Leukocytes, also known as white blood cells, are an integral component of the equine immune system, responsible for defending horses against infections and foreign substances. These cells are produced in the bone marrow and circulate throughout the bloodstream and tissues. In horses, leukocytes are categorized into several types, including neutrophils, lymphocytes, monocytes, eosinophils, and basophils, each with specific functions in immune response. Neutrophils are involved in phagocytosis and the destruction of pathogens, while lymphocytes are key players in adaptive immunity. Monocytes differentiate into macrophages and dendritic cells, contributing to pathogen clearance and antigen presentation. Eosinophils and basophils are associated with allergic reactions and parasitic infections. Variations in leukocyte counts and distribution can indicate underlying health conditions, making them valuable in veterinary diagnostics. This page aggregates peer-reviewed research studies and scholarly articles that explore the physiology, function, and diagnostic relevance of leukocytes in equine health.
Ramery E, Fraipont A, Richard EA, Art T, Pirottin D, van Delm W, Bureau F, Lekeux P.Inflammatory airway disease (IAD) affects performance and well-being of horses. Diagnosis is primarily reached by bronchoalveolar lavage (BAL) cytology which is invasive and requires sedation. Objective: The purpose of this study was to identify differential gene expression in peripheral blood of horses with IAD using species-specific expression microarrays. Methods: Equine gene expression microarrays were used to investigate global mRNA expression in circulating leukocytes from healthy, IAD-affected, and low-performing Standardbred and endurance horses. Results: Nine genes in Standardbred and...
Janda J, Lehmann M, Luttmann W, Marti E.Interleukin-3 is a growth and differentiation factor for various hematopoietic cells. IL-3 also enhances stimulus-dependent release of mediators and cytokine production by mature basophils. Function of IL-3 has not been studied in horses because of lack of horse-specific reagents. Our aim was to produce recombinant equine IL-3 and test its effect on sulfidoleukotriene and cytokine production by equine peripheral blood leukocytes (PBL). Equine IL-3 was cloned, expressed in E. coli and purified. PBL of 19 healthy and 20 insect bite hypersensitivity (IBH)-affected horses were stimulated with Culi...
Bauquier JR, Tudor E, Bailey SR.Despite the severity and common occurrence of equine endotoxaemia, the available anti-endotoxic treatments do not effectively target key inflammatory mechanisms such as leucocyte activation and cytokine production. In this study, four compounds with potential anti-endotoxic effects, namely rolipram, azithromycin, ethyl pyruvate and metformin, were investigated in vitro using equine whole blood stimulated with bacterial lipopolysaccharide. TNF-α and IL-1β production were measured in plasma. Rolipram was the most potent inhibitor of cytokine production (IC50 0.84 and 4.68 μm for TNF-α and IL...
Passamonti F, Vardi DM, Stefanetti V, Marenzoni ML, Prato S, Cévese P, Coletti M, Pepe M, Casagrande Proietti P, Olea-Popelka F.Early diagnosis and prevention of Rhodococcus equi pneumonia in foals represent important goals for equine clinicians. Recent protocols for diagnosis and treatment of Rhodococcosis in foals typically rely on a multimodal approach based on sonographic evidence suggestive of pyogranulomas, sonographic abscess scores and laboratory findings including plasma fibrinogen concentrations, blood biochemistry testing and platelet and leukocyte counts. The aim of this study was to assess the utility of weekly testing of serum amyloid A (SAA) and plasma fibrinogen concentrations in foals to achieve early ...
Battista JM, Tallmadge RL, Stokol T, Felippe MJ.We investigated how the equine fetus prepares its pre-immune humoral repertoire for an imminent exposure to pathogens in the neonatal period, particularly how the primary hematopoietic organs are equipped to support B cell hematopoiesis and immunoglobulin (Ig) diversity. We demonstrated that the liver and the bone marrow at approximately 100 days of gestation (DG) are active sites of hematopoiesis based on the expression of signature messenger RNA (mRNA) (c-KIT, CD34, IL7R, CXCL12, IRF8, PU.1, PAX5, NOTCH1, GATA1, CEBPA) and protein markers (CD34, CD19, IgM, CD3, CD4, CD5, CD8, CD11b, CD172A)...
Patan-Zugaj B, Gauff FC, Plendl J, Licka TF.To investigate effects of endotoxin on leukocyte activation and infiltration of the laminar tissue in isolated perfused equine limbs. Methods: 10 right forelimbs and 3 left forelimbs collected from 10 healthy adult horses after slaughter at a licensed abattoir. procedures: Isolated right forelimbs were randomly assigned to 2 groups (5 forelimbs/group): perfusion of the distal portion for 10 hours with 80 ng of endotoxin/L and perfusion under the same conditions without endotoxin. After perfusion, samples for immunohistochemical detection of leukocytes (by use of antibodies against calprotectin...
Bazzano M, Giannetto C, Fazio F, Rizzo M, Giudice E, Piccione G.The aim of the study was to assess changes in some haematological parameters of periparturient mares from the last three months of pregnancy until the third week after foaling. The study was carried out on 15 healthy pregnant mares (Group A) and 7 healthy non-pregnant non-lactating mares (Group B). Blood samples were collected by jugular venipuncture into EDTA tubes and tested for Haematocrit (Hct), Red Blood Cell (RBC), Haemoglobin (Hb), Platelets (Plt) and White Blood Cell (WBC). Peripheral blood smears were also performed to assess changes in the leucocyte differential count. Group A showed...
Canisso IF, Ball BA, Cray C, Williams NM, Scoggin KE, Davolli GM, Squires EL, Troedsson MH.Currently, placentitis, an important cause of late pregnancy loss in mares, is diagnosed by clinical signs and ultrasonography. Acute phase proteins (APP) are mainly produced and secreted by the liver in response to acute inflammatory stimuli. We hypothesized that APP are increased in mares with placentitis. Methods: Concentrations of serum amyloid A (SAA), haptoglobin (Hp), fibrinogen (Fb), and white blood cell counts (WBC) were determined in plasma of mares with experimentally induced placentitis and gestationally age-matched control mares. Placentitis was induced via intracervical inoculati...
Hessel LN, Bosch G, van Weeren PR, Ionita JC.Autologous platelet concentrates (APCs) are being used increasingly in horses to enhance regeneration in tissues that have poor natural healing capabilities. Numerous APC systems, which are based on different preparation techniques and were originally developed for human patients, are now routinely used in equine cases. However, preliminary process validation and adequate in vitro biochemical characterisation of most of these systems do not exist for horses. Objective: To compare haematological findings and growth factor concentrations of equine APCs obtained with 4 commercially available syst...
Stirn M, Moritz A, Bauer N.Modern automated haematology instruments are capable of performing leukocyte differentials faster, cheaper and with a higher precision than the traditional 100-cell manual differential count. Thus, in human laboratories, criteria are defined for performing a manual review of the blood smear resulting in a marked reduction of manual differential counts. While common in human laboratories, this approach to reducing the number of manual differentials in veterinary laboratories is still not commonly performed. Thus, our aim was to determine the rate and causes of manual leukocyte differentials in ...
Rapacz-Leonard A, Dąbrowska M, Janowski T.During pregnancy in larger mammals, the maternal immune system must tolerate the fetus for months while resisting external infection. This tolerance is facilitated by immunological communication between the fetus and the mother, which is mediated by Major Histocompatibility Complex I (MHC I) proteins, by leukocytes, and by the cytokines secreted by the leukocytes. Fetal-maternal immunological communication also supports pregnancy by inducing physiological changes in the mother. If the mother "misunderstands" the signal sent by the fetus during pregnancy, the fetus will be miscarried or deliver...
Demyda-Peyrás S, Anaya G, Bugno-Poniewierska M, Pawlina K, Membrillo A, Valera M, Moreno-Millán M.Sex chromosome aberrations are known to cause congenital abnormalities and unexplained infertility in horses. Most of these anomalies remain undiagnosed because of the complexity of the horse karyotype and the lack of specialized laboratories that can perform such diagnoses. On the other hand, the utilization of microsatellite markers is a technique widely spread in horse breeding, mostly because of their usage in parentage tests. We studied the usage of a novel combination of diagnostic approaches in the evaluation of a very uncommon case of chromosomal abnormalities in a Spanish purebred col...
Niwa H, Kato H, Hobo S, Kinoshita Y, Ueno T, Katayama Y, Hariu K, Oku K, Senoh M, Kuroda T, Nakai K.Clostridium difficile is an important cause of acute enterocolitis in horses. We describe five cases of C difficile infection occurring postoperatively in Thoroughbred racehorses. Following diarrhoea or colic accompanied by a marked increase in packed cell volume (to ≥60 per cent) and leucopenia (≤4000 cells/μl) within two to four days after surgery in all five horses, four of them died or were euthanased because of colitis or severe diarrhoea. In these four horses, necrotising entero-typhlo-colitis was revealed by postmortem examination, and C difficile was recovered from the contents of...
Mariella J, Pirrone A, Gentilini F, Castagnetti C.The purposes of this study were to determine physiological changes occurring in hematologic and biochemical parameters in mares between the last month of gestation and the first week after parturition. If a significant change was observed with respect to the reference interval of an adult horse, a further aim of the study was to establish different reference intervals. Blood samples were collected from 62 healthy pregnant Standardbred mares. Seventeen nonpregnant and nonlactating mares were used as a control group. In pregnant mares, blood sampling was conducted every three days from 1 month b...
Degroote RL, Hauck SM, Treutlein G, Amann B, Fröhlich KJ, Kremmer E, Merl J, Stangassinger M, Ueffing M, Deeg CA.Autoimmune uveitis is characterized by crossing of blood-retinal barrier (BRB) by autoaggressive immune cells. Equine recurrent uveitis (ERU) is a valuable spontaneous model for autoimmune uveitis and analyses of differentially expressed proteins in ERU unraveled changed protein clusters in target tissues and immune system. Healthy eyes are devoid of leukocytes. In ERU, however, leukocytes enter the inner eye and subsequently destroy it. Molecular mechanisms enabling cell migration through BRB still remain elusive. Previously, we detected decreased talin 1 expression in blood-derived granulocy...
Hemberg E, Einarsson S, Jones B, Mikko S.The objective of this study was to investigate the presence and origin of polymorphonuclear leucocytes (PMNLs) in the amniotic fluid of mares giving birth to healthy foals. Material from 25 mares was included. Amniotic fluid was collected during parturition before breakage of the amniotic vesicle. Manual microscopic cytologic evaluation was made on cytospin preparations after staining. PMNLs were found in all amniotic samples examined. The genomic DNA was extracted from 12 of the amniotic fluid samples and was genotyped. The results indicate that the PMNLs originate from the foetus.
Salciccia A, Sandersen C, Grulke S, de la Rebière de Pouyade G, Caudron I, Serteyn D, Detilleux J.The objectives of this study were to describe and relate perioperative changes in blood leukocyte counts to the outcome of surgical colic horses, determine a cut-off value in the early postoperative period to obtain an indicator of the outcome, and compare the obtained value to a validation population of horses. Fifty-three horses undergoing colic surgery were included in the descriptive part of the study. Total leukocyte counts were performed before, during and serially after surgery. A receiver operating characteristic analysis was performed on the leukocyte counts of 45 of these horses to d...
Vairo S, Favoreel H, Scagliarini A, Nauwynck H.Currently, little is known on the cellular pathogenesis of equine arteritis virus (EAV). The purpose of the present study was to identify the target cells in ponies experimentally inoculated with EAV 08P178 (EU, clade-1). EAV-target organs (respiratory tissues with associated lymphoid tissues and large intestines), collected at 3 and 7 days post inoculation (dpi) and with virus titers≥10(5.0) TCID50/g, were processed with double immunofluorescence staining for the simultaneous detection of EAV N-protein and one of the following cell markers: CD172a (myeloid cells), CD3 (T lymphocytes), IgM (...
Cian F, Tyner G, Martini V, Comazzi S, Archer J.A 16-year-old, Irish Draft mare was admitted to the referring veterinarian for an annual health check. A mild generalized lymphadenomegaly was noted. Rectal palpation and transrectal ultrasonographic examination revealed prominent mesenteric lymph nodes. A transcutaneous abdominal ultrasonographic evaluation was unremarkable. A CBC revealed a marked leukocytosis (63.06 × 10(3)/μL) and lymphocytosis (58.2 × 10(3)/μL) due to increased numbers of small lymphocytes. No evidence of anemia or thrombocytopenia was found and neutrophil counts were low-normal. Cytologic examination of fine-needle a...
Sarmiento J, Perez B, Morales N, Henriquez C, Vidal L, Folch H, Galecio JS, Morán G.A reduction in inflammatory cell apoptosis is an important concept in the maintenance of inflammation and a potential target for the resolution of inflammation in many inflammatory diseases. Dysregulation of apoptosis has been implicated in a range of diseases, including tumors, neurodegenerative disorders and autoimmunity, and may also be implicated in allergic asthma. In horses, recurrent airway obstruction (RAO) is an asthma-like condition that is characterized increased survival neutrophil bronchial. Tamoxifen is a synthetic, non-steroidal, anti-estrogen agent that is widely used for treat...
Tadros EM, Frank N, Donnell RL.To test the hypothesis that inflammatory responses to endotoxemia differ between healthy horses and horses with equine metabolic syndrome (EMS). Animals-6 healthy horses and 6 horses with EMS. Methods: Each horse randomly received an IV infusion of lipopolysaccharide (20 ng/kg [in 60 mL of sterile saline {0.9% NaCl} solution]) or saline solution, followed by the other treatment after a 7-day washout period. Baseline data were obtained 30 minutes before each infusion. After infusion, a physical examination was performed hourly for 9 hours and at 15 and 21 hours; a whole blood sample was collect...
Garrett KS, Bramlage LR, Spike-Pierce DL, Cohen ND.To determine the effects of treatment with platelet- and leukocyte-rich plasma (PRP) on future 2-, 3-, and 4-year-old racing performance of yearling Thoroughbreds with proximal sesamoid bone inflammation and associated suspensory ligament branch (SLB) desmitis. Methods: Randomized clinical trial. Methods: 39 yearling Thoroughbreds. Methods: Yearling Thoroughbreds with radiographic evidence of performance-limiting proximal sesamoid bone inflammation and ultrasonographic evidence of associated SLB desmitis were identified and randomly assigned to undergo PRP (treatment group) or saline (0.9% NaC...
Vendrig JC, Coffeng LE, Fink-Gremmels J.Deficient innate and adaptive immune responses cause newborn mammals to be more susceptible to bacterial infections than adult individuals. Toll-like receptors (TLRs) are known to play a pivotal role in bacterial recognition and subsequent immune responses. Several studies have indicated that activation of certain TLRs, in particular TLR-2, can result in suppression of inflammatory pathology. In this study, we isolated peripheral blood mononuclear cells (PBMCs) from adult and newborn horses to investigate the influence of TLR-2 activation on the inflammatory response mediated by TLR-4. Data we...
Kachroo P, Ivanov I, Seabury AG, Liu M, Chowdhary BP, Cohen ND.Rhodococcus equi is an intracellular bacterium primarily known as an equine pathogen that infects young foals causing a pyogranulomatuous pneumonia. The molecular mechanisms mediating the immune response of foals to R. equi are not fully elucidated. Hence, global genomic high-throughput tools like gene expression microarrays might identify age-related gene expression signatures and molecular pathways that contribute to the immune mechanisms underlying the inherent susceptibility of foals to disease caused by R. equi. The objectives of this study were 2-fold: 1) to compare the expression profil...
Ozaydın T, Celik I, Sur E, Oznurlu Y, Uluısık D.We attempted to characterize the cytochemical staining patterns of leukocytes and to determine the percentages of alpha-naphthyl acetate esterase (ANAE) and acid phosphatase (ACPase) positive lymphocytes in peripheral blood of thoroughbred foals at different ages. Blood samples were obtained from the jugular veins of 60 healthy thoroughbred foals, 1 day, 3 days and 1 year old. Each age group included 10 male and 10 female animals. Peroxidase (PO) activity was detected in neutrophils, eosinophils and monocytes. Lymphocytes were negative for PO staining. Periodic acid-Schiff (PAS) staining was o...
Cudmore LA, Muurlink T, Whittem T, Bailey SR.Pro-inflammatory cytokines, such as IL-1β and TNFα, play a major role in activating leukocytes and endothelial cells during the systemic inflammatory response to endotoxin in the horse. β2 agonist drugs, such as clenbuterol, inhibit leukocyte activation. This study aimed to determine the effects of oral clenbuterol on clinical and leukocyte responses, including production of TNFα, in an in vivo endotoxin challenge model. In a randomised crossover design, horses received either clenbuterol or a placebo product prior to the administration of low dose endotoxin (30 ng/kg over 30 min). Clinica...
Paillot R.Inactivated Parapoxvirus ovis (iPPVO) and Propionibacterium acnes (P. acnes) are currently used in equine medicine as immune-modulators for prophylactic treatment or adjunct to conventional therapy in order to improve immune defences, to prevent or treat infectious diseases. Their mode of action relies on a non-antigen specific interaction with the innate and/or adaptive immune responses. iPPVO stimulates and regulates cytokine secretion by leucocytes, while P. acnes acts primarily through the activation of macrophages. This report aims to describe their activity as immune-modulators and to su...
Fernandez NJ, Hecker KG, Gilroy CV, Warren AL, Léguillette R.Reliable enumeration of mast cells and eosinophils in equine bronchoalveolar lavage (BAL) fluid is important because small increases in the percentages of these cells support the clinical diagnosis of inflammatory airway disease (IAD). Increases in BAL neutrophils also occur with IAD but are not specific due to overlap between IAD and recurrent airway obstruction (RAO). Objective: The objectives of this study were to evaluate the reliability of a standard 400-cell leukocyte differential count and an alternate method evaluating 5 microscopic fields at 500× magnification in equine BAL fluid cyt...
Rossetti RB, Massoco Cde O, Penna AC, Silva LC.To assess comparatively the inflammatory response that follows CO(2) or Ringer's lactate joint capsular distension of horses submitted to experimental arthroscopy Methods: Each animal was submitted to a bilateral tarsocrural arthroscopy employing gas distention in one joint and fluid distention in the contralateral joint. Synovial fluid was evaluated at 0, six, 12, 24 and 48 hours post-operative. Results: The use of CO(2) for arthroscopy causes an acute and mild synovitis alike to the liquid capsular distension, showing similar synovial fluid increase of leukocytes, TP, and TNF-α. Although sy...
Palm F, Walter I, Nowotny N, Budik S, Helmreich M, Aurich C.In most mammalian species, progestins have a major function in maintaining pregnancy. In humans, the physiologic initiation of parturition bears similarities with inflammatory processes and anti-inflammatory effects of progestins have been suggested to postpone birth until term. To examine if comparable effects exist in the horse, mares were treated with the synthetic progestin altrenogest from day 280 of gestation until parturition (N = 5) or were left untreated as controls (N = 7). Tissue from the amnion (AMN), allantochorion (AC), and endometrium (EM) was collected at foaling and mRNA expre...
Fujimiya Y, Perryman LE, Crawford TB.Antibody-dependent cellular cytotoxicity and direct cytotoxicity assays were performed with equine infectious anemia virus-infected target cells, equine leukocytes, and equine anti-equine infectious anemia virus antibody to determine whether these mechanisms play a role in controlling viral replication in equine infectious anemia. Direct cytotoxicity was observed by using peripheral blood mononuclear cells from 7 of 10 infected horses. Antibody-dependent cellular cytotoxicity was not observed. The antibody-dependent cellular cytotoxicity reaction in horses was then studied by using sheep eryth...
Vinther AM, Skovgaard K, Heegaard PM, Andersen PH.In horses, insights into the innate immune processes in acute systemic inflammation are limited even though these processes may be highly important for future diagnostic and therapeutic advances in high-mortality disease conditions as the systemic inflammatory response syndrome (SIRS) and sepsis. Therefore, the aim of this study was to investigate the expression of 31 selected blood leukocyte immune genes in an equine model of acute systemic inflammation to identify significantly regulated genes and to describe their expression dynamics during a 24-h experimental period. Systemic inflammation ...
Dória RG, Carvalho MB, Freitas SH, Laskoski LM, Colodel EM, Mendonça FS, Silva MA, Grigoletto R, Fantinato Neto P.Treatment for horses with pythiosis of a limb is challenging. This study aims to evaluate the effects of administering amphotericin B in a 10 % solution of dimethylsulfoxide by intravenous regional limb perfusion (IRLP) to treat horses for cutaneous pythiosis of a limb. Results: All 15 of the horses treated had complete resolutions of their lesion between 6 to 9 weeks after a single IRLP treatment. No complications were observed at the site of venipuncture for IRLP. Before initiation of treatment, there was anemia and marked leucocytosis which resolved following treatment. Serum biochemistry ...
El-Sheikh Ali H, Legacki EL, Loux SC, Esteller-Vico A, Dini P, Scoggin KE, Conley AJ, Stanley SD, Ball BA.The current study aimed to elucidate the mechanisms underlying myometrial activation during equine placentitis related to progestogens and the progesterone receptor signaling pathways. Placentitis was induced via intracervical inoculation with Streptococcus equi ssp zooepidemicus in mares at approximately 290 days of gestation (placentitis group; n = 6) with uninoculated gestationally matched mares as controls (n = 4). Mares in the placentitis and control groups were euthanized, and myometrial samples were collected from two regions: region 1-parallel to active placentitis lesion with plac...
Leise BS, Fugler LA.Sepsis or systemic inflammatory response syndrome (SIRS) -associated laminitis is a sequela to primary inflammatory conditions (eg, colitis, ischemic intestinal injury, pneumonia, metritis) and results from a dysregulated systemic inflammatory response that ultimately affects the digital lamellae. Local chemokine production, leukocyte migration, and proinflammatory mediator production occur within the lamellae that can lead to catastrophic lamellar failure. Controlling the primary disease, providing supportive care and anti-inflammatory therapy, applying digital cryotherapy, and providing mech...
Cook VL, Neuder LE, Blikslager AT, Jones SL.The effect of lidocaine on in vitro migration and adhesion of equine neutrophils was evaluated. Neutrophils were isolated from equine whole blood using a Percoll-gradient centrifugation protocol. Purified neutrophils were incubated with lidocaine at concentrations from 0.1 to 1000 microg/ml for 30 min at 37 degrees C, after calcein loading. Neutrophil integrin-mediated adhesion in response to stimulation with 100 nM LTB(4), 100 nM PAF, or 100 ng/ml IL-8, or integrin-mediated migration in response to stimulation with 100 nM LTB(4), 150 nM PAF, or 100 ng/ml IL-8 was assessed. Statistical signifi...
Smith DJ, Iqbal J, Purewal A, Hamblin AS, Edington N.IL-2 and equine chorionic gonadotrophin (eCG) initiated reactivation of equid herpesvirus-1 (EHV-1) from venous lymphocytes at a frequency of 1/10(-5). Indirect immunofluorescence showed that > 80% of virus-positive leukocytes were CD5+/CD8+ with the remaining 20% being CD5+/CD8-/CD4-. Cocultivation demonstrated that the reactivated virus was infectious. In addition, virus was reactivated in vitro from leukocytes of > 70% of horses by the mitogens phytohaemagglutinin (PHA) and pokeweed mitogen (PWM). Transfer of supernatants showed that IL-2 and eCG acted indirectly by causing the releas...
Durando MM, MacKay RJ, Linda S, Skelley LA.Polymyxin B and an antiserum against an Re mutant Salmonella typhimurium were evaluated for protective effect in an equine model endotoxemia. Six 3- to 5-month-old foals were given endotoxin (0.25 micrograms/kg of body weight) IV after no pretreatment, or pretreatment with polymyxin B (6,000 U/kg, IV) or S typhimurium antiserum (1.5 ml/kg, IV). When given without pretreatment, endotoxin caused transient recumbency and increases in rectal temperature, and heart and respiratory rates. In addition, leukopenia and increases in circulating tumor necrosis factor (TNF) and interleukin 6 (IL-6) activi...
Benbarek H, Deby-Dupont G, Deby C, Caudron I, Mathy-Hartert M, Lamy M, Serteyn D.The activation of human polymorphonuclear leucocytes (the respiratory burst) can be studied by measuring their chemiluminescent response. This technique was adapted to equine leucocytes to investigate the effects of cell number, activator concentration, enhancers of chemiluminescence, pH, temperature and inhibitors. Leucocytes were isolated from citrated blood from healthy horses and chemiluminescence was measured with a Bio-Orbit luminometer sensitive to 900 nm light. The optimal cell density for the maximal chemiluminescent response ranged from 10(6) to 10(7) leucocytes 600 microliters-1. Ch...
Bottoms GD, Johnson MA, Lamar CH, Fessler JF, Turek JJ.Dispersed equine vascular endothelial cells grown in tissue culture, and freshly isolated neutrophils were used to determine direct effects of endotoxin on cyclooxygenase and lipoxygenase products. Endothelial cells (10(7)/ml) or neutrophils (2 X 10(6)/ml) were incubated with (a) buffer, (b) endotoxin (10 micrograms/ml), (c) endotoxin + flunixin meglumine (10 micrograms/ml), or (d) calcium ionophore, A23187 (10 micrograms/ml). Thromboxane (TxB2), prostacyclin (6-keto-PGF1 alpha), and leukotriene C4 (LTC4) were determined in the incubation fluid by radioimmunoassay. Thromboxane and prostacyclin...
Bullido R, Doménech N, Alvarez B, Alonso F, Babín M, Ezquerra A, Ortuño E, Domínguez J.A set of five monoclonal antibodies (mAb) against porcine major histocompatibility complex (MHC), or swine leukocyte antigens (SLA), class II molecules has been characterized. These mAbs appear to recognize monomorphic determinants on SLA-DR (2F4, 1F12 and 2E9/13) and SLA-DQ (BL2H5 and BL4H2) molecules, as assessed by flow cytometry and immunoprecipitation. By Western blot, the 2F4, 1F12, BL2H5 and BL4H2 epitopes were located on the beta-chains of these molecules. mAbs 2F4 and 1F12 crossreact with leucocytes of dog, cattle, horse and human; mAbs 2E9/13, BL2H5 and BL4H2 bind leucocytes of cattl...
Ibrahim S, Steinbach F.Earlier studies investigating the cross-reactivity of antibodies submitted to the HLDA8 had used flow cytometry as a method of choice to screen mAbs for reactivity with equine leukocytes, including two-color flow-cytometry to characterize the lymphocyte population they detect. In addition, immuno-histochemistry (IHC) was used to detect distribution of positive cells in lymphoid tissue sections. In this study we performed immunoprecipitation (IP) to complement the previous results and add valuable information regarding the molecules detected by the cross-reacting antibodies. Surface molecules f...
Gryspeerdt AC, Vandekerckhove AP, Baghi HB, Van de Walle GR, Nauwynck HJ.Equine herpes virus (EHV)-1 replicates in the epithelial cells of the upper respiratory tract and reaches the lamina propria and bloodstream in infected mononuclear cells. This study evaluated expression of the late viral proteins gB, gC, gD and gM in respiratory epithelial and mononuclear cells using: (1) epithelial-like rabbit kidney cells and peripheral blood mononuclear cells infected with EHV-1 in vitro; (2) an equine ex vivo nasal explant system; and (3) nasal mucosa tissue of ponies infected in vivo. The viral proteins were expressed in all late-infected epithelial cells, whereas expres...
Colahan PT, Kollias-Bakert C, Leutenegger CM, Jones JH.Physical exertion is a stimulus for the upregulation of cytokine production including IL-1beta, IL-1ra, IL-2, IL-4, IL-6, IL-10 and TNF-alpha in horses. To investigate that hypothesis, we initiated training of 5 stall-rested Thoroughbreds. Blood samples were drawn before and weekly during training. The relative transcription of mRNA within the leucocytes was measured using real time TaqMan quantitative PCR. The training protocol was walking (3 min), trotting (3 min) and cantering/galloping (6 min) increasing in intensity weekly (6 to 12 m/s) and culminating in an intense exercise period. Compa...
Arai T, Inoue A, Uematsu Y, Sako T, Kimura N.The activities of the enzymes involved in the malate-aspartate shuttle and lactate dehydrogenase (LDH) and the pattern of the isoenzymes of LDH were determined in plasma and peripheral leukocytes of lactating Holstein cows and thoroughbred riding horses as representative herbivorous animals. In the horse plasma, LDH activities were significantly lower and AST activities were significantly higher than those in the cow plasma. The specific activities of cytosolic malate dehydrogenase (MDH), LDH and AST in the horse leukocytes were higher than those in the cows. The cytosolic ratio of MDH/LDH act...
Macintyre AR, Dixon JB.To determine whether living hydatid tissue can, like hydatid fluid, regulate leukocyte growth, T-cell, B-cell, and macrophage lines were cocultured with protoscoleces of Echinococcus granulosus and their growth was compared with that of control cultures by thymidine uptake estimates and chemiluminescent assays of cell number. Protoscoleces supported mitosis of IL-1-deprived D10 T cells, but did not increase D10 count. The action of protoscoleces was affected by the species and organ of their origin and the length of time in culture. Unusually marked mitotic reaction, unaffected by parasite age...
Dubin A, Koj A, Chudzik J.Cytoplasmic granules were isolated from horse blood polymorphonuclear leucocytes by the heparin method and extracted with 0.9% NaCl by repeated freezing. Soluble proteins were separated on a column of Sephadex G-75 followed by chromatography on a column of CM-Sephadex with a NaCl gradient. Gel filtration, density-gradient centrifugation, isoelectric focusing and 0.1% sodium dodecyl sulphate/polyacrylamide-gel electrophoresis at pH 7.0 and at pH 4.5 were used to determine molecular parameters of proteinases. Three enzymes hydrolysing both casein and N-benzyloxycarbonyl-L-alanine nitrophenyl est...
Hart KA, Barton MH, Vandenplas ML, Hurley DJ.Low-dose hydrocortisone (LDHC) therapy modulates inflammatory responses in adults and improves outcomes in some septic adults and neonates, but its immunologic effects have not been evaluated in neonates. The objective of this study was to evaluate effects of LDHC therapy on ex vivo immune function in neonatal horses (foals). We hypothesized that LDHC treatment would dampen proinflammatory responses without impairing neutrophil function. Hydrocortisone (1.3 mg/kg/d i.v.) was administered to foals in a tapering 3.5 d course. Peripheral blood leukocytes were collected from foals before, during, ...
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...
Anton F, Morales C, Aguilar R, Bellido C, Aguilar E, Gaytán F.The existence of a physiological integration between the immune and endocrine systems has long been recognized. In spite of the abundant literature data on the presence of cells of the immune system in the testis, mast cells and eosinophil leukocytes have received little attention. We have studied the presence, distribution and numbers of mast cells and eosinophils in the testes of 12 mammalian species. Mast cells were frequently found in equine (stallion, ass and mule) and human testis, whereas eosinophils were nearly absent. On the contrary, eosinophils were abundant in the hare testis, whil...
Fairbairn SM, Page CP, Lees P, Cunningham FM.Previous studies have shown that bronchoalveolar lavage fluid from horses with allergic respiratory disease and showing clinical symptoms contains increased numbers of neutrophils. In some cases, the eosinophil count is also increased. In this study the time course of changes in lung function and the accumulation of radiolabelled leucocytes and platelets in the lungs of allergic and normal horses has been examined during a 7 hr allergen exposure. Antigen challenge had no effect on pleural pressure or the distribution of radiolabelled neutrophils, eosinophils or platelets in normal horses. In c...
Davis JL, Salmon JH, Papich MG.To determine the pharmacokinetics of itraconazole after IV or oral administration of a solution or capsules to horses and to examine disposition of itraconazole in the interstitial fluid (ISF), aqueous humor, and polymorphonuclear leukocytes after oral administration of the solution. Methods: 6 healthy horses. Methods: Horses were administered itraconazole solution (5 mg/kg) by nasogastric tube, and samples of plasma, ISF, aqueous humor, and leukocytes were obtained. Horses were then administered itraconazole capsules (5 mg/kg), and plasma was obtained. Three horses were administered itraconaz...
Hall JA, Van Saun RJ, Wander RC.The study objective was to determine the effect of feeding corn oil or fish oil to horses on plasma fatty acid profiles and leukotriene B (LTB) synthesis by stimulated peripheral blood neutrophils. Two groups of horses (n = 5) were randomly assigned to diets supplemented with either 3.0% (by weight) corn oil or fish oil for a period of 14 weeks. The ratio of (n-6) to (n-3) fatty acids in oil supplements was 68.1:1 for corn oil and 0.12:1 for fish oil. Production of LTB4 and LTB, by peripheral blood neutrophils stimulated with calcium ionophore A23187 and plasma cholesterol, triacylglycerol, an...
Wilmink JM, van Weeren PR.Second-intention repair is faster in ponies than in horses and faster in body wounds than in limb wounds. To a large extent, the differences between horses and ponies can be explained by differences in the local inflammatory response, which are a result of the functional capacity of leukocytes. In ponies, leukocytes produce more inflammatory mediators,resulting in better local defense, faster cellular debridement, and a faster transition to the repair phases, with more wound contraction. In horses,leukocytes produce fewer mediators, initiating a weak inflammatory response, which becomes chroni...
Cooper CJ, Keller SM, Arroyo LG, Hewson J, Kenney D, Bienzle D.Leukemia is broadly divided into acute and chronic lymphocytic and myeloid types based on the proportion of blasts, morphology of cells, and expression of specific antigens on neoplastic cells. Classifying leukemia in horses can be challenging if blasts predominate and since few antibodies to identify cell types are available. The objective of this study was to describe in detail the clinical and pathologic features of acute leukemia in horses. Twelve horses ranging from 0.2 to 25.9 years of age were diagnosed with acute leukemia. Six cases were classified as acute lymphocytic leukemia (ALL) b...
Ríos DL, López C, Carmona JU.The aims were as follows: (1) to evaluate the effects at 48 and 96 h of two concentrations (25 and 50%) of leukocyte and platelet-rich gel (L-PRG) and pure PRG (P-PRG) supernatants on the production/degradation in normal equine synovial membrane explants (SME) of platelet derived growth factor isoform BB, transforming growth factor beta-1, tumor necrosis factor alpha, interleukin (IL-) 4 (IL-4), IL-1 receptor antagonist (IL-1ra), and hyaluronan (HA) synthesis and (2) to correlate these molecules with their respective PRG supernatant treatments. SME from 6 horses were cultured for 96 h with...
Jiménez-Aristazábal RF, Carmona JU, Prades M.The aims of the present study were (1) to describe the microscopic and ultrastructural appearance of equine platelet-rich fibrin (PRF) clots and (2) to determine the release and degradation of transforming growth factor beta 1 (TGF-β) and insulin-like growth factor type I (IGF-I) from PRF clots incubated over 14 days. Whole blood from six horses was collected into plain tubes and centrifuged at 240 g for 8 minutes. Clots were evaluated by histology and by both transmission and scanning electronic microscopy (TEM and SEM). Growth factor concentrations were measured by ELISA at 48-hour inter...
Forbes G, Church S, Savage CJ, Bailey SR.Endotoxaemia is a major cause of equine morbidity, and plasma from horses immunised against Escherichia coli is used in its treatment. The aim of this study was to determine the effects of hyperimmune plasma on the clinical and leukocyte responses, including production and activity of TNFα, in an in vivo endotoxin challenge model. Pre-treatment with hyperimmune equine plasma had no significant effect on peak total plasma TNFα concentration (occurring 90min after the administration of 30ng/kg LPS). However, the bioavailable (unbound) TNFα measured by bioassay was significantly reduced in pla...
