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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.
Separation of mononuclear leukocytes and polymorphonuclear leukocytes from equine blood. The present study describes a two step technique for the separation of mononuclear leukocytes or mononuclear and polymorphonuclear leukocytes from whole equine blood. First, the leukocyte rich plasma was obtained by sedimentation of erythrocytes in the undiluted blood. Subsequently, separation of the different populations of white blood cells was performed by centrifugation with different gradients overlaid with the leukocyte rich plasma. The optimal separation of the mononuclear cells was obtained by the centrifugation of the leukocyte rich plasma overlaying the gradient containing 24 parts o...
Chemical mediators of anaphylaxis (histamine, 5-HT, and SRS-A) released from horse lung and leukocytes in vitro. Horses were sensitized to bovine plasma in Freund's complete adjuvant. Leukocytes, separated from venous blood, yielded histamine upon incubation with bovine plasma. Ioslated lung fragments incubated with bovine plasma liberated histamine and 5-HT, but not SRS-A. Pulmonary veins obtained from the same animals contracted to histamine, 5-HT and to antigen (Schultz-Dale reaction). Histamine and 5-HT probably contribute to immediate-type hypersensitivity in horses whereas the role of SRS-A is not proved.
A clinincal evaluation of abdominal paracentesis in the horse. This paper evaluates the usefulness of abdominal paracentesis as a diagnostic aid in abdominal disease in the horse and in particular considers whether or not it can be effectively utilised as an indication for surgical intervention in cases of colic. The results are based upon peritoneal fluid samples collected from 20 normal horses and from 20 cases of colic and peritonitis. Peritoneal fluid was collected from standing horses by inserting a bovine teat cannula into the horses abdomen through the linea alba after desensitisation of the skin on the ventral midline with local anaesthetic. Usual...
Isolation and some molecular parameters of elastase-like normal proteinases from horse blood leucocytes. 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...
Substrate specificity and modifications of the active centre of elastase-like neutral proteinases from horse blood leucocytes. Two proteinases (2A and 2B) purified from the granular fraction of horse blood leucocytes degrade casein (Km values 12.8 and 6mg/ml respectively) with maximum activity at pH 7.4 and in the presence of 2m-urea. Urea-denatured haemoglobin, fibrinogen, albumin and resorcin/fuchsin-stained elastin are digested at a slower rate. The enzymes hydrolyse synthetic substrates of elastase, N-benzyloxycarbonyl-L-alanine 4-nitrophenyl ester (Km 0.114 and 0.178 mM) and N-acetyl-tri-L-alanine methyl ester (Km 5.55 and 0.98 mM), but they do not hydrolyse synthetic substrates of trypsin, chymotrypsin and throm...
Ultrastructural observations on Ehrlichia equi organisms in equine granulocytes. The ultrastructure of the etiological agent of equine ehrlichiosis, Ehrlichia equi, was studied in equine peripheral leukocytes. The organisms occurred within membrane-lined cytoplasmic vacuoles of neutrophils and eosinophils. Ovoid, round, and rod-shaped profiles were observed. From 1 to 33 organisms were present in a thin-section profile of a cytoplasmic vacuole. Many cells contained multiple organism-containing vacuoles. The organisms had a cell wall and plasma membrane, and internally they consisted of electron-dense and lucid areas. A great variation in size was observed. The morphologica...
Acid phosphatase heterogeneity in horse neutrophil and eosinophil leukocytes. Two distinct groups of acid phosphatase containing granules were characterized in neutrophils, each group displaying different multiple forms of the enzyme. The heavy granule acid phosphatase showed a lysosomal location. A second lighter group of particles contained a thermolabile, thiol-dependent acid p-nitrophenyl and alpha-naphtylphosphatase, an enzyme clearly different from lysosomal acid phosphatase. Acid phosphatase activity from eosinophil leukocytes appeared to be totally associated with the typical eosinophil granules. On mechanical disruption of these particles, an acid phosphatase w...
[Effect of ultraviolet ray-irradiated autogenous blood on hematological indices in horses]. Comparative clinical and experimental investigations were carried out on 18 clinically normal horses. It was found that the single transfusion of in vitro UV-treated autogenous blood, following a previously described method, was tolerated well by horses and did not lead to any deviations from the normal indices. Under the effect of the treated blood there was an increase in the hemoglobin content, rise in the erythrocyte and leukocyte count with slightly expressed hyperleukocytosis and weak neutrophilia (simple regeneration of the blood). The sedimentation of erythrocytes also showed higher ra...
The influence of fetal genotype upon endometrial cup development and PMSG and progestagen production in equids. The influence of fetal genotype upon gonadotrophin (PMSG) and progestagen production in mares and donkeys during the first half of pregnancy was examined. The production of PMSG was greatly reduced in mares carrying mule conceptuses and greatly increased in donkeys carrying hinny conceptuses. Fetal genotype had no obvious influence upon progestagen production in mares, but donkeys carrying hinny conceptuses showed extremely high peripheral plasma progestagen concentrations when serum PMSG levels were elevated. Fetal genotype profoundly influences the intensity and rate of success of the matern...
Identification of multiple equine infectious anemia antigens by immunodiffusion reactions. Equine infectious anemia (EIA) cell antigens prepared from infected equine spleen, equine leukocyte cultures or a persistently infected equine dermis cell line contained at least two serologically reacting components. For convenience one component was designated as soluble antigen (SA) and the other as cell-associated antigen (CAA). The SA appeared as a single component when it was prepared from EIA virus precipitated from infectious tissue culture fluid with polyethylene glycol and ether treated but it was mixed with CAA when the source was infected cells. Cytolytic or mechanical disruption o...
Leucocyte myosin and its location in the cell. The intracellular location of the binding site of antibody against purified myosin prepared from equine leucocytes was investigated in neutrophils and lymphocytes by electron microscopy using peroxidase-labelled antibody method. The myosin extracted from equine leucocytes could bind skeletal muscle F-actin and the formed complex showed the biophysical and biochemical properties and electron microscopic appearance of actomyosin. On immunodiffusion, the leucocyte myosin formed a single precipitin line with its antibody prepared in rabbits. The antibody also formed single precipitin lines with my...
The kinetics of hematopoiesis in the light horse II. The hematological response to hemorrhagic anemia. Hemorrhagic anemia was experimentally produced in three Standardbred horses by removing approximately 63% of the red cell mass and the accompanying plasma during a three day interval. Red cell parameters were examined daily for 45 days and then weekly until termination of the experiment 250 days after production of the anemia. Leukocytes, platelets and bone marrow aspirates were examined at regular intervals for 25 days after the final phlebotomy. At 24 hours after the last bleeding, 75-selenomethionine was injected intravenously to measure the lifespan of the newly produced erythrocytes. The ...
ATPase activity and filament formation of partially purified myosin from leucocytes. Myosin was isolated from leucocytes in horse arterial blood by the same procedures used for the isolation of myosin from skeletal muscle. The Ca2+-, EDTA-, and Mg2+-ATPase [EC 3.6.1.3] activities of the protein was 0.148, 0.147, and 0.001 mumoles/min/mg, respectively, in 0.5 M KCl at pH 7.0 and 25 degrees. The Ca2+-ATPase activity decreased with decrease in the ionic strength. No difference was found between leucocyte myosin and skeletal myosin in the pH profiles of Ca2+- and EDTA-ATPases. The rate and amount of the initial burst of Pi liberation of leucocyte myosin were 0.002 mumoles/min/mg a...
The relation of infection to infertility in the mare and stallion. Many normally fertile stallions harbour bacteria in and on the genital organs. Many mares served by such stallions are unaffected by the bacteria to which they are thus exposed; however, some mares so exposed will become infected and diseased. Presumably, the genital defenses of such mares had been compromised. Strain differences in pathogenicity of bacteria do exist. Some mares affected with pyometra had irregular ovarian activity and some had normal ovarian cycles. In the former group, destruction of the endometrium many have prevented the production of endogenous luteolysin. The leukopenia ...
Effect of prednisolone on the leukocyte counts of ponies and on the reactivity of lymphocytes in vitro and in vivo. Treatment of ponies with a single dose of prednisolone markedly reduced the number of blood lymphocytes. A decrease of the number of eosinophils was also observed. In contrast, the number of neutrophils significantly increased. These profound changes were temporary and returned to the pretreatment level within 48 h. The number of monocytes did not show any of the significant changes post-prednisolone treatment. The reactivity of the blood lymphocytes of these ponies, in vitro, to stimulation with phytohemagglutinin (PHA) or streptokinase-strepto-dornase (SK-SD) was measured by incorporation of...
The kinetics of hematopoiesis in the light horse. I. The lifespan of peripheral blood cells in the normal horse. Three Standardbred horses were given 0.2 mg (1 mCi) of (75)selenomethionine intravenously and a second group of three were given 10 mCi of tritiated diisopropylfluorophosphate (0.5 mg) intravenously. Observations on labeled cells were continued for 250 days after radioselenium injection and 160 days after tritium injection. The lifespan of erythrocytes using (75)selenmethionine was 155 +/- 10 days and 148 +/- 7.8 days using tritiated diisopropylfluorophosphate. There was no significant difference at the 10% level between the lifespans, using these labels. The uptake of radioselenium into eryth...
The separation of peripheral blood cells of the horse. The peripheral blood cells from Standard bred horses were subjected to procedures which will separate equine peripheral blood cells with good precision and efficiency into red cell, leukocyte, and platelet fractions. The separated cells have normal morphology and the differential count of the separated granulocytes and lymphocytes is unchanged from that of the original sample.
Study of the one-step growth curve of equine infectious anemia virus by immunofluorescence. Primary horse leukocyte cultures were inoculated with 2 or 10 50% tissue culture infective doses (TCID(50)) of equine infectious anemia (EIA) virus per cell, and the titer of cell-associated and fluid-phase virus was determined from 1 to 72 hr postinoculation (PI). Cover slips were collected from 4 to 72 hr PI and stained for EIA viral antigen by the indirect immunofluorescent (FA) technique. Viral replication was detected after a latent period of approximately 18 to 24 hr and reached peak titers of approximately 10(4.5) to 10(6) TCID(50)/0.5 ml from 48 to 72 hr PI. The fluid phase contained 1...
Experimental infection of horses with an attenuated Venezuelan equine encephalomyelitis vaccine (strain TC-83). Ten horses (Equus caballus) were vaccinated with strain TC-83 Venezuelan equine encephalomyelitis (VEE) virus vaccine. Febrile responses and leukopenia due to a reduction of lymphocytes and neutrophils were observed in all animals. Viremias were demonstrable in eight horses, with a maximum of 10(3.5) median tissue culture infectious dose units per ml of serum in two horses. Clinical illness with depression and anorexia were observed in five horses. Neutralizing (N), hemagglutination-inhibiting, and complement-fixing antibodies to the vaccine virus were demonstrable by 5, 6.5, and 7 days, respe...
