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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.
Analysis of antigenic variation in equine 2 influenza A viruses. Influenza outbreaks involving viruses of the H3N8 subtype (equine 2) often occur in vaccinated horses. For this reason, a series of influenza viruses of the H3N8 subtype were examined to determine if antigenic variation could be detected in isolates during the period 1963-81. Antigenic analyses with post-infection ferret sera and monoclonal antibodies showed that the haemagglutinins of recent isolates were antigenically distinguishable from the prototype A/eq/Miami/1/63 and that antigenically distinguishable groups of equine 2 viruses co-circulate in the horse population. Based on these studie...
Isolation and characterization of horse alpha 2-macroglobulin protease inhibitor. Several publications have described in the past properties of partly purified horse alpha 2-macroglobulin (alpha 2M) which are strikingly different from the human alpha 2M. Horse alpha 2M was therefore isolated to purity by classical procedures, i.e. affinity chromatography, ion exchange chromatography and gel filtration, and its properties are compared with those of its human counterpart. The molecular weight of the native protein and its subunits, the isoelectrofocusing pattern and the change in electrophoretic mobility caused by interaction with protease were similar to those of human alpha...
Immunochemical studies of infectious mononucleosis–XI. comparison of heterophile antibody inhibitors from the erythrocyte membranes of four mammalian species. Immunochemical comparisons were made of the reactivity of membrane glycoproteins from horse, bovine, sheep and goat erythrocytes with heterophile antibodies of infectious mononucleosis. The four receptors were tested as competitive inhibitors of a sandwich-type solid-phase radioimmunoassay and of agglutination of glycoprotein-latex reagents by infectious mononucleosis serum. The results of this study showed that the bovine glycoprotein had a superior reactivity with this heterophile antibody system and sheep erythrocyte glycoprotein was the least reactive. The latter had negligible ability to ...
Antibody moieties within circulating immune complexes in heart transplant recipients. Circulating immune complexes were isolated from the sera of cardiac allograft recipients by bovine conglutinin/anti-conglutinin co-precipitation, or by gel filtration and protein A-Sepharose affinity chromatography. The antibody moieties within these isolated immune complexes were tested for specificity against heterologous anti-thymocyte globulins by solid phase radioimmunoassay, and bacterial and viral antigens by indirect immunofluorescence. The results showed that in addition to possessing specific anti-equine anti-thymocyte globulin antibodies, immune complexes also contained cross-reacti...
Venezuelan equine encephalomyelitis virus: concentration, partial purification, inactivation and immunogenicity. Venezuelan equine encephalomyelitis (VEE) TC-84 vaccinal virus, from 10-1. quantities of infected duck embryo fibroblast cell culture fluids, was isolated by combined continuous-flow centrifugation with isopycnic banding in sucrose. Most of the recovered infectivity and hemagglutinating activity were in a single band at a buoyant density (rho) of 1.2. About 90% of the total input protein (450-520 mg) was removed with the effluent, whereas most of the remaining 10% also banded at a rho of 1.2. Infectivity was inactivated with formalin at a final concentration of 0.05% at 37 degrees C for 24 hr....
Joint report of the First International Workshop on Lymphocyte Alloantigens of the Horse held 24-29 October 1981. Six equine lymphocyte alloantigen (ELA) specificities were defined by an international antiserum comparison test and workshop held in 1981. Twelve laboratories from four countries submitted 195 antisera for analysis. The antisera were exchanged among the 12 laboratories and tested in a standard lymphocyte microcytoxicity assay against the isolated lymphocytes at 1009 horses of several breeds. The data was pooled and analysed by a single computer analysis. The calculated chi 2 values of all cells with all antisera provided comparisons between antisera. Fifteen antisera clusters were formed by t...
Structural and functional properties of the non-muscle tropomyosins. The non-muscle tropomyosins (TMs), isolated from such tissues as platelets, brain and thyroid, are structurally very similar to the muscle TMs, being composed of two highly alpha-helical subunits wound around each other to form a rod-like molecule. The non-muscle TMs are shorter than the muscle TMs; sequence analysis demonstrates that each subunit of equine platelet TM consists of 247 amino acids, 37 fewer than for skeletal muscle TM. The major differences in sequence between platelet and skeletal muscle TM are found near the amino and carboxyl terminal ends of the proteins. Probably as the re...
Pyrimidine metabolism in peripheral and phytohemagglutinin-stimulated mammalian lymphocytes. 1. Activity of uridine kinase was very low in ovine lymphocytes and in those of some pigs. Lymphocytes of other pigs showed a significantly higher activity of this enzyme. Activity of uridine kinase in lymphocytes of man, horse and cattle was intermediate. 2. Activity of uridine phosphorylase was higher than that of uridine kinase with lymphocytes of all species. 3. Activity of uridine kinase in equine lymphocytes increases at PHA-stimulation and also in porcine lymphocytes with a low activity at the start of the culture. Activity of uridine kinase decreased in porcine lymphocytes with a high ...
Streptokinase-dependent delayed activation of horse plasminogen. Complete activation of purified horse plasminogen to plasmin was obtained with a 1:10 molar ratio of streptokinase to plasminogen after 5 min of incubation at 37 degrees C. At a 1:1 molar ratio, maximal activity did not appear until 15-30 min, while at a ratio of 6:1 complete activation was delayed for 120-180 min. Gel filtration studies of isotopically labeled streptokinase and horse plasminogen suggest that the delay was due to impaired formation of a streptokinase-plasminogen complex. The predominant streptokinase moiety within the streptokinase-plasmin complex which forms from the streptok...
Immunogenicity of equine herpesvirus type 1 (EHV1) and equine rhinovirus type 1 (ERhV1) following inactivation by betapropiolactone (BPL) and ultraviolet (UV) light. Some kinetic data on the inactivation of equine herpesvirus type 1 (EHV1) and equine rhinovirus type 1 (ERhV1) by betapropiolactone (BPL) and ultraviolet (UV) irradiation are reported. 0.25% BPL at 37 degrees C for 1 h reduced the titre of EHV1 by greater than 10(3 . 4) and of ERhV1 by greater than 10(4 . 1) TCID50/ml. UV irradiation (334 microW/cm2) produced similar reductions in titre after 2 min. These data were used as a basis for inactivating EHV1 and ERhV1 by the combined action of BPL and UV irradiation. Viruses were exposed to 0.1% BPL for 1 h at 4 degrees C with constant stirring, fol...
Characterization of the major antigens of Haemophilus equigenitalis (contagious equine metritis organism). Immunoelectrophoresis of ultrasonically disrupted Haemophilus equigenitalis (contagious equine metritis organism) cells against rabbit and equine antisera disclosed at least 11 precipitating antigens. Two of these, a polysaccharide and a lipopolysaccharide-protein complex, were of high molecular weight and located on the cell surface. The remaining antigens were intracellular and were small- to medium-sized proteins. The surface antigens were the most significant in relation to the serological response in infected horses. They also reacted with sera from apparently healthy cattle, but the reas...
Respiratory tract immune response to microbial pathogens. Effective resistance to respiratory tract infection depends principally on specific immunity on mucosal surfaces of the upper or lower respiratory tract. Respiratory tract immune response comprises antibody and cell-mediated systems and may be induced most readily by surface presentation of replicating agents but can result from parenteral or local presentation of highly immunogenic antigens. Upper and lower respiratory tract systems differ in immunologic competence, with the lungs having a greater inventory of protective mechanisms than the trachea or nose. Several effective vaccines have bee...
Structure and function of the major histocompatibility complex in domestic animals. The major histocompatibility complex (MHC) is a genetic region that has been intensively studied for the past 2 decades. Interest in the MHC has been high because of (i) the particular involvement of the MHC in transplantation reactions, including organ allograft rejection in human beings; and (ii) the more general role of MHC gene products in the genetic control of immune responses in all mammals. The MHC has several remarkable properties that include a distinctive genetic structure which has been well-preserved through evolution, and the extreme plasticity of form of the principal MHC genes,...
Blood groups in animals. The membrane of RBC is literally peppered with a great variety of antigenic determinants (blood factors). Some are fixed genetically, ie, they occur on the RBC of all members of the species under study. Others segregate genetically, ie, they occur on the RBC of some but not all members of the species under study. It is these segregrating determinants that form the blood groups proper, the classic example being blood factors A and B of the ABO system of human blood groups. The number of blood group determinants varies considerably between species (eg, greater than 80 in domestic cattle to only ...
Prevalence of anti-red blood cel antibodies in the serum and colostrum of mares and its relationship to neonatal isoerythrolysis. The sera of 390 pregnant Standardbred mares and 409 pregnant Thoroughbred mares were tested for anti-red blood cell (RBC) antibodies. Of the Standardbred mares and Thoroughbred mares, 20% and 10%, respectively, had anti-RBC antibodies detectable in hemolytic or saline agglutination tests. Most of the antibodies were specific for the CA blood-group antigen of horses. Other antibodies were specific for the Aa, Ab, Aa, Ab, Da, Df, Ka, Ua, or Qa blood-group antigens. The occurrence of these antibodies in the serum and colostrum was compared for 268 mares. With 3 exceptions, whenever antibodies wer...
In vitro blastogenesis of equine lymphocytes by inactivated equine adenovirus type 1 antigen. An inactivated equine adenovirus type 1 (EAdV1) vaccine was administered to 4 horses. The horses had virus-neutralizing (VN) antibody titers before they were vaccinated, but developed higher VN antibody titers in response to vaccination. Nonvaccinated control horses did not show increases in VN antibody during the study, indicating that any increase in antibody titer in vaccinated horses was a result of vaccination and not due to an EAdV1 epizootic during the study. Specific EAdV1 in vitro lymphocyte blastogenesis (LB) was evaluated, using lymphocytes from 4 vaccinated and 2 control horses. Ho...
Enhancement of Naja naja atra antivenin production in horses. As the conventional hyperimmunization schedule in horses introduced by Tanaka could not produce enough neutralizing antibody against Naja naja atra venom, the mixture of Carboxymethyl cellulose (CMC)-Cobra venom incorporated with adjuvant was used for immunization. The neutralizing antibody produced (30 LD50) seemed to be increased but still not to reach the satisfactory level. By using CMC-Cobratoxin adjuvant mixture as an immunizing agent, highly potent antivenin (220 LD50) was obtained.
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 ...
Experimental Brucella abortus infection in the horse: observations during the three months following inoculation. Five mares, one stallion and a colt foal were inoculated intraconjunctivally with Brucella abortus strain 544. No clinical signs of disease developed except mild pyrexia. Intermittent bacteraemia was detected in the mares but not in the stallion or foal. Antibodies to B abortus became detectable from the second week after inoculation. Titres in the serum agglutination and complement fixation tests declined substantially after six to eight weeks but reactions to the Coombs antiglobulin, 2-mercaptoethanol and immunodiffusion tests were maintained. No consistent changes in biochemical or haematol...
Equine leucocyte antigen system. III. Non-MHC linked alloantigenic system in horses. A new, non-MHC linked alloantigenic membrane antigen on the equine lymphocytes is described. This antigen was characterized with alloantisera in the two-stage microcytotoxicity test and designated as ELy-1 antigen. The frequency of ELy-1 antigen positive animals in various populations is close to 50%. ELy-1 shows an autosomal, dominant inheritance. Since an allelic antigen (s) could not be demonstrated in family studies, it is assumed that only two alleles ELy-1+ and ELy-1- exist. The ELy-1 antigen in positive animals is expressed on both T and B lymphocytes but it is not present on erythrocyt...
Equine lymphocyte antigens in a Welsh pony family. Lymphocytes from an extended family of Welsh ponies were tested in a microcytotoxicity test against Thoroughbred and Arabian horse-derived antisera, which defined 4 and 6 equine lymphocyte antigen (ELA) specificities, respectively. Mixed leukocyte culture (MLC) tests were also performed. Welsh pony lymphocytes reacted to the Thoroughbred antisera. Most of the ponies' lymphocytes showed reactivity to 2 of the Thoroughbred ELA specificities, the offspring inheriting 1 antigen from each parent. Antigenic determinants were only partially demonstrated with Arabian antisera, although results indicat...
Equine immunology 3: immunopharmacology–anti-inflammatory and antihypersensitivity drugs. This article reviews anti-inflammatory and antihypersensitivity drugs under these 4 headings: Functional or physiological antagonists; Selective pharmacological inhibitors; Broad spectrum anti-inflammatory drugs; Miscellaneous inhibitors. The compounds considered include sympathomimetic amines, anticholinergic drugs, antihistamine drugs, tryptamine antagonists and dopamine antagonists, glucocorticosteroids and non-steroidal anti-inflammatory drugs, disodium cromoglycate and diethylcarbamazine citrate. The relationship of the pharmacological actions of these compounds is considered in the conte...
Enzyme-linked immunosorbent assay for diagnosis of equine infectious anemia. An enzyme-linked immunosorbent assay (ELISA) was elaborated for the detection of specific antibody to equine infectious anemia (EIA) antigen. Sera from horses experimentally infected with EIA virus were assayed by ELISA, complement fixation (CF) and immunodiffusion (ID) tests for antibody to EIA antigen. The ELISA technique was found to be much more sensitive than CF and ID tests. In addition, EIA specific antibody could be detected by ELISA at an earlier stage of infection than by CF or ID techniques. The applicability of the technique to diagnosis of EIA is discussed.
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...
[Some physicochemical properties of native and polymerized glutaraldehyde-treated horse heart cytochrome c]. Glutaraldehyde treatment does not change the absorption of cytochrome c either in the visible or in UV spectra. It brings about the formation of dimers, trimers and high-polymeric forms of cytochrome c and shifts the pI of all cytochrome c isoelectric fractions to more acid pH. Polymerization also results in changes of kinetic parameters of cytochrome c benzidine reaction increasing its affinity to 3,3-diaminobenzidine with a simultaneous decrease in the effectiveness of H2O2 binding. These biochemical changes can be related to immunochemical differences of native and glutaraldehyde-treated cy...
