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.
Mossel EC, Ledermann JP, Phillips AT, Borland EM, Powers AM, Olson KE.Western equine encephalitis virus (WEEV) is a naturally occurring recombinant virus derived from ancestral Sindbis and Eastern equine encephalitis viruses. We previously showed that infection by WEEV isolates McMillan (McM) and IMP-181 (IMP) results in high (∼90-100%) and low (0%) mortality, respectively, in outbred CD-1 mice when virus is delivered by either subcutaneous or aerosol routes. However, relatively little is known about specific virulence determinants of WEEV. We previously observed that IMP infected Culex tarsalis mosquitoes at a high rate (app. 80%) following ingestion of an in...
Silva MG, Graça T, Suarez CE, Knowles DP.Theileriosis in horses and cattle is caused by tick-borne Apicomplexa parasites and results in death or life-long infection in their respective hosts. Transmission risk associated with persistent infection severely limits movement of horses and cattle resulting in economic losses. The recent reemergence of Theileria equi infection in U.S. horses demonstrates the continual threat Apicomplexa parasites represent to global animal health. A paucity of data concerning equine immune responses to T. equi, including antigens recognized by antibodies in clinically asymptomatic, persistently infected ho...
Gilliam LL, Carmichael RC, Holbrook TC, Taylor JM, Ownby CL, McFarlane D, Payton ME.Antivenom antibody titers following administration of rattlesnake venom for antivenom production in horses are well documented; however, antivenom antibody titers following natural rattlesnake envenomation in horses are not. Antibody titers produced in response to the commercially available rattlesnake venom vaccine are also not published. Our study objectives were to measure antivenom antibody titers in rattlesnake-bitten horses and compare them to titers in horses vaccinated with the rattlesnake venom vaccine. Additionally, titers were compared in pregnant versus nonpregnant horses to assess...
Azab W, Lehmann MJ, Osterrieder N.Herpesviruses enter cells either by direct fusion at the plasma membrane or from within endosomes, depending on the cell type and receptor(s). We investigated two closely related herpesviruses of horses, equine herpesvirus type 1 (EHV-1) and EHV-4, for which the cellular and viral determinants routing virus entry are unknown. We show that EHV-1 enters equine epithelial cells via direct fusion at the plasma membrane, while EHV-4 does so via an endocytic pathway, which is dependent on dynamin II, cholesterol, caveolin 1, and tyrosine kinase activity. Exchange of glycoprotein H (gH) between EHV-1...
van der Meide NM, Roders N, Sloet van Oldruitenborgh-Oosterbaan MM, Schaap PJ, van Oers MM, Leibold W, Savelkoul HF, Tijhaar E.Insect bite hypersensitivity (IBH) is an IgE-mediated (Type I) hypersensitivity reaction induced by allergens from biting midges of the Culicoides spp. The aim of the present study was to identify, clone and express recombinant allergens from C. obsoletus, the main species found feeding on horses in the Netherlands, by sequence homology searches on the C. obsoletus specific RNA database, with previously described allergens from C. nubeculosus and C. sonorensis. BLAST searches with these described allergens resulted in similarity hits with 7 genes coding for C. obsoletus allergens. These allerg...
Yeo WM, Osterrieder N, Stokol T.The alphaherpesvirus, equine herpesvirus type 1 (EHV-1), is a highly prevalent cause of equine infectious abortion and encephalomyelopathy. These syndromes have been attributed to ischemic necrosis from thrombosis in placental and neural vessels, although the mechanisms underlying thrombosis are unknown. After inhalation, EHV-1 establishes a peripheral blood mononuclear cell-associated viremia, with monocytes being a target of infection. Monocytes are also the main source of tissue factor (TF) in diseased states. Since TF is the primary activator of coagulation, increased monocyte TF expressio...
Moyo NA, Marchi E, Steinbach F.Dendritic cells (DC) are the main immune mediators inducing primary immune responses. DC generated from monocytes (MoDC) are a model system to study the biology of DC in vitro, as they represent inflammatory DC in vivo. Previous studies on the generation of MoDC in horses indicated that there was no distinct difference between immature and mature DC and that the expression profile was distinctly different from humans, where CD206 is expressed on immature MoDC whereas CD83 is expressed on mature MoDC. Here we describe the kinetics of equine MoDC differentiation and activation, analysing both ph...
Diaz-San Segundo F, Dias CC, Moraes MP, Weiss M, Perez-Martin E, Owens G, Custer M, Kamrud K, de los Santos T, Grubman MJ.We have previously shown that delivery of the porcine type I interferon gene (poIFN-α/β) with a replication-defective human adenovirus vector (adenovirus 5 [Ad5]) can sterilely protect swine challenged with foot-and-mouth disease virus (FMDV) 1 day later. However, the need of relatively high doses of Ad5 limits the applicability of such a control strategy in the livestock industry. Venezuelan equine encephalitis virus (VEE) empty replicon particles (VRPs) can induce rapid protection of mice against either homologous or, in some cases, heterologous virus challenge. As an alternative approach ...
Vendrig JC, Coffeng LE, Fink-Gremmels J.Increasing evidence suggests that reactions to lipopolysaccharide (LPS), particularly in the gut, can be partly or completely mitigated by colostrum- and milk-derived oligosaccharides. Confirmation of this hypothesis could lead to the development of new therapeutic concepts. Objective: To demonstrate the influence of equine colostral carbohydrates on the inflammatory response in an in vitro model with equine peripheral blood mononuclear cells (PBMCs). Methods: Carbohydrates were extracted from mare colostrum, and then evaluated for their influence on LPS-induced inflammatory responses in PBMCs...
Velez IC, Arnold C, Jacobson CC, Norris JD, Choi YH, Edwards JF, Hayden SS, Hinrichs K.Transvaginal ultrasound-guided follicle aspiration (TVA) is performed clinically but there is little information available on complications associated with this procedure. Objective: It is possible that TVA is associated with damage to the ovary and may induce peritonitis or peritoneal adhesions. This study was conducted to determine the effect of repeated TVA on mare health and ovarian status. Methods: Thirty-two mares were used for oocyte recovery via repeated TVA over a 3 year period; different mares were used each year. In Year 1, ovarian status was monitored in 11 mares by transrectal pal...
Jenvey C, Caraguel C, Howarth GB, Riley CB.Prior to the start of endogenous production of immunoglobulins (Igs), absorption of maternal Igs is important to protect against pathogens in the early neonatal period. It is possible that mare- or foal-associated factors may influence neonatal IgA concentrations. Objective: The temporal relationships among serum and milk IgA concentrations in Thoroughbred mare-foal pairs were explored to determine if periparturient mare- and foal-associated factors contribute to the prediction of foal serum IgA concentrations. Methods: Blood and milk samples as well as complete veterinary records, were collec...
Finger MA, Villalobos EM, Lara Mdo C, Cunha EM, Barros Filho IR, Deconto I, Dornbusch PT, Ullmann LS, Biondo AW.Toxoplasma gondii, the agent for toxoplasmosis, has worldwide distribution. Horses normally play a secondary role in its life cycle, but movement around urban areas, feeding on grass and the increasing use of carthorses for gathering recyclable material in some urban areas of Brazil may increase their exposure to T. gondii infection. The aim of the present study was to investigate the frequency of anti-T. gondii antibodies in carthorses in the metropolitan region of Curitiba, PR. IgG antibodies against T. gondii were detected using the indirect fluorescence antibody test (IFAT) (titers ≥ 64)...
Wong DM, Giguère S, Wendel MA.To compare the diagnostic performance of a point-of-care (POC) analyzer with that of established methods for the measurement of plasma IgG, total protein, and albumin concentrations in neonatal foals. Methods: Evaluation study. Methods: 100 neonatal foals < 7 days of age. Procedures-Plasma IgG, total protein, and albumin concentrations were measured with a POC analyzer via an immunoturbidimetric method. Corresponding measurements of plasma IgG, total protein, and albumin concentrations were measured by means of automated biochemical analyzers via automated immunoturbidimetric, biuret, and b...
Magori K, Park AW.The emergence and spread of mutant pathogens that evade the effects of prophylactic interventions, including vaccines, threatens our ability to control infectious diseases globally. Imperfect vaccines (e.g. those used against influenza), while not providing life-long immunity, confer protection by reducing a range of pathogen life-history characteristics; conversely, mutant pathogens can gain an advantage by restoring the same range of traits in vaccinated hosts. Using an SEIR model motivated by equine influenza, we investigate the evolutionary consequences of alternative types of imperfect va...
Theoret CL, Wilmink JM.Impaired wound healing represents an enormous clinical and financial problem for companion animals and humans alike. Unfortunately, most models used to study healing rely on rodents, which have significant differences in the healing and scarring process and rarely develop complications. In order to better simulate impaired healing, the model should strive to reproduce the natural processes of healing and delayed healing. Wounds on the limbs of horses display similarities to wounds in humans in their epithelialization/contraction ratio, genetic influence as well as dysregulated cytokine profile...
Cudmore LA, Muurlink T, Whittem T, Bailey SR.Pro-inflammatory cytokines, such as IL-1β and TNFα, play a major role in activating leukocytes and endothelial cells during the systemic inflammatory response to endotoxin in the horse. β2 agonist drugs, such as clenbuterol, inhibit leukocyte activation. This study aimed to determine the effects of oral clenbuterol on clinical and leukocyte responses, including production of TNFα, in an in vivo endotoxin challenge model. In a randomised crossover design, horses received either clenbuterol or a placebo product prior to the administration of low dose endotoxin (30 ng/kg over 30 min). Clinica...
Wagner B, Goodman LB, Rollins A, Freer HS.Lyme disease is caused by Borrelia burgdorferi, which is transmitted by infected ticks (Ixodes spp.). Reports on Lyme disease in horses have increased in recent years. Nevertheless, the diagnosis of Lyme disease in horses is still challenging owing to its vague clinical presentation and the limitations of diagnostic tests. Objective: This study used a new serological Lyme multiplex assay to examine antibody responses to 3 antigens of B. burgdorferi, outer surface protein (Osp) C, OspF and C6, and to verify their use as markers for early and late infection stages in horses. Methods: Multiplex...
Keggan A, Freer H, Rollins A, Wagner B.Horses have 11 immunoglobulin isotypes: IgM, IgD, IgA, IgE, and seven IgG subclasses designated as IgG1-IgG7, each of which are distinguished by separate genes encoding the constant heavy chain regions. Immunoglobulin (Ig) isotypes have different functions during the immune response and pathogen-specific isotypes can be used as indicators for immunity and protection from disease. In addition to existing monoclonal antibodies to various equine Igs, quantification of the individual isotypes requires pure isotype standards. In this report, we describe a fusion between X63-Ag8.653 mouse myeloma ce...
Renzi S, Riccò S, Dotti S, Sesso L, Grolli S, Cornali M, Carlin S, Patruno M, Cinotti S, Ferrari M.The use of Mesenchymal Stromal Cells (MSCs) in orthopedic practice has recently and rapidly acquired an important role. Therapies based on the use of MSCs for the treatment of acute injuries as well as chronic inflammatory disorders are gradually becoming clinical routine. These cells have demonstrated intriguing therapeutic potentialities (i.e.: inflammation control, tissue regeneration and pathological scar prevention), that have been taken into consideration for use in both human and veterinary medicine. In particular, horses represent high performance athletes considered models for human p...
Munkhjargal T, Sivakumar T, Battsetseg B, Nyamjargal T, Aboulaila M, Purevtseren B, Bayarsaikhan D, Byambaa B, Terkawi MA, Yokoyama N, Igarashi I.Equine piroplasmosis represents a serious problem in horse industry. Although, researchers suggested the possible use of sub-unit vaccines to control equine piroplasmosis, the genetic diversity of vaccine candidate antigens was not properly investigated. In the present study, we screened 250 horses reared in three different districts of Tov province, Mongolia, for Babesia caballi and Theileria equi using ELISA and nested PCR (nPCR) assays. Among these animals, piroplasms were detected in 128 (51.2%) horses by nPCR assays (B. caballi, 42.4%; T. equi, 6.4%; and mixed infections, 2.4%), while 204...
Sabban S, Ye H, Helm B.The binding of immunoglobulin E (IgE) to its high-affinity receptor (FcɛRI) is the central protein interaction in IgE-mediated allergic reactions. The cross-linking of the IgE/FcɛRI complex, through cognate allergens, on the surface of mast cells and basophil cells results in mediator release, and thus leads to the symptoms of type I hypersensitivity responses in mammals. To develop a baseline value for subsequent equine anti-allergy drug and vaccine research, the interaction of equine IgE with its high-affinity FcɛRI receptor was investigated following the cloning and expression of equine ...
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...
Bonin CP, Baccarin RY, Nostell K, Nahum LA, Fossum C, de Camargo MM.Engagement of Toll-like receptor 4 (TLR4) by lipopolysaccharide (LPS) is a master trigger of the deleterious effects of septic shock. Horses and humans are considered the most sensitive species to septic shock, but the mechanisms explaining these phenomena remain elusive. Analysis of tlr4 promoters revealed high similarity among LPS-sensitive species (human, chimpanzee, and horse) and low similarity with LPS-resistant species (mouse and rat). Four conserved nuclear factor kappa B (NFκB) binding sites were found in the tlr4 promoter and two in the md2 promoter sequences that are likely to be t...
Fortier G, Richard E, Hue E, Fortier C, Pronost S, Pottier D, Lemaitre L, Lekeux P, Borchers K, Thiry E.The aim of this trial was to investigate the putative involvement of equid herpesvirus 2 (EHV-2) in airway inflammation of adult horses. Six horses received corticosteroid treatment, before either mock infection (n=2) or EHV-2 strain LK4 inoculation (n=4). These four horses were also submitted to immunosuppression 84 days post inoculation. EHV-2 was detected by quantitative PCR in respiratory samples up to respectively 21 days and 14 days. Nested PCR, cloning and sequencing allowed the detection of five different 'field' strains throughout the trial. Neutrophils proportions were transiently in...
Guidolin FR, Tambourgi DV, Guidolin R, Marcelino JR, Okamoto CK, Magnoli FC, Queiroz GP, Dias da Silva W.Crotalus durissus terrificus, C. d. collilineatus, C. d. cascavella and C. d. marajoensis are responsible minor but severe snake bites in Brazil. The venoms of these snakes share the presence of crotoxin, a neurotoxin comprising of two associated components, crotapotin and phospholipase A2 (PLA2). Treatment of the victims with specific antiserum is the unique effective therapeutic measure. The ability of anti-Crotalus antisera produced by the routine using crude venom to immunize horses or purified crotoxin and PLA2 as individual immunogens was compared. Antisera obtained from horses immunized...
Murcia PR, Baillie GJ, Stack JC, Jervis C, Elton D, Mumford JA, Daly J, Kellam P, Grenfell BT, Holmes EC, Wood JL.Influenza A viruses are characterized by their ability to evade host immunity, even in vaccinated individuals. To determine how prior immunity shapes viral diversity in vivo, we studied the intra- and interhost evolution of equine influenza virus in vaccinated horses. Although the level and structure of genetic diversity were similar to those in naïve horses, intrahost bottlenecks may be more stringent in vaccinated animals, and mutations shared among horses often fall close to putative antigenic sites.
Wang L, Pawlak EA, Johnson PJ, Belknap JK, Eades S, Stack S, Cousin H, Black SJ.The digital laminae is a two layer tissue that attaches the distal phalanx to the inner hoof wall, thus suspending the horse's axial skeleton in the hoof capsule. This tissue fails at the epidermal:dermal junction in laminitic horses, causing crippling disease. Basal epithelial cells line the laminar epidermal:dermal junction, undergo physiological change in laminitic horses, and lose versican gene expression. Versican gene expression is purportedly under control of the canonical Wnt signaling pathway and is a trigger for mesenchymal-to-epithelial transition; thus, its repression in laminar ep...
Paillot R.Inactivated Parapoxvirus ovis (iPPVO) and Propionibacterium acnes (P. acnes) are currently used in equine medicine as immune-modulators for prophylactic treatment or adjunct to conventional therapy in order to improve immune defences, to prevent or treat infectious diseases. Their mode of action relies on a non-antigen specific interaction with the innate and/or adaptive immune responses. iPPVO stimulates and regulates cytokine secretion by leucocytes, while P. acnes acts primarily through the activation of macrophages. This report aims to describe their activity as immune-modulators and to su...
Olsen CW, McGregor MW, Dybdahl-Sissoko N, Schram BR, Nelson KM, Lunn DP, Macklin MD, Swain WF, Hinshaw VS.Two fundamentally different approaches to vaccination of BALB/c mice with the hemagglutinin (HA) of A/Equine/Kentucky/1/81 (H3N8) (Eq/KY) were evaluated, that is, administration of HA protein vs administration of HA-encoding DNA. Each vaccine was tested for its immunogenicity and ability to provide protection from homologous virus challenge. HA protein was synthesized in vitro by infection of Sf21 insect cells with a recombinant baculovirus. Intranasal administration of this vaccine induced virus-specific antibodies, as measured by enzyme-linked immunosorbent assay (ELISA), but did not induce ...
Baker JM, Bamford AI, Antczak DF.Maternal immune recognition of the developing conceptus in equine pregnancy is characterized by the strongest and most consistent alloantibody response described in any species, a response directed almost exclusively against paternal MHC class I Ags. This work investigated the cellular immune response to paternal MHC Ags in pregnant and nonpregnant horses and donkeys, and in horses carrying interspecies hybrid mule conceptuses. We observed profound decreases in classical, MHC-restricted, CTL activity to allogeneic paternal cells in peripheral blood lymphocytes from both horse mares and donkey ...
Osborne RL, Coggins MK, Walla M, Dawson JH.The heme-containing respiratory protein, myoglobin (Mb), best known for oxygen storage, can exhibit peroxidase-like activity under conditions of oxidative stress. Under such circumstances, the initially formed ferric state can react with H2O2 (or other peroxides) to generate a long-lived ferryl [Fe(IV)=O] Compound II (Cpd II) heme intermediate that is capable of oxidizing a variety of biomolecules. In this study, the ability of Mb Cpd II to catalyze the oxidation of carcinogenic halophenols is demonstrated. Specifically, 2,4,6-trichlorophenol (TCP) is converted to 2,6-dichloro-1,4-benzoquinone...
Adams AP, Oriol JG, Campbell RE, Oppenheim YC, Allen WR, Antczak DF.This research tested the hypothesis that immunological sensitization of mares by skin allografting, followed by the establishment of pregnancy using semen from the skin-graft donor, would give rise to secondary immune responses to the developing horse conceptus, resulting in an earlier demise of the fetally derived endometrial cups. Maiden mares received skin allografts from a stallion homozygous for Major Histocompatibility Complex (MHC) antigens and/or equivalent autografts and were subsequently mated to the skin-graft donor stallion during the next two breeding seasons. Mares that had been ...
Ranz AI, Miguet JG, Anaya C, Venteo A, Cortés E, Vela C, Sanz A.A panel of 32 hybridoma cell lines secreting monoclonal antibodies (MAbs) reactive with African horsesickness virus serotype 4 (AHSV-4) has been developed. Four of the MAbs recognized the major core antigen VP7, twenty recognized the outer capsid protein VP2 and eight reacted with the non-structural protein NS1. With the VP7-specific MAbs a rapid and sensitive double antibody sandwich immunoassay has been developed to detect viral antigen in infected Vero cells and in spleen tissue from AHSV-infected horses. The sensitivity of the assay is 10 ng viral antigen per 100 microliters. The NS1-speci...
Larson EM, Wagner B.Horses have many naturally occurring diseases that mimic similar conditions in humans. The ability to conduct environmentally controlled experiments and induced disease studies in a genetically diverse host makes the horse a valuable intermediate model between mouse studies and human clinical trials. This review highlights important similarities in the immune landscape between horses and humans using current research on two equine diseases as examples. First, equine herpesvirus type 1 (EHV-1) infection initiates a series of innate inflammatory signals at its mucosal entry site in the upper res...
Sun C, Zhang B, Jin J, Montelaro RC.The identification and characterization of a functional cellular receptor for equine infectious anemia virus (EIAV), designated equine lentivirus receptor-1 (ELR1), a member of the tumour necrosis factor receptor protein family, has been reported previously [Zhang, B. et al. (2005). Proc Natl Acad Sci U S A, 102 , 9918-9923]. The finding of a single receptor for EIAV is distinct from feline, simian and human immunodeficiency viruses, which typically utilize two co-receptors for infection, but is similar to avian and murine oncoviruses, which use single receptors. This study sought to determine...
Widders PR, Stokes CR, Newby TJ, Bourne FJ.This study identifies nonimmune binding of equine immunoglobulin by the causative organism of contagious equine metritis. Immunoglobulin binding to the bacterium was strongest for immunoglobulin G (IgG) and less for IgM; IgA was not bound. Binding of equine IgG was inhibited by human IgG, but not by IgG of domestic animals. Immunoglobulin binding by the bacterium appeared to be directed towards an epitope in the hinge region of the immunoglobulin molecule.
Dam Van P, Desmecht D, Garigliany MM, Bui Tran Anh D, Van Laere AS.Type I/III interferons provide powerful and universal innate intracellular defense mechanisms against viruses. Among the antiviral effectors induced, Mx proteins of some species appear as key components of defense against influenza A viruses. It is expected that such an antiviral protein must display a platform dedicated to the recognition of said viruses. In an attempt to identify such platform in human MxA, an evolution-guided approach capitalizing on the antagonistic arms race between MxA and its viral targets and the genomic signature it left on primate genomes revealed that the surface-ex...
Larson EM, Babasyan S, Wagner B.IL-8 is a potent chemokine that recruits neutrophils and basophils to promote inflammation in many species. IL-8 is produced by many cell types, including monocytes. In this study, we report a novel role for IgE-binding monocytes, a rare peripheral immune cell type, to promote allergic inflammation through IL-8 production in a horse model of natural IgE-mediated allergy. We developed a mAb with confirmed specificity for both recombinant and native equine IL-8 for flow cytometric analysis. Equine IL-8 was produced by CD14/MHC class II/CD16 monocytes, including a subpopulation of IgE-binding mon...
Satoh M, Fujinaga T, Okumura M, Hagio M.To measure the concentration of serum amyloid A (sAA) protein in horses, a sensitive and highly reproducible sandwich (ELISA) was established, using affinity purified SAA antibody. Results of the ELISA were found to have a high correlation (r = 0.95) with those of the single radial immunodiffusion test. Equine SAA concentration was measured by use of this ELISA. In clinically normal horses, the concentration of SAA was high immediately after birth to 2 weeks of age. After that, SAA concentration had periodic fluctuations in the range of approximately 1.0 to 30 micrograms/ml. Mean (+/- SD)) con...
Depuydt E, Broeckx SY, Chiers K, Patruno M, Da Dalt L, Duchateau L, Saunders J, Pille F, Martens A, Van Hecke L, Spaas JH.The use of mesenchymal stem cells (MSCs) for the treatment of equine tendon disease is widely investigated because of their regenerative and immunomodulatory potential. However, questions have been raised concerning the immunogenic properties of allogeneic MSCs. Therefore, two studies were conducted to assess the safety of equine allogeneic peripheral blood-derived tenogenic primed MSCs (tpMSCs). The objective was to evaluate if a single and repeated tpMSC administration induced a cellular and humoral immune response in horses suffering from tendon injuries. Horses enrolled in the first study ...
Dutta SK, Myrup AC, Thaker SR.Interference between equine herpesvirus types 1 (EHV-1) and 2 (EHV-2) was studied in equine dermis (ED) monolayer cell cultures and equine lymphocyte cultures. Cell cultures were infected with EHV-2, and after a short incubation period, the cultures were superinfected with EHV-1. At various intervals, different measurements of EHV-1 expression in dually infected cultures, compared with those in cultures infected with EHV-1 alone, were studied. In dually infected ED cell cultures, the EHV-1 cytopathic effect, EHV-1 titer, and EHV-1 enzyme-linked immunosorbent assay antigen titer were maximally ...
O'Neill W, McKee S, Clarke AF.This study was undertaken to compile new data on the efficacy of Echinacea in stimulating the immune system of the horse. Use of Echinacea is becoming widespread in horses, despite an absence of controlled laboratory research into its effectiveness or safety. This paper documents results of a double-blind, placebo-controlled, cross-over trial investigating the effect of standardised Echinacea extract on 8 horses. Animals were supplemented with Echinacea or placebo for 42 days, and their response to supplements recorded. Treatment with Echinacea increased phagocytic ability of isolated neutroph...
Zamansky GB, Arundel C, Nagasawa H, Little JB.The growth of two human diploid skin fibroblast cell lines, originally grown in medium supplemented with foetal bovine serum and later adapted to medium supplemented with newborn bovine, bovine calf or horse serum, has been studied. Prolonged generation times increased cell volumes and decreased plating efficiencies were observed in cultures grown in newborn bovine, bovine calf or horse serum. In general, the deleterious effects were most severe as a result of growth in bovine calf or horse serum. In the light of the present findings, we believe investigators should exert great caution in swit...
Pacholewska A, Marti E, Leeb T, Jagannathan V, Gerber V.Lipopolysaccharide (endotoxin, LPS) is a strong inducer of the innate immune response. It is widespread in our environment, e.g. in house dust and contributes to asthma. Compared to humans, horses are even more sensitive to LPS. However, data on LPS effects on the equine transcriptome are very limited. Using RNA-seq we analysed LPS-induced differences in the gene expression in equine peripheral blood mononuclear cells at the gene and gene-network level in two half-sib families and one group of unrelated horses. 24 h-LPS challenge of equine immune cells resulted in substantial changes in the t...
De-Simone SG, Souza ALA, Aguiar AS, Melgarejo AR, Provance DW.Hypersensitive diseases that involve IgE reactivity are important concern of public, especially those encompassing the potential pathogenesis from the administration of horse serum-based therapeutics such as antivenoms. A method for the definitive diagnosis of reactive IgE is important for identifying allergic patients to control severe collateral effects during planned and emergency application of immunotherapies when the allergy source cannot be avoided for treatment. To date, no tests have been developed to accompany the wide range of antivenoms produced from horse sera. The aim of this was...
Evans KS, Carpenter SL, Sevoian M.The enzyme-linked immunosorbent assay (ELISA) antigen-positive and agar-gel immunodiffusion test (AGID)-negative horses do not have infective equine infectious anemia (EIA) virus. The ELISA testing of horse leukocyte culture (HLC) supernatants did detect EIA virus in a HLC that was infected with the Wyoming strain of EIA virus and in HLC derived from horses in febrile, acute, or subacute stages of EIA infection. In supernatants of HLC derived from chronic and inapparent carrier horses, EIA virus was not detected with ELISA. Direct fluorescent antibody tests detected EIA virus in HLC infected w...
Daly JM, Elton D.The calculation of p(epitope) values, a sequence-based measure of antigenic distance between strains, was developed for human influenza. The potential to apply the p(epitope) value to equine influenza vaccine strain selection was assessed. There was a negative correlation between p(epitope) value and vaccine efficacy for pairs of vaccine and challenge strains used in cross-protection studies in ponies that just reached statistical significance (p=0.046) only if one pair of viruses was excluded from the analysis. Thus the p(epitope) value has potential to provide additional data to consider in ...
Van Cleemput J, Poelaert KCK, Laval K, Vanderheijden N, Dhaenens M, Daled S, Boyen F, Pasmans F, Nauwynck HJ.β-Defensins protect the respiratory tract against the myriad of microbial pathogens entering the airways with each breath. However, this potentially hostile environment is known to serve as a portal of entry for herpesviruses. The lack of suitable respiratory model systems has precluded understanding of how herpesvirus virions overcome the abundant mucosal β-defensins during host invasion. We demonstrate how a central alphaherpesvirus, equine herpesvirus type 1 (EHV1), actually exploits β-defensins to invade its host and initiate viral spread. The equine β-defensins (eBDs) eBD1, -2, and -3...
Taira T, Fujinaga T, Okumura M, Yamashita K, Tsunoda N, Mizuno S.Haptoglobin (Hp) was isolated from equine serum by ammonium sulphate precipitation, anion-exchange chromatography and gel filtration. Equine Hp which migrated to the alpha 2-globulin region in electrophoresis, contained 2 fractions with molecular weights (NW) of 108,000 and 105,000, and each fraction consisting of 2 subunits. Quantitative measurement of Hp in equine serum was performed by the single radial immunodiffusion method using anti-equine Hp serum. In clinically normal horses, the highest concentration of serum Hp was found in newborn foals and a high value was maintained until 12 mont...
Proft A, Spiesschaert B, Izume S, Taferner S, Lehmann MJ, Azab W.The serine-threonine protein kinase encoded by gene (pUS3) of alphaherpesviruses was shown to modulate actin reorganization, cell-to-cell spread, and virus egress in a number of virus species. However, the role of the US3 orthologues of equine herpesvirus type 1 and 4 (EHV-1 and EHV-4) has not yet been studied. Here, we show that is not essential for virus replication in vitro. However, growth rates and plaque diameters of a -deleted EHV-1 and a mutant in which the catalytic active site was destroyed were significantly reduced when compared with parental and revertant viruses or a virus in w...
Ushimi C, Henson JB, Gorham JR.Primary horse leukocyte cultures were inoculated with 2 or 10 50% tissue culture infective doses (TCID(50)) of equine infectious anemia (EIA) virus per cell, and the titer of cell-associated and fluid-phase virus was determined from 1 to 72 hr postinoculation (PI). Cover slips were collected from 4 to 72 hr PI and stained for EIA viral antigen by the indirect immunofluorescent (FA) technique. Viral replication was detected after a latent period of approximately 18 to 24 hr and reached peak titers of approximately 10(4.5) to 10(6) TCID(50)/0.5 ml from 48 to 72 hr PI. The fluid phase contained 1...
Burgueño A, Spinsanti L, Díaz LA, Rivarola ME, Arbiza J, Contigiani M, Delfraro A.St. Louis encephalitis virus (SLEV) and West Nile virus (WNV) belong to the Japanese encephalitis antigenic complex (Flavivirus genus, Flaviviridae family). They show antigenic close relationships and share many similarities in their ecology. Both are responsible for serious human diseases. The aim of this study was to investigate the presence of neutralizing antibodies to these viruses in horses from Uruguay. To do this, 425 horse sera were collected in 2007 and analyzed by plaque reduction neutralization tests. As a result, 205 sera (48.2%) were found positive for SLEV, with titers ranging b...
Kiemle J, Hindenberg S, Bauer N, Roecken M.Rapid, accurate detection of serum amyloid A (SAA) is needed in equine practice. We validated a patient-side point-of-care (POC) assay (Stablelab; Zoetis) compared to the turbidimetric immunoassays LZ-SAA (TIA-Hum) and VET-SAA (TIA-Vet; both Eiken Chemical). Analytical performance was assessed at 3 different concentration ranges and with interferences. Inter-method comparison using 49 equine serum samples revealed a significant difference between median SAA results ( < 0.0001), with the strongest bias between the POC and TIA-Vet (median 1,093 vs. 578 mg/L). The median SAA value obtain...
Chung C, Mealey RH, McGuire TC.Cytotoxic T lymphocytes (CTL) are critical for lentivirus control including EIAV. Since CTL from most EIAV carrier horses recognize Gag epitope clusters (EC), the hypothesis that carrier horses would have high functional avidity CTL to optimal epitopes in Gag EC was tested. Twenty-two optimal EC epitopes were identified; two in EC1, six in EC2, and seven each in EC3 and 4. However, only five of nine horses had high functional avidity CTL (<or=11 nM) recognizing six epitopes in EC; four in relatively conserved EC3; and one each in EC1 and 2. Horses with high functional avidity CTL had signif...
Equine recurrent uveitis serves as a spontaneous model for human autoimmune uveitis. Unpredictable relapses and ongoing inflammation in the eyes of diseased horses as well as in humans lead to destruction of the retina and finally result in blindness. However, the molecular mechanisms leading to inflammation and retinal degeneration are not well understood. An initial screening for differentially regulated proteins in sera of uveitic cases compared to healthy controls revealed an increase of the alternative pathway complement component factor B in ERU cases. To determine the activation status ...
Rhiner T, Fettelschoss V, Schoster A, Birkmann K, Fettelschoss-Gabriel A.Previously, virus-like particle (VLP)-based self-vaccinations targeting interleukin (IL)-5 or IL-31 have been suggested to treat equine insect bite hypersensitivity (IBH), a seasonal recurrent allergic dermatitis in horses. The IL-5-targeting equine vaccine significantly reduced blood eosinophil counts in horses, similar to human monoclonal antibodies targeting IL-5 or the IL-5 receptor alpha (IL-5Rα). Previous studies in humans have also reported an additional effect on reduction of basophil counts. The aim of the present study was to evaluate whether an equine anti-IL-5 vaccine affected blo...
Riley CB, McClure JT, Low-Ying S, Shaw RA.The economic, accurate, and rapid screening of foals for failure of transfer of passive immunity (FPT) is essential to ensure timely intervention. Objective: Infrared (IR) spectroscopy of foal sera and pattern recognition may be used to diagnose FPT and quantify serum IgG. Methods: Sera from 194 foals (24-72 hours) with serum immunoglobulin G (IgG) concentrations determined previously by radial immunodiffusion assay (RID) were used. Methods: IR spectra were recorded for the serum samples, and the data were randomly divided into training and independent test sets, each containing both FPT-posit...
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...
