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.
Robertson SA, Andrew SE.To determine if opioid growth factor (OGF, [Met5]enkephalin) and its specific receptor (OGFr) are present in normal cat, dog and horse cornea. Methods: Normal dog, cat and horse. Methods: Corneas were obtained from animals euthanized for reasons unrelated to this project. One cornea from each of three normal cats, dogs and horses was evaluated. The right or left cornea from each animal was chosen randomly. Corneas were harvested and placed in corneal storage media for transport to The M.S. Hershey Medical Center of The Pennsylvania State University where immunocytochemistry techniques were use...
Wieringa R, de Vries AA, Rottier PJ.Equine arteritis virus (EAV) is an enveloped, positive-stranded RNA virus belonging to the family Arteriviridae of the order NIDOVIRALES: Six transmembrane proteins have been identified in EAV particles: the nonglycosylated membrane protein M and the glycoprotein GP(5) (previously named G(L)), which occur as disulfide-bonded heterodimers and are the major viral envelope proteins; the unglycosylated small envelope protein E; and the minor glycoproteins GP(2b) (formerly designated G(S)), GP(3), and GP(4). Analysis of the appearance of the GP(2b), GP(3), and GP(4) proteins in viral particles by g...
Hooper-McGrevy KE, Wilkie BN, Prescott JF.Rhodococcus equi causes severe pyogranulomatous pneumonia in foals and in immunocompromised humans. Replication of virulent isolates within macrophages correlates with the presence of a large plasmid which encodes a family of seven virulence-associated proteins (VapA and VapC to VapH), whose functions are unknown. Although cell-mediated immunity is thought to be crucial in eliminating R. equi infection, antibody partially protects foals. The antibody response to both VapA and VapC was similar in six adult horses and six naturally exposed but healthy foals, as well as in eight foals with R. equ...
Szeredi L, Pálfi V, Molnár T.The objective of the investigations was to study the occurrence of the equine herpesvirus type 1 (EHV-1) infection in aborted equine fetuses and in newborn foals and to compare the sensitivity of virus isolation, immunohistochemistry and histology in 101 cases and of fetal serology in 68 cases in the diagnosis of the infection. Out of the 93 aborted equine fetuses and 8 weak foals, 15 (14.9%) (14 fetuses and 1 foal) proved to be EHV-1 infected by immunohistochemical and 13 (12.9%) by virological investigation. Characteristic microscopic changes were seen in several organs in all cases, while i...
Kalina WV, Pettigrew HD, Gershwin LJ.Equine disease with an allergic etiology is common. Environmental antigens most often implicated as allergens in horses include molds, dusty hay, grass pollen, hay dust mites, and insect saliva. Although intradermal testing with allergen is a useful diagnostic tool for some species, skin testing frequently produces false positive results in horses. Allergen deprivation as a diagnostic tool is often impossible and at best it is ineffective at diagnosing the specific allergic reactivity. Synthesis of IgE after exposure to allergen is the instigator of the allergic process. While IgE exerts its e...
Porter MB, Long MT, Getman LM, Giguère S, MacKay RJ, Lester GD, Alleman AR, Wamsley HL, Franklin RP, Jacks S, Buergelt CD, Detrisac CJ.To determine signalment, clinical findings, results of diagnostic testing, outcome, and postmortem findings in horses with West Nile virus (WNV) encephalomyelitis. Methods: Retrospective study. Methods: 46 horses with WNV encephalomyelitis. Methods: Clinical data were extracted from medical records of affected horses. Results: On the basis of clinical signs and results of serologic testing, WNV encephalomyelitis was diagnosed in 46 of 56 horses with CNS signs. Significantly more males than females were affected. Increased rectal temperature, weakness or ataxia, and muscle fasciculations were t...
Wattrang E, Jessett DM, Yates P, Fuxler L, Hannant D.The production of interferon (IFN), interleukin-6 (IL-6), and tumor necrosis factor (TNF) was monitored in horses during the course of influenza A2 virus infections. The effects of two virus strains, Newmarket/2/93 and Sussex/89, were compared, of which the latter is considered the more pathogenic in terms of clinical signs. Ten naive ponies were infected with influenza A/equine/Sussex/89 and 10 with influenza A/equine/Newmarket/2/93, respectively. As expected ponies infected with Sussex/89 showed the most pronounced clinical signs but there was no notable difference in viral excretion compare...
Criado-Fornelio A, Martinez-Marcos A, Buling-Saraña A, Barba-Carretero JC.Molecular epizootiology of piroplasmids (Babesia spp., Theileria spp.) and Hepatozoon canis was studied in mammals from southern Europe (mainly from Spain, but also from Portugal and France). Partial amplification and sequencing of the 18s rRNA gene was used for molecular diagnosis. In some particular cases (B. ovis and B. bovis) the complete 18s rRNA gene was sequenced. Blood samples were taken from domestic animals showing clinical symptoms: 10 dogs, 10 horses, 10 cows, 9 sheep and 1 goat. In addition, DNA samples were isolated from blood of 12 healthy dogs and from spleen of 10 wild red fox...
McAleese SM, Miller HR.The high-affinity receptor for IgE is expressed on the surface of mast cells and basophils. It is a transmembrane protein with one alpha, one beta and two gamma subunits. The cDNA sequences for the alpha subunit have already been determined. We report here the cDNA sequences for the beta and gamma subunits. The cytoplasmic domains of these subunits are important for intracellular signalling and the deduced amino acid sequences show the expected immunoreceptor tyrosine-based activation motifs. The gamma subunit is highly conserved between species but more variation is seen with the beta subunit...
Potgieter AC, Cloete M, Pretorius PJ, van Dijk AA.The outer capsid protein VP2 of African horsesickness virus (AHSV) is a major protective antigen. We have cloned full-length VP2 genes from the reference strains of each of the nine AHSV serotypes. Baculovirus recombinants expressing the cloned VP2 genes of serotypes 1, 2, 4, 6, 7 and 8 were constructed, confirming that they all have full open reading frames. This work completes the cloning and expression of the first full set of AHSV VP2 genes. The clones of VP2 genes of serotypes 1, 2, 5, 7 and 8 were sequenced and their amino acid sequences were deduced. Our sequencing data, together with t...
Giguère S, Gaskin JM, Miller C, Bowman JL.To determine efficacy of a commercially available hyperimmune plasma product for prevention of naturally acquired pneumonia caused by Rhodococcus equi in foals. Methods: Randomized clinical trial. Methods: 165 foals. Methods: Foals were randomly assigned to 1 of 2 groups (hyperimmune plasma or nontreated controls). Foals with failure of passive transfer (FPT) of immunity were treated with hyperimmune plasma and evaluated as a third group. Foals that received plasma were given 950 ml between 1 and 10 days of age and between 30 and 50 days of age. A tracheobronchial aspirate was obtained from fo...
Lucken R, Daas A, Behr-Gross ME.The European Directorate for the Quality of Medicines (EDQM) has organised an international collaborative study, divided in two phases, aimed at producing and establishing a suitable reference serum for serological potency testing of clostridial vaccines for batch consistency demonstration. In phase 1 a series of pools produced from sera provided by each manufacturer and raised against the broadest range of antigens possible were blended to obtain TN titres which were representative of the range normally elicited by the vaccines under test. Detailed statistical analysis of the data was not pos...
Giguère S, Hernandez J, Gaskin J, Miller C, Bowman JL.To evaluate WBC concentration, plasma fibrinogen concentration, and an agar gel immunodiffusion (AGID) test for early identification of Rhodococcus equi-infected foals. Methods: Prospective study. Methods: 162 foals from a farm with enzootic R equi infection. Methods: Blood samples were obtained from each foal at 4-week intervals for measurement of WBC and plasma fibrinogen concentrations and at 2-week intervals for detection of anti-R equi antibody by an AGID assay. Diagnostic performance of WBC and fibrinogen concentrations was assessed by use of receiver operating characteristic curve analy...
Wagner HM, Balasuriya UB, James MacLachlan N.In an effort to further characterize the humoral immune response of horses to equine arteritis virus (EAV), direct and competitive enzyme-linked immunosorbent assays (c-ELISAs) were developed using monoclonal and polyclonal anti-sera to structural (G(L), N and M) and non-structural (nsp1) viral proteins. A nsp1-specific monoclonal antibody was produced to facilitate development of a c-ELISA to this protein. Data obtained using the various c-ELISAs confirm that the M protein is a major target of the antibody response of horses to EAV. However, none of the c-ELISAs that were developed were as se...
Ashour J, Hondalus MK.Rhodococcus equi is a facultative intracellular opportunistic pathogen of immunocompromised people and a major cause of pneumonia in young horses. An effective live attenuated vaccine would be extremely useful in the prevention of R. equi disease in horses. Toward that end, we have developed an efficient transposon mutagenesis system that makes use of a Himar1 minitransposon delivered by a conditionally replicating plasmid for construction of R. equi mutants. We show that Himar1 transposition in R. equi is random and needs no apparent consensus sequence beyond the required TA dinucleotide. The...
Foster AP, Cunningham FM.The tachykinin, substance P (SP), affects eosinophil function by direct and indirect mechanisms and has been shown to cause equine eosinophils to adhere to vascular endothelium and to release cytokines that increase cell adherence. The aim of this study was to determine whether SP could act directly on equine eosinophils in vitro. Eosinophil activation was also compared in cells from normal ponies and those with insect hypersensitivity as SP may be released in the skin of hypersensitive animals. SP caused equine eosinophils to adhere, migrate and produce superoxide, although high concentration...
Hunter RP.Inflammation is a process consisting of a complex of cytological and chemical reactions which occur in and around affected blood vessels and adjacent tissues in response to an injury caused by a physical, chemical or biological insult. Much work has been performed in the past several years investigating inducible nitric oxide synthase (NOS, EC 1.14.13.39) and nitric oxide in inflammation. This has resulted in a rapid increase in knowledge about iNOS and nitric oxide. Nitric oxide formation from inducible NOS is regulated by numerous inflammatory mediators, often with contradictory effects, dep...
Wagner IP, Rees CA, Dunstan RW, Credille KM, Hood DM.To determine whether systemic immunologic hyperreactivity exists in horses with chronic laminitis, compared with responses for nonlaminitic horses. Methods: 7 nonlaminitic horses and 7 CL horses. Methods: In experiment 1, intradermal testing (IDT) was performed on 7 nonlaminitic and 7 CL horses to evaluate the response to a combination of 70 allergens at 15 and 30 minutes and 4 and 24 hours after injection. Three nonlaminitic and 3 CL horses used in experiment 1 were used in experiment 2 to determine whether histologic differences existed between the 2 groups. The H&E-stained tissue sectio...
Pardo Mateu L, Faubel Serra M, Llavero Segovia MT, Cano Cuenca B, Pérez Climent F, Giménez Vaillo F, Grau Alario E, Lazaro Santander R.The Rhodococcus equi is an aerobic gram positive pleomorphic bacillus, that was isolated for the first time like a producer of bronchopneumonia in young horses. Every time more often, it is being recognized as a pathogen in humans, mainly in the immunodepressed population. We described a case, until now exceptional, of laryngeal infection by Rhodococcus equi in a patient with positive serology for the virus of the human immunodeficiency (HIV), and we reviewed some clinical and epidemiological characteristics of the infections by this germ. The treatment is riphampicine and/or erythromycin, bei...
Wang T, Magnarelli LA, Anderson JF, Gould LH, Bushmich SL, Wong SJ, Fikrig E.Recombinant West Nile virus envelope (E) protein was examined in enzyme-linked immunosorbent assay (ELISA) to detect antibodies elicited during West Nile virus infection. Horses (nine of 10) and humans (six of six) with confirmed West Nile virus infection had IgG and/or IgM antibodies to the E protein. Antibodies to the recombinant West Nile virus membrane and nonstructural 1 proteins were not detected in any of these sera. An E protein-based ELISA may aid in the serological diagnosis of West Nile virus infection.
Haffner JC, Fecteau KA, Eiler H.To determine whether tetanus antitoxin, equine serum, and acetylcysteine, which are currently used in the treatment of equine corneal ulcer, inhibit the digestion of equine corneal collagen when exposed to collagenase in vitro. Methods: Corneas from 40 adult horses. Methods: Sections of equine corneas were incubated with saline, a solution of bacterial collagenase in saline, bacterial collagenase in saline plus equine tetanus antitoxin, bacterial collagenase in saline plus equine serum, or bacterial collagenase in saline plus acetylcysteine. Each one of the collagenase inhibitors was tested at...
De Cock HE, Labelle P, Magdesian KG.The clinical, gross morphological, histological and immunohistochemical characteristics of an ameloblastic carcinoma in a 30-year-old Quarter Horse mare are reported. This tumour was fast growing, locally invasive and destructive. Histologically, it showed an infiltrative pattern of large islands, broad sheets and, at the periphery, small cords of moderately pleomorphic round, oval to spindle-shaped cells. Immunohistochemical evaluation revealed positive labelling for vimentin, cytokeratin 5/6 and cytokeratin 14. In the oral cavity of human beings, this immunolabelling pattern is unique for th...
Boyd NK, Cohen ND, Lim WS, Martens RJ, Chaffin MK, Ball JM.Foals are uniquely susceptible to a wide variety of opportunistic infections normally associated with immunodeficiencies. Little is understood about the immune system of foals during the neonatal period. An apparent age-related susceptibility predisposes neonatal foals to infectious diseases and hinders therapeutic and preventative interventions for these diseases. Cytokine expression is correlated with the type of immune response as well as the severity of a disease. In this study, we measured foal peripheral blood mononuclear cell (PBMC)-specific mRNA cytokine expression from 72 foals from t...
Wagner B, Radbruch A, Rohwer J, Leibold W.In this study we describe the generation of monoclonal antibodies (mAbs), which recognize different epitopes of the equine IgE constant heavy chain. Equi-murine recombinant IgE (rIgE), composed of the murine V(H)186.2 heavy chain variable region, linked to the equine IgE constant heavy chain and expressed together with the murine lambda(1) chain in J558L cells was used to immunize BALB/C mice. A total of 17 different mAbs were obtained, which recognized the rIgE heavy chain constant region. None of the mAbs reacted with monoclonal equine isotypes IgM, IgG1 (IgGa), IgG3 (IgG(T)), IgG4 (IgGb) or...
Giguère S, Hernandez J, Gaskin J, Prescott JF, Takai S, Miller C.The performance of four enzyme-linked immunosorbent assays (ELISAs) (ELISA-6939, ELISA-33701, ELISA-VapA, and ELISA-California) and an agar gel immunodiffusion test for diagnosis of Rhodococcus equi pneumonia in foals was evaluated. Antibody concentrations of foals with culture-confirmed R. equi pneumonia (n = 41) were compared to those of age-matched pasturemates that remained clinically healthy during the entire breeding season (n = 24). For each serological assay evaluated, selection of a low cutoff resulted in high sensitivity but low specificity. Increasing the cutoff value resulted in be...
Hines SA, Stone DM, Hines MT, Alperin DC, Knowles DP, Norton LK, Hamilton MJ, Davis WC, McGuire TC.Rhodococcus equi is a gram-positive bacterium that infects alveolar macrophages and causes rhodococcal pneumonia in horses and humans. The virulence plasmid of R. equi appears to be required for both pathogenicity in the horse and the induction of protective immunity. An understanding of the mechanisms by which virulent R. equi circumvents protective host responses and by which bacteria are ultimately cleared is important for development of an effective vaccine. Six adult horses were challenged with either virulent R. equi or an avirulent, plasmid-cured derivative. By using a flow cytometric m...
Huang X, Xuan X, Yokoyama N, Xu L, Suzuki H, Sugimoto C, Nagasawa H, Fujisaki K, Igarashi I.The gene encoding a truncated merozoite antigen-2 (EMA-2t) of Babesia equi was cloned and highly expressed in Escherichia coli as a glutathione S-transferase fusion protein (G-rEMA-2t). Both G-rEMA-2t and rEMA-2t (after the removal of glutathione S-transferase) had good antigenicity. Either Western blot analysis with rEMA-2t or enzyme-linked immunosorbent assay (ELISA) with G-rEMA-2t clearly discriminated the sera of horses experimentally infected with B. equi from sera of horses infected with Babesia caballi and healthy horses, although rEMA-2t was not suitable for ELISA, probably owing to it...
Kohama M, Nio J, Hashimoto Y, Iwanaga T.The intimal lining cells of the synovium in joints have been studied morphologically and histochemically and shown to consist of macrophagic cells (type A) and fibroblast-like cells (type B). It is believed that the structure of the synovium in the tendon sheath is similar to that in the joint, but there have been only a few morphological studies of the tendon sheath. The present study revealed the cellular architecture of synovium in the tendon sheath of horses by histochemistry and scanning electron microscopy (SEM). Like the joint, the inner surface of the tendon sheath was covered with a c...
O Morris D, Lindborg S.Sixteen healthy horses with no history of skin or respiratory disease were used for an intradermal testing (IDT) threshold study, in order to determine the concentrations of 13 commercial allergenic insect extracts most appropriate for IDT. Five dilutions of each extract were used, which included the manufacturer's recommended concentrations for equine IDT, plus one dilution higher and three lower than these standard concentrations. Allergens tested included caddisfly (Trichoptera spp.), mayfly (Ephemeroptera spp.), horsefly (Tabanus spp.), deerfly (Chrysops spp.), fire ant (Solenopsis invicta...
Domeneghini C, Radaelli G, Arrighi S, Bosi G, Dolera M.The small and large intestine of adult horses were histochemically and immunohistochemically investigated in order to evidence components of the intramural nervous system. The general structural organization of the intramural nervous system was examined by using Nissl-thionin staining as well as the anti-neurofilament 200 (NF200) immunoreaction, which demonstrated the presence of neurons in the submucous as well as myenteric plexuses. The additional presence of subserosal ganglia was shown in the large intestine. Acetylcholinesterase (AChEase) activity was observed in both the submucous and my...
Lai SW, Lin JH, Lai SS, Wu YL.The characteristic ingredients of Ganoderma lucidum, such as polysaccharides, triterpenoids, nucleic acids and small proteins, have been found and proved to have many special pharmacological properties. Mice and rats have been extensively used to investigate the effects of G. lucidum. Experiments with horses as an animal model for investigating the effects of G. lucidum have never been reported. The purpose of this investigation was to understand the influence of G. lucidum feeding on blood biochemistry and immunocompetence in horses. Complete blood count (CBC) and blood biochemistry were surv...
Tu YB, Zhou T, Yuan XF, Qiu HJ, Xue F, Sun CQ, Wang L, Wu DL, Peng JM, Kong XG, Tong GZ.The long terminal repeats (LTRs) of equine infectious anemia virus donkey leukocyte-attenuated virus (EIAV-DLA) were substituted with those of the wild-type EIAV-L (wt EIAV-L, the parent virus of EIAV-DLA). The resulting chimeric plasmid was designated pOK-LTR DLA/L. Purified pOK-LTR DLA/L was transfected into monocyte-derived macrophage (MDM) cultures prepared from EIAV-negative, heparinized whole blood from a donkey. Eighth-passage cell cultures developed the typical cytopathogenic effects (CPE) of EIAV infection, and virions with typical EIAV profiles were observed with an electron microsco...
Kirchhoff H, Ammar AM, Heitmann J, Dubenkropp H, Schmidt R.Sera from horses with respiratory disease (RD) have been investigated using the complement fixation test, indirect hemagglutination test, enzyme immune assay, and the metabolic inhibition test, and sera from mares after abortion, using the complement fixation test, indirect hemagglutination test and enzyme immune assay, for antibodies against Mycoplasma equirhinis, M subdolum, M. equigenitalium, M. pulmonis, M. felis, Acholeplasma laidlawii, A. hippikon and A. equifetale. Antibodies were found against all mycoplasma and acholeplasma species tested, more often against acholeplasmas. The antibod...
Williams R, Du Plessis DH, Van Wyngaardt W.Group-reactive enzyme-linked immunosorbent assays (ELISAs) were developed to selectively detect antibodies to African horsesickness virus (AHSV) and equine encephalosis virus (EEV), 2 orbiviruses that infect equids. In indirect ELISA, guinea pig antisera to all known AHSV or EEV serotypes recognized immobilized AHSV serotype 3 or EEV Cascara, respectively. Antisera from naturally infected animals did not cross-react with their respective heterologous viruses. The ELISA was used in parallel with the complement fixation (CF) and agar gel immunodiffusion tests to detect antibodies in sera from an...
Barton AK, Shety T, Klier J, Geis S, Einspanier R, Gehlen H.Inhalation of immunostimulatory bacterial DNA segments (cytosine-phosphate-guanosine-oligodeoxynucleotides, CpG-ODN) normalizes clinical and cytologic parameters in severe equine asthma. We hypothesized that CpG-ODN inhalation also reduces the misbalance of elastinolytic activity in asthmatic horses. Methods: Twenty asthmatic horses diagnosed by clinical examinations using a scoring system were included. All horses inhaled CpG-ODNs for 14 days in 2-day intervals. Matrix metalloproteinase (MMP-2/-9) and tissue inhibitors of metalloproteinase (TIMP-1/-2) concentrations were measured in tracheal ...
Seahorn TL, Carter GK, Martens JG, Crandell RA, Martin MT, Scrutchfield WL, Cummins JM, Martens RJ.The immunotherapeutic effect of low-dose human alpha interferon on viral shedding and clinical disease was evaluated in horses inoculated with equine herpesvirus-1 (EHV-1). Eighteen clinically healthy weanling horses, 5 to 7 months old, were allotted to 3 equal groups. Two groups were treated orally with human alpha-2a interferon (0.22 or 2.2 U/kg of body weight), on days 2 and 1 before inoculation with EHV-1, the day of inoculation, and again on postinoculation day 1. The horses of the remaining group were given a placebo orally on the same days. The horses were monitored daily for changes in...
Ek N. Acta vet. scand. 1979, , 180–190. — Selected equine Pr phenotypes from a total of 55 horses of mixed breeds were investigated. The horse sera were subjected to acid starch gel electrophoresis at pH 4.8, followed by right angle electrophoresis in agarose gels containing rabbit-produced anti-Pr protein. This technique gives peaks in the agarose gels corresponding to the Pr zones in acid gels. The investigation revealed patterns of the Pr protein which were more complex than those seen when using ordinary acid starch gel electrophoresis. The phenotypes FF, II and LL showed a total of eight p...
Prieto JMB, Tallmadge RL, Felippe MJB.Identification and classification of B cell subpopulations has been shown to be challenging and inconsistent among different species. Our study tested aspects of ontogeny, phenotype, tissue distribution, and function of equine CD5 B cells, which represented a greater proportion of B cells early in development and in the peritoneal cavity. CD5 and CD5 B cells differentially expressed B cell markers (CD2, CD21, IgM) measured using flow cytometry, but similar mRNA expression of signature genes (DGKA, FGL2, PAX5, IGHM, IL10) measured using quantitative RT-PCR. Sequencing lambda light chain segment...
Nishita T, Matsushita H, Kai M.The location of carbonic anhydrase III (CA-III) in frozen sections of biopsies of Thoroughbred horse skeletal muscle was studied. Fibre types were determined by ATP-ase and succinate dehydrogenase staining. CA-III isozyme was detected using a peroxidase conjugated anti-CA-III antibody. CA-III was found to be localised in slow twitch oxidative fibres (ST), but was also present in fast twitch oxidative (FTH) fibres in small amounts. Fast twitch glycolytic (FT) fibres were stained lightly compared with control sections. The concentrations of CA-III in muscle and liver were 70 micrograms/mg protei...
Sutton GA, Viel L, Carman PS, Boag BL.The purpose of this experiment was to study the duration and distribution of equine influenza virus in actively infected ponies over a 3 wk period. Pony foals (6-8 mo old) were infected experimentally by nebulizing equine influenza subtype-2 virus ultrasonically through a face mask. Successful infection was clinically apparent as each of the foals (n = 6) had a febrile response, a deep hacking cough and mucopurulent nasal discharge for 7 to 10 d. The virus was isolated from nasopharyngeal swabs of all the ponies 3 and 5 d after infection and all the ponies seroconverted to the virus. Samples w...
McGowan JJ, Allen GP, Barnett JM, Gentry GA.Infection of horse KyED cells with equine herpesvirus type 3 (EHV-3) resulted in a sevenfold increase in cytosol deoxythymidine kinase (dTK) activity. The EHV-3 dTK was purified from KyED cytosol dTK by affinity chromatography on deoxythymidine-Sepharose and characterized with respect to its electrophoretic mobility, molecular weight, substrate specificity, phosphate donor specificity, and immunological specificity. The purified EHV-3 dTK migrated in polyacrylamide gels with an Rf of 0.30 and sedimented in glycerol gradients with an S value of 5.13, corresponding to a molecular weight of 83,00...
Schurink A, van der Meide NM, Savelkoul HF, Ducro BJ, Tijhaar E.Insect bite hypersensitivity (IBH) is a common allergic skin disease in horses, caused by biting insects of the Culicoides spp. In The Netherlands, Culicoides spp. of the Obsoletus complex are the most important midges involved in IBH. The aim of the present study was to identify and quantify associations between several endogenous (host) and exogenous (environmental) factors and immunoglobulin E (IgE) reactivity against Obsoletus complex-derived whole body extract or seven recombinant allergens, measured by ELISA. Data from 143 Icelandic horses and 177 Shetland ponies were analysed using mult...
Equine infectious anaemia (EIA) is a blood borne disease that is listed among the notifiable diseases of the World Organisation for Animal Health (OIE). EIA is also regulated by the OIE for the international trading provisions and is generally subject to control programmes. Since 2011, Italy has been conducting a surveillance plan based on a three-tier diagnostic system, using a serological ELISA as screening test, an agar gel immunodiffusion test (AGIDT) as a confirmatory method, and an immunoblot (IB) as an alternative confirmatory assay for discordant results between the first two tests. As...
Okumura M, Tagami M, Fujinaga T.The role of keratan sulphate (KS) as a marker of cartilage metabolism was evaluated by using an in vitro model of equine articular cartilage. Articular cartilage was harvested from clinically healthy 6-month-old foals (n=3). Chondrocytes were centrifuged and cultured as pellets. Chondrocyte pellets were stimulated by insulin-like growth factor (IGF)-Ialpha or interleukin (IL)-1alpha for 2 weeks. The sulfated glycosaminoglycans (GAG) and antigenic KS concentrations in the culture media were measured by a 1,9-dimethyl-methylene blue (DMMB) colorimetric assay and an inhibition ELISA using a 1/14/...
Durán MC, Willenbrock S, Carlson R, Feige K, Nolte I, Murua Escobar H.CD14 positive (CD14+) cells are the precursor cells of monocyte-derived dendritic cells (DCs). In horses their potent antigen-presenting capacity and ability to induce an effective immune response classify these cells suitable for several therapeutic approaches such as for equine sarcoid. However, in horses, the generation efficiency of DCs from adherent peripheral blood mononuclear cells (PBMCs) is currently still poor. Objective: Establishment of a simple short protocol to enhance DC generation in horses by using a human CD14 monoclonal antibody (mAb) and an automated magnetic activated cell...
Bertram TA, Coignoul FL.Equine neutrophils were evaluated ultrastructurally and by morphometric analysis. Homogeneous populations of neutrophils were isolated from peripheral blood at 4 degrees and 22 degrees C by centrifugation on two sequential Ficoll-Hypaque density gradients. Isolation procedures at both temperatures resulted in neutrophil degranulation but not cell swelling. Degranulation was more extensive in cells isolated at 22 degrees C. Isolation temperature affected the neutrophil content of secondary granules more than primary granules. A granule similar to immature specific granules of human neutrophils ...
Onzere CK, Fry LM, Bishop RP, Silva MG, Bastos RG, Knowles DP, Suarez CE.Theileria equi is a widely distributed apicomplexan parasite that causes severe hemolytic anemia in equid species. There is currently no effective vaccine for control of the parasite and understanding the mechanism that T. equi utilizes to invade host cells may be crucial for vaccine development. Unlike most apicomplexan species studied to date, the role of micronemes in T. equi invasion of host cells is unknown. We therefore assessed the role of the T. equi claudin-like apicomplexan microneme protein (CLAMP) in the invasion of equine erythrocytes as a first step towards understanding the role...
Nunes J, Mackie JT, Kiupel M.A 3.5-year-old Thoroughbred mare presented at necropsy with a large mass at the root of the mesentery and multiple smaller mesenteric masses. The mucosa of the small intestine contained numerous raised nodules. Histologic examination revealed severe granulomatous mesenteric lymphadenitis and enteritis. Epithelioid macrophages and multinucleated giant cells frequently contained numerous intracytoplasmic yeast organisms, which were strongly positive on immunohistochemical staining when using a polyclonal antibody against Histoplasma spp. A diagnosis of abdominal histoplasmosis was made based on ...
Foster AP, Cunningham FM.The tachykinin, substance P (SP), affects eosinophil function by direct and indirect mechanisms and has been shown to cause equine eosinophils to adhere to vascular endothelium and to release cytokines that increase cell adherence. The aim of this study was to determine whether SP could act directly on equine eosinophils in vitro. Eosinophil activation was also compared in cells from normal ponies and those with insect hypersensitivity as SP may be released in the skin of hypersensitive animals. SP caused equine eosinophils to adhere, migrate and produce superoxide, although high concentration...
Sallé G, Canlet C, Cortet J, Koch C, Malsa J, Reigner F, Riou M, Perrot N, Blanchard A, Mach N.The widespread failure of anthelmintic drugs against nematodes of veterinary interest requires novel control strategies. Selective treatment of the most susceptible individuals could reduce drug selection pressure but requires appropriate biomarkers of the intrinsic susceptibility potential. To date, this has been missing in livestock species. Here, we selected Welsh ponies with divergent intrinsic susceptibility (measured by their egg excretion levels) to cyathostomin infection and found that their divergence was sustained across a 10-year time window. Using this unique set of individuals, we...
Strasser A, Kühnel H, Velde K, Dadak A.Genotoxic DNA damage due to inhalation anaesthesia has been demonstrated in human lymphocytes. In order to evaluate anaesthesia-associated changes in cell-mediated immunity on the basis of a potential DNA damage as a health risk in horses, single cell gel electrophoresis and lymphocyte proliferation assay were performed on equine lymphocytes which were obtained before, during and after regular castration under inhalation anaesthetic. No significant lymphocytic DNA damage due to isoflurane anaesthesia was observed, whereas lymphocyte proliferative reactivity and lymphocyte counts decreased sign...
Wagner B, Overesch G, Sheoran AS, Holmes MA, Richards C, Leibold W, Radbruch A.Previous restriction analysis of cloned equine DNA and genomic DNA of equine peripheral blood mononuclear cells had indicated the existence of one c epsilon, one c alpha and up to six c gamma genes in the haploid equine genome. The c epsilon and c alpha genes have been aligned on a 30 kb DNA fragment in the order 5' c epsilon-c alpha 3'. Here we describe the alignment of the equine c mu and c gamma genes by deletion analysis of one IgM, four IgG and two equine light chain expressing heterohybridomas. This analysis establishes the existence of six c gamma genes per haploid genome. The genomic a...
Kitamura H, Okumura M, Sato F, Kimoto K, Kohama M, Hashimoto Y, Tagami M, Iwanaga T.Our previous study established protein gene product 9.5 (PGP 9.5), a ubiquitin C-terminal hydrolase, as a specific cytochemical marker of synovial lining cells (type B synoviocytes) in the horse joint. The present study aimed to detect PGP 9.5 in the synovial fluid and shows that PGP 9.5 is a valuable marker of osteoarthritis in the horse. Immunohistochemical staining confirmed rich and consistent localization of PGP 9.5 immunoreactivity in the cytoplasm of synovial lining cells in the normal horse joint. Western blot analysis of synovial fluid from normal joints could detect a significant ban...
Ruitenberg KM, Love DN, Gilkerson JR, Wellington JE, Whalley JM.We have shown previously that equine herpesvirus 1 (EHV-1) glycoprotein D (gD) DNA elicited protective immune responses against EHV-1 challenge in murine respiratory and abortion models of EHV-1 disease. In this study, 20 horses, all with pre-existing antibody to EHV-4 and two with pre-existing antibody to EHV-1, were inoculated intramuscularly with three doses each of 50, 200 or 500microg EHV-1 gD DNA or with 500microg vector DNA. In 8 of 15 horses, inoculation with EHV-1 gD DNA led to elevated gD-specific antibody and nine horses exhibited increased virus neutralising (VN) antibody titres co...
Niebauer GW, Wolf B, Yarmush M, Richardson DW.Thirty-one horses with secondary osteoarthritis as a sequel of trauma (chip fractures) or osteochondritis dissecans were screened for immune complexes (IC) and anticollagen antibodies. Eighty-two percent of horses with joint disease had circulating C1q-binding IC; 77% of those horses had IC in synovial fluids of affected joints. Although only a few horses had anticollagen type-II antibodies, anticollagen type-I antibodies were found in sera of 25% of the horses and in 41% of their synovial fluids. This correlated well with the clinical data and suggested that antibodies might have been elicite...
van der Meulen KM, Nauwynck HJ, Pensaert MB.Equine herpesvirus-1 (EHV-1) is an important pathogen of horses, causing abortion and nervous system disorders, even in vaccinated animals. During the cell-associated viremia, EHV-1 is carried by peripheral blood mononuclear cells (PBMC), mainly lymphocytes. In vitro, monocytes are the most important fraction of PBMC in which EHV-1 replicates, however, mitogen stimulation prior to EHV-1 infection increases the percentage of infected lymphocytes. The role of the cell cycle in viral replication and the role of cluster formation in cell-to-cell transmission of the virus were examined in mitogen-s...
Evans AG, Paradis MR, O'Callaghan M.Six horses with chronic obstructive pulmonary disease (COPD) and 8 horses with recurrent urticaria were skin tested with 67 extracts from 58 allergens, including pollens, epidermals, cultivated farm plants, dusts, molds, and insects. Reactions were evaluated 3 times over a 24-hour period immediately after the injections. Results were compared with those obtained from 11 clinically normal horses. All horses had positive skin test reactions. Significant differences was evident between horses with COPD and clinically normal horses for only 3.0% of the possible extract reactions, and between horse...
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...
Lalko CC, Deppe E, Ulatowski D, Lutgen A, Hart AP, Patton EA, Lunn DP, Suresh M, Darien BJ.Acute inflammatory diseases, such as colic, septicemia and endotoxemia are common in equines and have been shown to be correlated to vascular injury and thrombosis. In humans with similar thrombotic conditions, P-selectin and P-selectin glycoprotein ligand-1 (PSGL-1)-mediated platelet-leukocyte adhesion contributes to the pathogenesis of these disorders through the generation of inflammatory mediators and tissue factor. As such, we hypothesized that a P-selectin-PSGL-1 (platelet-leukocyte) interaction, similar to that in humans, may also exist in the horse. The objective of this study was to i...
