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.
Boulanger P, Bannister GL, Ruckerbauer GM, Corner AH.Clinical field cases of equine infectious anemia were studied and the disease was reproduced experimentally in horses. Attempts were made to adapt the complement-fixation test to the detection of antibodies in the serum of infected animals and to the demonstration of antigens in tissue extracts.A moderate complement-fixing antibody response was demonstrated in the serum of horses shortly after primary exposure to the infectious agent. However, this reactivity was of short duration and occurred with normal as well as with infected saline tissue extracts. It was therefore concluded that this rea...
Montgomery PC, Dorrington KJ, Rockey JH.Three independent methods have been used
to determine the molecular weights of the heavyand light-polypeptide chain subunits of equine yGab-,
yGc-, and yT-immunoglobulins. Extensively reduced
and alkylated proteins were filtered through standard
columns of Sephadex G-100 or G-200 in 8 M urea405
M propionic acid. Subunit molecular weights were obtained from the linear elution volume, V,, us. logarithm
molecular weight relationship defined for each column
with rabbit yG-globulin heavy and light chains and
horse heart cytochrome c. Molecular weights also were
determined by equilibrium se...
Wormstrand A.An immunological gel-diffusion test for the diagnosis of pregnancy in the mare is described. 56 blood samples from 50 different mares were tested. Control tests were made both by the Ashheim-Zondek method and by clinical examination. The accuracy of the immunological method was 96.4 %. No false positive reactions were observed. It is recommended to draw the blood sample at approximately 45 days or more after the last service. The immunological method is simple, cheap and accurate and is recommended as a routine test for the diagnosis of pregnancy in mares.
Karam B, Wilson WD, Chambers TM, Reedy S, Pusterla N.The use of a hemagglutination inhibition (HI) assay to assess humoral immune response to equine influenza virus (EIV) vaccines from various manufacturers administered to previously immunized adult horses was investigated. Subjects were allocated into one of 3 groups and vaccinated with various commercially available vaccines. Groups were subdivided into subjects that received 1 dose of a particular vaccine and those that received a second dose, 30 d later. Serum was collected at various times to assess antibody responses to contemporary EIV Florida sub-lineage strains. Statistical significance...
Mollerach-Gobbi B, Retegui LA, Peña C.The immunochemical behavior of several fragments of equine growth hormone (eGH) was examined using competitive binding assays with antibodies (Abs) to eGH obtained from different sources. Antigenicity was detected within the sequences 5-72 and 73-123 by rabbit Abs to eGH and by three mouse monoclonal antibodies (MAbs) produced by using bovine growth hormone as immunogen, but showing heteroclitic properties towards eGH. The polyclonal Abs to eGH also recognized as immunoreactive two smaller peptides corresponding to the amino acid residues 52-72 and 110-123. By contrast, the heteroclitic Abs to...
Lipscomb DL, Boudreaux MK, Paxton R, Spano J, Welles EG, Schumacher J.To establish the existence of platelet-derived proteins in equine plasma, with the future goal of developing an assay for the detection of in vivo platelet activation. Methods: 5 mature healthy horses. Methods: Platelet-rich plasma and platelet-poor plasma were prepared from anticoagulated blood. Platelets were separated from plasma proteins by gel filtration, then activated with 0.5 microM platelet-activating factor. Protease inhibitors were added, and the released platelet proteins were harvested. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was performed on the released platele...
Espino-Solis GP, Calderon-Amador J, Calderon-Aranda ES, Licea AF, Donis-Maturano L, Flores-Romo L, Possani LD.A three-dimensional model of the alphaX I-domain of the horse integrin CD11c from dendritic cells provided information for selecting two segments of the primary structure for peptide synthesis. Peptide 1 contains 20 amino acids and peptide 2 has 17 amino acid residues. The first spans from position Thr229 to Arg248 of an alpha-helix segment of the structure, whereas peptide 2 goes from Asp158 to Phe174 and corresponds to an exposed segment of the loop considered to be the metal ion-dependent adhesion site. Murine polyclonal antisera against both peptides were generated and assayed in periphera...
Aggarwal N, Holmes MA.Despite the importance of IgG Fc receptors in the regulation of various immunological mechanisms, these receptors have not been well characterised in the domesticated animals including equines. This paper describes the production of two monoclonal antibodies (CVS 59 and CVS 61) that recognise equine IgG Fc receptors. Fusions were conducted using BALB/c mice hyperimmunised with equine peripheral blood mononuclear cells. Hybridoma supernatants were screened on the basis of their ability to inhibit the rosetting of equine antibody coated sheep erythrocytes with equine peripheral blood mononuclear...
Baker JM, Stidworthy M, Gull T, Novak J, Miller JM, Antczak DF.Serological and cellular assays and molecular techniques were used to define features of the major histocompatibility complex (MHC) of the donkey With this information in hand, immune recognition of MHC determinants within and between donkeys and horses was compared. An antibody-mediated, complement-dependent, microcytotoxicity assay using a variety of antisera to donkey histocompatibility antigens, including those induced as a result of intraspecies or interspecies pregnancy in horse mares and jenny donkeys, delineated five donkey leukocyte antigen (DoLA) specificities. Antisera raised across...
Johnson JU, Oxender WD, Berkhoff HA.Effect of estrogen (E2) and progesterone (P4) on uterine antibacterial activity and immunoglobulin concentrations in mares was studied. In 2 in vitro experiments, 6 mixed-breed mares were ovariectomized, and uterine fluid and blood serum were analyzed. Antibacterial assay methods were used to determine inhibitory effects on Streptococcus zooepidemicus of uterine fluid samples collected on days 3, 5, and 8, and serum obtained on day 8 of treatment. Single radial immunodiffusion methods were used to quantify amounts of IgA and IgG in uterine fluid and serum on days 3, 5, 8, and 14 of treatment. ...
Bell K, Arthur H, Breen M.Eleven apparent mutations of the equine plasma transferrin and esterase gene (10 in TF and one in ES) were found in an analysis of approximately 240,000 thoroughbred horses. Eight of the transferrin mutations produced variants not previously recognized in horses. In the two remaining transferrin mutations and the esterase mutation, reduced plasma concentrations of the proteins were demonstrated by immunological techniques and together with the family data indicated the existence of 'null' alleles.
Bakst M, Hadick S, Proudman J, Maruyama K.This study was conducted to determine the crossreactivity of antisera to human prolactin (PRL), adrenocorticotropic hormone (ACTH), and growth hormone (GH) to turkey pituicytes. In addition, crossreactivities of the above antisera and antiserum to turkey GH to pituicytes of turkey, cat, rabbit, horse, owl monkey, and human were evaluated. Results of the immunocytochemical localizations showed that with one exception antisera to human hormones were positive for each species tested. Turkey pituicytes failed to crossreact with antiserum to human GH. Likewise, antiserum to turkey GH failed to cros...
Asmundsson T, Gunnarsson E, Johannesson T.Blood samples were taken from 18 healthy horses (Group A), 15 horses clinically diagnosed to have "haysickness" ("farmer's lung") (Group B), 10 closely related horses (Group C) and 14 inbred horses (Group D). Precipitins in sera were measured by double gel diffusion test against Micropolyspora faeni, Thermoactinomyces vulgaris, Aspergillus fumigatus, Alternaria, Penicillium and Rhizopus species. In Group A, all the horses were precipitin negative except one with a faint reaction to Rhizopus species. In Group B all had precipitin against M faeni. One horse also had precipitins against Rhizopus ...
Tajima M, Fujinaga T, Okamoto Y, Otomo K, Koike T.The relationship between the optimum concentration of mitogen which induces lymphocyte blastogenic response and the receptor occupancy by mitogen was investigated. The receptor occupancies which induced maximal blastogenic activity in equine, bovine and canine peripheral blood lymphocytes (PBL) were 31.1 per cent, 26.5 per cent and 38.4 per cent with phytohaemagglutinin-P, and 48.2 per cent, 17.9 per cent and 24.5 per cent with concanavalin A, respectively. The data clearly show that each animal species had its own optimum concentration of mitogen for stimulation of PBL. Optimum concentration ...
Dhawedkar RG, Jain NC, Mount ME, Bowling AT, Vegad JL.An enzyme-linked immunosorbent assay (ELISA) was standardised and applied for the detection of antiplatelet and antineutrophil antibodies using a heterologous system consisting of equine platelets or neutrophils and antisera raised in rabbits. The standardised technique consisted of using Immulon type 3 plate, 1 per cent gelatine as a blocking solution, poly-L-lysine buffer as a coating solution, unfixed antigen, 90 microliters test serum, horseradish peroxidase conjugated antibody and o-phenylenediamine dihydrochloride as a substrate. The number of unfixed platelets or neutrophils required fo...
Grünig G, Barbis DP, Zhang CH, Davis WC, Lunn DP, Antczak DF.Equine peripheral blood lymphocytes (PBL) were enriched by positive selection using panning with a mixture of monoclonal antibodies against putative equine CD4 (Equine Leucocyte Antigen Workshop antibodies WS 1 and WS 72), or CD8 molecules (Workshop antibodies WS 12, WS 49, and WS 74). RNA was extracted from CD4 enriched cells (99% purity), from CD8 enriched cells (69% purity), from peripheral blood lymphocytes, and from neonatal equine thymus. RNA extracted from equine granulocytes and from equine kidney served as negative control. The RNA was electrophoresed in agarose and transferred to nyl...
Reville-Moroz SI, Thompson DL, Archbald LF, Olsen LM.The in vitro incorporation of [3H]leucine into immunoprecipitable follicle-stimulating hormone (FSH) and luteinizing hormone (LH) was assessed for pituitaries from pony mares treated with testosterone propionate (TP) or oil (controls). Mares were treated every other day with TP (n = 4) at 350 micrograms/kg of body weight or with an equivalent volume of oil (n = 4). One day following the sixth injection of TP, each mare received an intravenous injection of gonadotropin releasing hormone (GnRH) at 1.0 micrograms/kg body weight and was bled frequently for 4 h. Treatment of mares with TP reduced F...
Sudarshan MK, Ashwath Narayana DH, Ravish HS.Rabies immunoglobulins are life-saving in patients with severe exposure to rabies. Despite the high degree of purification of equine rabies immunoglobulin (ERIG), the product inserts still recommend a skin sensitivity test before administration of this heterologous serum. A recent WHO recommendation states that there are no scientific grounds for performing a skin test before administering ERIG because testing does not predict reactions and it should be given irrespective of the result of the test. In this conflicting situation, we assessed the use of the skin sensitivity test in predicting ad...
Lindner A, von Wittke P, Thein P, Strube W.The effect of the prophylactic application of the paramunity inducer Baypamun on the incidence of diseases among foals (n = 63) in four Thoroughbred studs was evaluated. In a blind study, 38 of the foals received 2 ml of Baypamun intramuscularly while 25 of the foals received a placebo at six and four days before weaning and on the fifth day post-weaning. During the observation period of three weeks, beginning with the first and ending ten days after the last application, 7.9% of the foals treated with Baypamun (3 out of 38) suffered from respiratory infections compared to 24% of the foals tre...
Pellegrini A, Hägeli G, von Fellenberg R.1. Trypsin digestion of perchloric acid precipitated horse plasma yielded polypeptides with inhibitory properties for trypsin, chymotrypsin and, to a small extent, kallikrein. 2. The Mr of the inhibitory polypeptides were 73,000 and 24,000. 3. The number, enzyme specificity and Mr of the inhibitory polypeptides differed from the values known for the human being. 4. The inhibitory polypeptides were purified by affinity chromatography on Sepharose-trypsin and by gel filtration through Sephadex G-75. 5. Protease inhibitory polypeptides were generated in the same manner by chymotrypsin, elastase, ...
Schultheiss PC, Collins JK, Carman J.An indirect immunoperoxidase (IP) procedure using the avidin-biotin-peroxidase complex detection technique was developed to detect viral equine herpesvirus-1 (EHV-1) antigen in formalin-fixed paraffin-embedded tissues from aborted equine fetuses. The procedure was applied to liver, lung, and other tissues from 20 cases of confirmed or suspected EHV-1-induced abortions. Specific staining was observed in tissue sections from EHV-1-infected fetuses. Positive IP staining was present in tissues of 7 cases that were also positive by fluorescent antibody (FA) and virus isolation (VI) and that had typ...
Brown CM, Sonea I, Nachreiner RF, Obradovich JE.Using commercially available diagnostic reagents, serum immunoreactive gastrin activity was measured in five normal horses that were starved of food and water for 24 hours. Blood samples were taken every 15 minutes for two hours. The horses were then fed a pelleted diet for 15 minutes and samples were taken every 15 minutes for a further two hours. Three further samples were taken at hourly intervals. The total sampling period was seven hours. Basal immunoreactive gastrin activity was lower than that reported in other mammals, ranging from a mean of 7.0 pg/ml to 13.8 pg/ml. At 30, 60 and 75 mi...
Sievert M, Schuler G, Wehrend A.Due to the time-limited intestinal uptake of colostral immunoglobulins, the suggested treatment of hypogammaglobulinemia in new-born foals is usually plasma transfusion. The aims of this study were twofold: firstly, to investigate the course of serum IgG concentration after plasma transfusion in newborn foals; and secondly, to determine the amount of transfusion required for a significant increase in serum IgG concentration. For this purpose, the IgG concentration was measured in 23 foals at three different points in time: before transfusion, 1 hour after transfusion, and 24 hours after transf...
Timofeev BA, Bolotin IM, Stepanova LP, Bogdanov AA, Georgiu Kh, Malyshev SN, Petrovskiĭ , Klibanov AL, Torchilin VP.The cultures of Nuttalia eque mainly develop in the reticuloendothelial organs and so in treatment of nuttaliosis in horses and the Nuttalia carriers diamidine, an analog of imidocarb or imidozoline, was used encapsulated in liposomes. The liposomes were prepared with a modification of the phase inversion method (the lipids were dissolved in a mixture of freon-11 and chloroform). The content of the organic solvents in the preparation, as evidenced by gas liquid chromatography, was less than 0.2 per cent. The main fraction consisted of particles 1.5 to 2.5 microns in diameter. The tests on anim...
Katz J, Geer P.An enzyme-linked immunosorbent assay (ELISA) was developed for the serodiagnosis of contagious equine metritis (CEM), a sexually transmitted disease caused by Taylorella equigenitalis. Antigen preparation was simple, and antigens derived from both classical and atypical forms of T. equigenitalis enabled detection of antibody responses elicted in horses experimentally exposed to either form of the bacterium. Sera serially obtained from these horses from 0 to 63 days postexposure were tested by the traditional complement fixation test (CFT) for CEM and with the ELISA, using both antigens separat...
Brinsko SP, Ball BA.The equine oviduct is the site of fertilisation and location of embryonic development during the first 5 or 6 days. It therefore has an important influence on mare fertility. Although histopathological changes have been described previously, there is limited information regarding lymphocyte subtypes present in the mucosa of the normal equine oviduct. Objective: To characterise the distribution of CD3+, CD4+, CD8+ and B lymphocytes in the equine oviduct from inseminated mares during oestrus and dioestrus, and from noninseminated mares during the immediate post ovulatory period. Methods: Oviduct...
Randleff-Rasmussen PK, Mosca M, Knoerr F, Pin D, Desjardins I.Mycetoma is a chronic, proliferative lesion of cutaneous/subcutaneous tissue characterized by draining tracts and granules in the discharge caused by actinomycetes (actinomycetoma) or filamentous fungi (eumycotic mycetoma). Objective: This case report describes the unusual finding of a cutaneous mycetoma of the lateral wing of the right nostril in a gelding. Methods: A 16-year-old Fjord gelding with suspected pituitary pars intermedia dysfunction (PPID) was presented for evaluation of a nonpainful, firm and raised mass involving the lateral wing of the right nostril and the lip. Results: Cytol...
O'Rielly JL.The IgG concentration of plasma from 13 mares was measured by radial immunodiffusion when fresh and after storage at -4 degrees C and thawing by 3 methods. There was no significant (P > 0.05) reduction in the IgG concentration when plasma was thawed over 6 hours at 22 degrees C (1352.9 +/- 101.6 mg/dL) (mean +/- SEM) compared with the fresh sample (1369.5 +/- 88.1 mg/dL). In contrast, there was a significant (P < 0.05) reduction in the IgG concentration of plasma that was rapidly thawed at 57 degrees C over 50 minutes (1142.9 +/- 66.2 mg/dL), or placed in a microwave oven for 20 to 25 minutes ...
Perryman LE, Wyatt CR, Magnuson NS.Neoplastic lymphocytes from a horse with lymphosarcoma and IgM deficiency were analyzed for ability to grow in culture; surface and cytoplasmic IgM; functional activity in blastogenesis, cytoxicity, and suppressor assays; and activities of six enzymes involved in purine and pyrimidine metabolism. The cells lacked surface and cytoplasmic IgM. They had elevated activity of adenosine deaminase and reduced activity of purine nucleoside phosphorylase. Neoplastic cells were nonresponsive in blastogenesis assay and did not kill allogeneic lymphocyte target cells or YAC-1 targets in a lectin-dependent...
Köhne M, Kirch F, Tönissen A, Martinsson G, Rabe U, Sieme H, Schuberth HJ.To improve accuracy in evaluating stallion ejaculates, an antibody-based, flow cytometric assay for the detection and identification of leukocyte subpopulations (CD4-, CD8-, CD21-, CD172a-positive cells) in stallion semen (n = 12) was established. For establishment of the assay, native semen was supplemented with blood leukocytes (control: 20% leukocytes, 80% sperm cells) and analysed by flow cytometry. Adding antioxidants (ascorbic acid and butylated hydroxytoluol) to semen immediately after collection inhibited rapid death of lymphoid cells in sperm leukocyte mixtures. In control set-ups...
Kalemkerian PB, Metz GE, Peral-Garcia P, Echeverria MG, Giovambattista G, Díaz S.Polymorphisms at Major Histocompatibility Complex (MHC) genes have been associated with resistance/susceptibility to infectious diseases in domestic animals. The aim of this investigation was to evaluate whether polymorphisms of the DRA gene the Equine Lymphocyte Antigen is associated with susceptibility to Equine Arteritis Virus (EAV) infection in horses in Argentina. The equine DRA gene was screened for polymorphisms using Pyrosequencing® Technology which allowed the detection of three ELA-DRA exon 2 alleles. Neither allele frequencies nor genotypic differentiation exhibited any statistical...
Abraham G, Broddet OE, Ungemach FR.In this study, beta-adrenoceptors of intact equine lymphocytes were identified and subclassified by (-)-[125I]-iodocyanopindolol (ICYP) binding. ICYP binding to intact equine lymphocytes was rapid, saturable (maximal number of binding sites 320 +/- 20 ICYP binding sites/cell, n = 12) and of high affinity (KD value for ICYP 14.4 +/- 1.7 pmol/l, n = 12). Binding was stereospecific as shown by the 10 times greater potency of (-)-propranolol to inhibit binding than its (+)-isomer. Beta-adrenoceptor agonists inhibited ICYP binding with an order of potency: (-)-isoprenaline >(-)-adrenaline >(-...
Sugiura T, Nakajima H.An indirect hemagglutination was developed for the diagnosis of equine infectious anemia using sheep red blood cells coated with group specific virus antigen which had been highly purified by affinity chromatography. The presence of indirect hemagglutination antibodies was demonstrated in horses with equine infectious anemia since the cells were specifically agglutinated by all the serum samples obtained from experimentally infected horses. Antibodies appeared within 35 days after inoculation, and development of which coincided well with that of precipitating and complement fixing antibodies. ...
