Topic:Antigen
Antigens are substances that can induce an immune response in horses, typically by being recognized as foreign by the immune system. These substances can include proteins, polysaccharides, or lipids, and are often components of pathogens such as bacteria, viruses, or parasites. In horses, antigens are essential for the activation of both the innate and adaptive immune responses, leading to the production of antibodies and the activation of immune cells. The study of antigens in equines encompasses understanding their structure, the mechanisms by which they are recognized by the immune system, and their role in vaccine development. This page compiles peer-reviewed research studies and scholarly articles that explore the identification, characterization, and immunological impact of antigens in equine health and disease.
Protein profile of Brazilian Pythium insidiosum isolates. Pythium insidiosum is an important aquatic Oomycota that causes pythiosis in mammals, especially horses, dogs, and humans; these inhabit marshy environments in tropical and subtropical areas. The aim of this study was to determine the protein profile, as well as identify likely immunodominant proteins, of Brazilian P. insidiosum isolates from southern Brazil, an important equine pythiosis endemic area. P. insidiosum isolates (horses, n = 20 and dogs, n = 02) were analyzed by SDS-PAGE and Western blot techniques. Horse, cattle, dog, and rabbit sera of both diseased and healthy animals were used...
Whole-genome sequencing and antigenic analysis of the first equine influenza virus identified in Turkey. In 2013, there was an outbreak of acute respiratory disease in racehorses in Turkey. The clinical signs were consistent with equine influenza (EI). The aim was to confirm the cause of the outbreak and characterise the causal virus. A pan-reactive influenza type A real-time RT-PCR and a rapid antigen detection kit were used for confirmatory diagnosis of equine influenza virus (EIV). Immunological susceptibility to EIV was examined using single radial haemolysis and ELISA. Antigenic characterisation was completed by haemagglutinin inhibition using a panel of specific ferret antisera. Genetic cha...
Decreased Clinical Severity of Strangles in Weanlings Associated with Restricted Seroconversion to Optimized Streptococcus equi ssp equi Assays. Streptococcus equi ssp. equi causes characteristic clinical signs that are most severe in young horses, including fever, purulent nasal discharge, and lymph node abscessation in the head region. Objective: Clinical, serologic, and microbiologic factors related to unexpectedly mild disease severity in a natural outbreak of strangles in immunologically naïve weanlings were investigated. Methods: One-hundred and twelve warmblood weanlings. Methods: Prospective longitudinal observational study of a natural outbreak of strangles. The entire cohort was examined at the peak of the outbreak by deep n...
Characterization of respiratory dendritic cells from equine lung tissues. Dendritic cells (DCs) are professional antigen-presenting cells that have multiple subpopulations with different phenotypes and immune functions. Previous research demonstrated that DCs have strong potential for anti-viral defense in the host. However, viruses including alphaherpesvirinae have developed strategies to interfere with the function or maturation of DCs, causing immune dysfunction and avoidance of pathogen elimination. The goal of the present study was to isolate and characterize equine lung-derived DCs (L-DCs) for use in studies of respiratory viruses and compare their features wi...
Differential Diagnosis of Flavivirus Infections in Horses Using Viral Envelope Protein Domain III Antigens in Enzyme-Linked Immunosorbent Assay. In Australia, infection of horses with the West Nile virus (WNV) or Murray Valley encephalitis virus (MVEV) occasionally results in severe neurological disease that cannot be clinically differentiated. Confirmatory serological tests to detect antibody specific for MVEV or WNV in horses are often hampered by cross-reactive antibodies induced to conserved epitopes on the envelope (E) protein. This study utilized bacterially expressed recombinant antigens derived from domain III of the E protein (rE-DIII) of MVEV and WNV, respectively, to determine whether these subunit antigens provided specific...
Immunogenicity of plant-produced African horse sickness virus-like particles: implications for a novel vaccine. African horse sickness (AHS) is a debilitating and often fatal viral disease affecting horses in much of Africa, caused by the dsRNA orbivirus African horse sickness virus (AHSV). Vaccination remains the single most effective weapon in combatting AHS, as there is no treatment for the disease apart from good animal husbandry. However, the only commercially available vaccine is a live-attenuated version of the virus (LAV). The threat of outbreaks of the disease outside its endemic region and the fact that the LAV is not licensed for use elsewhere in the world, have spurred attempts to develop an...
Antigenic characterization of 52-55kDa protein isolated from Trypanosoma evansi and its application in detection of equine trypanosomosis. Trypanosoma evansi is a haemo-protozoan parasite responsible for the disease surra, an economically important disease of wide range of domestic and wild animals. The present diagnostic methods using soluble antigens have inherent problems like lack of standardized and reproducible antigens, as well as ethical issues. This entails further efforts for search of defined antigenic molecules with satisfying sensitivity and specificity for sero-epidemiology of trypanosomosis. In present investigation, we have identified and purified 52-55kDa immuno-dominant protein cluster in molecular mass ranges b...
Identification of a new diagnostic antigen for glanders using immunoproteome analysis. Glanders is a disease of horses, donkeys and mules. The causative agent Burkholderia mallei, is a biorisk group 3 pathogen and is also a biothreat agent. Simple and rapid diagnostic tool is essential for control of glanders. Using a proteomic approach and immunoblotting with equine sera, we identified 12 protein antigens that may have diagnostic potential. Various immunoreactive proteins e.g. GroEL, translation elongation factor Tu, elongation factor Ts, arginine deiminase, malate dehydrogenase, DNA directed RNA polymerase subunit alpha were identified on 2-dimentional immunoblots. One of thes...
Antigenicity of mesenchymal stem cells in an inflamed joint environment. OBJECTIVE To determine whether major histocompatability complex (MHC) class II expression in equine mesenchymal stem cells (MSCs) changes with exposure to a proinflammatory environment reflective of an inflamed joint. SAMPLE Cryopreserved bone marrow-derived MSCs from 12 horses and cartilage and synovium samples from 1 horse euthanized for reasons other than lameness. PROCEDURES In part 1 of a 3-part study, the suitability of a quantitative reverse transcriptase PCR (qRT-PCR) assay for measurement of MHC class II expression in MSCs following stimulation with interferon (IFN)-γ was assessed. I...
Th1/Th2 balance and humoral immune response to potential antigens as early diagnostic method of equine Strongylus nematode infection. The aim of this study was to investigate the early diagnosis of strongyle infection based on early changes in Th1 and Th2 cytokines beside the diagnostic accuracy values and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and western blotting profiles using prepared strongyles antigens. Methods: A total of 73 donkeys had a mean age of 4-32 years old were parasitologically examined for strongyle infection. The early changes in Th1 and Th2 cytokines were determined, and the diagnostic accuracy values and SDS-PAGE and western blotting profiles were performed using prepared st...
The sero-prevalence and sero-incidence of African horse sickness and equine encephalosis in selected horse and donkey populations in Zimbabwe. Sentinel herds and samples submitted by private equine practitioners were used to determine the sero-prevalence and sero-incidence of African horse sickness virus (AHSV) and equine encephalosis virus (EEV) in horse and donkey populations in the Highveld region of Zimbabwe. The sero-prevalence and sero-incidence of antibodies against these viruses were determined using the competitive enzyme-linked immunosorbent assay (ELISA) for the detection of serum antibodies. In donkeys, the median sero-prevalence of AHSV antibodies, across the three rainy seasons under study, was 75% (inter quartile...
Evolution and Divergence of H3N8 Equine Influenza Viruses Circulating in the United Kingdom from 2013 to 2015. Equine influenza viruses (EIV) are a major cause of acute respiratory disease in horses worldwide and occasionally also affect vaccinated animals. Like other influenza A viruses, they undergo antigenic drift, highlighting the importance of both surveillance and virus characterisation in order for vaccine strains to be kept up to date. The aim of the work reported here was to monitor the genetic and antigenic changes occurring in EIV circulating in the UK from 2013 to 2015 and to identify any evidence of vaccine breakdown in the field. Virus isolation, reverse transcription polymerase chain rea...
In vitro effects of the toll-like receptor agonists monophosphoryl lipid A and CpG-rich oligonucleotides on cytokine production by equine cells. Insect bite hypersensitivity (IBH) is an equine allergic dermatitis to Culicoides spp. antigens. Attempts at using allergen-specific immunotherapy (AIT) as a treatment for IBH have so far proven unsuccessful. Toll-like receptor (TLR) agonists can promote a shift in the immune response from the allergy-promoting T helper cell 2 (Th2) response towards a Th1 and/or regulatory response. The aim of this study was to evaluate two immunomodulatory TLR agonists in vitro as potential vaccine adjuvants for a more efficacious AIT in IBH. Peripheral blood mononuclear cells (PBMCs) from healthy and IBH-aff...
Equine dendritic cells generated with horse serum have enhanced functionality in comparison to dendritic cells generated with fetal bovine serum. Dendritic cells are professional antigen-presenting cells that play an essential role in the initiation and modulation of T cell responses. They have been studied widely for their potential clinical applications, but for clinical use to be successful, alternatives to xenogeneic substances like fetal bovine serum (FBS) in cell culture need to be found. Protocols for the generation of dendritic cells ex vivo from monocytes are well established for several species, including horses. Currently, the gold standard protocol for generating dendritic cells from monocytes across various species relies u...
Identification of the immunogenic epitopes of the whole venom component of the Hemiscorpius lepturus scorpion using the phage display peptide library. The venom of the Hemiscorpius lepturus scorpion contains mixtures of bioactive compounds that disturb biochemical and physiological functions of the victims. Hemiscorpius lepturus envenomation is recognized as a serious health concern in tropical regions. So far, there is no preventive procedure, and the main focus is on treatment of victims with an antiserum purified from hyper-immunized horses. Although antisera can neutralize the venom, they, in some cases, lead to anaphylactic shock and even death. Selection of peptides mimicking antigenic and immunogenic epitopes of toxins from random pep...
Equine Pulmonary Cryptococcosis: A Comparative Literature Review and Evaluation of Fluconazole Monotherapy. Cryptococcus is the most common fungal respiratory pathogen in Australian horses, manifesting primarily as pulmonary granulomas. Disease severity at presentation is dependent on the athletic use of the horse. The diagnosis and estimation of disease severity are centred around clinical findings, cytological evaluation of respiratory tract secretions, diagnostic imaging, and antigen titre testing. Both the lateral flow assay and the latex cryptococcal antigen titre are used, and important similarities and differences between species are discussed. Cryptococcus gattii occurs with greater frequenc...
Assessment of antigenic difference of equine influenza virus strains by challenge study in horses. We previously reported that horse antiserum against the Japanese equine influenza vaccine virus, A/equine/La Plata/1993 (LP93) exhibited reduced cross-neutralization against some Florida sublineage Clade (Fc) 2 viruses, for example, A/equine/Carlow/2011 (CL11). As a result, Japanese vaccine manufacturers will replace LP93 with A/equine/Yokohama/aq13/2010 (Y10, Fc2). To assess the benefit of updating the vaccine, five horses vaccinated with inactivated Y10 vaccine and five vaccinated with inactivated LP93 were challenged by exposure to a nebulized aerosol of CL11. The durations of pyrexia (≥3...
In vitro production of Trypanosoma equiperdum antigen and its evaluation for use in serodiagnosis of dourine. A modified Baltz's in vitro cultivation system for the propagation of Trypanosoma equiperdum strain OVI was established to develop a replacement for the conventional production procedure of dourine diagnostic antigen in rats. To increase trypanosome yields we designed an optimized culture medium by addition of supplemental compounds. Trypanosomes were adapted to this medium by two succeeding cultivation steps which led to a substantial proliferation rate and an increased cell density tolerance, respectively. As a result, adapted parasites could be propagated to maximum cell densities of >2...
Identification of immunodiagnostic antigens for cerebrospinal filariasis in horses by western blot analysis. In the present study, the serum and cerebrospinal fluid of horses diagnosed with Setaria digitata cerebrospinal filariasis were analyzed by western blot. The results revealed S. digitata protein bands measuring 65, 34, 22, and 18 kDa in molecular weight. In particular, the 18 kDa band is a possible candidate for clinical immunodiagnosis on the basis of western blot findings.
Evaluation of twenty-two rapid antigen detection tests in the diagnosis of Equine Influenza caused by viruses of H3N8 subtype. Equine influenza (EI) is a highly contagious disease caused by viruses of the H3N8 subtype. The rapid diagnosis of EI is essential to reduce the disease spread. Many rapid antigen detection (RAD) tests for diagnosing human influenza are available, but their ability to diagnose EI has not been systematically evaluated. Objective: The aim of this study was to compare the performance of 22 RAD tests in the diagnosis of EI. Methods: The 22 RAD tests were performed on fivefold serial dilutions of EI virus to determine their detection limits. The four most sensitive RAD tests (ImmunoAce Flu, BD Flu ...
Comparison of the antigenic relationship between Japanese encephalitis virus genotypes 1 and 3. The Japanese encephalitis virus (JEV) genotype circulating in Korea has changed from G3 to G1. Therefore, the purpose of this study was to compare the antigenic relationship between the two genotypes by using antibody tests. Methods: Blood samples from 42 sows and 216 horses were collected, and their seroprevalence was monitored using the hemagglutination inhibition and virus neutralization tests. Antisera against JEV G1 and G3 were isolated and prepared from guinea pigs. The cross-reactivity of these two viruses was then compared using the neutralizing antibody test. Results: We found that th...
Diagnostic application of recombinant equine merozoite surface antigen-1 in elisa for detection of Theileria equi specific antibodies. Theileria equi merozoite surface antigens have been an important candidate for development of diagnostics. We developed ELISA based on EMA-1 recombinant antigen, so as to widen our diagnostic confidence in detection of antibodies against T. equi in sero-surveillance studies. The 547 bp EMA-1 gene fragment encoding high hydrophilic antigenic region was expressed with glutathione-S-transferase tag in prokaryotic system and purified protein (43 kDa) was used for development of ELISA (EMA-1t/ELISA). The EMA-1t/ELISA clearly differentiated T. equi-infected from Babesia caballi-infected horse sera o...
Distribution of CD163-positive cell and MHC class II-positive cell in the normal equine uveal tract. Antigen-presenting cells (APCs) in the uveal tract participate in ocular immunity including immune homeostasis and the pathogenesis of uveitis. In horses, although uveitis is the most common ocular disorder, little is known about ocular immunity, such as the distribution of APCs. In this study, we investigated the distribution of CD163-positive and MHC II-positive cells in the normal equine uveal tract using an immunofluorescence technique. Eleven eyes from 10 Thoroughbred horses aged 1 to 24 years old were used. Indirect immunofluorescence was performed using the primary antibodies CD163, MHC...
Enhanced sensitivity of an antibody competitive blocking enzyme-linked immunosorbent assay using Equine arteritis virus purified by anion-exchange membrane chromatography. In an effort to improve a competitive blocking enzyme-linked immunosorbent assay (cELISA) for antibody detection to Equine arteritis virus (EAV), antigen purified by anion-exchange membrane chromatography capsule (AEC) was evaluated. Virus purification by the AEC method was rapid and easily scalable. A comparison was made between virus purified by the AEC method with that obtained by differential centrifugation based on the following: 1) the relative purity and quality of EAV glycoprotein 5 (GP5) containing the epitope defined by monoclonal antibody 17B7, and 2) the relative sensitivity of a c...
Improvement of an enzyme-linked immunosorbent assay for equine herpesvirus type 4 by using a synthetic-peptide 24-mer repeat sequence of glycoprotein G as an antigen. To increase the sensitivity of an enzyme-linked immunosorbent assay (ELISA) for equine herpesvirus type 4 (EHV-4) that uses a 12-mer peptide of glycoprotein G (gG4-12-mer: MKNNPIYSEGSL) [4], we used a longer peptide consisting of a 24-mer repeat sequence (gG4-24-mer: MKNNPIYSEGSLMLNVQHDDSIHT) as an antigen. Sera of horses experimentally infected with EHV-4 reacted much more strongly to the gG4-24-mer peptide than to the gG4-12-mer peptide. We used peptide ELISAs to test paired sera from horses naturally infected with EHV-4 (n=40). gG4-24-mer ELISA detected 37 positive samples (92.5%), whereas ...
Immune modulation of T regulatory cells and IgE responses in horses vaccinated with West Nile virus vaccine combined with a CpG ODN. Hypersensitivity reactions, such as hives or fatal anaphylactic shock, in response to vaccination constitute a health hazard for horses that develop allergies to vaccine components. In such horses vaccination with viral vaccines stimulates an IgE response to non-target antigens. Viral vaccines share contaminating non-target proteins, such as bovine serum albumin (BSA); these antigens can stimulate IgE production with each exposure. We hypothesized that the addition of a CpG oligodeoxynucleotide (ODN) administered in conjunction with a West Nile virus vaccine would decrease the IgE response; th...
Production and preliminary evaluation of Trypanosoma evansi HSP70 for antibody detection in Equids. The present immuno-diagnostic method using soluble antigens from whole cell lysate antigen for trypanosomosis have certain inherent problems like lack of standardized and reproducible antigens, as well as ethical issues due to in vivo production, that could be alleviated by in vitro production. In the present study we have identified heat shock protein 70 (HSP70) from T. evansi proteome. The nucleotide sequence of T. evansi HSP70 was 2116 bp, which encodes 690 amino acid residues. The phylogenetic analysis of T. evansi HSP70 showed that T. evansi occurred within Trypanosoma clade and is most c...
Recombinant Culicoides obsoletus complex allergens stimulate antigen-specific T cells of insect bite hypersensitive Shetland ponies in vitro. Ponies may suffer from Insect bite hypersensitivity (IBH), an allergic IgE-mediated pruritic skin disorder, induced by allergens from biting midges of the Culicoides spp. Objective: To determine whether recombinant Culicoides obsoletus allergens are able to activate T cells of ponies exposed to C. obsoletus and whether these allergen-specific responses differ between IBH-affected and healthy ponies. Methods: Ten IBH-affected Shetland ponies and 10 age-matched healthy controls taken from the same stables, to ensure similar exposure to midges. Methods: Peripheral blood mononuclear cells (PBMC) w...
Expression of genes involved in immune response and in vitro immunosuppressive effect of equine MSCs. The immunomodulatory capacities of mesenchymal stem cells (MSCs) have made them the subject of increased clinical interest for tissue regeneration and repair. We have studied the immunomodulatory capacity of equine MSCs derived from bone marrow (BM-MSCs) and adipose tissue (AT-MSCs) in cocultures with allogeneic peripheral blood mononuclear cells (PBMCs). Different isoforms and concentrations of phytohaemaglutinin (PHA) were tested to determine the best stimulation conditions for PBMC proliferation and a proliferation assay was performed for 7 days to determine the optimal day of stimulation o...
Effect of incubation temperature on the diagnostic sensitivity of the glanders complement fixation test. The complement fixation test (CFT) is the only serological test prescribed by the World Organisation for Animal Health (OIE) for the diagnosis of glanders in international trading of equids. However, false-positive reactions have caused financial losses to the animal owners in the past, and false-negative tests have resulted in the introduction of glanders into healthy equine populations in previously glanders-free areas. Both warm (incubation at 37°C for 1 h) and cold (overnight incubation at 4°C) procedures are recommended by the OIE for serodiagnosis of glanders. In a comparison of the se...