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Topic:Peptides
Peptides are short chains of amino acids that are involved in various biological processes in horses. They function as signaling molecules, influencing physiological activities such as metabolism, immune response, and tissue repair. Peptides can be naturally occurring or synthetically derived, and they may serve as therapeutic agents in veterinary medicine. In equine health, peptides are studied for their potential applications in enhancing performance, supporting recovery, and managing conditions like osteoarthritis. This page compiles peer-reviewed research studies and scholarly articles that explore the structure, function, and potential applications of peptides in the context of equine health and disease management.
Presentation and binding affinity of equine infectious anemia virus CTL envelope and matrix protein epitopes by an expressed equine classical MHC class I molecule. Control of a naturally occurring lentivirus, equine infectious anemia virus (EIAV), occurs in most infected horses and involves MHC class I-restricted, virus-specific CTL. Two minimal 12-aa epitopes, Env-RW12 and Gag-GW12, were evaluated for presentation by target cells from horses with an equine lymphocyte Ag-A1 (ELA-A1) haplotype. Fifteen of 15 presented Env-RW12 to CTL, whereas 11 of 15 presented Gag-GW12. To determine whether these epitopes were presented by different molecules, MHC class I genes were identified in cDNA clones from Arabian horse A2152, which presented both epitopes. This h...
Amyloid protofilaments from the calcium-binding protein equine lysozyme: formation of ring and linear structures depends on pH and metal ion concentration. The calcium-binding equine lysozyme has been found to undergo conversion into amyloid fibrils during incubation in solution at acidic pH. At pH 4.5 and 57 degrees C, where equine lysozyme forms a partially unfolded molten globule state, the protein forms protofilaments with a width of ca. 2 nm. In the absence of Ca(2+) the protofilaments are present as annular structures with a diameter of 40-50 nm. In the presence of 10 mM CaCl(2) the protofilaments of equine lysozyme are straight or curved; they can assemble into thicker threads, but they do not appear to undergo circularisation. At pH 2.0, ...
Mapping epitopes in equine rhinitis A virus VP1 recognized by antibodies elicited in response to infection of the natural host. Equine rhinitis A virus (ERAV) is an important respiratory pathogen of horses and is of additional interest because of its close relationship and common classification with foot-and-mouth disease virus (FMDV). As is the case with FMDV, the VP1 capsid protein of ERAV has been shown to be a target of neutralizing antibodies. In FMDV VP1, such antibodies commonly recognize linear epitopes present in the betaG-betaH loop region. To map linear B cell epitopes in ERAV VP1, overlapping fragments spanning its length were expressed in Escherichia coli as glutathione S-transferase (GST) fusion proteins....
Genetic engineering of streptavidin-binding peptide tagged single-chain variable fragment antibody to Venezuelan equine encephalitis virus. A recombinant gene encoding a single-chain variable fragment (scFv) antibody against Venezuelan equine encephalitis virus (VEE) was cloned into a prokaryotic T7 RNA polymerase-regulated expression vector. A streptavidin-binding peptide gene fused to a 6His tag was attached downstream to the scFv gene. The recombinant fusion protein was expressed in bacteria as inclusion bodies that were subsequently solubilized with 8 M urea and renatured by an arginine system. Purification of the fusion protein was achieved by immobilized metal affinity chromatography. Enzyme-linked immunosorbent assay (ELISA...
Matrix-assisted laser-desorption time-of flight ionisation and high-performance liquid chromatography-electrospray ionisation mass spectral analyses of two glycosylated recombinant epoetins. Mass spectrometric analyses of the recombinant proteins in Eprex and Aranesp were undertaken with the goal of producing reference mass spectra and evaluating strategies to improve its applicability as a method for equine and canine doping control of these substances. A simple, low chemical noise deglycosylation reaction removed microheterogeneity due to post-translational carbohydrate attachment and both proteins were detectable using MALDI-TOF-MS. Deglycosylated human erythropoietin (hEPO) was also detected using HPLC-ESI-MS. This is the first time that spectra of deglycosylated Eprex and Ara...
Potentiation of the extracellular release of equine neutrophil elastase and alpha-1-proteinase inhibitor by a combination of two bacterial cell wall components: fMLP and LPS. Lipopolysaccharide (LPS) and N-formyl-methionyl-leucyl-phenylalanine (fMLP)-like peptides are Gram-negative bacterial cell wall components which, when released into the peripheral circulation in endotoxaemia, have the potential to activate leucocytes. In vitro, equine neutrophils require priming with LPS in order to generate reactive oxygen intermediates (ROI) in response to fMLP. Objective: The aim of this study was to examine whether the release of other neutrophil products is similarly dependent on prior priming with LPS. In particular, neutrophil elastase (NE), a potent proteolytic enzyme,...
Response of ELA-A1 horses immunized with lipopeptide containing an equine infectious anemia virus ELA-A1-restricted CTL epitope to virus challenge. Lipopeptide containing an ELA-A1-restricted cytotoxic T lymphocyte (CTL) epitope from the envelope surface unit (SU) protein of the EIAV(WSU5) strain was used to immunize three horses having the ELA-A1 haplotype. Peptide-specific ELA-A1-restricted CTL were induced in all three horses, although these were present transiently in PBMC. These horses were further immunized with lipopeptide containing the corresponding CTL epitope from the EIAV(PV) strain. Then, the three immunized horses and three non-immunized horses were challenged by intravenous inoculation with 300 TCID(50) EIAV(PV). All horses...
Appearance of nitrite reducing activity of cytochrome c upon heat denaturation. The appearance of NO2- reducing activity of cytochrome c (Cyt c) upon heat denaturation was investigated with equine heart Cyt c. Denatured equine heart Cyt c (dCyt c), which was treated at 100 degrees C for 30 min, had NO2- reducing activity in the presence of dithionite and methylviologen in an aqueous solution under anaerobic conditions. In contrast, hemoglobin and myoglobin had no such activity under the same conditions. Using spectroscopic methods, we found that the appearance of this activity in the Cyt c was due to the following intramolecular changes: unfolding of the peptide chain, ex...
Serum and mucosal antibodies of infected foals recognized two distinct epitopes of VapA of Rhodococcus equi. Virulence-associated protein A (VapA) of Rhodococcus equi has been proposed for use both as a vaccine and as a target for antibodies in immunotherapy and diagnostic tests. Epitope mapping of VapA allowed the identification of two B cell epitopes associated with R. equi pneumonia. The peptide NLQKDEPGRASDT was confirmed as an immunodominant N-terminal B cell epitope recognized by all sera from infected foals while VSFQYNAVGPYLNINFFDSS (C-terminal B cell epitope) was exclusively recognized by IgA from the tracheal aspirates. Moreover, specific antibodies produced against the VapA-specific peptid...
Immunohistochemical localization of chromogranin a in the acinar cells of equine salivary glands contrasts with rodent glands. We investigated the existence of chromogranin A (CgA) in salivary glands of the horse by Western blotting and enzyme immunoassay (EIA) using an antiserum against a peptide sequence of equine CgA. We also compared its cellular distribution between the horse and rat salivary glands with a tyramide signal amplification immunofluorescence technique. Western blotting gave three significant immunoreactive bands (74, 56 and 48 kDa) in adrenal medulla and three major salivary glands of horses. Immunoreactivities for CgA measured by EIA in horses were 154.05 +/- 41.46, 20.32 +/- 5.59 and 4.43 +/- 2.23 ...
Separation and characterization of mares’ milk alpha(s1)-, beta-, kappa-caseins, gamma-casein-like, and proteose peptone component 5-like peptides. The equine alpha(s1)- and beta-caseins (CN) were purified by chromatography on DEAE-cellulose and by reversed-phase HPLC. The alpha(s1)-, beta-, and kappa-CN were characterized either by monodimensional urea-PAGE or sodium dodecylsulfate (SDS)-PAGE or by bidimensional electrophoresis. Kappa-casein was characterized after electrophoresis by glycoprotein-specific staining. To identify alpha(s1)-CN without ambiguity, internal sequences were determined after trypsin or chymosin digestion of purified alpha(s1)-CN. These sequences, that could be estimated to correspond to 62% of the full protein, pr...
Exercise-induced changes in atrial peptides in relation to neuroendocrine responses and fluid balance in the horse. Previous data show that, in horses, plasma atrial natriuretic peptides (ANP and NT-ANP) remain elevated for a long time after exercise. To study whether exercise-induced changes in hormonal and fluid balance explain this, we measured plasma concentrations of COOH- and NH2-terminal atrial natriuretic peptides (ANP(99-129) and NT-ANP(1-98) together with arginine vasopressin (AVP), adrenocorticotrophin (ACTH), beta-endorphin, cortisol, catecholamines, and indicators of fluid balance in six Finnhorses after a graded submaximal exercise test on a treadmill. After exercise, AVP and catecholamines di...
Identification of broadly recognized, T helper 1 lymphocyte epitopes in an equine lentivirus. Equine infectious anaemia virus (EIAV) is a horse lentivirus causing lifelong, persistent infection. During acute infection, CD8(+) cytotoxic T lymphocytes (CTL) are probably involved in terminating plasma viraemia. However, only a few EIAV CTL epitopes, restricted to fewer horse major histocompatibility complex (MHC) class I alleles, are known. As interferon-gamma (IFN-gamma)-secreting CD4(+), T helper 1 (Th1) lymphocytes promote CTL activity and help maintain memory CTL, identifying broadly recognized EIAV Th1 epitopes would contribute significantly to vaccine strategies seeking to promote s...
Lipopeptide stimulation of MHC class I-restricted memory cytotoxic T lymphocytes from equine infectious anemia virus-infected horses. The immunogenicity of equine infectious anemia virus (EIAV) Gag and Env equine leukocyte alloantigen (ELA)-A5.1, -A9, and -A1 restricted cytotoxic T lymphocyte (CTL) epitopes synthesized on multiple antigenic peptide (MAP) system coupled to tripalmitoyl-S-glycerylcysteine (P3C) was evaluated in vitro. P3C-MAP-peptide-stimulated peripheral blood mononuclear cells (PBMCs) from horses, chronically infected with EIAV, had memory CTL (CTLm) similar to that of PBMCs stimulated with either the minimal CTL epitopes, longer peptides containing the CTL epitopes, or EIAV. The stimulated CTL lysed EIAV-in...
Functional expression and membrane fusion tropism of the envelope glycoproteins of Hendra virus. Hendra virus (HeV) is an emerging paramyxovirus first isolated from cases of severe respiratory disease that fatally affected both horses and humans. Understanding the mechanisms of host cell infection and cross-species transmission is an important step in addressing the risk posed by such emerging pathogens. We have initiated studies to characterize the biological properties of the HeV envelope glycoproteins. Recombinant vaccinia viruses encoding the HeV F and G open reading frames were generated and glycoprotein expression was verified by metabolic labeling and detection using specific antis...
Nasal mucosal immunogenicity for the horse of a SeM peptide of Streptococcus equi genetically coupled to cholera toxin. The intranasal immunogenicity of cholera toxin (CT) genetically coupled to peptide sequence aa236-334 (F3) of the SeM protein of Streptococcus equi was studied in five young adult Welsh ponies. All ponies made rapid CTB- and SeMF3-specific serum antibody responses following the first immunization. Specific nasal IgA responses were detected in two ponies 14 days after the first immunization, in another two 14 days after a second immunization on day 14, and in all ponies 28 days after a third immunization on day 42. SeMF3-specific antibody responses in sera and nasal washes were dominated by IgG...
Characterisation of tryptase and a granzyme H-like chymase isolated from equine mastocytoma tissue. Mast cell proteinases are important inflammatory mediators in man and other species, but until now there has been no investigation of the nature of equine mast cell proteinases. These studies describe the purification and characterisation of two proteolytic components from equine mastocytoma tissue, detected using chromogenic substrates for trypsin and chymotrypsin. Following chromatographic purification, the trypsin-like component was found to be equine mast cell tryptase by N-terminal amino acid sequencing, showing a close similarity with human tryptase-beta (85% identity over 20 residues). ...
Immunohistochemical demonstration of chromogranin A in endocrine organs of the rat and horse by use of region-specific antibodies. Chromogranin A (CgA) is an acidic glycoprotein that is co-stored with hormones or neurotransmitters in granular components of endocrine cells and neurons, and released together with them in response to adequate stimulation. In addition to acting as a packaging protein, CgA functions as a precursor molecule that yields several bioactive peptides by proteolytic cleavage. The purpose of this study is to elucidate how different the processing of CgA is among endocrine tissues by immunostaining using multiple region-specific antisera, and to evaluate the availability of region-specific antisera. Wh...
Cytochrome c reconstituted from two peptide fragments displays native-like redox properties. Recombination of two fragments of horse cytochrome c (the heme-containing N-fragment, residues 1-56, and the C-fragment, residues 57-104), which are substantially unstructured at neutral pH, gives rise to a 1:1 fragment complex with a compact conformation, in which the alpha helical structure and the native Met80-Fe(III) axial bond are recovered. With respect to the native protein, the ferric complex shows a less rigid atomic packing and a decreased stability [Delta(DeltaG(o))D = 14.7 kJ.mol(-1)], ascribed to perturbations involving the Trp59 microenvironment and, to a lower extent, the heme p...
Validation of a competitive enzyme-linked immunosorbent assay for diagnosing Babesia equi infections of Moroccan origin and its use in determining the seroprevalence of B. equi in Morocco. A highly specific and sensitive competitive enzyme-linked immunosorbent assay for detection of specific antibody to Babesia equi in serum from equids was validated for use in Morocco. The assay is based on the specific inhibition of binding of a monoclonal antibody to a conserved epitope within a recombinant parasite peptide by serum from infected animals. The assay was compared to an established indirect immunofluorescence assay, with a concordance of 91%. The assay was used to determine seroprevalence for B. equi infections in donkeys and horses throughout Morocco. A total of 578 sera (163 h...
Endothelin in the equine hypoxic pulmonary vasoconstrictive response to acute hypoxia. Elevated concentrations of endothelin (ET), a potent endothelium-derived vasoactive peptide, have been reported in a number of pathophysiological conditions associated with pulmonary hypertension, both in the horse and other species. We have previously shown, both in vitro and in vivo, that the pulmonary and systemic vascular response to exogenous ET is mediated predominantly via ET(A) receptors. Our hypothesis in the present study was that ET is involved in the equine hypoxic pulmonary vasoconstrictive response to acute hypoxia. In this study, we investigated the effects of a selective ET(A) ...
Synthetic peptide-based electrochemiluminescence immunoassay for anti-Borna disease virus p40 and p24 antibodies in rat and horse serum. Borna disease virus (BDV) is a neurotropic pathogen that infects a wide variety of vertebrates. We have developed a new electrochemiluminescence immunoassay (ECLIA) for the detection of antibodies to BDV, using three synthetic peptides corresponding to the amino acid residues 3-20 and 338-358 of p40 and 59-79 of p24 peptide of BDV. Using the ECLIA, we examined serum samples for the presence of anti-BDV antibodies in 20 rats (experimentally BDV-infected and uninfected) and 38 horses (13 US horses, experimentally infected and uninfected, and 25 Japanese horses, feral and domestic). The ECLIA, pe...
Immunohistochemical study of the distribution of adrenergic and peptidergic innervation in the equine uterus and the cervix. Little is known about neurogenic regulation of uterine contractility in mares. The present study investigated the distribution of adrenergic and peptidergic nerves in the mare uterus. Samples from the uterine horn, body and cervix were collected from 18 cyclic mares for immunohistochemistry. The uterus was well supplied with adrenergic nerves. A large number of tyrosine hydroxylase- and dopamine beta-hydroxylase-immunoreactive nerve bundles and fibres were present in the myometrium and endometrium in all regions of the uterus and cervix. These adrenergic nerve bundles and fibres travelled para...
Equine pulmonary and systemic haemodynamic responses to endothelin-1 and a selective ET(A) receptor antagonist. Based on previous in vitro studies, we hypothesised that endothelin (ET) would induce vasoconstriction in the pulmonary circululation of the horse and that this action would be mediated via ET(A) receptors. Pulmonary and systemic haemodynamic responses to endothelin-1 (ET-1), a potent vasoactive endogenous peptide, were investigated in 6 conscious, nonsedated horses at rest. Bolus i.v. injections of exogenous ET-1 (0.1, 0.2 and 0.4 microg/kg bwt) caused significant increases in pulmonary (PAP) and carotid (CAP) artery pressures, with peak increases of 79% and 51% for mean PAP and CAP, respecti...
Use of an antineoepitope antibody for identification of type-II collagen degradation in equine articular cartilage. To develop an antibody that specifically recognizes collagenase-cleaved type-II collagen in equine articular cartilage. Methods: Cartilage specimens from horses euthanatized for problems unrelated to the musculoskeletal system. Methods: A peptide was synthesized representing the carboxy- (C-) terminus (neoepitope) of the equine type-II collagen fragment created by mammalian collagenases. This peptide was used to produce a polyclonal antibody, characterized by western analysis for reactivity to native and collagenase-cleaved equine collagens. The antibody was evaluated as an antineoepitope anti...
Amino acid modifications in canine, equine and porcine pituitary growth hormones, identified by peptide-mass mapping. Modified amino acid residues in porcine, canine and equine growth hormones purified from pituitary glands were characterised by tryptic mapping and high-performance liquid chromatography with on-line coupled electrospray ionisation mass spectrometry (HPLC-ESI-MS) detection. Hormones from all three species showed the same changes. Conversion of Asp128 to iso-Asp128 was a component of native hormones, while deamidation of Asn12 and Asn98 to Asp and iso-Asp, oxidation of Met4, and cyclisation to the pyroglutamyl derivative of Gln139, probably occurred in vitro, during isolation, storage or hydrol...
Biochemical characterization and surfactant properties of horse allergens. A new allergen from horse dander, Equ c 5 has been purified. Its biochemical and biophysical properties have been characterized and compared with those of Equ c 1, Equ c 2 and Equ c 4. Their molecular masses, determined by mass spectrometry, were 22 kDa for Equ c 1, 16 kDa for Equ c 2, 18.7 kDa for Equ c 4 and 16.7 kDa for Equ c 5. Their pI values were between 3.8 and 5.25. Equ c 2 and Equ c 5 are not glycosylated, while Equ c 4 contains a tri-antennary tri-sialylated N-linked glycan. Linkages of terminal N-acetylneuraminic acid to galactose were: alpha-(2-->6) in Equ c 4, and both alpha-(2...
B-Cell epitope mapping of the VapA protein of Rhodococcus equi: implications for early detection of R. equi disease in foals. Linear B-cell epitopes of the Rhodococcus equi virulence-associated protein (VapA) were mapped using a synthetic peptide bank in this study. The peptides were screened in an enzyme-linked immunosorbent assay (ELISA) with a total of 70 sera from foals with current R. equi disease (51 sera), as well as from foals that had either recovered from R. equi infection 10 months previously (3 sera) or that had no known history of R. equi disease (16 sera). An epitope with the sequence NLQKDEPNGRA was identified and was universally recognized by all 51 sera from foals with R. equi disease and was not rec...
Design and validation of an ELISA for equine infectious anemia (EIA) diagnosis using synthetic peptides. Three peptides derived from the equine infectious anemia virus (EIAV) surface proteins were synthesized to design and validate an ELISA for EIA diagnosis. Peptides identified as gp90-I and gp90-II correspond to the N- and C-terminal part of the surface glycoprotein gp90. Peptide gp45-1 overlaps the immunodominant epitope CIERTHVFC of the transmembrane glycoprotein gp45, and includes a hydrophilic chain close to the N-terminal end of this nonapeptide loop. Serum samples from 140 naturally infected horses with EIAV and a panel of 167 non-immune equine sera obtained from non-infected animals were...
Rate of intrachain contact formation in an unfolded protein: temperature and denaturant effects. We have measured the effect of temperature and denaturant concentration on the rate of intrachain diffusion in an unfolded protein. After photodissociating a ligand from the heme iron of unfolded horse cytochrome c, we use transient optical absorption spectroscopy to measure the time scale of the diffusive motions that bring the heme, located at His18, into contact with its native ligand, Met80. Measuring the rate at which this 62 residue intrachain loop forms under both folding and unfolding conditions, we find a significant effect of denaturant on the chain dynamics. The diffusion of the cha...
