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.
Rouse BT, Ditchfield WJ.The antibody response in serum and nasal secretions of groups of ponies vaccinated or infected with Myxovirus influenzae A-equi 2 was examined. Following infection by aerosol with live virus, a weak antibody response was recorded in both serum and secretions. Antibody levels were undetectable in secretions at 31 days after infection. After primary intramuscular vaccination with killed virus, using sodium alginate as an adjuvant, antibody was detected only in the serum. However, following revaccination, a pronounced antibody response was demonstrated in both serum and secretions. Antibody was s...
Rouse BT, Ditchfield WJ.Nasal secretions and serum were collected from ponies in order to determine the types of immunoglobulins responsible for antibody activity against Myxovirus influenzae A-equi 2. Using specific antisera to remove each immunoglobulin, the antiviral activity of serum was shown to be a property of IgG globulin, whereas in nasal secretions activity was found in both IgG and IgG(T) globulins. However in secretions the predominant activity was attributed to IgG(T) globulin. Because of its sensitivity to 2 mercaptoethanol, early serum antibody was assumed to belong to the IgM class of immunoglobulins....
Kemeny L, Pearson JE.An agent which possessed the properties of herpesviruses was isolated from the leukocytes of 71 out of 80 (88.7%) apparently normal Iowa horses. It was ether- and heat-sensitive, DNA type, and produced type-A intranuclear inclusion bodies in cell cultures. Electron micrographs revealed a virion of typical herpesvirus structure. Leukocyte isolate virus could be differentiated from equine rhinopneumonitis virus (ERV) by serum neutralization, by growth differences in rabbit kidney cells, and by fluorescent antibody staining. Specific neutralizing antibody against this agent was found in a pooled ...
Melnick JL, Hampil B.This paper smmarizes the results of the third part of co-operative studies undertaken by the WHO International Reference Centre for Enteroviruses and a number of WHO Regional Virus Reference Centres and WHO Virus Collaborating Laboratories and other laboratories in a comprehensive testing programme of enterovirus equine antisera prepared for long-term use as reference antisera. The studies were designed to appraise the specificity of the immune serum of horses inoculated with prototype enteroviruses (coxsackie-viruses A1, A5, A6, A12 and A22 and echoviruses 5, 6, 13-16, 18-20, 22-26, 29 and 32...
Müller F, Segerling M.Complement activity in the serum of eight species has been studied in two ways: by immobilization of sensitized with human or rabbit antibody and by haemolysis of sheep red cells sensitized with rabbit antibody. Serum of the pig, monkey and man was actively haemolytic but contained a heatlabile factor that immobilized unsensitized in the presence of guinea-pig complement and precluded the detection of immune immobilizing activity. Sera of other species, although without action on unsensitized treponemes, even with added guinea-pig complement, differed in their relative haemolytic and immobil...
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...
Winder NC, Pellegrini A, von Fellenberg R.Alpha 2-beta 1-glycoprotein may be found free in horse serum or complexed with alpha-1-proteinase inhibitor to form pre-alpha 2-elastase inhibitor. There has been little information published concerning alpha 2-beta 1-glycoprotein and its possible tissue sources in horses. A peroxidase-antiperoxidase technique was used to identify alpha 2-beta 1-glycoprotein in buffy coat and bone marrow neutrophils of healthy horses. Macrophages and neutrophils in bronchoalveolar lavage samples from clinically normal horses and from horses with chronic pulmonary disease also were positive for alpha 2-beta 1-g...
Knowles EJ, Hyde C, Harris PA, Elliott J, Menzies-Gow NJ.A chemiluminescent immunoassay is commonly employed to measure adrenocorticotrophic hormone (ACTH) concentrations to assist pituitary pars intermedia dysfunction diagnosis. In a previous study, seasonally-dependent assay cross-reactivity to endogenous equine corticotropin-like intermediate lobe peptide (CLIP, ACTH 18-39) was suspected. The present study aimed to demonstrate binding of endogenous equine CLIP to the capture antibody of the ACTH chemiluminescent immunoassay. Liquid chromatography - mass spectrometry (LCMS) methods were optimised to identify selected ions from synthetic human ACTH...
Wang Y, Zhang XY, Wei LL, Wu DL, Wang XJ, Xiang WH, Shen RX, Shao YM.To evaluate the relationship between the transcriptional level of IFN-gamma mRNA in peripheral blood mononuclear cells (PBMC) and immune protective response driven by inoculated horses with donkey leukocyte attenuated vaccine of EIAV(DLV), and to elucidate the immune mechanism of DLV. Methods: A real-time PCR method was established for quantitative detection of IFN-gamma mRNA level from horse PBMCs. Twelve horses were divided into vaccination group, healthy control group, challenging control group and EIAV natural infection group. The transcriptional level and distribution of IFN-gamma mRNA in...
Lee JY, Kang TY, Lee YD, Shin TK.The binding specificities of various lectins, such as the Dolichos biflorus agglutinin (DBA), soybean agglutinin (SBA), and the Bandeiraea simplicifolia BS-1 (Isolectin B4), Triticum vulgaris (WGA), Arachis hypogaea (PNA), and Ulex europaeus (UEA-I) lectins, were studied in the vomeronasal organ of the horse. The microvilli of the vomeronasal sensory epithelium were positive for DBA, SBA, Isolectin B4, WGA, PNA, and UEA-I. The receptor cells showed intense reactivity for DBA and WGA. Lectins were not detected in the supporting cells or basal cells. The Jacobson's glands were positive for WGA a...
Ma L, Sang M, Zhang J, Zhang S.Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF superfamily and plays multifunctional roles in the immune system. In the present study, a homolog of TRAIL from the Mongolian horse (named ecTRAIL) was identified and characterized. The 870-bp open reading frame encodes a polypeptide of 289 amino acid residues with a predicted molecular weight of 33.47 kDa and pI of 8.47. The genomic structure of ecTRAIL shares a five-exon/six-intron arrangement similar to its orthologs. Multiple alignments show that ecTRAIL is a type II transmembrane protein with a t...
Sellon DC, Russell KE, Monroe VL, Walker KM.Seven ponies were infected with the virulent wild-type Wyoming strain of equine infectious anaemia virus (EIAV). Infection status was monitored by serum reverse transcriptase activity, rectal temperature, and complete blood count. Preinfection serum and serum obtained during the initial febrile episode following infection were assayed for interleukin 6 (IL-6) activity. Postinfection IL-6 activity was significantly increased as compared to preinfection values. The magnitude of increase in IL-6 was positively correlated with reverse transcriptase activity (an indirect measure of viraemia) but wa...
Galeano R, Germanà A, Abbate F, Calvo D, Naves FJ, Hidaka H, Germanà G, Vega JA.Neurocalcin (NC) is a recently characterized EF-hand calcium-binding protein present in a discrete population of sensory neurons and their peripheral mechanoreceptors, but its presence in peripheral nervous system neurons other than in the rat is still unknown. The present study was designed to investigate the occurrence of NC in the dorsal root ganglia (DRG) of several mammalian species (horse, buffalo, cow, sheep, pig, dog, and rat), including humans. DRG were fixed, embedded in paraffin, and processed for immunohistochemistry using a polyclonal antibody against NC. The size of the immunorea...
Boudreault A, Boulay G, Marois P, Pavilanis V.Live human and equine influenza virus strains modified by serial passage on allantois-on-shell system (AOS) in the presence of normal horse serum were administered orally or intranasally to volunteers or horses. Mostly mild clinical short-lasting reactions, replication in nasal mucosae, transmission to placebo recipients and significant local or circulating antibody rises were observed following administration to volunteers of strains modified by five or less serial passages on AOS in the presence of normal horse serum (NHS). Milder clinical reactions, no replication, no viral transmission and...
Muñoz L, Sepúlveda-Calderón P, Villaguala-Pacheco C, Aqueveque CL.The aim of this research was to assess the copro-prevalence of Fasciola hepatica in owned Chilean breed horses (Equus caballus) residing in the province of Concepción, Chile. The study was carried out throughout October 2017. Samples were taken from all (100%) Chilean breed horse (124 specimens; 45 females and 79 males, aged between 7 months and 24 years old) from the Concepción province. A rectal stool sample was obtained from each animal. This was analyzed using the Army Medical School method (AMS III) technique to detect F. hepatica eggs. Information about the horse's age, sex, previous f...
Zaleska M, Anusz K, Winnicka A, Kita J.Twelve horses, all of them 10 years old, were vaccinated intramuscularly on 0 and 28 days of the experiment with inactivated vaccine containing only antigens of A-equi-2/Miami/63. Another three unvaccinated horses, each at the age of 10 years, were the negative control group. One, ten-year-old horse was vaccinated with commercial inactivated vaccine containing both antigens of A-equi-2/Miami/63 as well as A-equi-1/Praha/56 as positive control. Three horses were challenged intranasally with homotypic strain of Miami/63, while six other were challenged with heterotypic strains--three with Suffol...
Baum B, Hewicker-Trautwein M, Wohlsein P.A 10-year-old Knabstrupper stallion was euthanatized because of severe dyspnea and exercise intolerance. Postmortem examination revealed diffuse severe alveolar emphysema and chronic fibrosing pleuritis of the caudal lung. Parts of both caudal lung lobes were covered with multiple raised firm gray to yellow plaques. Histologically, these areas consisted of circumscribed pleural fibroses and cysts of metaplastic keratinizing squamous epithelium. Immunohistochemistry revealed intense labeling for cytokeratins 5/6 and 10. In addition, caudal lung lobes were severely affected by a chronic partiall...
Gaskin JM, Neal FC, Rubin HL.Precipitin lines not associated with equine infectious anemia (EIA) were observed in routine agar gel immunodiffusion (AGID) testing for the infection. The serums which produced these lines were obtained from horses which had been given multiple vaccinations with commercially available cell culture-origin equine virus vaccines as part of a comprehensive herd health program. The lines formed against cell culture-derived, but not spleen-derived EIA viral antigens. Investigation revealed that bovine serum proteins in the vaccines induced precipitating antibodies which reacted with bovine serum pr...
Pusterla N, James K, Bain F, Barnett DC, Chappell D, Gaughan E, Craig B, Schneider C, Vaala W, Papich M.The aim of this study was to determine if bi-weekly administration of diclazuril at half the label dose would reduce seroprevalence and magnitude of titers to S. neurona in healthy horses naturally exposed to the apicomplexan protozoal parasite. 12 healthy adult horses were moved from a low-risk exposure to a farm with high exposure rate to S. neurona in their horse population. The horses were randomly assigned to either a treatment or a control group. Treatment consisted in the administration of half the label dose (0.5 mg/kg) of diclazuril (Protazil) pelleted top dress twice weekly (every 3-...
Szeredi L, Makrai L, Dénes B.The first objective of this study was to develop an immunohistochemical procedure for rapid detection of Rhodococcus equi in impression smears from affected organs of foals on postmortem examination. The second aim was to demonstrate whether R. equi can be detected in smears of tracheal exudates collected from the same foals using an immunohistochemical method. Impression smears and cryostat and paraffin-embedded sections were made from the lungs and mediastinal lymph nodes of three foals (A, B and C) that had died of respiratory disease caused by R. equi, and also from the caudal mesenteric l...
Costa LR, Santos IK, Issel CJ, Montelaro RC.Cardinal features of equine infectious anemia (EIA) include fever, hemolytic anemia and thrombocytopenia during the acute phase of the disease, and cachexia and anemia seen during the chronic phase. These signs are thought to result from the release of inflammatory cytokines such as TNF-alpha. In order to determine if TNF-alpha has a role in the pathogenesis of acute EIA and vaccine-induced disease enhancement, we measured plasma concentrations of TNF-alpha in ponies immunized with virus enriched major core protein-p26 and/or experimentally infected with EIAV. Naturally infected inapparent EIA...
Matsumura T, Mashiko R, Sato T, Itokawa K, Maekawa Y, Ogawa K, Isawa H, Yamamoto A, Mori S, Horita A, Ginnaga A, Miyatsu Y, Takahashi M, Taki H....The redback spider (Latrodectus hasseltii Thorell) reportedly invaded Japan in September 1995. To date, 84 redback spider bite cases have been reported; 7 of these cases employed the antivenom. Antivenom has been imported from Australia in the past, but because of restrictions on exportation it was evident that nearly all of the antivenom present in Japan would expire during 2014. In 2014, a plan was proposed to experimentally manufacture and stockpile a horse antiserum for ourselves, using redback spiders indigenous to Japan. A total of 11,403 female spiders were captured alive: 1,217 from th...
Christensen RA, Malinowski K, Scanes CG, Hafs HD.Our goal was to establish a time of day and(or) interval from feeding that would avoid the refractory period after a somatotropin (ST) surge and optimize the responsiveness of horses to ST secretagogues. Two experiments were conducted with eight geldings conditioned to consume grain at 0800 and 1600 daily. In Exp. 1, during a 24-h period, these geldings averaged 3.2 +/- .3 pulses of ST with peak amplitude of 4.2 +/- .4 ng/mL, pulse duration of 55 +/- 6 min, and interpeak interval of 400 +/- 57 min. No ST peaks occurred within 2 h after either grain feeding. In Exp. 2, eight geldings were given...
Mini-myoglobin (mini-HHMb) is a fragment of horse-heart myoglobin (HHMb) considered to be the prototype of the product encoded by the central exon of the HHMb gene. For this reason, mini-HHMb has been studied extensively showing that carbonylation and oxygenation properties of the ferrous form are similar to those of the full-length protein, while kinetics and thermodynamics of azide binding to the ferric form are significantly different from those of HHMb. To analyze the structure-function relationships in mini-HHMb and the role of conformational fluctuations in ligand accessibility, the mole...
Eguchi M, Kuniyasu C, Kishima M.The passive hemagglutination (PHA) test was improved to enable the detection of antibodies to Taylorella (Haemophilus) equigenitalis in the sera of mares. Horse red blood cells (RBC) fixed with glutaraldehyde were compared with similarly treated RBC of a cow, pig and sheep for the PHA test. The horse RBC were superior to those of the other animals tested in detecting mares affected with contagious equine metritis (CEM). A PHA test using these cells as indicator and an antigen prepared from T. equigenitalis by sonication following treatment with hyaluronidase was the most satisfactory in terms ...
Yu YY, Xu MS, Liang H, Wang HY, Yu CQ, Liu Q.Despite over 40 years of research on the human immunodeficiency virus type 1 (HIV-1) vaccine, we still lack a considerable progress. Equine infectious anemia virus (EIAV) is a lentivirus in the Retroviridae family, akin to HIV-1 in genome structure and antigenicity. EIA is an important infectious disease in equids, characterized by anemia, persistent infection, and repeated fevers. The EIAV attenuated vaccine in China is the only lentiviral vaccine used on a large scale. Elucidating the mechanism of waning and induction of protective immunity from this attenuated vaccine strain will provide a ...
Pemberton AD, John HA, Ricketts SW, Rossdale PD, Scott AM.Failure to inhibit proteinases can lead to excessive tissue damage. The possibility that the severity of endometritis in Thoroughbred mares correlates with the haplotypes of plasma alpha 1-proteinase inhibitor (alpha 1-PI) expressed was investigated in two groups of mares. In mares with pyometritis before treatment, the frequency of the N haplotype, which is already high in the Thoroughbred population, was significantly increased when compared with that in a large published population. In mares with acute endometritis which persisted after treatment followed by sexual rest, the absence of S an...
Hudson BJ, Chicken C, Blishen A, Todhunter KH, Begg AP, Chan L, Karagiannis T, Raymond B, Bogema D, Adkins AR, O'Sullivan CB, O'Rourke BA....We describe three cases of osteoarticular infection (OAI) in young thoroughbred horses in which the causative organism was identified by MALDI-TOF as . The pattern of OAI resembled that reported with infection in humans. Analysis by 16S rRNA PCR enabled construction of a phylogenetic tree that placed the isolates closer to and , rather than . Average nucleotide identity (ANI) comparison between the new isolate and and however revealed low probability that the new isolate belonged to either of these species. This preliminary analysis suggests the organism isolated is a previously unrecognis...
Otani S, Arimitsu Y, Akama K.Antileptospiral sera from hyperimmunized horses were fractionated by gel filtration on Sephadex G-200 or by starch block electrophoresis. The fractions were examined quantitatively for leptospiricidal, agglutinating and complement fixing activities. The leptospiricidal activity was higher in the 78 globulin fraction than in the 19S globulin fraction, while the agglutinating activity was shared by both the fractions being higher in the 19S fraction. Complement fixing activity was found evenly in both the fractions. Leptospiricidal and complement fixing activities were higher in gamma-globulin t...
Abdou NI, Amare M, Sagawa A, Abdou NL.To understand the mechanism by which deaggregated horse anti-human thymocyte globulin (dATG) fails to induce untoward immunological reactions in man, three patients who received ATG and two patients who received dATG were studied for evidence of sensitization or tolerance to the foreign globulin. The ATG but not the dATG recipients developed allergic or serum sickness reactions; antihorse serum antibody could be detected in their serum and their blood cells proliferated in vitro in the presence of horse serum and secreted antihorse serum antibodies (P less than 0.001). Tolerance of the dATG re...
Pelegrino JL, Vázquez S, Morier L, Castillo A, Guzmán MG, Kourí G.We present the results attained in the identification of Eastern equine encephalomyelitis virus isolations in Vero and XL-2 cell systems, using a double-antibody ELISA technique and the indirect immunofluorescence method. The results attained through these two techniques coincided by 100% with identification through neutralization. With the former, the virus was detected within 6-8 hours after inoculation. Better results were attained with XL-2 cells.
Monzon CM, Jara GA, Hoyos CB.The usefulness of the direct agglutination test (DA) to diagnose Mal de Caderas disease was evaluated. Forty four sera samples from two lots of horses with natural T. evansi infection (Lot 1 and Lot 2) were used. Thirteen (81.2%) of sixteen horses in which parasites were isolated gave positive agglutination titres (> or = 1:512) in the DA test. Treatment of these positive sera with 2-mercaptoethanol drops three to eight dilutions the agglutination titres in twelve samples (92%), showing the IgM nature of these antibodies. The DA test was also positive in seventeen of twenty eight horses in ...
Page AE, Stills HF, Horohov DW.In the horse, Lawsonia intracellularis infection results in equine proliferative enteropathy (EPE). While upwards of 100% of weanlings on an endemic farm may seroconvert, only a small percentage (approximately 5%) will develop clinical disease. Cell-mediated immune mechanisms likely play a role in resistance to L. intracellularis and the absence of a L. intracellularis-specific IFN-γ response has been associated with the development of EPE. The goal of this study was to determine whether protection from clinical EPE is associated with the induction of a systemic IgG sub-isotypic response cons...
Timoney JF.An R antigen of the group C streptococcus S. equi that cross reacts with a similar antigen of S. zooepidemicus has been identified and characterized. It is acid, heat and trypsin resistant, but pepsin sensitive and has an isoelectric point of 4.8. The amino acids in highest concentration are glutamic, aspartic, alanine, leucine, and valine. Bacterial components released in a French Press contain large amounts of R antigen, which is present also in culture supernatants and acid extracts. It has a molecular weight of about 82,000. Trypsin extraction of cells yields molecules of predominantly 56,...
Milne EM, Pemberton AD, McGorum BC, Dixon PM, Miller HR.The equine alpha-1 proteinase inhibitor (alpha 1PI) system differs from that of man in that the equine system consists of four closely-linked genes (Spi1-Spi4) whereas in man, a single gene encodes for alpha 1PI. We have previously found differences in the proportion of the Spi proteins in equine serum and bronchoalveolar lavage fluid (BALF). We therefore wished to determine whether, as reported in man, there was any molecular weight difference between the Spi proteins in serum and BALF. alpha 1PI and albumin from equine BALF migrated further towards the anode compared with serum alpha 1PI on ...
Groschup M, Müller HP, Weiss R, Schliesser T.For the determination of a species-specific antigen of Streptococcus (S.) equi, acid extracts of group C streptococcal strains from horses (S. equi, S. zooepidemicus, S. equisimilis) were investigated using polyacrylamide gel electrophoresis and the immunoblotting technique. Using sera of horses suffering from strangles as well as sera from horses with respiratory infection of unknown etiology, Western blotting yielded more or less multiple banding reactions with bands in the 70, 54, 42, 40, and 31-28 kd molecular weight ranges against extracts of all of the 3 different bacterial species. Howe...
