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Topic:Lymphocytes
Lymphocytes are a type of white blood cell found in horses that are integral to the immune system. They are involved in the body's defense mechanisms against infections and other diseases. Lymphocytes are primarily categorized into T cells, B cells, and natural killer (NK) cells, each playing distinct roles in immune responses. T cells are involved in cell-mediated immunity, B cells are responsible for antibody production, and NK cells contribute to the destruction of infected or cancerous cells. The study of lymphocytes in horses includes their development, function, and response to various pathogens. This page compiles peer-reviewed research studies and scholarly articles that explore the biology, regulation, and clinical relevance of lymphocytes in equine health.
[Comparative study of six methods for lymphocyte isolation from several mammalian sources and determination of their carbohydrate composition (author’s transl)]. The present paper deals with a comparative study on six methods for isolation of peripheral blood lymphocytes from various mammalian sources: Bos taurus L. (adult cow), Equus caballus L. (adult horse), Equus asinus L. (adult and young donkeys) and Sus scropha L. (adult pig). The following systems were used: a) Filtration through sand columns (a modification of Blaszczyszyn's method); b) Sodium metrizoate and "Ficoll 400" c) "Lymphoprep"; d) "Urovison" and dextran T150 (a modification of GILI et al.'s method); e) "Urografin" and dextran T150; f) "Ficoll-Paque". The final preparation of lymphocy...
In vitro and in vivo effects of corticosteroids on peripheral blood lymphocytes from ponies. The in vitro and in vivo effects of corticosteroids on peripheral blood lymphocytes (PBL) from ponies were studied. Prednisolone inhibited lymphocyte stimulation by phytohemagglutin (PHA) in a dose-dependent manner, without inducing lysis even at large doses. The PBL from horses heterozygous for the combined immunodeficiency trait responded to corticosteroid treatment the same as did PBL from normal ponies. Removal of the corticosteroid after incubation with PBL from normal ponies partially restored responsiveness of these cells to PHA. Chronic in vivo treatment of ponies with corticosteroids ...
Microculture method for mixed lymphocyte cultures in the horse. A miniaturized method for the mixed lymphocyte culture test in the horse is described. The test is performed in either round- or flat-bottom microtitration tissue culture plates. Concentrations of responsing and stimulating cells are varied, depening on the experiment. Significant discrimination between isogeneic and allogenic mixtures is possible after 120 hours' culture when cells are labeled ([3H]thymidine) for the last 16 to 18 hours of the test.
Chronic enteritis associated with the malabsorption and protein-losing enteropathy in the horse. Chronic granulomatous enteritis associated with weight loss and hypoproteinemia was identified in 2 horses. Both horses continued to have normally formed feces. Malabsorption of carbohydrate and lipid, with concomitant gastrointestinal protein loss was demonstrated in 1 case. One horse was treated symptomatically and gained 108 kg. In both cases, principal gastrointestinal lesions were partial to total villus atrophy and transmural mononuclear leukocytosis, with lymphocytes and histiocytes predominating. The cause of the condition was not identified in either case.
Mixed lymphocyte culture responses in combined immunodeficiency of horses. Combined immunodeficiency in horses is a genetic disorder in which there is a defect in the production of committed B and T lymphocytes. In this study, peripheral blood mononuclear leukocytes from foals with combined immunodeficiency were examined for their capacity to stimulate and respond in one-way mixed lymphocyte cultures. Irradiated cells from combined immunodeficient foals were uniformly capable of stimulating cells from unrelated horses. However, none were able to respond to allogeneic stimulation. Examination of cells from known carrier horses revealed no difference in capacity to sti...
The ‘normal range’ and precision of phytohaemagglutinin-induced equine lymphocyte transformation in vitro. Data are presented on lymphocyte transformation by phytohaemagglutinin in 20 normal horses. The logarithms of transformation ratios were found to have an approximately normal distribution, giving (for the transformation ratios themselves) a geometric mean of 23.6, a range of 1.92 to 97.3, and an estimated 95 per cent tolerance interval of 1.1 to 488. Analysis of variance on the logarithms of the transformation ratios gave a coefficient of variation of 140 per cent of the transformation ratios themselves for the variation between horses; whereas the coefficient of variation between duplicate sa...
Activity of adenosine deaminase and purine nucleoside phosphorylase in erythrocytes and lymphocytes of man, horse and cattle. 1. Activities of ADA and PNP were measured in erythrocytes and lymphocytes of man, horse and cattle. 2. In bovine hemolysates both enzyme activities are low when compared with activities in human hemolysates. In horse hemolysates both enzyme activities are virtually absent. 3. Enzyme activities are consistently lower (about 50%) in intact lymphocytes than in sonicated lymphocytes. This finding suggests that the uptake of nucleosides is rate-limiting for both enzymes in intact lymphocytes. 4. The activity of ADA in horse lymphocytes is comparable to that in lymphocytes of patients with severe c...
Erythrocyte rosette formation of equine peripheral blood lymphocytes. Erythrocyte rosette (ER) formation of equine peripheral blood lymphocytes (PBL) was characterized. Guinea pig and, to a lesser extent, human erythrocytes formed ER; cat, cow, dog, hamster, mouse, rat, and sheep erythrocytes showed negligible rosetting properties. Conditions of the assay were varied to determine which procedure allowed the largest percentage of rosette formation. The PBL from 20 normal horses were then assayed, averaging 38 +/- 2% ER. To characterize the erythrocyte receptor as being on T or B cells, equine thymocytes from 6 foals were assayed; the thymocytes formed an average ...
A case of primary lymphoid leukaemia in a horse. Progressive leukaemic changes and a persistent anaemia were demonstrated in the blood of a 7 year old gelding, which had shown early signs of lowered performance and unthriftiness, and later developed dependent oedema and became dull and listless. The total leucocyte count, initially within the normal range although reflecting an absolute lymphocytosis, increased fourfold in 6 days from excessive lymphoid production involving predominantly the more immature cell types; lymphoblasts, prolymphocytes and large lymphocytes. The severity of the condition was confirmed by bone marrow biopsy.
Cell mediated immunity in equine herpesvirus type 1 infection I. In vitro lymphocyte blastogenesis and serum neutralization antibody in normal parturient and aborting mares. Blastic transformation of peripheral blood mononuclear cells and serum neutralization antibody levels for equine herpesivurs type 1 were measured in 19 mares from three farms at the time of termination of their pregnancy by normal foaling or viral abortion. The stimulation indexes of lymphocytes obtained from the mares from two farms (Farm 1 and 2) which had virus abortions, ranged from 2.1 to 10.8. But there was no significant difference in stimulation index levels between the aborting and normal foaling mares on these two farms. Equine herpesvirus type 1 was isolated from the mononuclear cel...
Human lymphocyte subpopulations: rosette formation with sheep, human and horse red blood cells. Rosette formation between human lymphocytes and horse red blood cells could be promoted by a low pH medium, overnight incubation and a temperature of 4 degrees C. The percent of sheep, horse and human rosette-forming cells in the peripheral blood were 71.7 +/- 1.8, 30.5 +/- 2.8 and 28.3 +/- 3.4 respectively. However, their percentages in thymuses were 97.1 +/- 1.1, 91.4 +/- 2.4 and 89.0 +/- 3.4. Using preparations of isolated subpopulations, it was observed that the horse and human red cell rosette-forming cells were probably also "early" sheep red cell rosette-forming cells. Rosette formation...
Alterations of the thymus and other lymphoid tissue in young horses with combined immunodeficiency. Combined immunodeficiency (CID) is a significant disease in terms of prevalence in Arabian foals and is a useful animal for study of a similar condition in children. Thymuses from all CID foals examined were extremely hypoplastic. Light and electron microscopic examination of thymuses from CID foals, as well as a thymus from an aborted CID fetus, demonstrate that the basic thymic structure is intact, despite a number of dissimilar morphologic appearances. From these data, we inferred that the thymic hypoplasia was caused by a failure of committed lymphocytes from the bone marrow to populate th...
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...
Immunity to equine herpesvirus type 1 (rhinopneumonitis): in vitro lymphocyte response. Twenty-two ponies were examined for serum-neutralizing (SN) antibody to equine herpesvirus type 1 and for in vitro lymphocyte transformation in the presence of viral antigen. Six ponies had undetectable levels of neutralizing antibody (titer less than 1:2) and had lymphocytes which did not respond in culture with viral antigen (stimulation index less than 2.0). Four ponies which had SN antibody to equine herpesvirus type 1 did not manifest lymphocyte transformation in vitro. The 12 remaining seropositive ponies had lymphocyte transformation with viral antigen in vitro (stimulation indexes from...
Preparation and immunosuppressive potency of equine anti-human thymocyte membrane IgG. Anti-human thymocyte cell membrane antibody prepared by hyperimmunization of the horse produced an antiserum capable of prolonging skin allografts in the rhesus monkey for an average of 26 days. Lymphocyte depletion was present in paracortical areas of mesenteric lymph nodes of these animals after 28 days of treatment; the intravenous administration was tolerated without ill effects. Immunofluorescent studies identified both broad specificity antibodies reacting with numerous human cell types as well as thymus-dependent (T) cell antibodies reactive with human thymocytes and peripheral T-cells....
Agammaglobulinemia in a horse with evidence of functional T lymphocytes. Agammaglobulinemia was diagnosed in a 1-year-old Thoroughbred horse on the basis of the following observations: (1) absence of serum immunoglobulins M, A, and G(T); (2) small amounts of serum immunoglobulin G (16 mg/100 ml); (3) absence of specific antibody in the serum of the horse following immunization and challenge exposure to 2 antigens; (4) absence of plasma cells, primary follicles, and germinal centers in a lymph node removed after antigenic stimulation; (5) absence of "natural" serum antibodies to rabbit-erythrocytes which were easily detectable in age-matched control horse serums; an...
Treatment of horses with chronic diarrhea: immunologic status. All chronically diarrheal horses given (orally) 2 series of treatments with normal horse serum recovered in 2 to 4 weeks. However, mild diarrhea sometimes persisted several months in the group of horses with severe diarrhea. Weight gains were approximately 35% in horses with severe diarrhea and approximately 10% in horses with mild diarrhea. Serum specimens from 12 diarrheal and 20 normal horses were examined for immunoglobulins by single radial immunodiffusion technique. Concentration of immunoglobulin A in serum of diarrheal horses was approximately 50% lower than that in serum of normal hor...
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...
Serum immunoglobulin, dermal response, and lymphocyte transformation studies in horses with chronic diarrhea. Serum specimens from 12 sick and 20 normal horses were examined for levels of different classes of immunoglobulin (Ig) by a single radial immunodiffusion. The level of IgA in the sera of sick horses was about 50% lower than in the sera of normal horses. By contrast, the level of serum IgG was higher in sick than in normal horses. Phytohemagglutinin (PHA) responsiveness of blood lymphocytes showed transient suppression during the stage of severe diarrhea. The regaining of PHA responsiveness of lymphocytes was observed simultaneously with the recovery process. However, the responsiveness of lymp...
The effect of isoprenaline on 86-Rb uptake by horse lymphocytes in vitro. The research studies the effect of a drug called isoprenaline on the intake of a radioactive isotope, 86-Rb, in horse lymphocytes. It finds that isoprenaline has a significant effect increasing [...]
Surface receptors on neutrophils and monocytes from immunodeficient and normal horses. Surface receptors on peripheral blood neutrophils and monocytes from normal and immunodeficient horses have been studied. Sheep erythrocytes (SRBC) coated with IgG, IgM, and complement but not IgG(T), readily bound to normal equine monocytes and neutrophils. More than 4000 molecules of IgG were required to sensitize each SRBC for adherence to monocytes, and more than 12,000 molecules were required for adherence to neutrophils. Young horses with a severe combined immunodeficiency had an almost total absence of lymphocytes, but normal numbers of monocytes and neutrophils. The number of receptors...
Histological development of the thymic and intestinal lymphoid tissue of the horse. The basic components of the immune system, and the defence mechanisms in the gastrointestinal tract, are briefly reviewed. Histological studies in 84 equine foetuses showed that lymphoid cells begin populating the thymic primordium at 11-12 weeks, the mesenteric lymph nodes at 13 weeks, the spleen at 25 weeks and the intestinal lamina propria at 13-14 weeks' gestation. Lymphocytes were seen in the intestinal epithelium very early in gestation. Histological signs of response to antigenic stimulation were seen in five foetuses, indicating that the horse is likely to be capable of mounting an imm...
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 pathogenesis of single experimental infections with Strongylus vulgaris in foals. The clinical signs, pathology and clinical pathology associated with single experimental infections of Strongylus vulgaris in worm-free pony foals are described. The major clinical signs which became apparent in the infected foals during the first three weeks were pyrexia, anorexia, dullness and abdominal pain. Within the first two weeks of infection lesions were confined to the intestine and terminal branches of the intestinal arteries and consisted of mucosal, submucosal and serosal haemorrhage together with arteritis of submucosal and serosal arteries and also a marked inflammatory reaction...
Detection of tumor-specific antigens in an equine sarcoid cell line. Indirect immunofluorescence and lymphocyte cytotoxicity experiments demonstrated the presence of a tumor-specific antigen(s) on the surface of cells from an equine sarcoid cell line (Mc1). Autologous serum (taken from the horse from which the Mc1 cells were derived) and sera from three other sarcoid-bearing horses revealed a similar membrane immunofluorescence when reacted with Mc1 cells, indicating the existence of cross-reacting antibodies. Results of serum colony inhibition experiments indicate that these antibodies are not cytotoxic. Incubation of Mc1 cells with autologous lymphocytes resu...
Quantitation of immunoglobulin-bearing lymphocytes and lymphocyte response to mitogens in horses persistently infected by equine infectious anemia virus. A defect in lymphocyte function could be responsible for persistent infection by the equine infectious anemia virus. The number of lymphocytes bearing surface immunoglobulin, as detected by immunofluorescence, and lymphocyte response to mitogens were the same in uninfected and equine infectious anemia-infected animals. A defect in T or B lymphocyte numbers or ability to respond to stimuli was not detected in this chronic virus disease.
