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Topic:Immune System
The immune system in horses is a complex network of cells, tissues, and organs that work together to protect the body from pathogens, such as bacteria, viruses, and parasites. This system includes both innate and adaptive immune responses, which function to identify and eliminate foreign invaders. The innate immune response provides an immediate, non-specific defense, while the adaptive immune response involves a more targeted and long-lasting protection through the production of antibodies. Key components of the equine immune system include white blood cells, such as lymphocytes and macrophages, as well as various signaling molecules like cytokines. This page compiles peer-reviewed research studies and scholarly articles that explore the structure, function, and regulation of the immune system in horses, with an emphasis on understanding its role in maintaining equine health and its response to diseases.
Cellular aspects of inflammation. The Ciba-Geigy Prize for Research in Animal Health. The migration of leucocytes to sites of acute and chronic inflammation is an event of central importance to the maintenance of inflammatory processes; extravascular leucocytes are responsible for generating chemical mediators of inflammation and the phagocytosis of particulate matter. They may also be involved in the conversion of acute to chronic inflammatory lesions. Leucocytes are attracted to sites of tissue injury by a range of chemoattractants. This paper describes the development of a method for separating on Percoll gradients purified populations of equine polymorphonuclear and mononuc...
Effect of povidone-iodine on in vitro locomotion of equine neutrophils. Incubation of equine neutrophils with povidone-iodine solutions of greater than or equal to 0.2 per cent resulted in total inhibition of migration under agarose. This was caused by the cytotoxic effects of the solutions as shown by pyknosis and cell lysis. Lower concentrations of povidone-iodine, however, did not adversely affect neutrophil viability or locomotion.
Phagocytic function of equine neutrophils exposed to Mycoplasma felis in vitro and in vivo. Neutrophils were isolated from the peripheral blood of adult equids (group 1) and were purified on a density gradient of polyvinylpyrrolidone-coated silica gel. A bactericidal assay was developed, using an equine skin isolate of Staphylococcus epidermidis as target bacterium in medium containing pooled fresh equine serum for opsonization. Significant (P less than 0.05) killing was observed after 60 or 120 minutes' incubation. Reduction in bactericidal function of blood neutrophils was not found after incubation with a virulent strain of Mycoplasma felis for 30 or 60 minutes. Similarly, the fun...
[Endometrial cups in horses]. Endometrial cups in horses are outgrowths appearing in the uterine wall of the pregnant horn between approximately 38 days and 150 of gestation. The cups are structures which vary in shape from oval to irregular and have distinct raised edges, showing an ulcer-like form. The maximum measurements are approximately 5 X 2.5 X 2.5 cm. Microscopic examination shows that they consist of large epithelioid decidual-like cells having large nucleoli. Pregnant Mare Endometrium Gonadotrophin (PMEG) is produced in the endometrial cups. PMEG may be regarded as a precursor of Pregnant Mare Serum Gonadotrophi...
Influence of administration of ovarian steroids on the function of neutrophils isolated from the blood and uterus of ovariectomized mares. The function of blood and uterine luminal neutrophils from ovariectomized mares treated with ovarian steroids was investigated 18 h after intrauterine infusion of 1 X 10(9) Streptococcus zooepidemicus. Random migration of blood neutrophils under agarose was reduced by treatment with progesterone compared with that of neutrophils from oestradiol-treated and control mares. In-vitro addition of progesterone to blood neutrophils from acyclic ponies also reduced migration. Uterine neutrophils did not migrate under agarose which was probably an effect of bacterial phagocytosis. Hormone treatment had...
Effect of ovarian hormones on promotion of bactericidal activity by uterine secretions of ovariectomized mares. The bactericidal and phagocytic activities of blood neutrophils suspended in uterine washings and the mobilization of neutrophils into the uterine lumen were studied in ovariectomized mares receiving oestradiol benzoate (N = 4), progesterone (N = 4) or oily vehicle (N = 4). Uterine lavage was performed sequentially up to 144 h after induction of endometritis by intrauterine infusion of glycogen (1%). There was no significant difference between the 3 groups in speed of mobilization of neutrophils into the uterus in the first 6 h after infusion but there were significantly more uterine luminal n...
Serological study of leptospiral infections and endogenous uveitis among horses and ponies in the United Kingdom. The prevalence of antibody titres to a range of 20 leptospira antigens in the serum of horses and ponies with no ophthalmic abnormalities and with ophthalmoscopic evidence of endogenous uveal inflammatory disease was determined using a microscopic agglutination technique. Titres against leptospira antigens were observed in 13 out of 138 (9.1 per cent) animals with no ophthalmic abnormalities, and in three out of 27 (11.1 per cent) animals with anterior uveitis. Serovar sejroe was common to all seropositive animals with anterior uveitis. The results show that leptospira infection is not a major...
Inhibition of equine neutrophil chemotaxis and chemokinesis by a Taenia taeniaeformis proteinase inhibitor, taeniaestatin. Taeniaestatin, a recently isolated Taenia taeniaeformis proteinase inhibitor, was used to inhibit equine neutrophil migration. Taeniaestatin itself was not chemotactic when used as a chemotactic factor but taeniaestatin did inhibit neutrophil chemokinesis when tested in a Zigmond-Hirsch checkerboard assay. A dose-dependent inhibition of both chemokinesis and chemotaxis was observed when zymosan activated bovine sera (ZABS) was used as the chemotactic factor. This inhibition was greater than 95% when 5 mu of taeniaestatin was present on both the cell and chemotactic factor side of the chambers....
Hybridoma cell lines secreting monoclonal antibodies against equine infectious anemia virus. A monoclonal anti-equine infectious anemia virus (anti-EIAV) antibody (1B15) has been generated by fusion of X63 Ag 8.653 myeloma cells and spleen cells from mice hypersensitized with viral antigen p29. Ouchterlony double-diffusion analysis indicated that antibody 1B15 is of the IgG class. The specificity of the immune reaction for p29 was confirmed by cross-over immunoelectrophoresis and disc-gel electrophoresis. MAb 1B15 was used to devise a solid-phase 'capture' RIA for EIAV-p29 antigen. The antigen, bound by 1B15 adsorbed onto wells of flexible microtitre plates, was detected using a rabbi...
Immune-mediated hemolytic anemia and thrombocytopenia in a foal. A one-month-old Quarter Horse filly had unilateral epistaxis, hyphema, icterus, petechial hemorrhages in the oral, nasal, conjunctival, and vulvar mucous membranes, anemia, thrombocytopenia, negative antinuclear test result, and a positive direct Coombs' test result. Megakaryocytes or cell-associated IgG (fluorescent antibody and immunoperoxidase stains) were not found in bone marrow biopsy specimens. Treatment consisted of glucocorticoids, antibiotics, and a single whole blood transfusion. The foal responded well to treatment, did not develop relapses of the disease, and was clinically normal...
Dynamics of the acute uterine response to infection, endotoxin infusion and physical manipulation of the reproductive tract in the mare. The uterine responses after the infusion of saline (PBS), a bacterial suspension, or lipopolysaccharide derived from Escherichia coli, and after stimulation of the reproductive tract were compared. All infusions provoked a response involving both serum proteins and leucocytes. Protein levels peaked within a few hours of infusion, whereas leucocyte concentration peaked later at around 6 h. Bacterial recovery from the uterus followed a similar pattern, with recovery falling dramatically by 12 h. In mares known to be susceptible to infection large numbers of bacteria were again recovered after 24...
Changes in nonspecific immunity factor in some Equidae, Camelidae and Capridae species. Plasma lysozyme activity changed during the 2 years of the investigation period. In some species (e.g. ponies and goats) there are only seasonal fluctuations with the highest levels during summer and autumn in ponies and during winter in goats. In two Camelidae species, guanacos and llamas, only, downward trends were found, whereas in donkeys, both types of changes: seasonal variations with the maximal level during autumn and an upward long-term trend were found.
Methodological issues in behavioural immunology. Sunrise over the Rincon Mountains revealed a procession of fifty horses groaning under their burden of psychologists and immunologists as a recent desert workshop got under way. The participants later sat, some rather gingerly, around a table to discuss methodological questions central to the new and sometimes embattled field variously called behavioural immunology, psychoneuroimmunology, and neuroimmunomodulation.
Evidence of a second polymorphic ELA class I (ELA-B) locus and gene order for three loci of the equine major histocompatibility complex. Two antisera, B-442 and R-2046, were produced by immunizing offspring with purified peripheral blood lymphocytes from a parent matched for the ELA-A specificity carried on the unshared haplotype. Absorption analysis demonstrated that these antisera contained at least two families of cytotoxic antibodies, one directed against antigens present on T and B cells, and a second directed preferentially against antigens present on surface Ig positive cells. Immunoprecipitation studies using these antisera demonstrated that both antisera contain antibodies specific for glycoproteins with molecular weig...
Comparison of systemic and local respiratory tract cellular immunity in the neonatal foal. Blood neutrophils from 10 Thoroughbred and 2 Pony foals were evaluated using in-vitro cellular function tests of chemotaxis, chemiluminescence, phagocytosis and intracellular killing. A comparison of the functional capacities of these cells before and 2-4 days after the ingestion of colostrum indicated an improvement in blood neutrophil chemotaxis and chemiluminescence. Bronchopulmonary lavage was carried out on 9 Thoroughbred and 2 Pony 36-h-old foals. The technique used did not require sedation or anaesthesia. Pulmonary alveolar macrophages were the predominant cell type recovered. When comp...
Chemotactic and phagocytic function of peripheral blood polymorphonuclear leucocytes in newborn foals. Chemotactic and phagocytic responsiveness of peripheral blood polymorphonuclear leucocytes (PMNLs) from 11 foals were analysed immediately after birth (pre-colostral) and at different times after colostrum ingestion. The number of foal PMNLs per microscopic field that had migrated through the filter in chemotaxis and the number of yeast particles ingested per foal PMNL in phagocytosis were significantly lower when tested with foal plasma before colostrum ingestion (chemotaxis, 2.0 +/- 0.55 (s.e.m.); phagocytosis, 0.98 +/- 0.352) than in tests 4 or more days after colostrum ingestion (chemotaxi...
Nocardia epididymo-orchitis in an immunosuppressed patient. The immunocompromised patient after organ transplantation is susceptible to unusual and life-threatening infections. We report a case of epididymitis that evolved into testicular nocardiosis after cardiac transplantation. An awareness of the potential for these infections and early diagnosis may prevent extensive morbidity in the post-transplantation patient.
Eicosanoids and equine leucocyte locomotion in vitro. The research article investigates the role of chemicals called eicosanoids, particularly prostaglandin E2 (PGE2) and leukotriene B4 (LTB4), in the movement of certain cells, polymorphonuclear and mononuclear leucocytes, during inflammation […]
Review of Corynebacterium (Rhodococcus) equi lung abscesses in foals: pathogenesis, diagnosis and treatment. Corynebacterium (Rhodococcus) equi is becoming increasingly significant as a cause of bronchopneumonia and lung abscessation in foals. The organism can survive within macrophages and may thus escape normal pulmonary defence mechanisms, particularly in immunocompromised animals. The disease has hitherto been associated with mortality rates as high as 80 per cent, partly as a result of inappropriate therapy. The selection of lipid-soluble antibiotics capable of intracellular penetration is critical for the successful treatment of C equi lung abscesses. A combination of two such antibiotics, eryt...
Preliminary characterisation of torovirus-like particles of humans: comparison with Berne virus of horses and Breda virus of calves. Pleomorphic virus-like particles have been observed by electron microscopy in the faeces of children and adults with diarrhoea. Some of these particles were approximately 100 nm in diameter and had a "fringe" of closely applied peplomers approximately 10 nm long; they closely resembled Berne virus of horses and Breda virus of calves, the two representatives of a newly proposed family called the Toroviridae. In one sample a toroidal nucleoprotein-like structure was observed within the particles. For two samples a buoyant density of 1.14 g/ml was determined by centrifugation through a sucrose de...
Immunity and potential of vaccination. This article will focus on current information available on the equine immune response to helminth parasites as it relates to acquired resistance, hypersensitivity reactions, and vaccine development.
Equine leucocyte antigen system. IV. Recombination within the major histocompatibility complex (MHC). A case of recombination between the putative class I ELA antigen series and the structure(s) governing mixed lymphocyte reactivity in an informative horse family is described. The results of serological typing, 'lysostripping' and mixed lymphocyte culture tests strongly suggest that the recombination took place between two loci and is not intragenic. An alloantigenic membrane structure, provisionally called B1, which does not belong to the known ELA series, was also involved in the cross-over. The B1 antigen resembles the class II gene products of other species in two respects: it is not prese...
Correction of equine severe combined immunodeficiency by bone marrow transplantation. A 32-day-old horse with severe combined immunodeficiency was transplanted with equine bone marrow cells in an attempt to establish immunologic responsiveness. A histocompatible, mixed-leukocyte-culture-nonreactive, sex-matched, full sibling was used as the donor. Recipient total lymphocyte count, T and B lymphocyte numbers, and response of peripheral blood mononuclear cells to phytolectin stimulation increased by 14 days following transplantation. Circulating lymphocytes exceeded 1000 cells/microliter blood by 40 days posttransplantation, and by 170 days following transplantation, T and B lymp...
Innate immunity during Equid herpesvirus 1 (EHV-1) infection. Intrinsic phagocytosis and killing of C. albicans by equine monocytes and polymorphonuclear leucocytes (PMN) was examined during Equid Herpesvirus 1 (EHV-1) (subtypes 1 or 2) and Adenovirus infections. Monocyte function increased during EHV-1 subtype 2 and Adenovirus infection. Conversely, there was an impairment of monocyte ingestion during EHV-1 subtype 1 infection which was ascribed to virus replication in peripheral blood mononuclear cells. PMN phagocytosis was not decreased in any of the infections studied. The raised levels of haemolytic complement in animals which subsequently developed...
Nitroblue tetrazolium reduction by neutrophils of newborn foals, adult horses, and a foal infected with Rhodococcus (Corynebacterium) equi. Equine neutrophil function was studied in 24 newborn foals, 10 adult horses, and a foal infected with R. equi by the quantitative nitroblue tetrazolium (NBT) reduction test. There was no difference between results in newborn foals and adult horses. A foal naturally infected with R. equi showed normal values of NBT reduction test at birth, and after the initial clinical signs, the spontaneous reduction of NBT by neutrophils was found to be remarkably increased until a week before death
[Development of autoimmune reactions in horses serving to produce antitetanus serum]. The hyperimmunization of horses with large doses of tetanus toxoid is accompanied by an increase in the levels of both specific antitoxic antibodies and autoantibodies to the tissue antigens of the liver, the spleen, the heart. The reverse relationship between the level of autoantibodies and the titer of antitoxin has been established. The authors suggest that the synthesis of autoantibodies is stimulated by the presence of antigen-antibody immune complexes in the circulating blood, as well as by the action of exo- and endopolyclonal stimulators.
In vitro bactericidal efficacy of equine polymorphonuclear leukocytes against Corynebacterium equi. Polymorphonuclear leukocytes from adult horses were separated from whole blood, using a 2-step Percoll gradient, and were tested for bactericidal function against Corynebacterium equi. Staphylococcus aureus, an organism against which equine neutrophils have proved efficacy, was a positive control. The percentage of uptake after a 15-minute preincubation of the neutrophils and bacteria in the presence of normal horse serum was also calculated. The results indicated that equine neutrophils effectively phagocytosed and killed C equi and S aureus. The percentage of uptake for S aureus (95% +/- 3%)...
