Topic:Immunology
The equine immune system is a complex network of cells, tissues, and organs that work collaboratively to defend against pathogens and maintain homeostasis. It consists of innate and adaptive components, each with distinct functions and mechanisms. The innate immune system provides the first line of defense through physical barriers, phagocytic cells, and the complement system. The adaptive immune system involves lymphocytes, such as B cells and T cells, which generate specific responses to antigens and provide immunological memory. Research in equine immunology explores the interactions between these components, the impact of genetic and environmental factors on immune function, and the development of vaccines and therapeutics. This page gathers peer-reviewed studies and scholarly articles focusing on the mechanisms, regulation, and clinical applications of the equine immune system in health and disease.
The interaction of Corynebacterium equi and equine alveolar macrophages in vitro. The in-vitro interaction of Corynebacterium equi and foal alveolar macrophages was examined qualitatively and quantitatively using cells collected by sequential bronchoalveolar lavage at 2-week intervals from birth until 14 weeks of age. Total and differential counts were performed on the recovered cells. Macrophages were identified using the non-specific esterase strain. Cultures of the alveolar macrophages were challenged with C. equi suspensions and the process and extent of ingestion was examined by light and electron microscopy. Few macrophages were recovered from the lungs of foals less ...
Preliminary characterization of equine interferons and their antiviral activities on bovine, ovine, and human cells. Equine dermal cells induced with poly I:C + DEAE-dextran produced low levels of interferon tentatively classified as equine interferon beta (EqIFN-beta). In contrast, dermal cells initially primed with EqIFN-beta and then superinduced with poly I:C + DEAE-dextran in the presence of cycloheximide and actinomycin D produced greater than 100-fold EqIFN-beta. Equine blood mononuclear cells induced with Newcastle disease virus and phytohemagglutinin produced high levels of interferons tentatively classified as equine interferon alpha (EqIFN-alpha) and equine interferon gamma (EqIFN-gamma), respecti...
Immune recognition of Echinococcus granulosus. 1. Parasite-activated, primary transformation by normal murine lymph node cells. Culture of murine lymph node cells together with living protoscolices of Echinococcus granulosus is described. The presence of the parasite induced potent blastic transformation in lymphocytes of unimmunized mice as indicated by tritiated thymidine incorporation. The response was markedly reduced by killing the parasite immediately prior to culture. No blastogenic activity was detectable in supernatants from living parasites cultured alone. Protoscolices from artificially infected syngeneic mice were effective stimuli, as were protoscolices from naturally infected horse and sheep. Stimulation ...
Immunodeficiency disease in animals. Significant contributions to understanding the role of lymphocyte subpopulations in the immune response and to the characterization of immunodeficiencies in children have been achieved through study of animal models of immunodeficiency. Additional contributions can be made in two important areas. One is through identification of relevant, naturally-occurring models of adenosine deaminase deficiency and purine nucleoside phosphorylase deficiency. The second, and potentially more important contribution, would be the identification of the metabolic basis for existing immune deficiencies. The nece...
Indirect haemagglutination reaction with Sarcocystis dispersa antigen. A description is given of the preparation of antigen from Sarcocystis dispersa cystozoites and the procedure of the indirect haemagglutination test (IHA). The antibodies against this antigen were detected in experimentally infected mice from day 20 p.i. (1: 640). In the following weeks the antibody titres reached the value of 1: 40,960. The sera of pigs, sheep and horses spontaneously infected with other Sarcocystis species reacted with this antigen in low titres only. The bovine sera gave negative reactions even in cases when Sarcocystis cysts were present in the muscles of the examined anima...
Inhibition of sperm binding to porcine ova by antibodies to equine zonae pellucidae. Sera and follicular fluid from mares previously determined as having antibodies to the zona pellucida were exposed to porcine ovarian oocytes before insemination with boar spermatozoa in vitro. There was a dramatic decline in the number of spermatozoa bound to zonae compared to treatments with sera and follicular fluid from mares negative for zona antibodies. These data suggest that antibodies reactive with the zona pellucida may be responsible for reduced or even complete infertility in some mares. In a group of 50 randomly selected mares tested for antizona antibodies, 2 pregnant mares were ...
Species specificity of estrogen biosynthesis in pregnancy. Immunochemical difference of placental NADPH-cytochrome c (P-450) reductase in human, baboon and horse. NADPH-cytochrome c (P-450) reductases from human placental aromatase II and from horse placental microsomes were solubilized and purified to show a single band of 83,000 daltons in SDS-polyacrylamide gel electrophoresis. Rabbits were immunized with purified human placental aromatase II NADPHcytochrome c (P-450) reductase. The resulting antibodies (Reduc-Ab) were used to examine the species specificity of estrogen biosynthesis and the reductase activity in humans, baboons, horses and rats. Rcduc-Ab suppressed androstenedione aromatase activity in human, baboon and horse placental microsomes wit...
Serologic and molecular comparisons of several equine herpesvirus type 1 strains. The molecular and serologic relatedness of 2 recent respiratory tract isolates of equine herpesvirus type 1, designated T1 and T2, were compared with the Army 183, Kentucky-A hamster-adapted (KyA-ha), and L-M cell-adapted (KyA-LM) strains. Electrophoresis in polyacrylamide gels revealed differences in virion structural proteins among 4 purified strains. Seven envelope glycoproteins (molecular weight of 93,000, 65,000, 62,000, 60,000, 36,000, 20,000, and 18,000) corresponding to virion proteins 13, 16, 17, 18, 23, 25, and 26a, respectively, found in both the Army 183 and KyA-ha strains had slig...
Hemagglutination-inhibition tests with different strains of equine infectious anemia virus. The serologic relationships between 6 strains of equine infectious anemia (EIA) viruses were investigated by hemagglutination-inhibition (HI) tests. Cross HI tests, using sera from horses in the early stage of infection, revealed that all strains were inhibited only by homologous strain antisera and that HI antibody was always detectable before virus-neutralizing antibody. In the later stages of infection, both homologous and heterologous HI antibodies were detected in a sera of most of the horses, and the order of appearance of heterologous HI antibodies was random in 2 horses inoculated with...
Antigenic and structural conservation of herpesvirus DNA-binding proteins. Previously, we have shown a common antigen of several herpesviruses (pseudorabies virus, equine abortion virus and bovine mammillitis virus) to be antigenically related to the major DNA-binding proteins of herpes simplex virus types 1 and 2. In this study we have purified the cross-reacting polypeptide from cells infected with pseudorabies virus, equine abortion virus and bovine mammillitis virus and shown the cross-reacting protein to be a major DNA-binding protein for each virus. Tryptic peptide analysis of the cross-reacting DNA-binding proteins of all five viruses has shown structural simi...
Equine immunology: an introductory review. This article attempts to relate some of the more recently accepted concepts of immunology to an understanding of the mechanisms of immunity in the horse. The cellular mechanisms involved in the immune response are outlined, with an indication of their likely role in humoral and cell-mediated immunity. In describing the humoral immune response, the structure and function of the different equine immunoglobulins are reviewed. The significance of humoral and cell-mediated immune responses are considered in relation to actively and passively acquired immunity.
Immunochemical and biological properties of horse parathyroid hormone. No abstract available
[Prevalence of lungworm D. arnfieldi (Cobbold 1884) in donkeys in Denmark and in horses in herds together with donkeys (author’s transl)]. During a 5 months' period from January to May 1981 faecal samples of 176 donkeys from 59 herds all over the country were examined at the Institute of internal medicine, The Royal Veterinary and Agricultural University, Copenhagen. In addition, the investigation also included 106 horses from 30 of the donkey herds and 34 horses hospitalized with symptoms of dyspnoea and chronic coughing. In all, 87.5% of the donkeys were shown to excrete D. arnfieldi larvae, often in very high numbers, and the larval excretion was the only symptom of lungworm infection. There was no significant correlation betw...
The relationship of two equine mycoplasmas to Mycoplasma mycoides. Two unidentified mycoplasmas, N3 and N11, isolated from the respiratory tract of horses, were found to cross-react with strains of M. mycoides subsp. mycoides in indirect immunofluorescence tests, growth-inhibition tests carried out by the running drop/agar-well method, and in complement-fixation and double immunodiffusion tests. Serologically, the equine mycoplasmas were not completely identical with any of the reference strains of M. mycoides with which they were compared. Their cultural characteristics, ability to digest coagulated serum and casein, and survival at 45 degrees C, however, su...
Treatment of equine phycomycosis by immunotherapy and surgery. Treatment of equine phycomycosis with a vaccine derived from ultrasonicated hyphae of Hyphomyces destruens was attempted in 30 cases of clinical hyphomycosis, 10 cases of hyphomycosis following unsuccessful surgery and 5 cases of basidiobolomycosis. Approximately 53% of animals with clinical hyphomycosis were cured after vaccination, while a further 33% clinically improved. All horses with hyphomycosis treated within 2 weeks of unsuccessful surgery were cured. There was no response to vaccination with a Hyphomyces preparation in horses with basidiobolomyucosis, while surgery alone resulted in ...
Diagnosis of eastern equine encephalomyelitis by immunofluorescent staining of brain tissue. Brain tissues were obtained from 5 horses with clinical encephalomyelitis during an epizootic in southwestern Michigan in August-September 1980. These tissues were tested for virus by intracerebral inoculation of suckling mice and by examination of frozen sections and impression smears by the indirect fluorescent antibody (FA) technique. Eastern equine encephalomyelitis virus was isolated and detected by FA technique in brains of 3 horses which died or were euthanatized within approximately 24 hours of onset of the disease but not from 2 horses at 2 and 3 days after onset. The latter 2 animals...
The interaction of equine platelet tropomyosin with skeletal muscle actin. Whereas skeletal muscle tropomyosin binds strongly to muscle F-actin in a buffer containing 30 mM KCl and 1-2 mM free Mg2+, equine platelet tropomyosin only binds stoichiometrically (1 tropomyosin molecule per 6 actin monomers) at higher Mg2+ concentrations (7-8 mM free Mg2+). At low free Mg2+ concentrations (1.5 mM) the binding of the platelet protein is only marginally increased by raising the KCl concentration to an optimal value (0.10-0.20 M). This weaker binding can be attributed to the relatively poor head-to-tail polymerization of platelet tropomyosin and its fewer actin-binding sites. ...
Antigenic analyses of tissues and excretory and secretory products from Strongylus vulgaris. Rabbit antisera were prepared against veronal buffered saline extracts of L4 and L5 Strongylus vulgaris, adult S. vulgaris and adult Strongylus equinus retrieved from naturally infected horses. In agar gel diffusion with these antisera, adult S vulgaris and S. equinus each appeared to have at least one unique antigen; larval S. vulgaris appeared to have two species-specific and two stage-specific antigens. There were several common antigens. Excretory and secretory products were collected also from L4 and L5 an maintained over several days in tissue culture fluid. In agar gel diffusion against...
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...
Contagious equine metritis: antibody response of experimentally infected pony mares. Intrauterine inoculation of pony mares with the bacterium that is the causative agent of contagious equine metritis (CEM) resulted in clinical disease. A humoral immune response could be detected by agglutination and complement fixation (CF), and in some cases precipitating antibody was found by immunodiffusion tests. Agglutinating antibody was the most reliable serological indicator of overt infection and was detected in 8 ot 28 mares after initial intrauterine inoculation of 3-4 x 10(5) bacteria. Seventy percent of mares given a second inoculation and all mares given a third inoculation of 3...
Equine influenza in the Netherlands during the winter of 1978-1979; antigenic drift of the A-equi 2 virus. Influenza virus A-equi 2(Heq2Neq2) caused an epizootic in the Netherlands in the winter of 1978-1979. Horses vaccinated with A/Equi/Praha/56 (HEq1Neq1) and A/Equi/Miami/63 (Heq2Neq2) were also infected and showed clinical signs. The virus involved showed a marked antigenic drift from the prototype and vaccine strain A/Equi/Miami/63 (Heq2Neq2). Infection of ferrets with the Dutch/79 isolates gave rise to high haemagglutination-inhibition antibody titres to a number of A-Equi 2-1963, 1968 and 1979 viruses. The incorporation of this virus into future influenza vaccines should be considered.
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...
Major histocompatibility locus in the Arabian horse. Combined immunodeficiency disease (CID) is a genetic disorder of T and B lymphocyte production which results in a nonfunctional immune system. It is inherited as an autosomal recessive trait and has been reported in humans and in horses of the Arabian breed. Arabian horses known to have the CID gene and horses of unknown carrier status were tested using a microlymphocytotoxicity technique. Computer chi 2 analysis distinguished six serologically defined specificities. The study of unrelated horses and a limited number of families showed that the specificities behave as codominant alleles segreg...
An evaluation of contribution derived from investigations of equine immunodeficiencies. Following the descriptions of immunodeficiencies in horses beginning in 1973, there has been considerable effort to develop methods for differential diagnosis and to determine the cause and prevalence of the disorders. In addition, the equine immunodeficiencies, especially combined immunodeficiency, have been studied from a comparative viewpoint with the goal of finding information applicable to similar diseases of children. Coincident with the development of knowledge about the immunodeficiencies per se, considerable information about several aspects of immunology has been obtained. It is the...