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.
Ozawa Y, Bahrami S.Formalized African horse-sickness (AHS) type 9 virus cultivated in monkey kidney stable (MS) cell cultures was experimentally used for immunizing horses. Inactivated vaccines prepared either from viscerotropic or neurotropic type 9 AHS virus produced antibodies in vaccinated horses. Immunity developed in all horses vaccinated with various amounts of the vaccine, and protected them from infection, when challenged 5 weeks after vaccination.
Croxton-Smith P, Benson JA, Dawson FL, Powell DG.A complement fixation test (CFT) based on that used for brucellosis (Brinley Morgan and others 1971) has been developed for use on the sera of horses exposed to the contagious equine metritis (CEM) organism. None of 50 single samples from horses thought to be unexposed to the CEM organism was positive to the test, although five showed inconclusive reactions. Samples were examined from 41 mares either proved to be infected or from an infected stud. Of these 21 were positive, 11 were inconclusive and nine were negative. The relationship of the CFT to reactions in the other tests used in this con...
Mehdizadeh Gohari I, Parreira VR, Nowell VJ, Nicholson VM, Oliphant K, Prescott JF.A role for type A Clostridium perfringens in acute hemorrhagic and necrotizing gastroenteritis in dogs and in necrotizing enterocolitis of neonatal foals has long been suspected but incompletely characterized. The supernatants of an isolate made from a dog and from a foal that died from these diseases were both found to be highly cytotoxic for an equine ovarian (EO) cell line. Partial genome sequencing of the canine isolate revealed three novel putative toxin genes encoding proteins related to the pore-forming Leukocidin/Hemolysin Superfamily; these were designated netE, netF, and netG. netE a...
Horin P, Osickova J, Necesankova M, Matiasovic J, Musilova P, Kubickova S, Hubertova D, Vyskocil M, Rubes J.In previous work, we found significant associations of horse chromosome 15 (ECA15) microsatellite markers HMSO1 and HTG06 with two horse infections, Rhodococcus equi and Lawsonia intracellularis, respectively. Interleukin-1 beta subunit and interleukin-1 receptor antagonist encoding genes (IL1B and IL1RN) could be considered as candidate genes underlying the associations reported. Therefore, we identified single nucleotide polymorphisms (SNPs) within three interleukin-1 beta functionally related genes: IL1B, IL1RN and Casp1 (interleukin-1 beta converting enzyme/caspasel encoding gene). Using a...
Deeg CA, Pompetzki D, Raith AJ, Hauck SM, Amann B, Suppmann S, Goebel TW, Olazabal U, Gerhards H, Reese S, Stangassinger M, Kaspers B, Ueffing M.The development, progression, and recurrence of autoimmune diseases are frequently driven by a group of participatory autoantigens. We identified and characterized novel autoantigens by analyzing the autoantibody binding pattern from horses affected by spontaneous equine recurrent uveitis to the retinal proteome. Cellular retinaldehyde-binding protein (cRALBP) had not been described previously as autoantigen, but subsequent characterization in equine recurrent uveitis horses revealed B and T cell autoreactivity to this protein and established a link to epitope spreading. We further immunized h...
Woldehiwet Z.Anaplasma phagocytophilum is the recently designated name replacing three species of granulocytic bacteria, Ehrlichia phagocytophila, Ehrlichia equi and the agent of human granulocytic ehrlichiosis, after the recent reorganization of the families Rickettsiaceae and Anaplasmataceae in the order Rickettsiales. Tick-borne fever (TBF), which is caused by the prototype of A. phagocytophilum, was first described in 1932 in Scotland. A similar disease caused by a related granulocytic agent was first described in horses in the USA in 1969; this was followed by the description of two distinct granulocy...
Rüfenacht S, Marti E, von Tscharner C, Doherr MG, Forster U, Welle M, Roosje PJ.The pathogenesis of equine urticaria is not well understood. In man, urticaria has been associated with immunological and nonimmunological mechanisms leading to the release of various mediators by mast cells. Skin biopsies of 32 horses with a history of urticaria were stained with toluidine blue, a double-labelling method for chymase and tryptase, and immunohistochemistry for immunoglobulin (Ig)E. These horses were compared with horses with pemphigus foliaceus, insect bite hypersensitivity and control horses with healthy skin. Neither formalin fixation time nor biopsy site influenced the stain...
van Kasteren PB, Bailey-Elkin BA, James TW, Ninaber DK, Beugeling C, Khajehpour M, Snijder EJ, Mark BL, Kikkert M.Protein ubiquitination regulates important innate immune responses. The discovery of viruses encoding deubiquitinating enzymes (DUBs) suggests they remove ubiquitin to evade ubiquitin-dependent antiviral responses; however, this has never been conclusively demonstrated in virus-infected cells. Arteriviruses are economically important positive-stranded RNA viruses that encode an ovarian tumor (OTU) domain DUB known as papain-like protease 2 (PLP2). This enzyme is essential for arterivirus replication by cleaving a site within the viral replicase polyproteins and also removes ubiquitin from cell...
Kölle S, Dubois CS, Caillaud M, Lahuec C, Sinowatz F, Goudet G.In the equine, the zona pellucida (ZP) is the major barrier to successful in vitro fertilization. Therefore the aim of our studies was to analyze species-specific features of the equine ZP in regard to structure and glycoprotein ZPB and ZPC expression sites during oocyte development and embryogenesis. The equine ZP revealed high immunological cross-reactivity to porcine ZPB and ZPC. In the ovary, the distribution of ZPB and ZPC was co-localized and correlated with the developmental stage of the follicle. ZPB and ZPC expression started in the oocyte of the late primordial and primary follicle. ...
La Perle KM, Piercy RJ, Long JF, Blomme EA.Multisystemic, eosinophilic, epitheliotropic disease and intestinal lymphosarcoma were diagnosed in a Paso Fino mare that presented with anorexia and weight loss. The stomach, ileum, cecum, colon, pancreas, and lungs were infiltrated by large numbers of eosinophils forming prominent eosinophilic granulomas, as well as lymphocytes and plasma cells. Two jejunal masses composed of solid sheets of neoplastic lymphocytes were present. In contrast to the regions of inflammation, the infiltrates in these masses did not contain plasma cells, eosinophils, and eosinophilic granulomas. Immunohistochemica...
Gao X, Jiang CG, Han XE, Zhao LP, Shen RX, Xiang WH, Zhou JH.To elucidate the function of the S2 gene in equine infectious anemia virus (EIAV) and its role in the attenuation of the Chinese attenuated EIAV vaccine strains, the S2 in the EIAV vaccine strain EIAV (FDDV) was reverse-mutated and the in vitro replication character of the resultant virus was evaluated. Based on the sequence variation of the S2 gene between the EIAV virulent strains and vaccine strains, all the four vaccine-specific sites in the S2 of an EIAV(FDDV) infectious clone, pFDDV3-8, were reverse-mutated to the sequences of the virulent strain EIAV(DV115). The reverse-mutated molecula...
Wattle O.The equine skin and its appendages (chestnut, hoof capsule, ergot, sebaceous glands, sweat glands and hair) consist mainly of keratinocytes. The intermediate filament cytoskeleton of these cells in involved in specialised functions, such as mechanical co-ordination of the cytoskeleton of the cell or tissue. In this study, 7 monoclonal antibodies, one polyclonal antibody and immunoblot analysis were used to characterise cytokeratins (separated by 1- and 2-dimensional gel electrophoresis) from the hoof wall and chestnut. The tissue distribution of these cytokeratins was studied by immunohistoche...
Camp CJ, Leid HW.Extracts of Onchocerca cervicalis, an equine parasite, were incubated with radiolabeled equine neutrophils and neutrophil migration was assessed for factors derived from the parasite itself or for host-derived factors after incubation of these same parasite extracts with equine serum. No stimulus for cell migration was observed in saline extracts of adult worms, uterine microfilariae, or skin microfilariae at any dosage tested. However, after incubation of saline extracts with fresh normal equine sera a marked stimulus for neutrophil migration was observed. Ablation of this biologic activity w...
Miglio A, Morelli C, Gialletti R, Lauteri E, Sforna M, Marenzoni ML, Antognoni MT.The clinical, histological, and immunophenotypic findings are presented for 4 horses affected by different types of lymphoma. Diagnoses of a monomorphic epitheliotropic intestinal T-cell lymphoma, a diffuse splenic large B-cell lymphoma, a peripheral T-cell lymphoma, and a T-cell rich large B-cell lymphoma of the third eyelid were made. Constatations cliniques et immunophénotypiques pour quatre formes de lymphomes équins. Les constatations cliniques, histologiques et immunophénotypiques sont présentées pour quatre chevaux affectés par différents types de lymphome. Des diagnostics d’un...
Matthews JB, Hodgkinson JE, Dowdall SM, Proudman CJ.Intestinal helminths are an important cause of equine disease. Of these parasites, the Cyathostominae are the commonest group that infect horses. These nematodes consist of a complex tribe of 51 species, although individual horses tend to harbour 10 or so common species, in addition to a few rarer species. The Cyathostominae can be extremely pathogenic, and high levels of infection result in clinical symptoms ranging from chronic weight loss to colic, diarrhoea and death. As part of their life cycle, immature cyathostomins penetrate the large intestinal wall, where they can enter a state of in...
Flaminio MJ, Rush BR, Shuman W.Inactivated Propionibacterium acnes is a biologic response modifier for treatment of non-specific respiratory disease in horses. The objectives of this investigation were to determine alterations in phagocytic activity, phenotypic expression of lymphocyte subpopulations and lymphokine-activated killing cell response in healthy young horses. Samples were collected on day 0, 7 and 14 of the investigation. Blood samples were obtained via jugular venipuncture and pulmonary leukocytes were recovered via bronchoalveolar lavage (BAL). Commercially available P. acnes (Eqstim) was administered intraven...
Yamamoto K.Monospecific (MSp-) antisera against E1 and E2 glycoproteins of western equine encephalitis (WEE) virus were prepared and examined for binding activities to whole virions, hemagglutination-inhibition (HI), neutralization (NT) and protection. Both anti-E1 and anti-E2 MSp-Abs protected mice against WEE virus challenge. A competition experiment with monoclonal antibodies showed that these MSp-antisera appear to lack the antibody population for some epitopes involved in viral neutralization.
Irvine KL, Hopkins LJ, Gangloff M, Bryant CE.TLR2 recognises bacterial lipopeptides and lipoteichoic acid, and forms heterodimers with TLR1 or TLR6. TLR2 is relatively well characterised in mice and humans, with published crystal structures of human TLR2/1/Pam3CSK4 and murine TLR2/6/Pam2CSK4. Equine TLR4 is activated by a different panel of ligands to human and murine TLR4, but less is known about species differences at TLR2. We therefore cloned equine TLR2, TLR1 and TLR6, which showed over 80% sequence identity with these receptors from other mammals, and performed a structure-function analysis. TLR2/1 and TLR2/6 from both horses and hu...
Bai Y, Tong TG, Zhang WJ, Xu SL, Wang Q, Liu GL, Wu DL.To develop a quantitative ELISA by measuring interferon (IFN-gamma) of equine lymphocytes. Methods: Sandwich ELISA for equine IFN-gamma was developed using mAb A5 as a capture antibody and biotinylated mAb SB10 as a detection antibody. Results: The detection limit of the sandwich ELISA for equine IFN-gamma was 1 microg/L and did not show cross-reactivity with recombinant equine IL-18. Equine IFN-gamma was detected by ELISA in culture medium of the peripheral blood mononuclear cells (PBMCs) stimulated with ConA or PMA/Ionomycin. Conclusions: This method can be used to help understand the role o...
Brandt S, Schoster A, Tober R, Kainzbauer C, Burgstaller JP, Haralambus R, Steinborn R, Hinterhofer C, Stanek C.Equine hoof canker is a chronic proliferative pododermatitis of as yet unknown aetiology. Like equine sarcoid disease, canker is a therapy-resistant disorder characterised by hyperkeratosis, acanthosis and a marked tendency to recur. Objective: There is an association of sarcoid-inducing bovine papillomaviruses of types 1 and 2 (BPV-1, BPV-2) with hoof canker disease. Methods: Using PCR-based techniques, we assessed canker tissue, intact skin and/or peripheral blood mononuclear cells (PBMCs) of 25 canker-affected horses for the presence of sarcoid-associated BPV-1 and -2. Results: Conventional...
Matteri RL, Baldwin DM, Lasley BL, Papkoff H.Previous studies from this laboratory have described the properties of purified luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from horse and donkey anterior pituitary glands. The present study afforded the opportunity to further characterize these previously purified hormone preparations and to compare them with enriched gonadotropin fractions from zebra pituitary glands. Although a single LH and FSH fraction was usually obtained for each pool of pituitaries, two separate zebra LH and two donkey FSH preparations were generated. Purified hormone preparations from the horse wer...
Singh S, Jindal AK, Pilania RK.Kawasaki disease (KD) is a medium vessel vasculitis with predilection for coronary arteries. Due to lack of a reliable confirmatory laboratory test, the diagnosis of KD is based on a constellation of clinical findings that appear in a typical temporal sequence. These diagnostic criteria have been modified from time to time and the most recent guidelines have been proposed by the American Heart Association (AHA) in 2017. However, several children may have incomplete or atypical forms of KD and the diagnosis can often be difficult, especially in infants and young children. In this review, we hav...
Hagedorn HW, Schulz R, Jaeschke G.An enzyme linked immunosorbent assay (ELISA) was developed to detect the anabolic steroid boldenone in equine blood and urine. The polyclonal antiserum was raised in rabbits, employing boldenone-17-hemisuccinate-bovine serum albumin as antigen. Boldenone-17-hemisuccinate-horseradish peroxidase served as enzyme conjugate. Sensitivity of the assay was 26.0 +/- 3.0 pg/well. Among the endogenous steroids tested only progesterone and testosterone exhibited moderate cross-reactivities, 3.4 and 2.5%, respectively. These cross-reactivities are of no importance for the boldenone assay. For the reductio...
Warnken T, Brehm R, Feige K, Huber K.The aim of the study was to analyze key proteins of the equine insulin signaling cascade and their extent of phosphorylation in biopsies from muscle tissue (MT), liver tissue (LT), and nuchal AT, subcutaneous AT, and retroperitoneal adipose tissues. This was investigated under unstimulated (B1) and intravenously insulin stimulated (B2) conditions, which were achieved by injection of insulin (0.1 IU/kg bodyweight) and glucose (150 mg/kg bodyweight). Twelve warmblood horses aged 15 ± 6.8 yr (yr), weighing 559 ± 79 kg, and with a mean body condition score of 4.7 ± 1.5 were included in the s...
Seide RK, Kehoe JM.Studies of the molecular biology of lymphoid cells have markedly increased our understanding of how millions of different antibodies can be synthesized by a single animal. To date, the most detailed understanding has been achieved for the mouse, primarily because of the relatively greater experimental availability of this species. These studies, as well as those involving other species, have shown that the complete genes for antibody polypeptide chains are assembled from disparate genetic elements which are originally widely separated in the genome. The assembly process itself, together with t...
Muehlmann LA, Michelotto PV, Nunes EA, Grando FC, da Silva FT, Nishiyama A.Phagocytosis exerted by alveolar macrophages and neutrophils is crucial in the clearance of exogenous particles deposited in the airways. Therefore, substances that activate these phagocytes in the airways can exert important effects on the particle clearance rate. PAF, particularly, was proved to be a potent activator of several immune cells and was shown to be present in the equine lower airways in specific conditions, such as after exercise. The present study aimed to investigate if PAF is able to increase the phagocytic capacity and the production of superoxide anion in equine alveolar mac...
Williams RC.The evolutionary distance between two sets of proteins was estimated using the techniques of Miyata and Yasunaga (1980) and Kimura (1980). Human beta 2-microglobulin was compared with the homologous murine molecule, while human and equine alpha-globin were similarly treated. It was found that a large amount of molecular evolution has occurred in beta 2-microglobulin since its divergence from the common ancestor of mice and humans. Kimura's estimate of evolutionary distance, K, is 0.353, while those of Miyata and Yasunaga are KS = 0.708 and KA = 0.171. The respective values for human and equine...
Aida Y, Okada K, Kageyama R, Amanuma H.Tumor-associated antigens that are expressed in lymphosarcoma B cells of cattle with enzootic bovine leukosis had been analyzed in terms of their reactivity with 13 monoclonal antibodies (MAB). By use of flow cytometry and radioimmunoprecipitation, 1 of the MAB (c143) that recognized a tumor-associated antigen cross-reacted with blood lymphocytes (BL) from various mammalian species. By use of flow cytometry, the c143 MAB reacted with 10 to 49% of BL derived from human beings, mice, dogs, horses, pigs, llamas, sheep, goats, and cattle. Titer of the c143 MAB with BL from horses, pigs, human bein...
Fan Y, Lou J, Tam CC, Wen W, Conrad F, Leal da Silva Alves P, Cheng LW, Garcia-Rodriguez C, Farr-Jones S, Marks JD.Equine-derived antitoxin (BAT) is the only treatment for botulism from botulinum neurotoxin serotype G (BoNT/G). BAT is a foreign protein with potentially severe adverse effects and is not renewable. To develop a safe, more potent, and renewable antitoxin, humanized monoclonal antibodies (mAbs) were generated. Yeast displayed single chain Fv (scFv) libraries were prepared from mice immunized with BoNT/G and BoNT/G domains and screened with BoNT/G using fluorescence-activated cell sorting (FACS). Fourteen scFv-binding BoNT/G were isolated with K values ranging from 3.86 nM to 103 nM (median K 2...
Amann JF, Smith RM, Ganjam VK, Paull WK, McClure RC, Green EM, Garner HE.The distribution of cells that stain positive for beta-endorphin and ACTH immunoreactivity was studied in the pars intermedia (PI) of the hypophysis in 3 healthy horses and 2 healthy ponies. Serial sections treated with commercial antibodies generated against beta-endorphin or ACTH were processed for immunocytochemical studies, using the avidin biotin immunoperoxidase-complex method. Distribution patterns of cells reacting with antibodies were similar in cells from all equids. Cells immunostained for ACTH were numerous and widely distributed in the PI. Cells immunopositive for ACTH probably co...
Posthuma CC, Pedersen KW, Lu Z, Joosten RG, Roos N, Zevenhoven-Dobbe JC, Snijder EJ.The replication/transcription complex of the arterivirus equine arteritis virus (EAV) is associated with paired membranes and/or double-membrane vesicles (DMVs) that are thought to originate from the endoplasmic reticulum. Previously, coexpression of two putative transmembrane nonstructural proteins (nsp2 and nsp3) was found to suffice to induce these remarkable membrane structures, which are typical of arterivirus infection. Here, site-directed mutagenesis was used to investigate the role of nsp3 in more detail. Liberation of the hydrophobic N terminus of nsp3, which is normally achieved by c...
