Topic:Leukocytes
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.
Increased acidophilia of eosinophil granules after EDTA treatment. The acidophilic reaction of eosinophil leucocyte granules from human, pig and horse blood smears was investigated by using May-Grünwald-Giemsa staining after previous treatment with EDTA and sodium citrate solutions. The same peak at 530 nm, but absorption values considerably higher than those of controls, were found in eosinophil granules after application of chelating agents, indicating that removal of metal cations could unmask basic groups in these structures.
Diurnal changes in the hematological indices in the blood of racing Arabian horses. In 8 stallions and 6 mares of pure Arabian horses the diurnal changes in the number and certain parameters of red and white blood cells were studied. All of them showed distinct diurnal changes but they did not fulfill the conditions of circadian rhythm according to Halberg. It was found that most of peaks occurred during the dark phase of 24 hr period except the percentage of eosinophils, erythrocyte diameters and cell rate sedimentation. The majority of indices studied showed the higher mean diurnal levels in the mares than in the stallions.
Equine sarcoid: BCG immunotherapy compared to cryosurgery in a prospective randomised clinical trial. A total of 30 horses with single or multiple sarcoid tumors of the skin were randomly divided into three treatment groups: (i) cryosurgical treatment, (ii) intralesional immunotherapy with a live BCG vaccine, (iii) intralesional immunotherapy with a BCG cell wall preparation. Complete tumour regression was obtained in all 10 cryosurgically treated horses, in 6 of 10 live BCG treated horses, and in 7 of 10 BCG cell wall treated horses. One live BCG and 2 BCG cell wall treated horses showed partial tumour regression of more than 50% of the tumour area. Eleven horses with sarcoid tumours were not...
Comparison of specificity of human and horse leucocyte proteinases with synthetic peptide substrates. Highly purified horse leucocyte proteinases 1, 2A and 2B hydrolyze synthetic substrates which are decomposed also by human leucocyte elastase but they are unable to hydrolyze typical substrates of cathepsin G. Thus in distinction to other mammalian species horse leucocytes are devoid of cathepsin G and contain only elastases.
Lysosomal arylsulfatases A and B from horse blood leukocytes: purification and physico-chemical properties. Lysosomal arylsulfatases A and B (aryl-sulfate sulfohydrolases, EC 3.1.6.1) from horse leukocytes were purified about 680-fold and 70-fold, respectively, starting from a crude extract of the azurophil and specific granules of leukocytes, by affinity, ion exchange, and gel filtration chromatography. Purified arylsulfatase A displayed anomalous kinetics, a pH optimum at 5.2, an isoelectric point at 4.3, and a Km value for p-nitrocatechol sulfate (pNCS) of 0.37 mM. This enzyme was found to exist in two association states depending on pH: a high molecular weight form at pH 5.0 and a low molecular ...
[Normal values of the hematological, biochemical and enzymological indices of the donkey]. Studied were a total of 85 (33 male and 52 female) donkeys of the Martina Franca breed of the domestic ass, aged from one to twelve years. Stated are the results for the normal values of hemoglobin, hematocrit, ESR, total erythrocyte and leukocyte counts, leukocyte formula, blood sugar, cholesterin, urea, total protein and protein fractions, some micro- and macroelements, and enzymes as tabulated in four diagrams. No differences have been established with regard to sex. It has been found that with young animals the normal values of hemoglobin and erythrocytes are lower than with adult ones. Wi...
Equine leukocyte antigens: relationships with sarcoid tumors and laminitis in two pure breeds. Frequencies of equine leukocyte antigen distribution were determined by complement-mediated cytotoxicity testing among populations of Thoroughbred and Standardbred horses, including animals affected with equine sarcoid and laminitis. A highly significant association is described between the presence or history of sarcoid lesions in Thoroughbreds and the expression of the major histocompatibility complex (MHC)-encoded antigens, W3 and B1. No association was found between antigenic expression frequencies and laminitis in either breed. These findings suggest that a strong relationship exists betw...
The interaction between some serine proteinases and horse leucocyte inhibitor. Horse blood leucocyte cytosol exhibits a broad inhibitory activity against serine proteinases. The purified inhibitor was exposed to investigated enzymes (trypsin, chymotrypsin, elastases and serine proteinase from S. aureus) for variable time and the products were analyzed by gradient polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate. The molar ratio I:E, association rate constants k on and inhibition constants Ki for the enzymes and inhibitor were determined. The examined elastases form stable, stoichiometric complexes with the inhibitor (Ki less than 10(-10) M), ...
Effects of horse and fetal calf serum on the expression of tumor-associated antigen and tumorigenicity of L5178Y leukemia/lymphoma cells. A tumor antigen (TA) associated with murine leukemia-lymphoma L5178Y cells has been identified by the enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence (IIF) techniques. The antigen was present in both non-solubilized and 0.5% NP-40 solubilized membrane extracts. Rabbit anti-L5178Y lymphoma serum (RALS), extensively absorbed with normal mouse tissues, identified TA in extracts of L5178Y lymphoma and L5178Y leukemia cells grown in horse serum (L5178Y/HS), but not in extracts of L5178Y cells grown in fetal calf serum (L5178Y/FCS). Similarly, absorbed rabbit anti-L5178Y/HS...
Opsonization of bacteria by uterine secretions of cyclic mares. Uterine flushings collected from mares before and after bacterial-induced inflammation were assayed for ability to opsonize Streptococcus zooepidemicus for phagocytosis by polymorphonuclear leukocytes. Opsonization was measured as the peak phagocytic rate of bacteria preincubated with uterine flushings relative to the peak phagocytic rate of unopsonized bacteria. Flushings from four mares with noninfected uteri were unable to opsonize bacteria regardless of whether uteri were flushed at estrus or on day 10 postovulation. In a second experiment, 7 X 10(9) live S. zooepidemicus were inoculated i...
Effect of intra-articular gentamicin sulfate on normal equine synovial membrane. Gentamicin sulfate (3 ml; 50 mg/ml) was administered intra-articularly into 30 normal equine radiocarpal joints after arthrocentesis. Arthrocentesis alone was performed on 10 normal radiocarpal joints. Synovial fluid evaluations and gross and microscopic examinations were performed on synovial fluid and synovial membrane of designated joints at selected daily intervals over a period of 10 days. Synovial fluid from gentamicin-injected joints had greater turbidity, higher RBC and WBC counts, and higher refractive indices than did joints not injected with gentamicin. The largest increases develop...
Mononuclear phagocytes of transport-stressed horses with viral respiratory tract infection. Twelve horses comprised 3 treatment groups; all horses in 2 of the groups had recently been transported and had clinical and laboratory evidence of respiratory tract infection, with equine influenza type 2 virus being the principal pathogen. Mononuclear phagocytes and other leukocytes from blood, lung, and peritoneal cavity were studied in phagocytosis and erythrocyte-antibody (EA) rosette assays. Total numbers of pulmonary alveolar macrophages were increased over control values in bronchoalveolar lavage (BAL) fluid of group 3 horses after recovery from influenza (P less than 0.02), whereas th...
Experimental reactivation of equid herpesvirus 1 (EHV 1) following the administration of corticosteroids. Eight ponies were experimentally infected with equid herpesvirus 1 (EHV 1) (subtype 1). All animals showed clinical and serological evidence of infection and virus was isolated from nasal swabs and leucocytes. These ponies were kept in isolation for a further three months during which time complement fixing antibody decreased at least four-fold. Following immunosuppression with dexamethasone and prednisolone subtype 1 virus was recovered from six of the eight animals within 14 days. Five of these six ponies were viraemic and three of them shed virus in nasal secretions; only four displayed sig...
Causative ehrlichial organisms in Potomac horse fever. An ehrlichia was consistently isolated from the peripheral blood leukocyte fraction of ponies that had been experimentally infected with Potomac horse fever by whole blood transfusion from naturally infected horses. The organism was propagated in a human histiocyte cell line for 3 to 5 weeks and then inoculated intravenously or intradermally into healthy adult ponies. Clinical signs of Potomac horse fever, which varied in the degree of severity, occurred 9 to 14 days post-inoculation in all of the ponies. One pony died 20 days post-inoculation. The ehrlichial organism was reisolated in the hum...
Phagocytic and killing capacities of uterine-derived polymorphonuclear leukocytes from mares resistant and susceptible to chronic endometritis. The host defense competence of uterine-derived polymorphonuclear leukocytes (PMN) from mares considered resistant (grade I uteri) and susceptible (grade III uteri) to chronic endometritis was evaluated for phagocytic and killing (bactericidal) capacities, using a fluorochrome assay. Peripheral blood PMN from noncategorized mares and from grade I and grade III mares were used as controls. Uterine-derived PMN from mares with grade I uteri were functionally competent for phagocytosis and killing of Candida albicans, whereas uterine-derived PMN from mares with grade III uteri had significantly les...
Equine leucocyte antigen system: progress and potential. Leucocyte antigens are cell-surface glycoproteins, the structure of which is under the genetic control of a chromosome region called the major histocompatibility complex. Progress in the study of the equine leucocyte antigen (ELA) system has been achieved in two ways; first by the fact that the ELA system is intensively investigated in different laboratories all over the world and parallels can be drawn to the information gained from research in more extensively studied species, and secondly by the collaborative efforts of the participants in three international workshops. The potential applic...
Equine leucocyte antigens in sarcoid-affected horses. The distribution of equine leucocyte antigens (ELA) in horses affected by equine sarcoid tumours was determined and compared with unaffected controls. ELA-haplotype W3,B1 occurred more frequently in affected riding horses of Irish, Swiss and French background. The combined data for the three breeds resulted in a chi 2 value of 20.35 (P less than 0.0005 after correction). Simultaneously, ELA-specificity W11 was more frequently found in horses of Irish background, while W5 was found in Swiss and French horses with sarcoids. The combined data for haplotype W3,B1 and/or W5 specificity demonstrated...
Functional and biochemical characterization of immunologically derived equine platelet-activating factor. Antigen-specific challenge of equine leukocytes induced the non-lytic release of a platelet-activating factor in vitro. The equine platelet-activating factor stimulated the release of serotonin from equine platelets in a dose-responsive manner, independent of the presence of cyclo-oxygenase pathway inhibitors such as indomethacin. Rabbit platelets were also responsive to equine platelet-activating factor. The release of equine platelet-activating factor was a rapid reaction with near maximal secretion taking place in 30 seconds. Addition of equine platelet-activating factor to washed equine pl...
Use of 111In-labeled autologous leukocytes to image an abdominal abscess in a horse. Indium 111-labeled autologous leukocytes were used to image an abdominal abscess in a horse with a palpable abdominal mass and history of Streptococcus equi infection. A focal area of radioactivity was identified in the location corresponding to the abscess. Imaging of this focal uptake was optimal 48 hours after injection. Similar scans obtained in 2 clinically normal horses revealed no evidence of focal radioactivity in this region. The cell labeling procedure gave acceptable labeling efficiency (87.5%) but an excessive number of damaged WBC, resulting in persistent lung radioactivity on all...
Alterations in coagulation and hemograms of horses given endotoxins for 24 hours via hepatic portal infusions. This experiment was designed to establish a model for the study of gastrointestinal disturbances as a result of prolonged endotoxin uptake in the horse. The hepatic portal vein of 7 horses was catheterized (through flank incisions) to give chronic hepatic portal infusions of lipopolysaccharide (LPS, endotoxin). Lipopolysaccharide was infused at a rate of 1 microgram/kg of body weight/hr for 24 hours. Two of the horses were infused with saline solution for 12 hours before LPS infusions were given. Lipopolysaccharide was shown to affect behavior and hematologic and coagulation values. The 1st ho...
Comparison of peripheral blood and uterine-derived polymorphonuclear leukocytes from mares resistant and susceptible to chronic endometritis: chemotactic and cell elastimetry analysis. The functional competence of peripheral blood and uterine-derived polymorphonuclear leukocytes (PMN) from 12 mares were analyzed for chemotactic responsiveness using a chemotactic chamber (filter) assay and for deformability by cell elastimetry analysis. Peripheral blood PMN obtained from control mares and from 8 mares experimentally inoculated via the uterus with 1 x 10(9) Streptococcus zooepidemicus had similar normal chemotactic responsiveness and were highly deformable before and at 12 hours after inoculation. Uterine PMN obtained 12 hours after uterine inoculation with S zooepidemicus fro...
Flunixin meglumine attenuation of endotoxin-induced damage to the cardiopulmonary vascular endothelium of the pony. Endotoxic shock was induced in 5 ponies by intraperitoneal injections of 20, 40, 60, 80, and 80 micrograms of Escherichia coli endotoxin (LPS)/kg of body weight at 0, 6, 12, 18, and 24 hours, respectively. At 24 hours, the ponies also were given 20 micrograms of LPS/kg via catheter in the left ventricle of the heart. A 2nd group of 4 ponies was given 1.1 mg of flunixin meglumine (FM)/kg, IV, at 6, 12, 18, and 24 hours just before the corresponding LPS injection. Two hours after the 24-hour LPS injection, the ponies in both groups were anesthetized, the lungs were perfused with fixative, and po...
Quantification of unscheduled DNA synthesis in mononuclear leukocytes of the horse. This study compares the relationship between N-acetoxy-2-acetylaminofluorene (NA-AAF) and u.v. induced unscheduled DNA synthesis (UDS) and their respective relationships to age and blood pressure in horse mononuclear leukocytes with earlier, similar investigations on human leukocytes. U.v. induced UDS was found to proceed more rapidly than NA-AAF induced UDS. A pronounced lag period associated with the rapid demand for 3H-dThd into DNA after u.v. damage was observed. NA-AAF induced UDS correlated significantly with NA-AAF binding, age and the blood pressure of male horses. UDS values, induced ...
Horse leucocyte proteinase-inhibitor system. Kinetic parameters of the inhibition reaction. Horse leucocyte neutral proteinase inhibitor reacts with all tested elastases at the molar ratios of 1:1 and yielding stable complexes (Ki = 10(-10) M). The above reactions are very rapid, characterized by the high values of association rate constant kon = 10(7) M-1s-1.
Seasonal changes in the white blood cell system, lyzozyme activity and cortisol level in Arabian brood mares and their foals. In 34 pure-breed Arabian horses divided into four groups (Gr. I, ten pregnant mares; Gr. II, seven barren mares; Gr. III, ten foals born in 1981; Gr. IV, seven foals born in 1982) seasonal changes in the white blood cell system, cortisol level and lyzozyme activity were studied. Seasonal periodicity was found in all groups for the number of lymphocytes, segmented neutrophils and eosinophils and cortisol level. Leukocyte periodicity was found in three groups, but not in the barren mares. In lyzozyme activity there was periodicity in three groups but not in the youngest foals. In the stab neutro...
Endotoxin-induced eicosanoid production by equine vascular endothelial cells and neutrophils. 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...
Neutrophilic leukocyte structure and function in domestic animals. Differences in neutrophil morphology between various species of domestic animals are evident when morphometric techniques are used. Morphometric analysis can be coupled with functional assays of degranulation to demonstrate changes in granule volume after neutrophil activation (Bertram and Jensen, 1984). Morphometric and functional analysis of the neutrophil can also be used to evaluate the response of neutrophils to infectious agents (Coignoul et al., 1984a). Comparison of these assays between animal species may provide insight into the susceptibility of animals to various microbial pathogens...
Endotoxin-induced hematologic and blood chemical changes in ponies: effects of flunixin meglumine, dexamethasone, and prednisolone. To evaluate the effect of certain drugs on hematologic changes, blood chemical values, and survival in endotoxin shock, anesthetized ponies were given (IV) endotoxin (Escherichia coli O55:B5) and then treated as follows: Group A ponies--given a saline infusion at 5 minutes and at 3 hours after they were given endotoxin; group B ponies--given flunixin meglumine at 5 minutes and at 3, 6, 9, and 24 hours after they were given endotoxin; group C ponies--treated with dexamethasone; and group D ponies--treated with prednisolone at 5 minutes and at 3, 9, and 24 hours after they were given endotoxin. ...
A new surface marker on equine peripheral blood lymphocytes. II. Characterization and separation of purified blood lymphocytes with receptors for Helix pomatia A hemagglutinin (HP). In a preceding report we have shown that the lectin Helix pomatia A hemagglutinin (HP) binds to two subpopulations of neuraminidase-treated equine peripheral blood lymphocytes (PBL), constituting about 20% and 75% of PBL, respectively. The aim of the present study was to further characterize these HP+ cells in regard to other surface markers such as receptors for guinea pig erythrocytes (GPR+ cells), membrane-bound immunoglobulins (sIg+ cells), receptors for activated complement (C3R+ cells) and receptors for IgG (Fc alpha R+ cells). This was done by double marker analysis and by lymphocyte fr...
Flunixin inhibits prostaglandin E2 production in equine inflammation. A model of acute inflammation was used in a cross-over study in Welsh mountain ponies to assess the actions of flunixin meglumine on selected components of a localised inflammatory reaction induced by injecting 0.5 ml of a 2 per cent carrageenin solution into subcutaneously implanted tissue cages. Samples of exudate were harvested at predetermined times between three and 48 hours. Increases in leucocyte numbers and protein concentration were not prevented by flunixin treatment. Prostaglandin E2-like activity was present in exudates from untreated ponies with the highest mean concentration occu...