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Topic:Immunology
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.
Increased immunogenicity of a DNA-launched Venezuelan equine encephalitis virus-based replicon DNA vaccine. A novel genetic vaccine that is based on a Venezuelan equine encephalitis virus (VEE) replicon launched from plasmid DNA is described. The plasmid encodes a VEE replicon under the transcriptional control of the cytomegalovirus immediate-early promoter (VEE DNA). The VEE DNA consistently expressed 3- to 15-fold more green fluorescent protein in vitro than did a conventional DNA vaccine. Furthermore, transfection with the DNA-launched VEE replicon induced apoptosis and type I interferon production. Inoculation of mice with VEE DNA encoding human immunodeficiency virus type 1 gp160 significantly ...
Direct stimulation of the oxidative activity of isolated equine neutrophils by TNF-alpha and IL-1beta. The capacity of the two cytokines TNF-alpha and IL-1beta to directly stimulate the oxidative activity of polymorphonuclear neutrophils remains debated. The purpose of this study was to verify if a direct stimulation of equine neutrophils by TNF-alpha and IL-1beta was possible. Equine neutrophils were isolated from blood by discontinuous density gradient centrifugation. The cell viability after isolation was >98%. The neutrophils were used at 1.25 x 10(6) cells by assay, immediately after isolation. The oxidative activity of neutrophils was measured by luminol- or lucigenin-enhanced chemilumine...
Characterization of equine P-selectin glycoprotein ligand-1 by using a specific monoclonal antibody. P-selectin glycoprotein ligand (PSGL-1) is a widely distributed adhesion molecule that plays a critical role in regulating lymphocyte homing and leukocyte trafficking during inflammation. The lack of specific reagents for equine PSGL-1 (ePSGL-1) has prevented mechanistic studies regarding its function and regulation in the horse. We synthesized a ePSGL-1 peptide to generate a monoclonal antibody (mAb), ePL1. Using flow cytometry and Western blot, we showed that ePL1 binds specifically to ePSGL-1 in transfected mammalian cells. We also demonstrated that ePL1 binds to equine leukocytes and recog...
Abortion in a thoroughbred mare associated with an infection with avirulent Rhodococcus equi. An eight-year-old thoroughbred mare with no previous history of illness aborted a fetus at 196 days of gestation, and its internal tissues were examined immunohistologically and bacteriologically. The placenta was not examined, but specimens of the intrauterine fluids and the dam's faeces were collected four days after the abortion and examined bacteriologically. No significant histological lesions were found in the fetus but the amnion and the umbilical cord were oedematous and had petechial haemorrhages. Rhodococcus equi was isolated in pure culture from the lung, heart and stomach contents ...
Equine recurrent airway obstruction does not alter airway muscarinic acetylcholine receptor expression and subtype distribution. In recurrent airway obstruction (RAO) or heaves, bronchospasm has been attributed to enhanced cholinergic activity. However, the expression and function of muscarinic acetylcholine receptors (mAChR) and their signaling components are not yet known. Thus, we examined the expression, subtype distribution and postreceptor signaling pathways of mAChR in the peripheral lung, bronchial and tracheal epithelia with the underlying smooth muscle from nine horses with RAO and 11 healthy control horses. In RAO horses, no significant segment-dependent alteration in mAChR density and subtype distribution (a...
New assays to measure equine influenza virus-specific Type 1 immunity in horses. Equine influenza virus (EIV) is a leading cause of respiratory disease in horses. Equine influenza infection induces a long-term immunity to re-infection. Recent strategies of vaccination aim to mimic this immunity by stimulating both antibody and cellular immune responses. Cell-mediated immunity (CMI) to influenza is well defined in man, but little has been done to characterise the responses in the horse. Additionally, the development of reliable assays for the measurement of equine CMI has lagged behind serological methods and vaccine development. In this study, two methods of measuring EIV-...
Gag genetic heterogeneity of equine infectious anemia virus (EIAV) in naturally infected horses in Canada. Gag genetic heterogeneity of equine infectious anemia virus (EIAV) variants in naturally infected horses in Canada was studied since very limited information is available on the variability of EIAV Gag sequences in public database. A phylogenetic analysis based on 414nts of Gag gene sequences amplified by a nested polymerase chain reaction (PCR) revealed the distinct divergence of these variants compared to other published strains in a corresponding region. Significant predicted amino acid sequence variations were also identified in an immunorelevant region within this fragment which correspon...
Culicoides species attracted to horses with and without insect hypersensitivity. The aims of this study were to determine (1) which species of Culicoides is most commonly attracted to horses, (2) whether horses suffering insect hypersensitivity attract more Culicoides spp. than unaffected horses, and (3) the times when Culicoides spp. are most active. Horses affected by insect hypersensitivity and unaffected horses were placed inside mosquito netting tents for 30 min at different times of the day. All Culicoides spp. trapped inside the tents were collected and identified. C. obsoletus was the most common species found, followed by C. pulicaris. Healthy horses attracted sli...
Humoral immune responses in the horse after intrathecal challenge with ovalbumin. Diagnosis of neuro-inflammatory conditions in the horse can be challenging. Current methods include evaluation of cerebrospinal fluid (CSF) for inflammation and determination of specific antibody status. The antibody index (AI) and Goldman-Witmer coefficient (C-value) can be used to aid in the interpretation. Objective: The null hypothesis to be tested was that the Al and C-values do not change in horses with neuroinflammation. Methods: Twelve horses of various ages (3-17 years) and breeds (Thoroughbred, Thoroughbred cross, draft, and Arabian) were included in the study. Methods: The study was...
Use of Fourier-transform infrared spectroscopy for the diagnosis of failure of transfer of passive immunity and measurement of immunoglobulin concentrations in horses. 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...
Purification of equine IgG using membrane based enhanced hybrid bioseparation technique: a potential method for manufacturing hyperimmune antibody. Hyperimmune equine IgG is widely used as antivenom and anti-rabies agents. This article discusses a membrane based enhanced hybrid bioseparation technique for efficient and scalable purification of equine immunoglobulin G (IgG) from horse serum. This technique is an improved version of a standard hybrid bioseparation technique developed within our group earlier for fractionation of human plasma proteins (Ghosh. 2004. J Membr Sci 237: 109-117). In the presence of a high antichaotropic salt concentration, equine IgG is selectively and reversibly captured within a stirred cell membrane module fro...
Systematic epitope analysis of the p26 EIAV core protein. The major core protein of equine infectious anemia virus (EIAV), p26, is one of the primary immunogenic structural proteins during a persistent infection of horses and is highly conserved among antigenically variants of viral isolates. In order to investigate its immune profile in more detail for a better diagnostic, an epitope mapping was carried out by means of two libraries of overlapping peptide fragments prepared by simultaneous and parallel SPPS on derivatized cellulose membranes (SPOT synthesis). Polyclonal equine sera from infected horses were used for the biological assay. Particularl...
Low-dose ginseng (Panax quinquefolium) modulates the course and magnitude of the antibody response to vaccination against equid herpesvirus I in horses. The purpose of this study was to determine if ginseng fed at low levels enhances a horse's antibody response to vaccination against Equid herpesvirus 1 (EHV-1). For 28 d, 5 horses received ground, powdered ginseng (35 mg/kg body weight, 1.7 mg/kg total ginsenosides) in molasses as a carrier, and 5 received molasses only. On day 14, each horse was vaccinated against EHV-1. The time course of the antibody response to vaccination was significantly altered in the horses receiving ginseng, a clinically relevant increase in antibody titer being observed by postvaccination day 2 compared with day 6 i...
A comparison of intradermal testing and detection of allergen-specific immunoglobulin E in serum by enzyme-linked immunosorbent assay in horses affected with skin hypersensitivity. Skin hypersensitivities (allergies) in horses are often diagnosed using clinical signs only. Intradermal testing or serological assays are diagnostic options to confirm the allergic nature of the disease and to identify the allergen(s). Our objective was to develop an allergen-specific enzyme-linked immunosorbent assay (ELISA) using a monoclonal antibody specific for horse IgE and to examine its potential for allergen detection in serum in comparison to intradermal testing. Intradermal testing with 61 allergen extracts was performed on 10 horses affected with skin hypersensitivity. Their sera ...
The diversity of coliphages and coliforms in horse feces reveals a complex pattern of ecological interactions. The diversity of coliphages and indigenous coliform strains (ICSs) simultaneously present in horse feces was investigated by culture-based and molecular methods. The richness of coliforms (as estimated by the Chao1 method) is about 1,000 individual ICSs distinguishable by genomic fingerprinting present in a single sample of feces. This unexpectedly high value indicates that some factor limits the competition of coliform bacteria in the horse gut microbial system. In contrast, the diversity of phages active against any selected ICS is generally limited to one to three viral genotypes present in...
Pro-inflammatory and antiviral cytokine expression in vaccinated and unvaccinated horses exposed to equine influenza virus. Most studies of the cytokine response to influenza virus infection have been carried out in human, porcine and murine models, however the data available on equine cytokines is limited. An experimental challenge study was undertaken in unvaccinated naïve horses and horses vaccinated with a commercial inactivated influenza vaccine. The humoral antibody response to vaccination and virus challenge was measured by single radial haemolysis (SRH) assay and clinical signs of influenza and viral shedding were monitored post-challenge. Levels of three equine pro-inflammatory cytokines interleukin (IL)-...
Comparative efficacies of three commercially available vaccines against West Nile Virus (WNV) in a short-duration challenge trial involving an equine WNV encephalitis model. We used a severe challenge model that produces clinical West Nile virus (WNV) disease to test the efficacy of three commercially available equine WNV vaccines in horses. Twenty-four healthy, WNV-seronegative horses of varying ages and genders were placed, in random and blind manner, into three trial groups consisting of eight horses each; two horses in each group received (i) an inactivated WNV vaccine (K-WN), (ii) a modified-live vaccine (CP-WN) containing the WNV prM and E proteins expressed by a canarypox vector, (iii) a live-chimera vaccine (WN-FV) containing WNV prM and E proteins express...
Characterization and structure analysis of a novel bacteriocin, lacticin Z, produced by Lactococcus lactis QU 14. A novel bacteriocin, lacticin Z, produced by Lactococcus lactis QU 14 isolated from a horse's intestinal tract was identified. Lacticin Z was purified through a three step procedure comprised of hydrophobic-interaction, cation-exchange chromatography, and reverse-phase HPLC. ESI-TOF MS determined the molecular mass of lacticin Z to be 5,968.9 Da. The primary structure of lacticin Z was found to consist of 53 amino acid residues without any leader sequence or signal peptide. Lacticin Z showed homology to lacticin Q from L. lactis QU 5, aureocin A53 from Staphylococcus aureus A53, and mutacin BH...
Horse heart myoglobin catalyzes the H2O2-dependent oxidative dehalogenation of chlorophenols to DNA-binding radicals and quinones. 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...
An investigation of equine infectious anaemia infection in the central Anatolia region of Turkey. In this study, 162 horses, 80 donkeys and 51 mule serum samples were collected in Konya city. Additionally, 64 horse serum samples from Ankara and 49 samples from Kayseri city were included in the study. A total of 406 serum samples were examined by agar gel immunodiffusion (AGID) and enzyme-linked immunosorbent assay (ELISA) for antibody to equine infectious anaemia virus (EIAV) and no positive result was detected.
The different effector function capabilities of the seven equine IgG subclasses have implications for vaccine strategies. Recombinant versions of the seven equine IgG subclasses were expressed in CHO cells. All assembled into intact immunoglobulins stabilised by disulphide bridges, although, reminiscent of human IgG4, a small proportion of equine IgG4 and IgG7 were held together by non-covalent bonds alone. All seven IgGs were N-glycosylated. In addition IgG3 appeared to be O-glycosylated and could bind the lectin jacalin. Staphylococcal protein A displayed weak binding for the equine IgGs in the order: IgG1>IgG3>IgG4>IgG7>IgG2=IgG5>IgG6. Streptococcal protein G bound strongly to IgG1, IgG4 and IgG7, moderately t...
Correlation between colic and antibody levels against Anoplocephala perfoliata in horses in The Netherlands. The importance of Anoplocephala perfoliata in horses with colic was studied in 139 horses referred for colic and 139 control horses with no signs of colic for at least three years. The serodiagnostic method of Proudman and Trees, which measures the level of A. perfoliata antibody, was used to detect A. perfoliata infection. Thirty-two horses were examined at necropsy, to determine whether the presence of A. perfoliata in the ileocaecal region was associated with the A. perfoliata antibody level. The mean A. perfoliata antibody level was significantly higher in horses with colic than in horses ...
Failure of low-dose recombinant human IL-2 to support the survival of virus-specific CTL clones infused into severe combined immunodeficient foals: lack of correlation between in vitro activity and in vivo efficacy. Although CTL are important for control of lentiviruses, including equine infectious anemia virus (EIAV), it is not known if CTL can limit lentiviral replication in the absence of CD4 help and neutralizing antibody. Adoptive transfer of EIAV-specific CTL clones into severe combined immunodeficient (SCID) foals could resolve this issue, but it is not known whether exogenous IL-2 administration is sufficient to support the engraftment and proliferation of CTL clones infused into immunodeficient horses. To address this question we adoptively transferred EIAV Rev-specific CTL clones into four EIAV-...
Immunocytochemical localization of lysozyme and beta-defensin in the apocrine glands of the equine scrotum. The present study revealed in detail the subcellular localization of lysozyme and beta-defensin in the apocrine glands of the equine scrotal skin, a specific body region. The apocrine glandular cells were equipped with a varying number of secretory granules, a well-developed Golgi apparatus and abundant cisternae of the rough endoplasmic reticulum within their cytoplasm. In these cells, reactive gold particles representing lysozyme were detectable in the secretory granules as well as the Golgi apparatus and elements of the rough endoplasmic reticulum. Additionally, the antimicrobial peptide gr...
Validation of the indirect fluorescent antibody and the complement fixation tests for the diagnosis of Theileria equi. The indirect fluorescent antibody (IFA) test for Theileria equi was evaluated to assess test's suitability for the serological diagnosis of equine piroplasmosis, to provide performance parameters for the purpose of test validation, and to compare it with the complement fixation (CF) test. Using a protocol that included Evan's blue, the specificity of the IFA test was estimated at 99.0% for T. equi by the classical method of analysis, and 96.6% by the Bayesian method. The use of Evan's blue in the test protocol increased test specificity and contributed to an excellent test agreement between tw...
A novel horse alpha-defensin: gene transcription, recombinant expression and characterization of the structure and function. Defensins are a predominant class of antimicrobial peptides, which act as endogenous antibiotics. Defensins are classified into three distinct sub-families: theta-, beta-, and alpha-defensins. Synthesis of alpha-defensin has been confirmed only in primates and glires to date and is presumably unique for a few tissues, including neutrophils and Paneth cells of the small intestine. Antimicrobial activities of these peptides were shown against a wide variety of microbes including bacteria, fungi, viruses and protozoan parasites. In the present study, we report the characterization of the equine a...
Evidence-based immunization in horses. Evidence of vaccine efficacy is essential for practitioners when giving advice to clients about the relative merits of different vaccines or when trying to evaluate the economic benefits of instituting a vaccine program. In equine veterinary medicine, this sort of data, which are necessary to make informed decisions about vaccine use and effectiveness, are often not available. Veterinarians need to consider the epidemiology of the disease in question, the type of vaccine that they are administering to the animal, the immunologic constraints of the vaccine technology, and the available evidence...
