Topic:White Blood Cells
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.
Genetic analysis of haematological and plasma biochemical parameters in the Spanish purebred horse exercised on a treadmill. The novel aim of this study was to describe the reference values of different haematological and biochemical parameters in the Spanish purebred horse (Andalusian, SPB) in each of the stages of a programmed exercise on a treadmill system, and to establish heritability and genetic correlations for these haematological and biochemical parameters. For this, 94 young SPB male horses (4.22 ± 2.27 years old) were used. An increasing intensity exercise test at 4, 5, 6 and 7 m/s was carried out on a treadmill (6% inclination). Total red blood cells, total white blood cells, neutrophils and lymphocytes...
Age-related changes following in vitro stimulation with Rhodococcus equi of peripheral blood leukocytes from neonatal foals. 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...
Blood phagocyte activity after race training sessions in Thoroughbred and Arabian horses. Intensive exercise and exertion during competition promote many changes that may result in the impairment of immunity and increased susceptibility to infections. The aim of this study was to evaluate the activity of "the first line of defense": neutrophils and monocytes in racing Thoroughbred and Arabian horses after routine training sessions. Twenty-three (12 Thoroughbred and 11 Arabian) horses were examined. Routine haematological (number of red blood cells - RBC, haemoglobin concentration - HGB, haematocrit - HCT, total number of white blood cells - WBC), biochemical (creatine phosphokinase...
Age and gender related changes in hematological parameters of thoroughbred foals. Hematological and biochemical profiles commonly are required in equine medicine. We studied hematological parameters including red blood cells (RBC), white blood cells (WBC), hemoglobin (Hb), hematocrit (PCV), differential leukocyte counts, mean cell volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) in thoroughbred foals at different ages and for both sexes. Sixty healthy thoroughbred foals, 1 day, 3 days and 1 year old were used. Each age group consisted of 10 male and 10 female animals. We found significant differences related to age in RBC...
Intra-articular use of a platelet-rich product in normal horses: clinical signs and cytologic responses. (1) To report the clinical and synovial effects of a platelet-rich product (PRPr) in normal equine joints, (2) to assess the persistence of platelets within synovial fluid after intra-articular injection, (3) to compare responses to different preparations of that product, and (4) to evaluate a gravity filtration system for PRPr preparation in horses. Methods: Experimental. Methods: A platelet-rich saline product (PRPr) was prepared from 7 normal horses using a proprietary preparation device and was divided into 3 treatments: resting, CaCl2 -activated (23 mM, final), and bovine thrombin-activ...
Cellular and humoral immunity in chronic equine laminitis. Chronic equine laminitis causes persistent pain and lameness in affected animals and often necessitates euthanasia when pain management strategies become ineffective. Published studies as well as anecdotal reports suggest that this chronic inflammatory disease is associated with systemic alterations in immune responsiveness, perhaps involving an autoimmune component. We investigated this broad hypothesis by measuring a variety of immune indicators in healthy control horses (CON) and horses with chronic laminitis (LMN). We found that white blood cells from LMN horses produced more IFNγ than di...
Effect of transportation on fecal bacterial communities and fermentative activities in horses: impact of Saccharomyces cerevisiae CNCM I-1077 supplementation. This study evaluated the effect of transportation on fecal bacterial communities and activities in horses with or without supplementation of live yeast and attempted to link those effects with changes in blood stress markers. Four mature horses were assigned to a crossover design and fed a basal diet (60:40 forage to concentrate; 1.45% BW on a DM basis), with or without supplementation, of 2 × 10(10) cfu/d of Saccharomyces cerevisiae CNCM I-1077. After a 14-d adaptation to dietary treatments, the 5-d experiment started 1 d before transportation (d -1). At d 0, horses were simultaneously trans...
Reliability of 400-cell and 5-field leukocyte differential counts for equine bronchoalveolar lavage fluid. 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...
Gene biomarkers in peripheral white blood cells of horses with experimentally induced osteoarthritis. To use microarray analysis to identify genes that are differentially expressed in horses with experimentally induced osteoarthritis. Methods: 24 horses. Methods: During arthroscopic surgery, a fragment was created in the distal aspect of the radiocarpal bone in 1 forelimb of each horse to induce osteoarthritis. At day 14 after osteoarthritis induction, horses began exercise on a treadmill. Blood and synovial fluid samples were collected before and after surgery. At day 70, horses were euthanized and tissues were harvested for RNA analysis. An equine-specific microarray was used to measure RNA ...
The effect of blood contamination on equine synovial fluid analysis. Based on a systemic complete blood count and a synovial fluid sample, to develop a mathematical model enabling the approximation of corrected values for synovial fluid white blood cell (WBC) count, neutrophil percentage, and total protein concentration in samples of synovial fluid that were contaminated by blood. Methods: Peripheral venous blood and synovial fluid samples were obtained from ten horses. A pooled synovial fluid sample from each horse was separated into 2 mL aliquots, which were subsequently contaminated with a known percentage of autogenous blood (0 to 50% of the synovial fluid ...
Optimization of leukocyte concentration in platelet-rich plasma for the treatment of tendinopathy. Numerous methods are available for platelet-rich plasma (PRP) generation, but evidence defining the optimum composition is lacking. We hypothesized that leukocyte-reduced PRP would result in lower inflammatory cytokine expression compared with concentrated-leukocyte PRP and that maintaining the platelet:white blood cell (WBC) ratio would compensate for the effect of increased WBC concentration. Methods: Blood and flexor digitorum superficialis tendons were collected from young adult horses. Three PRP groups were generated with the same platelet concentration but different WBC concentrations: i...
Gastrointestinal nematode burden in working equids from humid tropical areas of central Veracruz, Mexico, and its relationship with body condition and haematological values. The east coast of Veracruz, Mexico, has an important equine population used for working in rural production systems. The objectives of this study were (1) to calculate the prevalence of tropical working equids (donkeys, mules and horses) infected with gastrointestinal nematodes (GINs) and the GINs involved, and (2) to measure the body condition score (BCS) and haematological values for each working equid and its relationship with faecal worm egg count (EPG). One hundred and forty working equids were randomly selected from five different villages along the central coast of the state of Veracruz...
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...
Evaluation of the inflammatory response in experimentally induced synovitis in the horse: a comparison of recombinant equine interleukin 1 beta and lipopolysaccharide. 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...
Immunohistochemical and immunopathologic characterization of superficial stromal immune-mediated keratitis in horses. To describe the immunopathologic characteristics of superficial stromal immune-mediated keratitis (IMMK) immunopathologically by characterizing cellular infiltrate in affected corneas of horses. Methods: 10 client-owned horses with IMMK. Methods: Immunohistochemical staining was performed on keratectomy samples with equine antibodies against the T-cell marker CD3 and B-cell marker CD79a (10 eyes) and the T-helper cytotoxic marker CD4 and T-cell cytotoxic marker CD8 (6 eyes). Percentage of positively stained cells was scored on a scale from 0 (no cells stained) to 4 (> 75% of cells stained)....
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...
An African horse sickness virus serotype 4 recombinant canarypox virus vaccine elicits specific cell-mediated immune responses in horses. A recombinant canarypox virus vectored vaccine co-expressing synthetic genes encoding outer capsid proteins, VP2 and VP5, of African horse sickness virus (AHSV) serotype 4 (ALVAC(®)-AHSV4) has been demonstrated to fully protect horses against homologous challenge with virulent field virus. Guthrie et al. (2009) detected weak and variable titres of neutralizing antibody (ranging from <10 to 40) 8 weeks after vaccination leading us to hypothesize that there could be a participation of cell mediated immunity (CMI) in protection against AHSV4. The present study aimed at characterizing the CMI ind...
Effects of collecting serial tracheal aspirate and bronchoalveolar lavage samples on the cytological findings of subsequent fluid samples in healthy Standardbred horses. To evaluate the effect of collecting serial tracheal aspirate (TA) and bronchoalveolar lavage (BAL) samples on the cytological findings of subsequent fluid samples obtained from horses without clinical signs of respiratory disease. Methods: Experimental. Methods: Six healthy Standardbred horses. Methods: Endoscopically-guided TA samples, and BAL samples collected using the blind field technique were obtained from the six horses on days 1, 2, 3, 4, 5, 12, and 17. On day 17, horses were sampled three times: at baseline and at 2.5 h and 4 h apart. The differential cytology of the fluid samples co...
Highly deoxynivalenol contaminated oats and immune function in horses. The aim of the present study was to investigate the impact of deoxynivalenol (DON) on cellular and humoral immune parameters in horses. A feeding trial using naturally contaminated oats with high (20.2 mg/kg) and low (0.49 mg/kg) levels of DON was conducted. Two groups of five mares were fed 2 kg oats daily with high or low DON levels for two weeks, using a crossover design with a three-week wash-out period. No adverse effects on general health were observed. Only minor diet-related changes in differential blood counts and serum biochemistry were noted. Serum haptoglobin concentration was sign...
Infected dendritic cells are sufficient to mediate the adjuvant activity generated by Venezuelan equine encephalitis virus replicon particles. Replicon particles derived from Venezuelan equine encephalitis virus (VEE) are infectious non-propagating particles which act as a safe and potent systemic, mucosal, and cellular adjuvant when delivered with antigen. VEE and VEE replicon particles (VRP) can target multiple cell types including dendritic cells (DCs). The role of these cell types in VRP adjuvant activity has not been previously evaluated, and for these studies we focused on the contribution of DCs to the response to VRP. By analysis of VRP targeting in the draining lymph node, we found that VRP induced rapid recruitment of TNF-s...
Evaluation of the veterinary application of a point-of-care device measuring white blood cell counts. A point-of-care device (POCD) for measuring total white blood cell count was evaluated for feline, canine, equine and bovine blood samples collected into EDTA. Mean biases were -9.2% (range, -12% to -6.3%) for feline samples, 20.2% (range, 15.3-25.1%) for canine samples, -7.1% (range, -8.3% to -5.9%) for equine samples, and 0.7% (range, -1.1% to 2.5%) for bovine samples. The results were influenced by the presence of nucleated red blood cells. The POCD provided precise, reliable data for feline, equine and bovine samples but the values obtained for the canine counts were overestimations.
Evaluation of the automated hematology analyzer Sysmex XT-2000iV™ compared to the ADVIA® 2120 for its use in dogs, cats, and horses: Part I–precision, linearity, and accuracy of complete blood cell count. The automated laser-based hematology analyzer Sysmex XT-2000iV™ providing a complete blood cell count (CBC) and 5-part differential has been introduced in large veterinary laboratories. The aim of the current study was to determine precision, linearity, and accuracy of the Sysmex analyzer. Reference method for the accuracy study was the laser-based hematology analyzer ADVIA® 2120. For evaluation of accuracy, consecutive fresh blood samples from healthy and diseased cats (n = 216), dogs (n = 314), and horses (n = 174) were included. A low intra-assay coefficient of variation (CV) of approxim...
Virus-specific CD8⁺ T-cells detected in PBMC from horses vaccinated against African horse sickness virus. African horsesickness (AHS) is an infectious but noncontagious viral disease affecting all species of Equidae. The recall immune response of AHSV naïve horses immunised with an attenuated African horsesickness virus serotype 4 (AHSV4) was characterised using immune assays including ELISPOT, real-time PCR (qPCR) and flow cytometry. The recall immune response detected in PBMC isolated from three inoculated horses showed an upregulation of circulating B lymphocytes that correlated with elevated IL-4 mRNA expression indicative of humoral immunity, but reduced frequency of CD4⁺ cells. In additio...
Influence of transportation on serum concentrations of acute phase proteins in horse. The modifications of Haptoglobin (Hp), Serum Amyloid A (SAA), Fibrinogen (Fbg) and White Blood Cells (WBCs) were evaluated in 15 Saddle Italian horses. Ten horses were transported covering a distance of about 320 km within 4 h with an average speed of 80 km/h (experimental group) and five horses were not subject to transportation (control group). Blood was collected via jugular venipuncture before the transportation (T0), immediately after the transportation (T1), 12 (T12), 24 (T24) and 48 (T48)hours after the transportation in experimental group and at the same time point in control group. Fo...
Systemic inflammation and priming of peripheral blood leukocytes persist during clinical remission in horses with heaves. To compare innate immune responses of peripheral blood leukocytes from healthy and asymptomatic heaves-affected horses. Methods: Heaves-affected horses (n=5-6) and healthy controls (n=4-5) kept under low dust environments (pasture or shavings and pellets). Methods: Blood neutrophil and neutrophil-depleted cell populations were isolated using MACS system. Cells were incubated with or without bacterial products (lipopolysaccharide (LPS), 100 ng/mL and fMLP, 5 ng/mL, 5 h). Cytokine (IL-1β, IL-8, TNF, IL-4, INFγ and IL-10) and receptor (TLR4) mRNA expression was assessed by qPCR. TNF concentrati...
Synovial fluid chondroitin sulphate indicates abnormal joint metabolism in asymptomatic osteochondritic horses. Alternative methods to evaluate the joint condition in asymptomatic osteochondrosis dissecans (OCD) and other joint diseases may be useful. Objective: To investigate possible changes in synovial fluid composition that may lead to joint conditions in asymptomatic OCD, in mature horses. Methods: Animals aged >2 years, of different breeds, with OCD in the intermediate ridge of distal tibia, symptomatic or not, were studied. Synovial fluid samples (10 healthy; 11 asymptomatic OCD; 25 symptomatic OCD) were collected by arthroscopy from 29 horses. Glycosaminoglycans (GAGs) were analysed by a comb...
Immunological correlates of vaccination and infection for equine herpesvirus 1. Equine herpesvirus 1 (EHV-1) induces a variety of disease manifestations, including respiratory disease, abortions, and myeloencephalopathy. Several vaccines are commercially available but could not previously be distinguished by serologic testing from infection with EHV-1 (or the closely related EHV-4). Currently available vaccines are not reliably protective against the severe manifestations of the disease, including fatal myeloencephalopathy. We determined immunological parameters that can differentiate vaccinated from previously infected animals by comparing humoral and cellular EHV-1-spec...
Distal aortic aneurysm presumed to be secondary to an infected umbilical artery in a foal. A 3-month-old female Warmblood foal was presented after displaying signs of colic with pyrexia for 5 days. Results: The foal continued to show signs of colic, frequently passed urine, and was pyrexic with an elevated white blood cell count. The umbilical stalk was thickened but there was no evidence of purulent material. Exploratory laparotomy revealed an enlarged left umbilical artery remnant tightly adhered to the bladder wall. The left umbilical artery continued to an aneurysm involving the distal aorta. The foal was subject to euthanasia and post-mortem examination confirmed a spherical ao...
Neutrophil function of neonatal foals is enhanced in vitro by CpG oligodeoxynucleotide stimulation. Rhodococcus equi is an intracellular bacterium that causes pneumonia in foals and immunocompromised adult horses. Evidence exists that foals become infected with R. equi early in life, a period when innate immune responses are critically important for protection against infection. Neutrophils are innate immune cells that play a key role in defense against this bacterium. Enhancing neutrophil function during early life could thus help to protect foals against R. equi infection. The objective of our study was to determine whether in vitro incubation with the TLR9 agonist CpG 2142 would enhance d...
Oral rosmarinic acid-enhanced Mentha spicata modulates synovial fluid biomarkers of inflammation in horses challenged with intra-articular LPS. A biological extract of high-rosmarinic acid mint (HRAM) has previously demonstrated inhibitory effects on lipopolysaccharide (LPS)-induced prostaglandin E(2) (PGE(2)), nitric oxide (NO) and glycosaminoglycan (GAG) release in vitro. This study was undertaken to determine whether HRAM added to feed produces similar effects in horses challenged with intra-articular LPS. Eight horses received HRAM (0 or 28.1 ± 1.3 g/day; n = 4 per group) in their feed for 24 days in a blinded manner. On day 21, all horses received an intra-articular injection of LPS (0.3 ng) into their left or right intercarpal ...