Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Neutrophils
Neutrophils are a type of white blood cell that play a significant role in the immune system of horses. They are involved in the body's defense mechanisms against infections and are typically one of the first responders to microbial invasion or tissue damage. Neutrophils function by engulfing and destroying pathogens through processes such as phagocytosis and the release of antimicrobial substances. In horses, the number and activity of neutrophils can be indicative of immune status and are often assessed in the context of infectious diseases, inflammation, and other health conditions. This page compiles peer-reviewed research studies and scholarly articles that explore the function, regulation, and clinical implications of neutrophils in equine health.
Leucocyte counts in the healthy English Thoroughbred in training. Total and differential leucocyte counts have been determined by electronic counting techniques in 474, two-to-four-year-old healthy Thoroughbreds in training. The ranges of values observed (particular those for neutrophils and lymphocytes) were narrower than previously described. Absolute and percentage lymphocyte values were significantly decreased with advancing age causing a relative increase in percentage neutrophils. The fall in absolute lymphocyte numbers was the main cause for a significant decrease in total leucocytes with age. Frequency plots for each variable showed that, with the ex...
Uterine defense mechanisms in the mare: Serum opsonins affecting phagocytosis of Streptococcus zooepidemicus by equine neutrophils. The addition of serum to uterine secretions was shown to opsonize Streptococcus zooepidemicus and significantly enhance bacterial phagocytosis by equine neutrophils. Treatment of serum by heat inactivation at 56 degrees C, EDTA treatment, and C3 consumption reduced phagocytosis and therefore demonstrated that the process was complement-dependent. The amount of C3 present in uterine secretions was measured in a series of 14 mares infected with Streptococcus zooepidemicus . Ten of the 14 mares had detectable amounts of C3; however, the C3 had been cleaved and rendered nonfunctional. The importan...
Granules of blood eosinophils are stained directly by anti-immunoglobulin fluorescein isothiocyanate conjugates. Direct staining of the granules of blood eosinophils by anti-immunoglobulin fluorescein isothiocyanate (FITC) conjugates was observed when feline blood smears were tested for presence of feline leukemia virus (FeLV) antigen by immunofluorescent antibody. When blood smears of other species including swine, horses, cattle, dogs, sheep, birds, and human beings were examined, direct staining of eosinophils by FITC conjugates was also detected. This FITC staining was restricted to eosinophils and was not observed in neutrophils, lymphocytes, and platelets. Direct FITC staining of eosinophils does n...
Phagocytosis and intracellular killing of the contagious equine metritis organism by equine neutrophils in genital secretions. Equine neutrophils were combined with contagious equine metritis organism (CEMO) or Escherichia coli in vitro in the presence of seminal plasma, uterine flushings, or Hank's balanced salt solution (HBSS). Phagocytosis and intracellular killing were estimated by bacterial culture and light and electron microscopy. With lysed neutrophils, the numbers of colony-forming units of CEMO and E coli increased in seminal plasma and uterine flushings. Numbers of CEMO decreased in HBSS. The numbers of CEMO increased more in the presence of seminal plasma than the other media. When neutrophils were in the ...
Mycoplasma felis as a cause of pleuritis in horses. Mycoplasma felis was the only organism recovered from the thoracic cavity of a horse with pleuritis. Large numbers of mildly degenerative neutrophils were in the pleural fluid. The horse developed a serologic response to M felis and recovered during hospitalization. Experimentally, a pony was inoculated in the thoracic cavity with a pure culture of the M felis isolate suspended in the pony's serum. A control pony was inoculated with serum only. Within 48 hours, the principal pony developed fever, increased respiratory rate, pleural effusion, and signs of pain. A highly cellular exudate with no...
Isolation of horse mononuclear cells, especially of monocytes, on Isopaque-Ficoll neutral density gradient. Horse mononuclear cells were separated from whole blood using neutral density gradient centrifugation on Isopaque-Ficoll. The resulting cell suspension was comparable in composition with similarly prepared human and bovine mononuclear cell preparations. The relative concentration of monocytes was increased by the use of a gradient with density lower than that originally proposed by Böyum (Böyum, A. 1968. Scand. J. Clin. Lab. Investig. 21 supple. 97:77-89). Contamination by neutrophils was limited either by using a gradient medium of lower density or by replacing Isopaque-Ficoll by Percoll-0....
Haematological response to racing and training exercise in Thoroughbred horses, with particular reference to the leucocyte response. The haematological response to racing and to fast and slow training exercise was investigated in studies involving two populations of horses which differed widely in geographical location, climatic factors and management (Newmarket and Hong Kong). The well documented elevations in erythrocyte parameters were demonstrated and changing responses in leucocyte parameters, resulting in variations in the neutrophil to lymphocyte (N/L) ratio were described. It was shown that the immediate response to the anticipation or stress of exercise was a decrease in N/L ratio in association with an increase in...
Equine complement activation as a mechanism for equine neutrophil migration in Onchocerca cervicalis infections. Extracts of Onchocerca cervicalis, an equine parasite, were incubated with radiolabeled equine neutrophils and neutrophil migration was assessed for factors derived from the parasite itself or for host-derived factors after incubation of these same parasite extracts with equine serum. No stimulus for cell migration was observed in saline extracts of adult worms, uterine microfilariae, or skin microfilariae at any dosage tested. However, after incubation of saline extracts with fresh normal equine sera a marked stimulus for neutrophil migration was observed. Ablation of this biologic activity w...
Polymorphonuclear neutrophil leucocytes of peritoneal fluid. Cells in the peritoneal fluid from 179 horses were examined in Giemsa stained preparations using light microscopy. Neutrophils were found in all samples whether transudative or exudative although their proportions varied enormously. They were well preserved in "normal" or sterile effusions and hardly differed morphologically from those seen on a peripheral blood film although hypersegmentation was commonly observed. In purulent effusions a reliable correlation was found between degenerative changes in neutrophils such as karyolysis and karyorrhexsis and the presence of toxin-producing microorg...
Isolation of equine neutrophils and analysis of functional characteristics by chemiluminescence and bacterial assays. Equine neutrophils (PMN) were isolated to greater than 99% purity by isopyknic sedimentation on coated colloidal silica particles. A cell recovery of 84.7 +/- 4.0%, with a viability of greater than 99%, was observed with this method. The isolated PMN were compared with mixed population of equine peripheral leukocytes with respect to functional integrity by chemiluminescence and bactericidal assays. There was no significant difference (P less than 0.01) observed in either assay between the isolated equine PMN and the mixed-cell populations. The methods used in both the isolation as well as the ...
Changes in blood neutrophil/lymphocyte ratio related to adrenocortical function in the horse. Blood neutrophil/lymphocyte ratio and plasma cortisol levels were measured before and after (1) the injection of adrenocorticotrophic hormone (ACTH1-24) in 8 Thoroughbreds and (2) exercise in 5 Thoroughbreds in training. Plasma cortisol levels were significantly (P less than 0.01) increased within 60 mins of injection of ACTH1-24 and immediately after exercise. The mean neutrophil/lymphocyte ratio altered significantly (P less than 0.01) at 240 mins after ACTH1-24 administration and at 180 mins after a training gallop. A transient lymphocytosis occurred following exercise.
Mononuclear phagocytes of peritoneal fluid. Cells in the peritoneal fluid from 179 horses were examined in Giemsa stained preparations using light microscopy. Mononuclear phagocytes were a common cell type observed in normal fluids. In the absence of stimulation they were morphologically similar to the peripheral blood monocyte and the unstimulated mesothelial cell. In acute inflammatory effusions their proportion decreased significantly but, as the condition resolved, monocytes began to migrate into the cavity gradually becoming more numerous, transforming into larger macrophages and assuming an increasing phagocytic role. They were of...
Phagocytosis and intracellular killing of the contagious equine metritis organism by equine neutrophils in serum. Equine neutrophils were combined with Haemophilus equigenitalis (contagious equine metritis organism; CEMO) or Escherichia coli in low- and high-antibody-titer serum to evaluate the neutrophils ability to phagocytize and kill these bacteria. More E. coli than CEMO were phagocytized at each time period. After 120 min in low-antibody-titer serum, 56.3% of the E. coli and 34.3% of the CEMO were phagocytized. A total of 45% of CEMO and 74.9% of E. coli were phagocytized by 120 min when neutrophils were in high-antibody-titer serum. More than 75% of the ingested E. coli and 90% of the ingested CEMO...
Morphometry of equine neutrophils isolated at different temperatures. Equine neutrophils were evaluated ultrastructurally and by morphometric analysis. Homogeneous populations of neutrophils were isolated from peripheral blood at 4 degrees and 22 degrees C by centrifugation on two sequential Ficoll-Hypaque density gradients. Isolation procedures at both temperatures resulted in neutrophil degranulation but not cell swelling. Degranulation was more extensive in cells isolated at 22 degrees C. Isolation temperature affected the neutrophil content of secondary granules more than primary granules. A granule similar to immature specific granules of human neutrophils ...
The enzymic reduction and kinetics of oxidation of cytochrome b-245 of neutrophils. 1. The absorption coefficient of human neutrophil plasma-membrane reduced-minus-oxidized cytochrome b-245 was determined [delta epsilon (mM; 559-540 nm) = 21.6 cm-1]. 2. Neutrophil polymorphonuclear leucocytes (neutrophils) were prepared from human, ox, horse and pig blood. In each case plasma-membrane fractions were found to contain low-potential cytochrome b. When membranes from horse neutrophils were incubated anaerobically with either NADH or NADPH the cytochrome b became reduced. Prior stimulation of the cells with phorbol myristate acetate did not increase the rate or extent of cytochrom...
Chemotaxis of radiolabeled equine neutrophils. A method for the isolation of equine neutrophils was developed using metrizamide cushions. A purity of greater than 95% was routinely obtained with greater than 90% viability. These cells were radiolabeled and tested for their chemotactic response in Boyden chambers to zymosan-activated equine serum, the partially purified equine complement component C5a, and formyl-L-methionyl-L-leucyl-L-phenylalanine. The time and ionic requirements for chemotaxis of radiolabeled equine neutrophils were investigated and maximal movement was observed at 2 hours' incubation and 1.0 mM Ca and 0.5 mM Mg. Dinitro...
Effects of dexamethasone on endotoxin shock in the anesthetized pony: hematologic, blood gas, and coagulation changes. The effects of dexamethasone (1 mg/kg of body weight) on hematologic, blood gas, and blood coagulation values in anesthetized ponies during endotoxin-induced shock were evaluated. Fifteen ponies were assigned to 3 groups of 5 ponies each: group 1, anesthetized nontreated and dexamethasone-treated controls; group 2, endotoxin, nontreated; group 3, endotoxin, dexamethasone treated. The hematologic changes in this endotoxin shock model included leukopenia and hemoconcentration. Significant hematologic effects were not seen in ponies after administration of dexamethasone. However, dexamethasone tr...
Haematological changes associated with endurance exercise. Blood counts and noradrenaline estimations were performed in 14 horses competing in a 160 km endurance ride. Samples were collected before the ride, immediately after the ride. 30 minutes after the ride and the day after the ride. For statistical analysis, a group of seven horses that completed the ride at a mean speed of 234 m/minute (fast group) was compared with seven horses that completed the ride at a mean speed of 144 m/minute (slow group). Immediately after the ride the fast group of horses had higher packed cell volume, haemoglobin, neutrophils and lower lymphocyte counts than the slow...
Subcellular distribution of particle-associated enzymes in horse neutrophil leukocytes. The subcellular components of purified neutrophil leukocytes from horse blood were fractionated by isopyknic equilibration in sucrose and metrizamide gradients. Five classes of particles have been identified: dense azurophil granules containing the bulk of the lysosomal acid hydrolase and peroxidase activity (A); less dense particles, containing all the lysozyme activity, but not resolved from a second population of azurophils B, and particles of low density, biochemically characterized as a plasma membrane fraction (C). Isopyknic equilibration in sucrose disclosed a minor membrane fraction (D...
Factors affecting phagocytosis of bacteria by neutrophils in the mare’s uterus. Ten mares, 5 resistant and 5 susceptible to bacterial endometritis, were examined for differences pertaining to the efficiency of phagocytosis of bacteria by neutrophils in the uterus. An assay for chemiluminescence was used to evaluate various schemes of opsonization and relate them to phagocytic rate. 123I-labelled albumin was used to measure protein migration to the inoculated uterus. Neutrophil numbers moving to the uterine lumen were determined. Before inoculation resistant mares were found to have substances in their uterine secretions that opsonized bacteria, resulting in effective phag...
Response of the adrenal cortex to tetracosactrin (ACTH1-24) in the premature and full-term foal. The changes in plasma cortisol concentration in the immediate postnatal period were examined in 3 groups of newborn foals and the response of the adrenal cortex to exogenous ACTH1-24 (tetracosactrin) was tested in 2 of these groups. In full-term Thoroughbred and Pony foals a rise in plasma cortisol occurred between 0 and 30 min after birth, whereas no significant cortisol changes could be detected within 2 h of birth in the group of prematurely delivered foals. These differences in plasma cortisol between term and premature foals were accompanied by differences in blood pH and lymphocyte and n...
Bronchoscopy and cytological examination of bronchial secretions of horses with chronic obstructive pulmonary disease (COPD). On the basis of cytological similarities in chronic obstructive disease (COPD) in human beings and in horses during 1981 a total number of 144 horses with COPD were examined. Bronchial secretions were taken under endoscopic control and stained with a modified Hansel staining procedure. Whereas 26 horses did not exhibit signs of allergic reactions cytologically and 94 horses showed low amounts of eosinocytes and/or mast cells in their secretion; only the secretions of 24 horses (16,67%) were characterized by fairly high contents of these allergy associated cells and low numbers of neutrophilic ...
Separation and identification of equine leukocyte populations and subpopulations. Various methods of separation and identification of major equine leukocyte populations and subpopulations were used. The purity of T and B lymphocytes separated in Sephadex anti-equine F(ab')2 columns was 87% to 99% and 83% of 97%, respectively. The purity of T lymphocytes separated in nylon-wool columns was 89% to 98%. Preparations of B lymphocytes separated in glass-bead columns were 68% to 79% pure. The presence (or absence) of surface immunoglobulin by immunofluorescence was the most consistent and reliable method for the identification of B or T lymphocytes, respectively. However, the ery...
Intravascular neutrophilic granulocyte kinetics in horses. Intravascular granulocyte kinetics in 4 healthy horses were determined with chromium-51 as the cell label. The disappearance rate of labeled granulocytes was an exponential function. Mean total blood granulocyte pool (+/- 1 SD) was 5.65 +/- 1.514 X 10(8) granulocytes/kg of body weight, of which 2.71 +/- 0.715 X 10(8) granulocytes/kg were circulating and 2.94 +/- 0.876 X 10(8) granulocytes/kg were marginated along blood vessel walls. The mean disappearance half-life (T1/2) was 10.5 +/- 1.33 hours and the mean granulocyte turnover rate was 8.84 +/- 1.495 X 10(8) granulocytes/kg/day. A granulokin...
Studies on the chromosomes and sex chromatin in the horse. This study provides accumulated data to assist the definition of karyotypes from normal and infertile horses. The normal karyotype of the horse (2n = 64) was characterized following Giemsa staining and C- banding, and 23% aneuploidy was found among chromosome counts of cells prepared from 44 clinically normal horses and 24 equine embryos. These expected variations in chromosome counts are especially important in the evaluation of potential mosaicism. Centromere staining was shown to be a valuable aid for the identification of specific chromosomes, in particular the sex chromosomes. Sex chromat...
The effects of repeated administration of Escherichia coli lipopolysaccharides to ponies. Repeated exposure of ponies in Escherichia coli endotoxin resulted in attenuation of the packed cell volume, beta-glucuronidase, capillary refill time and neutrophil responses usually accompanying endotoxin administration. An overall decrease in severity of clinical response including reduced mortality was also apparent in ponies with repeated endotoxin exposure. Modification of the febrile response was not observed in any of the experimental groups.
Evaluation of delayed hypersensitivity responses in normal horses and immunodeficient foals. Delayed hypersensitivity (DH) responses of normal and immunodeficient horses were evaluated with antigens [dinitrochlorobenzene (DNCB), keyhole limpet hemocyanin (KLH)] and phytolectins [phytohemagglutinin (PHA), concanavalin A (Con A)]. Immunologically normal horses sensitized with 5 daily applications of 2 mg of DNCB developed positive skin reactions upon challenge with 0.4 mg of DNCB. The delayed onset of the reaction and the predominately mononuclear cell infiltration at the test site indicated these were DH reactions. Normal horses sensitized with 500 microgram of KLH and challenged with ...
