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.
Montgomery PC, Bello AC, Rockey JH.N-terminal tetrapeptides from heavy chains of equine γGab- and γT-globulins, and of human γG and γA myeloma proteins and a γM macroglobulin, have been studied. The equine and human heavy chains lacked free α-amino-terminal groups. After mild alkaline hydrolysis, glutamic acid was identified as the terminal amino acid by reaction with dimethylaminonaphthalenesulfonyl chloride, tentatively identifying pyrrolid-2-one-5-carboxylic acid (PCA) as the unreactive terminal residue of each heavy chain. Peptides lacking a free α-amino group were isolated from subtilisin and pronase digests of the ...
Ameniya H, Kashiwagi N, Putnam CW, Starzl TE.In the sera of ten normal humans and twenty-eight candidates for organ transplantation, the passive haemagglutination test detected a 50% incidence of preformed antibodies of low titre directed against horse serum. Such antibodies were also found to cross react with goat or rabbit sera in most instances. Seventeen of the organ recipients were later studied after the institution of treatment with horse antihuman-lymphocyte globulin (ALG). The incidence of anti-horse-serum antibodies rose to 100%. At the same time, an increased activity against goat serum developed; cross-reactions against rabbi...
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...
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...
Wolf TM, Gandolf AR, Dooley JL, Atkinson MW, Wolfe BA.Vaccination has been an important component of preventative health care programs of North American zoologic institutions in their protection of valuable species against West Nile virus (WNV) infection since its detection in 1999. Although approved only for horses, commercial WNV vaccine has been used for the purpose of protection of nondomestic species, including avian, equid, and rhinoceros species. Currently, there are two commercial equine vaccines available, a killed vaccine and a recombinant viral-vectored vaccine. Both products have been used for the vaccination of Greater One-horned rhi...
Marcum JA, Highsmith RF, Kline DL.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...
Sergeant ES, Cowled BD, Bingham P.This observational study was undertaken in order to evaluate the diagnostic specificity of the blocking enzyme-linked immunosorbent assay (bELISA) for serum antibodies to influenza A virus nucleoprotein during the equine influenza (EI) outbreak response in New South Wales, Australia, in 2007. Using data collected during the outbreak response, bELISA testing data were collated for assumed uninfected horses from areas where EI infection was never recorded. Diagnostic specificity of the bELISA used during the EI response was high, but varied significantly between some regions, although the reason...
Schönberg A, Caldas EM, Sampaio MB, Costa E, Plank SJ.IN the State of Bahia (Brazil) the leptospirin produced in Germany for experimental use by the Institute for Veterinary Medicine, Federal Health Office, Berlin, was administered to humans and animals in order to diagnose leptospirosis in collaboration with this Institute. The results were compared with the microscopic agglutination reaction. The total number of test persons or animals was 268; this group included 81 human patients. 60 heads of cattle, 50 goats, 40 pigs, 25 horses, and 12 dogs. All were tested serologically and simultaneously the intracutaneous test was carried out. This test w...
Respiratory diseases are a major cause of morbidity and mortality in the horses of all ages including foals. There is limited understanding of the expression of immune molecules such as tetraspanins and surfactant proteins (SP) and the regulation of the immune responses in the lungs of the foals. Therefore, the expression of CD9, SP-A and SP-D in foal lungs was examined. Results: Lungs from one day old (n = 6) and 30 days old (n = 5) foals were examined for the expression of CD9, SP-A, and SP-D with immunohistology and Western blots. Western blot data showed significant increase in the...
Furness JB, Poole DP.The functioning of the gastrointestinal tract is under the control of the most extensive system of peripheral neurons in the body, the enteric nervous system, and the largest endocrine system of the body, the GEP endocrine system. The enteric nervous system in large mammals contains 500 million neurons, and the GEP endocrine system produces more than 30 hormones. Numerous enteric neuropathies affecting both humans and animals have been described and digestive disorders affect commercially important species, such as horses and cattle. The most severe enteric neuropathies (e.g., lethal white syn...
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...
