derived MSCs (BM-MSCs) to healthy horses. Methods: We injected three doses of 25 × 10(6) allogeneic MSCs fro...
Ardanaz N, Vázquez FJ, Romero A, Remacha AR, Barrachina L, Sanz A, Ranera B, Vitoria A, Albareda J, Prades M, Zaragoza P, MartÃn-Burriel I....Mesenchymal stem cells (MSCs) transplantation has become a promising therapeutic choice for musculoskeletal injuries. Joint-related disorders are highly prevalent in horses. Therefore, these animals are considered as suitable models for testing MSC-based therapies for these diseases. The aim of this study was to investigate the clinical and inflammatory responses to intra-articular single and repeat dose administration of autologous or of pooled allogeneic MSCs in healthy equine healthy joints. Six horses were intra-articularly injected with a single autologous dose of bone marrow derived MSCs...
Paebst F, Piehler D, Brehm W, Heller S, Schroeck C, Tárnok A, Burk J.Horses are an approved large animal model for therapies of the musculoskeletal system. Especially for tendon disease where cell-based therapy is commonly used in equine patients, the translation of achieved results to human medicine would be a great accomplishment. Immunophenotyping of equine mesenchymal stromal cells (MSCs) remains the last obstacle to meet the criteria of the International Society for Cellular Therapy (ISCT) definition of human MSCs. Therefore, the surface antigen expression of CD 29, CD 44, CD 73, CD 90, CD 105, CD 14, CD 34, CD 45, CD 79α, and MHC II in equine MSCs from a...
Garcia-Tapia D, Loiacono CM, Kleiboeker SB.A cell model of primary monocytes and other mononuclear cells isolated from equine blood was used to study the kinetics of West Nile virus (WNV) replication in a natural host. West Nile virus has emerged on the North American continent as a significant cause of morbidity and mortality in a wide range of avian and mammalian species. While other flaviviruses are known to infect monocytes and lymphocytes, the ability of WNV to productively replicate in specific immune cells of peripheral blood has not been assessed. In this study, enriched populations of monocytes and lymphocytes as well as purif...
Bertone AL, Ishihara A, Zekas LJ, Wellman ML, Lewis KB, Schwarze RA, Barnaba AR, Schmall ML, Kanter PM, Genovese RL.To evaluate intra-articular autologous protein solution (APS) for the treatment of osteoarthritis in horses. Animals-40 client-owned horses with naturally occuring osteoarthritis. Methods: APS was generated from a dual-device system that concentrated plasma and WBC proteins and enriched platelet growth factors. Horses were randomly assigned to receive an intra-articular injection of 5 mL of saline (0.9% NaCl) solution (n = 20) or APS (20), exercised on a treadmill, and evaluated on the basis of lameness grades, kinetic gait analysis, joint circumference, and range of motion for 14 days. Horses...
Colbath AC, Dow SW, Phillips JN, McIlwraith CW, Goodrich LR.The use of allogeneic bone marrow-derived mesenchymal stem cells (BMDMSCs) may provide an effective alternative to autologous BMDMSCs for treatment of equine musculoskeletal injuries. However, concerns have been raised regarding the potential safety and effectiveness of allogeneic BMDMSCs. We conducted studies to assess the immunological properties of equine allogeneic BMDMSCs compared with those of autologous BMDMSCs. For assessment of inherent immunogenicity, the relative ability of allogeneic and autologous BMDMSCs to stimulate spontaneous proliferation of equine lymphocytes was compared. T...
Kydd J, Antczak DF, Allen WR, Barbis D, Butcher G, Davis W, Duffus WP, Edington N, Grünig G, Holmes MA.The First International Workshop on Equine Leucocyte Antigens was organized and convened for the purposes of identifying immunologically relevant cell surface molecules of equine leucocytes and establishing a system of nomenclature for those molecules. Participating members of the workshop represented the majority of laboratories world-wide engaged in the tasks of production and characterization of equine leucocyte and lymphocyte markers using monoclonal antibodies. The workshop confirmed the identification of several equine CD molecules described previously by individual laboratories, and in ...
Belgrave RL, Dickey MM, Arheart KL, Cray C.To compare serum amyloid A (SAA) concentration, plasma fibrinogen concentration, total WBC count, and serum albumin-to-globulin concentration ratio (A:G ratio) in clinically normal (CN) and clinically abnormal (CA) horses. Methods: Prospective cohort study. Methods: 111 CN horses and 101 CA horses hospitalized at a specialty clinical practice. Methods: Shortly after admission, a blood sample (20 mL) was collected from each horse for a CBC, serum protein electrophoresis, and determination of plasma fibrinogen concentration; SAA concentration was assessed with a previously validated immunoturbid...
Nemoto M, Oue Y, Morita Y, Kanno T, Kinoshita Y, Niwa H, Ueno T, Katayama Y, Bannai H, Tsujimura K, Yamanaka T, Kondo T.Recently, outbreaks associated with equine coronavirus (ECoV) have occurred in Japan and the United States. While ECoV is likely to be pathogenic to horses, it has not been shown that experimental inoculation of horses with ECoV produces clinical signs of disease. In this study, we inoculated three Japanese draft horses with an ECoV-positive diarrheic fecal sample to confirm infection after inoculation and to investigate the clinical course and virus shedding patterns of ECoV. Virus neutralization tests showed that all three horses became infected with ECoV. Two of the three horses developed c...
Venner M, Rödiger A, Laemmer M, Giguère S.Mass antimicrobial treatment of foals with small ultrasonographic pulmonary lesions is common on farms with endemic disease caused by Rhodococcus equi. The objectives of this study were to compare the relative efficacy of three antimicrobial protocols for the treatment of pulmonary abscesses on a farm with endemic infections caused by R. equi and to determine the frequency of spontaneous resolution of subclinical pulmonary lesions. Foals with ultrasonographic evidence of pulmonary abscesses ≥ 1.0 cm in diameter (n=128) were randomly allocated to one of four equal treatment groups. Animals wi...
Mealey RH, Zhang B, Leib SR, Littke MH, McGuire TC.Equine infectious anemia virus (EIAV) is a lentivirus that causes persistent infections in horses. We hypothesized that high-avidity CTL specific for nonvariable epitopes might be associated with low viral load and minimal disease in EIAV-infected horses. To test this hypothesis, memory CTL (CTLm) responses were analyzed in two infected horses with high plasma viral loads and recurrent disease (progressors), and in two infected horses with low-to-undetectable viral loads and mild disease (nonprogressors). High-avidity CTLm in one progressor recognized an envelope gp90 epitope, and the data doc...
Duncan JL, Pirie HM.The clinical signs, pathology and clinical pathology associated with single experimental infections of Strongylus vulgaris in worm-free pony foals are described. The major clinical signs which became apparent in the infected foals during the first three weeks were pyrexia, anorexia, dullness and abdominal pain. Within the first two weeks of infection lesions were confined to the intestine and terminal branches of the intestinal arteries and consisted of mucosal, submucosal and serosal haemorrhage together with arteritis of submucosal and serosal arteries and also a marked inflammatory reaction...
Neuder LE, Keener JM, Eckert RE, Trujillo JC, Jones SL.Endotoxemia occurs when bacterial lipopolysaccharide (LPS) in the blood induces a dysregulated inflammatory response, resulting in circulatory shock and multi-organ failure. Laminitis is a common complication in endotoxemic horses and is frequently the reason for humane euthanasia of these cases. Blood leukocytes are a principal target of LPS in endotoxemia leading to activation of multiple signal transduction pathways involved in the induction of a number of pro-inflammatory genes. In other animal models, the p38 mitogen activated protein kinase (MAPK) pathway has been associated with induced...
Ross TN, Kisiday JD, Hess T, McIlwraith CW.To compare two transient models of synovitis-osteoarthritis (OA) in horses by characterizing biological changes in synovial fluid and joint tissue. Methods: Twelve skeletally mature mares were utilized in a block design. Synovitis was induced by an intra-articular injection of 100 ng recombinant equine interleukin 1 beta (reIL-1β) or 0.5 ng lipopolysaccharide (LPS) into a middle carpal joint in 1 ml volumes. One ml of saline was injected into the contra-lateral control joint. Lameness evaluations were conducted through post-injection hour (PIH) 8 (at which time arthroscopic removal of syno...
Paterson YZ, Rash N, Garvican ER, Paillot R, Guest DJ.Autologous mesenchymal stem cells (MSCs) are an attractive concept in regenerative medicine, but their mechanism of action remains poorly defined. No immune response is reported after in vivo injection of allogeneic equine MSCs or embryo-derived stem cells (ESCs) into the equine tendon, which may be due to the cells' immune-privileged properties. This study further investigates these properties to determine their potential for clinical application in other tissues. Methods: Mitomycin C-treated MSCs, ESCs, or differentiated ESCs (dESCs) were cultured with allogeneic equine peripheral blood mono...
Allen G, Yeargan M, Costa LR, Cross R.An experimental system that permits sensitive and reproducible detection of equine herpesvirus 1 (EHV-1)-specific cytotoxic T-lymphocyte (CTL) activity in the horse was developed. Peripheral blood mononuclear cells (PBMC) collected from immune horses were restimulated in vitro by culture with live EHV-1. Cytotoxic activity against virus-infected, pokeweed mitogen-stimulated lymphoblast targets was assessed in a 4-h 51Cr release assay. The optimal conditions for in vitro stimulation of equine memory CTLs and for preparation of EHV-1-infected target cells expressing viral antigens were systemati...
Stull CL, Rodiek AV.Fifteen mature horses (mares, n = 6); geldings, n = 9) were used to assess the physiological responses of 24 h of transport in a commercial van under California summer conditions. The study was conducted on four consecutive days, and data were collected on d 1 and d 2 to obtain baseline values and to determine any diurnal variation in the individual measurements. Travel commenced on d 3 at 0800 for 24 h, with a total of 1,622 km traveled. Blood samples were collected at 0800, 1100, 1400, 2000, and 0200 each day. Horses were weighed and rectal temperatures recorded at 0800 each day and at 2000 ...
Padalino B, Raidal SL, Knight P, Celi P, Jeffcott L, Muscatello G.This study aimed to document the effects of an eight hour journey on behavioural, clinical, haematological, environmental and respiratory parameters, and to identify possible associations between factors. Twelve horses underwent clinical examination, respiratory endoscopy with tracheal wash (TW) aspiration, and collection of venous and arterial blood before (BJ) and after the journey (AJ). TW were submitted for conventional quantitative bacteriological evaluation and genetic microbiome analyses. Behaviour was assessed in stables prior to transportation and throughout the journey. Transportatio...
Perkins GA, Wagner B.The development of equine immunity from the fetus to adulthood is complex. The foal's immune response and the immune mechanisms that they are equipped with, along with changes over the first months of life until the immune system becomes adult-like, are only partially understood. While several innate immune responses seem to be fully functional from birth, the onset of adaptive immune response is delayed. For some adaptive immune parameters, such as immunoglobin (Ig)G1, IgG3, IgG5 and IgA antibodies, the immune response starts before or at birth and matures within 3 months of life. Other antib...
Hines SA, Stone DM, Hines MT, Alperin DC, Knowles DP, Norton LK, Hamilton MJ, Davis WC, McGuire TC.Rhodococcus equi is a gram-positive bacterium that infects alveolar macrophages and causes rhodococcal pneumonia in horses and humans. The virulence plasmid of R. equi appears to be required for both pathogenicity in the horse and the induction of protective immunity. An understanding of the mechanisms by which virulent R. equi circumvents protective host responses and by which bacteria are ultimately cleared is important for development of an effective vaccine. Six adult horses were challenged with either virulent R. equi or an avirulent, plasmid-cured derivative. By using a flow cytometric m...
Zhang W, Lonning SM, McGuire TC.Most equine infectious anemia virus (EIAV)-infected horses have acute clinical disease, but they eventually control the disease and become lifelong carriers. Cytotoxic T lymphocytes (CTL) are considered an important immune component in the control of infections with lentiviruses including EIAV, but definitive evidence for CTL in the control of disease in carrier horses is lacking. By using retroviral vector-transduced target cells expressing different Gag proteins and overlapping synthetic peptides of 16 to 25 amino acids, peptides containing at least 12 Gag CTL epitopes recognized by virus-st...
Adams AA, Breathnach CC, Katepalli MP, Kohler K, Horohov DW.A number of model systems have been employed to investigate age-associated changes in immune function. The purpose of the current study was to characterize senescent T cells and to investigate the inflamm-aging phenomenon both in vitro and in vivo using the old horse as a model. We examined whether decreased T cell proliferation induced by Con A is caused by increased apoptosis. We also utilized intracellular CFSE to analyze changes within each round of cell proliferation, in particular cytokine production. Intracellular staining with flow cytometry, RT-PCR, and ELISA were used to measure pro-...
Andersen SA, Petersen HH, Ersbøll AK, Falk-Rønne J, Jacobsen S.European and American guidelines for vaccination against tetanus and influenza in horses recommend annual and annual/semi-annual vaccinations, respectively, against the two pathogens. Too-frequent vaccination may, however, have adverse effects, among other things because an inflammatory response is elicited with subsequent alterations in homeostasis. The objective of the study was to compare the acute phase response (APR) in 10 horses following administration of two different types of vaccines, namely, an inactivated Immune Stimulating COMplex (ISCOM) vaccine and a live recombinant vector vacc...
