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.
Allen TE, Bligh J.1. The temporal patterns of cutaneous water vapour loss from the skin of the sheep, goat, ox, horse, donkey and llama during exposure to 40°C Ta and during i.v. injections and infusions of adrenaline are examined.
2. It is concluded that there are marked species variations in the extent to which the discharge of sweat is affected by periodic contractions of the myoepithelium, or by simple displacement of fluid from the filled lumen as more fluid is secreted into it.
Tajima M, Nakajima H, Ito Y.Equine infectious anemia (EIA) virus was observed in thin sections of infected cultured horse leukocytes by electron microscopy. The virus particles had a spherical shape and were between 80 and 120 nm in diameter. Most of them contained an electron-dense nucleoid 40 to 60 nm in diameter. They were observed to form by a process of budding from the plasma membrane and appeared to have thin surface projections. The particles described were not detected in uninfected cultured cells, and their appearance could be prevented by adding EIA immune serum to the inoculum. The implications of these findi...
Van den Oord AH, Wesdorp JJ, Van Dam AF, Verheij JA.In commercial samples of equine myoglobin and samples of equine and bovine myoglobin prepared in the laboratory, a small amount of the protein was present as an aggregate. The presence of the myoglobin aggregate could be demonstrated by gel filtration on Sephadex G-100 Superfine, which also provided a means of isolating it. Gel filtration on Sephadex G-100 showed the molecular weights of the equine and bovine moyglobin aggregates to be about 35000 and 34000 respectively, thus supporting the hypothesis that they are dimers. This was confirmed for the equine myoglobin by ultracentrifugation meas...
Zientara S, Sailleau C.The authors briefly review the clinical forms of equine rhinopneumonitis and indicate changes in the nomenclature of equine herpesviral infections. The value of restriction profiles for epidemiological studies is described, taking as an example the strains of virus isolated in France. A technique is given for preparing molecular probes, as well as the application of these probes in direct diagnosis from biological specimens.
Grünig G, Von Fellenberg R, Maier R, Corboz L.Seventeen out of 21 horses had pulmonary microbial organisms which reached considerable numbers in seven cases. Elastase-producing microorganisms from the environment (Streptomyces species and to a lesser extent Bacillus species) constituted 22 per cent to 99 per cent (mean 79 per cent) of the total growth. There was a considerable number of microorganisms with in vitro-produced elastases which were not or only slightly affected by horse serum. There was no correlation between numbers of organisms and pulmonary histopathological findings thus the significance of these microorganisms in the pat...
Rogerson BA, Condron RJ, Baker J, Craven JA.Inoculation of Haemophilus equigenitalis into the uterus of 7 mares caused a disease clinically indistinguishable from contagious equine metritis. The duration of clinical signs varied from 4 to 11 days. The causative organism persisted for a relatively short time (2 to 10 weeks) in 5 mares, but in 2 others it established a carrier status and persisted until they were killed 6 and 10 months after infection. H. equigenitalis was recovered from the vestibule of the vagina and from a combined swab of the clitoral fossa and sinuses throughout the course of the infection. In some mares there were e...
Kingston JK, Bayly WM, Sellon DC, Meyers KM, Wardrop KJ.To investigate the potential use of fluorescent-labeled annexin V, anti-human fibrinogen antibody, and anti-human thrombospondin antibody for detection of the activation of equine platelets by use of flow cytometry. Methods: Platelets obtained from 6 Thoroughbreds. Methods: Flow cytometry was used to assess platelet activation as indicated by detection of binding of fluorescent-labeled annexin V, anti-human fibrinogen antibody, and anti-thrombospondin antibody to unactivated and ADP-, collagen-, platelet activating factor (PAF)-, and A23187-activated equine platelets. Human platelets were used...
Ferrer MS, Canisso IF, Podico G, Ellerbrock RE, Hurley DJ, Palomares R.Different stallions exhibit a high level of variation in the ability of their sperm to survive cryopreservation. A large fraction of stallions show poor post-thaw sperm motility, and their semen is not suitable for commercial freezing. In this study, we hypothesized that the presence of sperm-bound antisperm antibodies (ASAs) was associated with poor cryosurvival of stallion sperm. Our objective was to assess the level of ASA binding to stallion sperm, and determine if it was associated with good or poor sperm cryosurvival. In Experiment 1, cooled shipped semen from 27 stallions was frozen usi...
Albrecht BA, MacLeod JN, Daels PF.In the pregnant mare, luteal estrogen production increases at the onset of equine chorionic gonadotropin (eCG) secretion by endometrial cups. In previous studies, we have demonstrated that eCG stimulates luteal androgen and estrogen production in pregnant mares. To further elucidate the regulation of steroidogenesis within the equine corpus luteum (CL) of pregnancy, we examined the expression of 3beta-hydroxysteroid dehydrogenase (3beta-HSD), cytochrome P450 17alpha-hydroxylase/17,20 lyase (P450(17alpha)) and cytochrome P450 aromatase (P450(arom)) in luteal tissue samples collected during dies...
Phillips AW, Woodrooffe JG, Courtenay JS, Whitaker AM, Thomas D, Woiwod AJ.Antibodies to cultured human lymphoblasts were raised in horses using a schedule employing both subcutaneous and intravenous routes of injection. Plasma from groups of horses was pooled and the IgG prepared from each pool was tested extensively for safety and immunosuppressive efficacy in vitro and in vivo. On the basis of the results of skin grafting in monkeys, only globulins derived from the first main bleeds were blended to produce a bulk for clinical use. One early pool of globulin was discarded because when undiluted, it was lethal in monkeys by the intravenous route, and another pool wa...
Pellegrini A, von Fellenberg R.Pre-alpha 2-elastase inhibitor of horse plasma has recently been isolated in our laboratory. In this article we demonstrate that the inhibitor is a composite structure built of alpha 1-proteinase inhibitor and alpha 1-beta 1-glycoprotein. The compound inhibitor is biologically active, although it has previously been shown that its enzyme specificity is different from that of free alpha 1-proteinase inhibitor. Our observations are based on immunochemical cross-reactions between pre-alpha 1-elastase inhibitor and antibodies to alpha 2-beta 1-glycoprotein as well as antibodies to alpha 1-proteina...
Antal A, Szabó I, Vajda G, Antal VD, Polner A, Totth B, Szollár I, Stipkovits L.Clinical, microbiological, haematological, and immunological investigations were carried out in mares and their foals of 2 studs. A considerable number of foals fell ill with pneumonia, the mortality rate was high. Mycoplasmas were mostly isolated from nasal swabs and from the lungs. The isolation rate of bacteria was lower. Serum IgG concentration was reduced in the diseased or dead foals compared to that of healthy animals, the data stress in importance of IgG in the development of respiratory diseases also in foals.
Winder NC, von Fellenberg R.Pulmonary parenchymal tissues from 6 healthy horses and from 9 horses with chronic bronchiolitis were evaluated by use of an indirect immunofluorescent technique. In horses of both groups, the diffuse interstitial immunofluorescence was most intense for immunoglobulin (Ig)G, moderate for IgA, and minimal for IgM. Intensity of fluorescence was increased markedly in diseased lungs exposed to anti-IgA and anti-IgG. Around small bronchi and large bronchioles of healthy horses, IgA-containing cells generally were more numerous than were IgG-Fc fragment (Fc)-containing cells; in small bronchioles, h...
Dai CM, Zhang XY, Zhang RR, Shao YM, Shen RX.To develop a novel vaccine candidate of Equine infectious anemia virus(EIAV). Methods: env genes of EIAV Chinese donkey leukocyte attenuated strain (EIAV DLV) and its parental virus strain (EIAV LN) were expressed using the BAC-To-BAC system, and Env proteins were confirmed by SDS-PAGE and Western blot. BALB/c mice were immunized with recombinant vaccinia viruses containing env genes of EIAV alone or boosted with Env proteins expressed by recombinant baculovirus. Both protective humoral and cellular immune responses were detected. Results: Recombinant baculovirus could express complete Env pro...
Liu X, Liu Q, Feng X, Tang Q, Wang Z, Li S, Feng Z, Zhu J, Guan X.Due to the disadvantages of human and equine rabies immunoglobulin, it is necessary to develop a substitute for HRIG and ERIG, especially for those people living in the developing countries. Because of higher affinity and lower immunogenicity of rabbit's immunoglobulins, anti-rabies immunoglobulins specific to rabies virus were produced in rabbits as a bioreactor, and had been characterized by ELISA, affinity assay, immunofluorescence assay (IFA), immunocytochemistry, rapid fluorescent focus inhibition test (RFFIT). ELISA, affinity assay and IFA showed that rabbit RIG (RRIG) bound specifically...
Diesing L, Steuber S, Ahmed JS, Hörchner F.The sequential appearance of variable antigen types (VATs) of a clone of Trypanosoma evansi was studied in four ponies. Using luminol-dependent chemiluminescence, VAT populations which had been isolated from parasitemic peaks of single ponies, were tested for specificity with serum samples collected from other ponies. When antibody activity was demonstrated in a combination of trypanosomes and serum, it was concluded that a major VAT appeared in common. In the serum of all animals antibody activity was demonstrated to all VAT populations isolated from the other ponies during the first 4 weeks ...
Ross MW, Stephens PR, Reimer JM.A 9-year-old pregnant Standardbred broodmare was evaluated for signs of mild abdominal pain, failure to defecate, and mild abdominal distention. Rectal examination revealed the leading edge of a small colon intussusception, and peritoneal fluid analysis indicated suppurative peritonitis. Surgical management, including reduction of the intussusception and small colon resection with end-to-end anastomosis, resulted in successful outcome (1-year follow-up evaluation). Postoperative complications including dehiscence of the ventral midline surgical incision and simple obstruction at the anastomosi...
Kakoi H, Kikuchi M, Ishige T, Hirosawa Y, Tanaka S, Nagata SI.To confirm the positive conversion of antibodies against erythrocyte antigens in horses, possible blood transfusion donor horses selected from draft horse populations were periodically monitored with an indirect antiglobulin (Coombs) test for approximately 3 years. In this study, 19 horses (16 females and 3 males) were investigated, and five mares showed alloantibodies during the monitoring period. Four mares were typically pregnant when positive conversion was detected, whereas no particular cause of conversion could be observed for one mare based on its clinical records. In the analyzed hors...
Mobarak MS, Ryan MF.Adult Strongylus vulgaris, collected from the caecum of infected horses and embedded in paraplast using standard methods, were sectioned for immunohistochemistry (IHC) studies. Antibodies were raised in rabbit against the excretory-secretory product (ESP) and against two constituent protein bands (28-30 kDa). The use of sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), enzyme-linked immunosorbent assay (ELISA) and immunoblotting indicated the immunogenicity of ESP and of the subunits (28-30 kDa). In ELISA, both rabbit hyperimmune sera recognized the ESP and (28-30 kDa) ban...
Bannai H, Nemoto M, Tsujimura K, Yamanaka T, Kokado H, Kondo T.In order to establish an efficient system for serological diagnosis of equine viral arteritis in Japan, we compared enzyme-linked immunosorbent assays (ELISAs) provided by two manufacturers (Nisseiken Co., Ltd., Tokyo, Japan, and VMRD Inc., Pullman, WA, U.S.A.) by testing a series of horse sera. The results revealed that 159 of 160 virus-neutralizing (VN) antibody-positive serum samples were positive in both the Nisseiken-ELISA and VMRD-ELISA. Of the VN-negative sera (n=157), 134 and 154 samples were negative in the Nisseiken-ELISA and VMRD-ELISA, respectively. Sensitivity was 99.4% for both t...
Richa , Grover YP, Charan S.The authors describe a rapid and simple dot immunobinding assay (DIA) for detection and identification of equine herpesvirus-1 antigen in field samples from cases of abortion, stillbirth, perinatal foal mortality and paralysis. The assay employs a nitrocellulose membrane to which antigen is adsorbed as a dot. Antigen is identified as a coloured dot using a procedure based on the principle of enzyme-linked immunosorbent assay (ELISA). In all, 61 samples were tested by DIA and the test was compared with conventional agar gel immunodiffusion (AGID). With DIA, 44 (72%) samples gave positive result...
Dall'Aglio C, Mercati F, Pascucci L, Ceccarelli P.The aim of the present study was to demonstrate the presence and the distribution of leptin and its receptor in the pancreas of horses of both sexes by immunohistochemical techniques. The presence and the distribution of leptin receptor were also investigated in the initial portion of the duodenum, near the duodenal ampulla. The immunohistochemical investigation demonstrates the immunolocalization of both leptin and its receptor in the endocrine cells of pancreatic islets, which led us to hypothesize that leptin may possibly exert an autocrine/paracrine action on the endocrine pancreas. Examin...
Eberhardt C, Gerhards H.The three tests (EQUI Z-Test, AGLUTINADE FOAL IMMUNITY, CITE Foal IgG-Test) were evaluated for their accuracy and usefulness in the field. Single radial immunodiffusion was used as reference method. All tests were easily and rapid to perform and results were obtained within a few minutes. It was easy to get the results of the CITE Foal IgG-Test, but use of the EQUI Z-Test and the FOAL AGLUTINADE IMMUNITY-Test needed some practice to get correct results. Results obtained by the CITE Foal IgG-Test correlated to single radial immunodiffusion in 94%, those obtained by FOAL AGLUTINADE IMMUNITY-Test...
Bouchard PR, Fortna CH, Rowland PH, Lewis RM.Granular cell tumor (GCT) is a morphologic designation for tumors of varied histogenesis. Most GCTs in human beings are derived from Schwann cells, and rat meningeal GCTs are believed to originate in the neural crest. Three equine pulmonary GCTs from aged horses were studied immunohistochemically with primary antibodies directed against vimentin, cytokeratins (AE1/AE3), S-100, Leu 7, desmin, and neuron-specific enolase (NSE) using a steptavidin-biotin procedure. All three tumors stained similarly with strong and diffuse staining of neoplastic cells for vimentin and S-100 and negative staining ...
Mobarak MS, Ryan MF.Light, scanning, and transmission electron microscopy were employed to provide further data on the putative origins of the immunogenic secretory-excretory product (ESP) of Strongylus vulgaris (Looss 1900). The sharply delineated but superficial attachment to the equine caecum by the mouth leaves behind an oval area devoid of epithelial cells. Attachment does not extend deeply enough to reach the muscularis mucosa layer of the equine intestine. The progressive digestion of the ingested plug of tissue (epithelial cells, blood cells and mucous) was visualized. The coelomocytes, floating cells and...
Yu DT, Gale RP, Kacena A, Pearson CM.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...
Riley CB, Jenvey CJ, Baker FJ, Corripio A. To determine if an ELISA for measurement of IgA in equine serum could be used to measure concentrations of IgA in foal faeces and to determine correlations with concentrations in the milk of the dam. Faeces from 20 Welsh Cob and Welsh Pony foals and milk from their dams were collected within 12 hours (Day 0) and at 6 days after parturition (Day 6). On Day 6, faeces could not be collected from 2/20 foals, and milk samples could not be collected from 3/20 mares. An equine IgA ELISA validated for serum and plasma was used to measure concentrations of IgA in all samples in triplicate. The preci...
Greiner EC.Potential methods of incriminating insects as the cause of insect hypersensitivity are presented. A listing of the biting midges known to attack horses in North America is presented also. An example of how species may be determined to be the cause of the hypersensitivity is given using data from a recent study in Florida. Light trap collections indicated the temporal and geographic distribution of potential contributing species and collections made by vacuuming horses further delineated species by proving they feed on horses and the correct locations on the horses to match lesion distribution....
Liang CZ, Cao RB, Wei JC, Zhu LH, Chen PY.According to the antigenic analysis of equine arteritis virus (EAV) GL protein, one pair of primers were designed, with which the gene fragment coding the high antigenic domain of EAV GL protein was amplified from the EAV genome. The cloned gene was digested with BamH I and Xho I and then inserted into pET-32a and resulted pET-GL1. The pET-GL1 was transformed into the host cell BL21(DE3) and the expression was optimized including cultivation temperature and concentration of IPTG. The aim protein was highly expressed and the obtained recombinant protein manifested well reactiongenicity as was c...
Bai Y, Tong T, Liu G, Chen W, Zhang W, Wang Q, Yang T, Bu Z, Wu D.Interferon gamma (IFN-gamma) is a pleiotropic cytokine that is recognized as an important modulator of the immune response. To date, there is no report that prokaryocyte-derived recombinant equine IFN-gamma has antiviral activity. In this report, the gene coding equine IFN-gamma (EIFN-gamma) mature protein was cloned into pET-28a (+) and the recombinant EIFN-gamma was expressed in Escherichia coli (E. coli). The antiviral activity of expressed recombinant EIFN-gamma was evaluated by using a recombinant Vesicular Stomatitis Virus expressing green fluorescence protein (rVSV-GFP) system in the eq...
Nasu T, Sueishi A, Morimoto M.We used immunohistochemical techniques to analyze the localization and distribution of the catecholamine-synthesizing enzyme tyrosine hydroxylase (TH) and the neuropeptides methionine-endephalin (M-Enk), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), calretinin (Cal), calcitonin gene-related peptide (CGRP), substance P (SP), and galanin (Gal) in the stellate ganglia of two species of domestic animal (cattle and horses). NPY, VIP and Gal immunoreactive neurons (both cell body and nerve fiber) were observed in the stellate ganglia of both animals. M-Enk and CGRP immunoreactive ne...
Chung CJ, Grimm AL, Wilson CL, Balasuriya UB, Chung G, Timoney PJ, Bandaranayaka-Mudiyanselage CB, Lee SS, McGuire TC.In an effort to improve a competitive blocking enzyme-linked immunosorbent assay (cELISA) for antibody detection to Equine arteritis virus (EAV), antigen purified by anion-exchange membrane chromatography capsule (AEC) was evaluated. Virus purification by the AEC method was rapid and easily scalable. A comparison was made between virus purified by the AEC method with that obtained by differential centrifugation based on the following: 1) the relative purity and quality of EAV glycoprotein 5 (GP5) containing the epitope defined by monoclonal antibody 17B7, and 2) the relative sensitivity of a c...
Crisman MV, Hodgson DR, Bayly WM, Liggitt HD.To determine whether road transport affected pulmonary phagocyte activity, 7 healthy Thoroughbred horses were shipped 1,160 kilometers over 36 hours. Fluid collected by bronchoalveolar lavage (BAL) 12 hours, and 7 and 14 days after transport was analyzed. Results were compared to those from the same horses pre-transport, and 7 non-transported control horses that had BAL performed at the same times as the transported horses. Of cells recovered with BAL the percentage of viable pulmonary alveolar macrophages (PAMs) declined from 90.0 +/- 0.9% pre-transport to 80.0 +/- 3.7% by 2 weeks post transp...
