Chemokines are a family of small cytokines or signaling proteins secreted by cells that play a key role in the immune system of horses. They are involved in the chemotaxis, or directed movement, of immune cells towards sites of inflammation, infection, or injury. Chemokines facilitate communication between cells and help coordinate the body's response to various pathological conditions. In horses, chemokines are studied for their involvement in inflammatory processes and their potential as biomarkers for disease detection and progression. This page provides a collection of peer-reviewed research studies and scholarly articles that explore the function, regulation, and clinical relevance of chemokines in equine health.
Watson ED.Incubation of blood neutrophils with uterine flushings collected from ovariectomised mares treated with oestradiol, stimulated migration under agarose, whereas flushings from mares treated with progesterone or oily vehicle, inhibited migration. After intra-uterine infusion of bacteria, however, flushings from oestradiol-treated and vehicle-treated mares inhibited migration, whereas progesterone treatment stimulated migration. Migration of uterine-derived neutrophils under agarose was less than that of blood neutrophils and was not influenced by treatment with ovarian steroids. Uterine suscepti...
Muhktar MM, Timoney JF.Streptococcus equi infection in horses is characterised by intense infiltration of lymph nodes by polymorphonuclear leucocytes (PMNs) suggesting a potent chemotactic response to the organism or its products. Equine PMNs were separated using Ficoll-Hypaque medium and used in an assay of chemotaxis under agarose to study the components of S equi involved in this response. Results showed that complement-derived chemotactic factors generated by activation of the alternative complement pathway were important in chemotactic responses to S equi. Both whole bacteria and peptidoglycan preparations were...
Watson ED, Stokes CR, Bourne FJ.The influence of arachidonic acid metabolites on migration of equine neutrophils under agarose was investigated. Leukotriene B4 (LTB4) was chemotactic at concentrations between 0.1 and 1000 ng ml-1 and prostaglandin E2 (PGE2) at 1 and 10 ng ml-1 but not at higher or lower concentrations. Prostaglandin F2 alpha (PGF2 alpha) was not chemotactic for equine neutrophils at any concentration. Random migration was significantly inhibited (P less than 0.05) by suspension of neutrophils in LTB4 (0.1 to 1000 ng ml-1) and PGF2 alpha (0.1 ng ml-1) but not at high concentrations. There was a significant po...
Sedgwick AD, Dawson J, Lees P.Subpopulations of equine leucocytes, polymorphonuclear and mononuclear cells, were separated from whole blood on a discontinuous Percoll gradient and used in studies of chemokinesis and chemotaxis. Polymorphonuclear cells responded to the chemo-attractant properties of zymosan-activated plasma in Boyden chamber and agarose microdroplet assays but they responded only slightly (Boyden chamber) or not at all (agarose microdroplet) to the peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP). Equine mononuclear cell movement was increased by FMLP in both assay systems and these cells also respond...
Sedgwick AD, Lees P, Dawson J, May SA.The migration of leucocytes to sites of acute and chronic inflammation is an event of central importance to the maintenance of inflammatory processes; extravascular leucocytes are responsible for generating chemical mediators of inflammation and the phagocytosis of particulate matter. They may also be involved in the conversion of acute to chronic inflammatory lesions. Leucocytes are attracted to sites of tissue injury by a range of chemoattractants. This paper describes the development of a method for separating on Percoll gradients purified populations of equine polymorphonuclear and mononuc...
Leid RW, Grant RF, Suquet CM.Taeniaestatin, a recently isolated Taenia taeniaeformis proteinase inhibitor, was used to inhibit equine neutrophil migration. Taeniaestatin itself was not chemotactic when used as a chemotactic factor but taeniaestatin did inhibit neutrophil chemokinesis when tested in a Zigmond-Hirsch checkerboard assay. A dose-dependent inhibition of both chemokinesis and chemotaxis was observed when zymosan activated bovine sera (ZABS) was used as the chemotactic factor. This inhibition was greater than 95% when 5 mu of taeniaestatin was present on both the cell and chemotactic factor side of the chambers....
Bernoco M, Liu IK, Wuest-Ehlert CJ, Miller ME, Bowers J.Chemotactic and phagocytic responsiveness of peripheral blood polymorphonuclear leucocytes (PMNLs) from 11 foals were analysed immediately after birth (pre-colostral) and at different times after colostrum ingestion. The number of foal PMNLs per microscopic field that had migrated through the filter in chemotaxis and the number of yeast particles ingested per foal PMNL in phagocytosis were significantly lower when tested with foal plasma before colostrum ingestion (chemotaxis, 2.0 +/- 0.55 (s.e.m.); phagocytosis, 0.98 +/- 0.352) than in tests 4 or more days after colostrum ingestion (chemotaxi...
Potter KA, Leid RW, Kolattukudy PE, Espelie KE.Lipoxygenase products of arachidonic acid are important mediators of inflammation, affecting several aspects of cell function. Monohydroxyeicosatetraenoic acid (mono-HETE) and 5,12-dihydroxyeicosatetraenoic acid (LTB4) enhance migration of both neutrophils and eosinophils in several species. The relative ability of positional isomers of HETE and of LTB4 to affect migration of equine eosinophils was studied. The 5, 8, 9, 11, 12, and 15 isomers of HETE were prepared by autooxidation of arachidonic acid, separated by sequential normal phase and reverse phase high performance liquid chromatography...
Liu IK, Cheung AT, Walsh EM, Miller ME, Lindenberg PM.The functional competence of peripheral blood and uterine-derived polymorphonuclear leukocytes (PMN) from 12 mares were analyzed for chemotactic responsiveness using a chemotactic chamber (filter) assay and for deformability by cell elastimetry analysis. Peripheral blood PMN obtained from control mares and from 8 mares experimentally inoculated via the uterus with 1 x 10(9) Streptococcus zooepidemicus had similar normal chemotactic responsiveness and were highly deformable before and at 12 hours after inoculation. Uterine PMN obtained 12 hours after uterine inoculation with S zooepidemicus fro...
Blue HB, Blue MG, Kenney RM, Merritt TL.Forty uterine fluid samples were obtained from 4 mares classified as resistant to uterine bacterial infection. The uterus of each mare was flushed with 50 ml of saline solution during estrus and diestrus of successive estrous cycles. Bacteria or fungi were isolated from 4 samples, and 7 additional samples were obtained from a mare with active intrauterine infection. Fluid volumes obtained during estrus (means = 40.3 +/- 11 ml) tended to be greater than those recovered during diestrus (means = 36.8 +/- 7.9 ml), but the difference was not significant. Concentrations and yields of protein in reco...
Jacobsen K, Gintz T, Reed SM, Newbry J, Bayly WM, Perryman LE, Leid RW.Equine neutrophils (PMN) were isolated to greater than 99% purity by isopyknic sedimentation on coated colloidal silica particles. A cell recovery of 84.7 +/- 4.0%, with a viability of greater than 99%, was observed with this method. The isolated PMN were compared with mixed population of equine peripheral leukocytes with respect to functional integrity by chemiluminescence and bactericidal assays. There was no significant difference (P less than 0.01) observed in either assay between the isolated equine PMN and the mixed-cell populations. The methods used in both the isolation as well as the ...
Naef A, Damerau B, Keller HU.The relationship between the short transient intracellular increase in cAMP levels on the one hand and chemotaxis or crawling movements on the other hand was investigated using human and equine granulocytes. C5ades arg, f-met-leu-phe, human serum albumin and immunoglobulin were used as stimulating agents. There was no strict correlation between the induction of crawling movements or of chemokinesis in general and the generation of the cAMP peak. But there was so far a strict parallelism between the occurrence of the chemotactic response and the cAMP peak. However, the magnitude of the peak was...
Zinkl JG, Brown PD.Horse polymorphonuclear leukocytes (PMN) isolated from horse blood by sedimentation and isotonic lysis and having about 25% accompanying lymphocytes were as effective at chemotaxis as nearly pure PMN isolated by density gradient techniques. N-Formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP), used as a representative of the formylmethionyl peptides (produced by prokaryocytic organisms), was effective as a chemoattractant only at the high concentration of 10(-4) M. When serum was preincubated with FMLP at concentrations as low as 10(-8) M, the serum attracted horse PMN. This activity was not g...
Camp CJ, Leid RW.A method for the isolation of equine neutrophils was developed using metrizamide cushions. A purity of greater than 95% was routinely obtained with greater than 90% viability. These cells were radiolabeled and tested for their chemotactic response in Boyden chambers to zymosan-activated equine serum, the partially purified equine complement component C5a, and formyl-L-methionyl-L-leucyl-L-phenylalanine. The time and ionic requirements for chemotaxis of radiolabeled equine neutrophils were investigated and maximal movement was observed at 2 hours' incubation and 1.0 mM Ca and 0.5 mM Mg. Dinitro...
Benbarek H, Deby-Dupont G, Caudron I, Deby C, Lamy M, Serteyn D.Divergent results have been reported on the effects of lipopolysaccharides (LPS) on the activation of equine polymorphonuclear leukocytes (PMN). We therefore attempted to determine whether LPS alone can stimulate equine PMN or whether plasma factors are necessary. PMN were isolated from citrated blood on a discontinuous density gradient of Percoll. The luminol (10(-3) mol/L)-enhanced chemiluminescence (CL) of 1.25 x 10(6) cells was measured after addition of Escherichia coli LPS (0.001-10 micrograms/ml) alone or after incubation in autologous plasma (1 h, 37 degrees C). After direct stimulatio...
Weston MC, Collins ME, Cunningham FM.Inappropriately activated eosinophils can contribute to disease pathogenesis and intracellular signalling pathways that regulate functional responses may represent a therapeutic target. Little is known about intracellular signalling in equine eosinophils and this study examined the role of phospholipase C (PLC) and a range of protein kinases on responses to histamine and CCL11. Histamine (10(-4) M) or CCL11 (5.6 x 10(-9) M)-induced actin polymerization, migration and superoxide production by eosinophils from healthy horses were compared in the presence and absence of selective kinase inhibitor...
Pycock JF, Allen WE.The uteri of normal pony mares in oestrus were infected experimentally with Streptococcus zooepidemicus. Uterine contents were collected 30, 60, 120 or 240 minutes later and were tested for their chemotactic effect on equine-neutrophils both with a morphological assay based on neutrophil shape changes and with a modified Boyden chamber technique. By 30 minutes after infection the uterine contents were markedly chemotactic for isolated peripheral neutrophils and remained so at the 240-minute collection. Uterine contents from uninfected mares had minimal chemotactic properties. These results cou...
Watson ED, Sertich PL, Zanecosky HG.Ovulation has been likened to an inflammatory process. Inflammatory cells accumulate in the ovulating follicle, presumably because of chemotactic factors. Chemotactic activity was measured in fluid aspirated from follicles of estrous mares 0, 12, 24, and 36 hours after ultrasonographic detection of a 35-mm follicle and IV treatment with 2,500 IU of human chorionic gonadotropin. Chemotaxis was assessed by measuring directional migration of equine neutrophils under agarose. Follicular fluid acted as a chemoattractant for neutrophils, but there was no significant difference in chemotactic activit...
Troedsson MH, Lee CS, Franklin RD, Crabo BG.The effect of seminal plasma on polymorphonuclear neutrophil (PMN) chemotaxis, PMN phagocytosis and complement-induced cytolysis was determined using blood plasma pooled from four horses and seminal plasma pooled from two stallions. To investigate chemotaxis, complement in blood plasma was activated with E. coli lipopolysaccharide in the presence of 0-50% seminal plasma diluted with a standardized volume of McCoy's medium and placed in a chemotactic chamber. Chemotaxis of blood derived equine PMNs toward the chemoattractants was determined after incubation at 37 degrees C for 45 min. To invest...
Weston MC, Cunningham FM, Collins ME.CCL11 (also known as eotaxin) is a very potent and selective mediator of eosinophil migration which exerts its effects through its receptor, CCR3. In this study we report the cloning of an equine CCR3 cDNA sequence and investigation of the localization of CCR3 mRNA expression in horse tissues. Equine CCR3 displayed high levels of sequence identity with CCR3 sequences in other species. RT-PCR analysis revealed the expression of CCR3 in colon, lung and spleen of normal horses. In situ hybridisation experiments indicated that expression of CCR3 mRNA in colon was predominantly in eosinophils and t...
Weston MC, Collins ME, Cunningham FM.To assess the biological effects of purified recombinant equine CCL11 on equine eosinophil function. Methods: Following stimulation of eosinophils from normal horses, the polymerised form of actin was measured by flow cytometry using fluorescently labelled phalloidin. Migration was determined in a 96 well plate chemotaxis assay using 8 microm pore membranes, and adherence of eosinophils to serum-coated plastic was assessed using a colorimetric assay for eosinophil peroxidase. Superoxide generation was measured by the reduction of cytochrome C in a colorimetric assay. Results: Equine CCL11 indu...
Hudgens E, Tompkins D, Boyd P, Lunney JK, Horohov D, Baldwin CL.This report describes the cloning and characterization of expressed gene sequences of bovine, equine, and swine CXCL9 from RNA obtained from peripheral blood mononuclear cells (PBMC) and other tissues. The bovine coding region was 378 nucleotides in length, while the equine and swine coding regions were 381 nucleotides. Mapping showed that all three sequences were coded for in four exons in the genome, as are the human and mouse genes. The bovine, equine, and swine coding regions shared 83%, 86%, and 84% homology with human CXCL9, respectively, and all three were 74% homologous with mouse CXCL...
Moore GE, Leatherwood JL, Glass KG, Arnold CE, Paris BL, Carter MM, George JM, Fontenot AB, Martinez RE, Franklin MA, Norton SA, Bradbery AN....The objective was to evaluate dietary fermentation product (SCFP) on joint inflammation and cartilage metabolism in exercising yearlings challenged with intra-articular lipopolysaccharide (LPS), hypothesizing dietary SCFP (TruEquineC, Diamond V Mills, Inc.) would ameliorate joint inflammation and increase cartilage metabolism. Thirty Quarter Horse yearlings were stratified by bodyweight (BW), age, sex, and randomly assigned to dietary treatments (n = 10/treatment): control (0), 46, or 92 mg/kg BW/d SCFP. Treatments were top-dressed to 1% BW/d concentrate void of added microbials. Horses ...
Roth SP, Liso G, Brehm W, Wagner B, Schnabel CL, Troillet A.The anti-inflammatory and regenerative effects of autologous conditioned serum (ACS) in joint-associated disorders are presumably mediated by the biomolecules it contains, such as cytokines and chemokines. ACS is commonly used in equine practice after storage. Data regarding the influence of storage conditions of ACS on cytokine and chemokine concentrations are not available. Unassigned: To evaluate the effect of commonly used storage conditions on selected cytokine and chemokine concentrations in equine ACS. Unassigned: From 10 horse patients with clinically indicated ACS preparation six ACS ...
Scoggin KE, Rakha SI, Abdellatif AM, Adlan F, Helmy YA, Ruby R, Ball B, Boakari Y, Ali HE.Ascending placentitis is a significant cause of equine pregnancy loss, yet the upstream inflammatory triggers are poorly defined. Recently, we identified S100A8/S100A9 (S100A8/A9) alarmins as potential upstream regulators in a chronic equine placentitis model. The current study aimed to determine whether this upregulation is sustained in the acute model and in clinical cases, and to elucidate the expression of their downstream inflammatory mediators. Using an experimental model, we quantified mRNA expression in acute ( = 5) and chronic ( = 6) placentitis induced by ssp. . We found mRNA expre...
Lection J, Schnobrich M, Wagner B, Byron M, Back B, Rollins A, Castro Alves RF, Cheong SH, Diel de Amorim M.To evaluate inflammatory cytokine and chemokine concentrations in endometrial samples collected by cytobrush or swab as a potential screening diagnostic marker for equine endometritis. Unassigned: 88 mares had endometrial samples collected, which included cytobrush, swab, and/or biopsy. Clinical reproductive records, reproductive ultrasound examination, endometrial cytology and culture results, and biopsy grading score were recorded. Fluorescent bead-based multiplex assays for the inflammatory markers interferon-γ, interferon-α, IL-1β, IL-4, IL-10, IL-17A, soluble CD14, tumor necrosis facto...
Mitlyng N, Hobbs KJ, Cooper BL, Sheats MK.Lipopolysaccharide (LPS) is frequently used in equine research to model clinical endotoxemia; however, there is no standardized protocol for inducing cytokine production in equine whole blood. To address this knowledge gap, the goal of this study was to compare the cytokine responses elicited by three different LPS stimulation protocols. Whole blood was collected from six healthy horses (aged 5-30 years; mixed breeds and genders) from the North Carolina State University teaching herd (IACUC #23-412). Sixty milliliters of heparinized blood were aseptically drawn and divided into 15 mL aliquots....
Clark KF, Lemcke RA, Gasiorowski JC, Wagner B.Lyme arthritis, a well-documented subtype of arthritis in humans and dogs, is caused by Borrelia burgdorferi and spread primarily through ticks (Ixodes spp.). While Lyme disease in horses is known to cause a variety of clinical signs, its involvement in the development of equine arthritis is controversial. As climate change enables tick populations to expand, more horses could be exposed to B. burgdorferi; therefore, a greater understanding of how Lyme disease affects joints is critical to preserving soundness. Objective: To determine if systemic, naturally occurring Lyme disease had a discern...
