Phagocytosis in horses refers to the process by which certain cells, known as phagocytes, engulf and digest foreign particles, bacteria, and cellular debris. This cellular mechanism is a part of the innate immune response, helping to protect horses from infections and maintain tissue homeostasis. Key phagocytic cells in horses include neutrophils and macrophages, which are responsible for identifying and eliminating pathogens. Research on phagocytosis in equines explores the efficiency, regulation, and impact of this process on overall health and disease resistance. This page includes peer-reviewed research studies and scholarly articles that investigate the mechanisms, cellular interactions, and implications of phagocytosis in equine immunology.
Macedo IS, Lara FA, Barbosa HS, Saraiva EM, Menna-Barreto RFS, Mariante RM., responsible for causing toxoplasmosis, is a prevalent food and waterborne pathogen worldwide. It commonly infects warm-blooded animals and affects more than a third of the global human population. Once ingested, the parasite enters the host's small intestine and rapidly disseminates throughout the body via the bloodstream, infiltrating various tissues. Leukocyte-driven responses are vital against , with neutrophils playing a dual role: swiftly recruited to infection sites, releasing inflammatory mediators, and serving as a replication hub and Trojan horses, aiding parasite spread. Neutrophil...
Alghamdi AS, Fedorka CE, Scoggin KE, Esteller-Vico A, Beatty K, Davolli G, Ball BA, Troedsson MHT.Sperm-neutrophil binding is an important facet of breeding and significantly impacts fertility. While a specific seminal plasma protein has been found to reduce this binding and improve fertility (CRISP-3), additional molecule(s) appear to promote binding between defective sperm and neutrophils. Recent work has suggested one of these proteins is lactoferrin (LF), an 80 kDa iron-binding protein found throughout the body, but the purity of the protein was not confirmed. It is unknown if LF binds to sperm selectively based on viability, and if receptors for LF are located on equine sperm. To eval...
Cui JQ, Liu WH, Zang YX, Zhang C, Zou L, Sun HZ, Pan Q, Ren HY.A lytic bacteriophage vB_EcoM_DE7 (hereafter designated DE7) that could infect donkey-derived Escherichia coli was isolated. The bacteriophage was examined by transmission electron microscopy, and the result showed that DE7 belonged to the family Myoviridae. The microbiological characterization revealed that DE7 was stable over a broad range of pHs (3 ∼10) at 40-50 °C. The latent period was 10 min, and the burst size was 43 PFUs/infected cell. The whole-genome sequencing showed that DE7 was a dsDNA virus and had a genome of 86,130 bp. The genome contained 124 predicted open reading frames...
Herbst AC, Reedy SE, Page AE, Horohov DW, Adams AA.Studies investigating age-related changes in the function of monocytes are currently limited for horses. Thus, the main goal of this study was to determine the effect of aging on monocyte phagocytic capacity and pro-inflammatory cytokine responses to bacterial lipopolysaccharide (LPS). A second goal of this work was to examine the effect of aging on the inflammatory cytokine responses to LPS in a whole blood ex vivo model. Seven healthy young adult (4-6 years of age) and seven healthy senior horses (>20 years of age) were enrolled. Phagocytosis of E. coli, and pro-inflammatory cytokine (TNF...
Salinas C, Espinosa G, Morales N, Henríquez C, Morán G, Gajardo G, Burgos RA, Uberti B.Obesity and insulin dysregulation (ID) are increasingly prevalent conditions in equid populations worldwide. Immune impairment is well described in humans with metabolic dysfunction and is reported but still incompletely understood in horses. This study evaluated the effect of acute induced transient hyperglycemia on apoptosis, phagocytosis and oxidative burst activity of peripheral blood polymorphonuclear cells (PMN) of lean and obese adult horses with or without insulin dysregulation. Seventeen adult horses were allocated into three groups based on their body condition score (BCS) and metabo...
Di Pietro R, Dubuc V, Manguin E, Giroux-Lafond R, Bédard C, Boivin R, Lavoie JP, Vesper SJ, Leclere M.To quantify dectin-1 expression in bronchoalveolar lavage fluid (BALF), create polyclonal antibodies against equine dectin-1 and localize it in tissues, and quantify fungal exposure in pastured and stabled asthmatic and nonasthmatic horses. Methods: BALF samples from 6 controls and 6 horses with severe asthma. Stored lung and nasal wash samples. Methods: Dectin-1 expression was quantified by quantitative PCR (qPCR). Purified peptide from equine dectin-1 was used to generate polyclonal antibodies and was confirmed with immunological testing. Fungal exposure was quantified in BALF samples by cou...
Zandoná Meleiro MC, de Carvalho HJC, Ribeiro RR, da Silva MD, Salles Gomes CM, Miglino MA, de Santis Prada IL.Racehorses are constantly exposed to stress. Aiming to verify the state of blood components and cortisol alterations during their routine and after races, phagocytosis and oxidative neutrophil burst assays, serum cortisol determination, erythrocytes apoptosis evaluation, lymphoproliferation assays, and blood count tests were performed in thirty Thoroughbred racehorses, which were divided in two groups. The samples were taken right after races (moment 0 d), during rest periods (-11 d, +1 d, +3 d), and after training (-8, +2, +5). In both groups, the phagocytosis showed a decrease in percentage ...
Lee GKC, Kang H, Beeler-Marfisi J, Sears W, Lillie BN, Bienzle D.Salivary scavenger and agglutinin (SALSA) is a secreted protein with various immunomodulatory roles. In humans, the protein agglutinates and inactivates microorganisms, and inhibits the release of pro-inflammatory cytokines. Saliva, which is rich in SALSA, accelerates bacterial phagocytosis, but SALSA's contribution is unclear. In horses, the functions of SALSA in inflammation remain undetermined, so they were investigated through phagocytosis and cytokine assays. Equine SALSA was purified from duodenal tissue, which contains abundant SALSA. To assess phagocytosis, fluorescently-labelled bacte...
Baakhtari M, Imaizumi N, Kida T, Yanagita T, Ramah A, Ahmadi P, Takebe N, Iwamoto Y, Korosue K, Tsuzuki N, Yasuda M.High-intensity exercise and competition are associated with depressed immune function. Young horses, which participate in high-intensity exercise and competitions, are at increased risk for the development of infectious disease due to depression of immune function. The effects of branched-chain amino acid (BCAA) supplementation on the immune status of young racing horses were evaluated, determining whether BCAA might help to avoid or reduce immune suppression during exercise and competitions. Twenty horses (10 male and 10 female) were treated with BCAA supplementation; another twenty untreated...
Lauková A, Micenková L, Kubašová I, Bino E, Kandričáková A, Plachá I, Štrkolcová G, Gálik B, Kováčik A, Halo M, Simonová MP.The beneficial influence of bacteriocin-producing, probiotic, mostly non-autochthonous bacteria has already been reported in various animals. However, their use in horses provides limited information, and results with autochthonous bacteria have not been reported. Therefore, the main objective of this model study was to test the effect of autochthonous, bacteriocin-producing faecal strain Enterococcus faecium EF 412 application in horses. One gram of freeze-dried EF 412 strain (10 CFU/mL for 21 days) was applied to horses in a small feed ball. Clinically healthy horses (12), Slovak warm-blood ...
Vail KJ, da Silveira BP, Bell SL, Cohen ND, Bordin AI, Patrick KL, Watson RO.Rhodococcus equi is a major cause of foal pneumonia and an opportunistic pathogen in immunocompromised humans. While alveolar macrophages constitute the primary replicative niche for R. equi, little is known about how intracellular R. equi is sensed by macrophages. Here, we discovered that in addition to previously characterized pro-inflammatory cytokines (e.g., Tnfa, Il6, Il1b), macrophages infected with R. equi induce a robust type I IFN response, including Ifnb and interferon-stimulated genes (ISGs), similar to the evolutionarily related pathogen, Mycobacterium tuberculosis. Follow up studi...
Yánez-Ortiz I, Catalán J, Mateo-Otero Y, Dordas-Perpinyà M, Gacem S, Yeste N, Bassols A, Yeste M, Miró J.Jenny shows a large endometrial reaction after semen influx to the uterus with a large amount of polymorphonuclear neutrophils (PMN) migrating into the uterine lumen. PMN act as a sperm selection mechanism through phagocytosis and NETosis (DNA extrudes and, together with proteins, trap spermatozoa). While a reduced percentage of spermatozoa are phagocytosed by PMN, most are found to be attached to neutrophil extracellular traps (NETs). This selection process together with sperm metabolism produces a large amount of reactive oxygen species (ROS) that influence the reproductive success. The pres...
Miró J, Catalán J, Marín H, Yánez-Ortiz I, Yeste M.While artificial insemination (AI) with frozen-thawed sperm results in low fertility rates in donkeys, the addition of seminal plasma, removed during cryopreservation, partially counteracts that reduction. Related to this, an apparent inflammatory reaction in jennies is induced following AI with frozen-thawed sperm, as a high amount of polymorphonuclear neutrophils (PMN) are observed within the donkey uterus six hours after AI. While PMN appear to select the sperm that ultimately reach the oviduct, two mechanisms, phagocytosis and NETosis, have been purported to be involved in that clearance. ...
Muko R, Matsuda H, Oikawa MA, Shin T, Matsuda K, Sato H, Sunouchi T, Tanaka A.Histidine-rich glycoprotein (HRG) is an abundant plasma protein that has been identified in most mammals. We first identified whole genome sequence of equine HRG (eHRG) and succeeded to purify eHRG from plasma of horses. Since HRG interacts with various ligands, this protein is thought to be involved in immune response, coagulation, and angiogenesis. Systemic inflammatory response syndrome (SIRS) is characterized as a non-specific, clinical, pro-inflammatory immune response that damage organs and tissues in the host. Recent reports revealed that blood HRG levels in human patients with SIRS are...
Allegro AR, Barhoumi R, Bordin AI, Bray JM, Cohen ND.Rhodococcus equi is a soil saprophytic bacterium and intracellular pathogen that causes pneumonia in foals. Strains of R. equi that are virulent in foals contain a plasmid that encodes a virulence-associated protein A (VapA) necessary for replication in macrophages. Because other intracellular pathogens survive and replicate inside amoebae, we postulated that the VapA-bearing plasmid (pVAPA) confers a survival advantage for R. equi against environmental predators like amoebae. To test this hypothesis, we compared phagocytosis by and survival in Acanthamoeba castellanii of isogenic strains of p...
Picetti TS, Soveral LF, Miotto R, Erpen LMS, Kreutz Y, Guizzo JA, Frandoloso R, Kreutz LC.Immune-modulating molecules mainly act on innate immune cells, which are central to early defense against invading pathogens and contribute to developing adaptive immunity. Yeast-extracted β-glucan, a model immune-modulating molecule, is widely used in several animal species; however, its effect on horse immune parameters has not been thoroughly investigated yet. This study aimed to evaluate the effects of orally administered β-glucan on selected innate immune parameters in horses. Methods: Eighteen thoroughbred horses were assigned equally into three groups as follows: One control group (no...
Pezzanite LM, Chow L, Johnson V, Griffenhagen GM, Goodrich L, Dow S.To evaluate effects of Toll-like and nucleotide-binding oligomerization domain (NOD)-like receptor (TLR, NLR) ligand stimulation of equine mesenchymal stromal cells (MSCs) on antibacterial and immunomodulatory properties in vitro. Methods: Controlled laboratory study. Methods: Equine bone-marrow-derived MSCs (three horses). Methods: MSCs were stimulated with TLR (polyinosinic:polycytidylic acid [pIC] and lipopolysaccharide [LPS]) and NLR agonists (γ-d-Glu-mDAP [IE-DAP]) for 2 h, and plated at 1 × 105 cells/well 24 h. MSC-conditioned media (MSC-CM) were collected and assessed for antimicr...
Zhang H, Zhou T, Su L, Wang H, Zhang B, Su Y.Strangles, which is caused by Streptococcus equi subspecies equi (S. equi), is one of the most prevalent equine infectious diseases with worldwide distribution and leads to serious economic loss in the horse industry. Sortase A (srtA) is a transpeptidase that anchors multiple virulence-associated surface proteins to the cell surface of S. equi. srtA plays a major role in S. equi infection and colonization of the host cell. In this study, we aimed to investigate the effects of srtA mutation on the phagocytic activity and immunogenicity of S. equi. The point-mutated recombinant sortases, includi...
Harvey AB, Bordin AI, Rocha JN, Bray JM, Cohen ND.Evidence regarding the efficacy of equine hyperimmune plasma to prevent pneumonia in foals caused by Rhodococcus equi is limited and conflicting. Objective: Opsonization with R. equi-specific hyperimmune plasma (HIP) will significantly increase phagocytosis and decrease intracellular replication of R. equi by alveolar macrophages (AMs) compared to normal plasma (NP). Methods: Fifteen adult Quarter Horses were used to collect bronchoalveolar lavage cells. Methods: In the first experiment, AMs from 9 horses were pretreated (incubated) with either HIP, NP, or media only (control) and then infecte...
Papas M, Catalán J, Recuero S, Morrell JM, Yeste M, Miró J.This study sought to determine whether single layer centrifugation (SLC) of fresh donkey semen with Equicoll has any impact on sperm quality parameters and on the modulation of endometrial reaction following semen deposition using an in vitro model. Seventeen ejaculates from five jackasses were obtained using an artificial vagina and diluted in a skim-milk extender. Samples were either selected through SLC (Equicoll) or non-treated (control). Two experiments were performed. The first one consisted of incubating selected or non-selected spermatozoa at 38 °C for 180 min. Integrity and lipid dis...
Conrado FO, Iapoce N, Batista-Linhares M, Lopez S, Matthews MH, McKinney CA, Rothacker C.An 18-year-old, grey, Thoroughbred Cross gelding was referred to the Cummings School of Veterinary Medicine at Tufts University following a 3-week history of low-grade fever of unknown origin, distal limb swelling, and weight loss. Clinical examination identified a few black, round, smooth nodules along the ventral aspect of the proximal tail. Transabdominal ultrasound showed a markedly enlarged heterogenous spleen, hyperechoic liver nodules, and evidence of peritonitis with fibrin deposition. A mature neutrophilia was noted on complete blood count with variable numbers of phagocytized granule...
Lopez BS, Hurley DJ, Giancola S, Giguère S, Hart KA.Immunological and endocrine immaturity in foals increases foal morbidity and mortality from bacterial sepsis. Dendritic cells (DC) are critical in activating the adaptive immune response, but foal DC are phenotypically and functionally different than those of adult horses. Age-related variations in availability of some soluble plasma factors, such as hormones, might govern some age-related differences in DC function. Effects of exposure to plasma factors on equine DC phenotype and function have not been described. We hypothesized that exposure to plasma from foals or adult horses would differe...
Salinas C, Espinosa G, Morales N, Henríquez C, Morán G, Gajardo G, Uberti B.Obesity is a highly prevalent condition in horses. Dysfunctional neutrophil activity has been reported in metabolically healthy obese humans, but minimal data exist regarding horses. The present study evaluated the effect of obesity on apoptosis, phagocytosis and oxidative burst activity of peripheral blood neutrophils from lean and obese non-insulin dysregulated horses. Seven lean (BCS, body condition score 4-6/9) and five obese (BCS 8-9) horses were enrolled in the study. All animals underwent two metabolic tests (OGT, oral glucose test; IRT, insulin response test) before their selection to ...
Miró J, Marín H, Catalán J, Papas M, Gacem S, Yeste M.In the donkey, artificial insemination (AI) with frozen-thawed semen is associated with low fertility rates, which could be partially augmented through adding seminal plasma (SP) and increasing sperm concentration. On the other hand, post-AI endometrial inflammation in the jenny is significantly higher than in the mare. While previous studies analyzed this response through recovering Polymorphonuclear Neutrophils (PMN) from uterine washings, successive lavages can detrimentally impact the endometrium, leading to fertility issues. For this reason, the first set of experiments in this work inten...
Lauková A, Styková E, Kubašová I, Strompfová V, Gancarčíková S, Plachá I, Miltko R, Belzecki G, Valocký I, Pogány Simonová M.The effects of non-authochtonous Enterococcus faecium AL41 = CCM 8558, enterocin M-producing and probiotic strain were tested on the microbiota, phagocytic activity, hydrolytic enzymes, biochemical parameters and dry matter in horses based on its previous benefits demonstrated in other animals. E. faecium CCM 8558 sufficiently colonized the digestive tract of horses. At day 14, its counts reached 2.35 ± 0.70 CFU/g (log 10) on average. The identity of CCM 8558 was confirmed by means of PCR after its re-isolation from horse faeces. The inhibition activity of CCM 8558 was demonstrated a...
Martin LM, Johnson PJ, Amorim JR, DeClue AE.Resveratrol, a phytophenol, is a commonly used equine nutraceutical supplement touted to exert anti-inflammatory effects. The effect of orally administered resveratrol on tumor necrosis factor (TNF), interleukin-1β (IL-1β), leukocyte phagocytic activity or oxidative burst function have not been reported in horses. The objective of this study was to determine the effects of a commercially available, orally administered resveratrol product on innate immune functions in healthy adult horses. Whole blood was collected from 12 horses prior to and following 3 weeks of treatment with either the man...
Espinosa G, Plaza A, Schenffeldt A, Alarcón P, Gajardo G, Uberti B, Morán G, Henríquez C.Polymorphonuclear neutrophils (PMN) are the largest leukocyte population in the blood of most mammals including horses, and play an important defensive role in many infectious diseases. However, the mechanisms that increase PMN as one of the main cellular subsets in the defense against pathogens could also be involved in the pathophysiology of dysregulated inflammatory conditions. Mesenchymal stem/stromal cells (MSCs) are a heterogeneous population with a modulatory potential on the inflammatory response and are known to interact with nearly all cells of the immune system, including PMN. In th...
Vanderstock JM, Lecours MP, Lavoie-Lamoureux A, Gottschalk M, Segura M, Lavoie JP, Jean D.OBJECTIVE To evaluate in vitro phagocytosis and bactericidal activity of circulating blood neutrophils in horses with severe equine asthma and control horses and to determine whether circulating blood neutrophils in horses with severe equine asthma have an increase in expression of the proinflammatory cytokine tumor necrosis factor (TNF)-α and the chemokine interleukin (IL)-8 and a decrease in expression of the anti-inflammatory cytokine IL-10 in response to bacteria. ANIMALS 6 horses with severe equine asthma and 6 control horses. PROCEDURES Circulating blood neutrophils were isolated from h...
Smith AD, Panickar KS, Urban JF, Dawson HD.Vitamins and minerals (micronutrients) play an important role in regulating and shaping an immune response. Deficiencies generally result in inadequate or dysregulated cellular activity and cytokine expression, thereby affecting the immune response. Decreased levels of natural killer, granulocyte, and phagocytic cell activity and T and B cell proliferation and trafficking are associated with inadequate levels of micronutrients, as well as increased susceptibility to various adverse health conditions, including inflammatory disorders, infection, and altered vaccine efficacy. In addition, most s...
de Jong NWM, Vrieling M, Garcia BL, Koop G, Brettmann M, Aerts PC, Ruyken M, van Strijp JAG, Holmes M, Harrison EM, Geisbrecht BV, Rooijakkers SHM.Staphylococcus aureus is a versatile pathogen capable of causing a broad range of diseases in many different hosts. S. aureus can adapt to its host through modification of its genome (e.g. by acquisition and exchange of mobile genetic elements that encode host-specific virulence factors). Recently, the prophage φSaeq1 was discovered in S. aureus strains from six different clonal lineages almost exclusively isolated from equids. Within this phage, we discovered a novel variant of staphylococcal complement inhibitor (SCIN), a secreted protein that interferes with activation of the human complem...
Hondalus MK, Mosser DM.Rhodococcus equi is a facultative intracellular bacterium of macrophages that can cause serious pneumonia in both young horses and immunocompromised people. Essential to understanding rhodococcus pathogenesis is a quantitative documentation of the intracellular events that follow macrophage phagocytosis of the organism. By using a bacterial immunofluorescence staining assay, we verified the intracellular survival and replicative potential of R. equi in both murine peritoneal macrophages and equine alveolar macrophages in vitro. Following an initial lag period of 6 to 12 h, the intracellular nu...
Katila T.This review attempts to summarize the current knowledge on uterine inflammatory response after mating in horses, pigs and cattle. Post-mating endometritis has been extensively studied in horses as it has been considered to cause infertility. The inflammation is known to occur also in cattle, but it has not been investigated to a similar extent. There are a number of publications about mechanisms of post-mating uterine inflammation in pigs, which seem to resemble those in horses. The major focus of this review is the horse, but relevant literature is presented also on swine and cattle. Spermato...
Hietala SK, Ardans AA.The interaction of Rhodococcus equi with alveolar macrophages from adult horses, foals experimentally exposed to R. equi (sensitized foals) and non-exposed foals was studied using in vitro bactericidal assays, cytochemical staining and transmission electron microscopy. It was demonstrated that R. equi is a facultative intracellular parasite, able to survive and multiply within the alveolar macrophages of the host by interfering with phagosome-lysosome fusion. Opsonization of R. equi with antibody against capsular components was associated with increased phagosome-lysosome fusion and significan...
Côté O, Clark ME, Viel L, Labbé G, Seah SY, Khan MA, Douda DN, Palaniyar N, Bienzle D.Secretoglobin family 1A member 1 (SCGB 1A1) is a small protein mainly secreted by mucosal epithelial cells of the lungs and uterus. SCGB 1A1, also known as club (Clara) cell secretory protein, represents a major constituent of airway surface fluid. The protein has anti-inflammatory properties, and its concentration is reduced in equine recurrent airway obstruction (RAO) and human asthma. RAO is characterized by reversible airway obstruction, bronchoconstriction and neutrophilic inflammation. Direct effects of SCGB 1A1 on neutrophil functions are unknown. We have recently identified that the SC...
Rebordão MR, Carneiro C, Alexandre-Pires G, Brito P, Pereira C, Nunes T, Galvão A, Leitão A, Vilela C, Ferreira-Dias G.Besides the classical functions, neutrophils (PMNs) are able to release DNA in response to infectious stimuli, forming neutrophil extracellular traps (NETs) and killing pathogens. The pathogenesis of endometritis in the mare is not completely understood. The aim was to evaluate the in vitro capacity of equine PMNs to secrete NETs by chemical activation, or stimulated with Streptococcus equi subspecies zooepidemicus (Szoo), Escherichia coli (Ecoli) or Staphylococcus capitis (Scap) strains obtained from mares with endometritis. Ex vivo endometrial mucus from mares with bacterial endometritis wer...
Troedsson MH, Loset K, Alghamdi AM, Dahms B, Crabo BG.Insemination of mares with bacteria-free equine spermatozoa results in an influx of polymorphonuclear neutrophils (PMNs) into the uterine lumen. In vitro studies have demonstrated that equine spermatozoa activate complement, resulting in cleavage of factors C5a and C3b. Since uterine secretion is rich in complement, it is likely that an interaction between spermatozoa and uterine secretion results in C5a-mediated chemotaxis and migration of PMNs into the uterine lumen. Once in the uterine lumen, the PMNs phagocytize bacteria and spermatozoa, which is an important part of sperm elimination from...
Smith AD, Panickar KS, Urban JF, Dawson HD.Vitamins and minerals (micronutrients) play an important role in regulating and shaping an immune response. Deficiencies generally result in inadequate or dysregulated cellular activity and cytokine expression, thereby affecting the immune response. Decreased levels of natural killer, granulocyte, and phagocytic cell activity and T and B cell proliferation and trafficking are associated with inadequate levels of micronutrients, as well as increased susceptibility to various adverse health conditions, including inflammatory disorders, infection, and altered vaccine efficacy. In addition, most s...
Brazil TJ, Dagleish MP, McGorum BC, Dixon PM, Haslett C, Chilvers ER.Neutrophil apoptosis and phagocytic clearance have been proposed as key determinants affecting the resolution of airway inflammation. Objective To determine the kinetics of neutrophil priming, recruitment, activation and subsequent clearance in a naturally occurring equine disease model of neutrophilic pulmonary inflammation. Results: A 5 h mouldy hay/straw challenge in hypersensitive horses induced transient pulmonary dysfunction lasting 4 days. At 24 h circulating neutrophils were primed and displayed delayed rates of spontaneous apoptosis in vitro. Neutrophil numbers in the airspaces peaked...
Flaminio MJ, Rush BR, Davis EG, Hennessy K, Shuman W, Wilkerson MJ.Studies in infants and foals indicate an age-dependent maturation of peripheral lymphocyte subsets. The age-dependent relationship for maturation of cellular immune responses, such as phagocytosis and lymphocyte responses of the peripheral and pulmonary-derived leukocytes, has not been characterized in foals. Lymphocyte subpopulations, mitogen stimulation response of lymphocytes, lymphokine-activated killing cell activity, phagocytosis and oxidative burst activity, and serum immunoglobulin (Ig) classes G and M concentrations were determined in developing foals. This study illustrates age-depen...
Messick JB, Rikihisa Y.The binding, internalization, and proliferation of Ehrlichia risticii in P388D1 cells and equine polymorphonuclear (PMN) leukocytes were studied by immunofluorescent staining and flow cytometric analysis. The binding of ehrlichiae to P388D1 cells at 4 degrees C was dose dependent, and the antigens of bound organisms were susceptible to pronase treatment. Additionally, the binding of ehrlichiae to P388D1 cells was diminished when either P388D1 cells or ehrlichiae were treated with 1% paraformaldehyde for 30 min or 0.25% trypsin for 15 min. These results indicate that the ehrlichial ligand and h...
Massoco C, Palermo-Neto J.Benzodiazepines (BDZ) are among the most frequently used class of psychotropic drugs employed in veterinary medicine in Brazil and worldwide due to their anxiolytic, muscle relaxant and anticonvulsant effects [J. Clin. Pharmacol. 33 (1993) 124]. Peripheral benzodiazepine receptor (PBR) sites were described in peripheral organs, endocrine steroidogenic tissues and immune organs and cells. Midazolam is a mixed-type agonist of PBRs. The present study is focused on the effects of midazolam on equine peripheral blood neutrophils, peritoneal macrophages and cortisol levels in plasma. Adult horses we...
Anzai T, Walker JA, Blair MB, Chambers TM, Timoney JF.To determine whether streptococcal pneumonia is caused by strains of Streptococcus zooepidemicus similar to those obtained from the tonsils of healthy horses. Methods: 5 tonsils from healthy horses, 8 tracheal washes and 6 lung specimens from foals with pneumonia, and 5 nasopharyngeal swab specimens from donkeys with acute bronchopneumonia. Methods: Variable M-like protectively immunogenic SzP proteins of 5 isolates of S. zooepidemicus from each tonsil and clinical specimen were compared, using immunoblots. The SzP gene of 13 isolates representative of various SzP immunoblot phenotypes from 1 ...
Troedsson MH, Desvousges A, Alghamdi AS, Dahms B, Dow CA, Hayna J, Valesco R, Collahan PT, Macpherson ML, Pozor M, Buhi WC.Seminal plasma has been suggested to be involved in sperm transport, and as a modulator of sperm-induced inflammation, which is thought to be an important part of sperm elimination from the female reproductive tract. This article reports on recent experiments on the importance of seminal plasma components in sperm transport and elimination. In Experiment 1, hysteroscopic insemination in the presence (n = 3) or absence (n = 3) of 2 ng/mL PGE showed an increased portion of spermatozoa crossing the utero-tubal junction in the presence of PGE in two mares, while no difference was observed between ...
Miró J, Marín H, Catalán J, Papas M, Gacem S, Yeste M.In the donkey, artificial insemination (AI) with frozen-thawed semen is associated with low fertility rates, which could be partially augmented through adding seminal plasma (SP) and increasing sperm concentration. On the other hand, post-AI endometrial inflammation in the jenny is significantly higher than in the mare. While previous studies analyzed this response through recovering Polymorphonuclear Neutrophils (PMN) from uterine washings, successive lavages can detrimentally impact the endometrium, leading to fertility issues. For this reason, the first set of experiments in this work inten...
Meehan M, Lynagh Y, Woods C, Owen P.The major cell-wall-associated protein of the equine pathogen Streptococcus equi subsp. equi is an M-like fibrinogen-binding protein (FgBP) which binds equine fibrinogen (Fg) avidly, through residues located at the extreme N-terminus of the molecule. In this study, it is shown that FgBP additionally binds equine IgG-Fc. When tested against polyclonal IgG from ten other animal species, it was found that FgBP binds human, rabbit, pig and cat IgG, but does not bind mouse, rat, goat, sheep, cow or chicken IgG. Through the use of a panel of recombinant FgBP truncates containing defined deletions of...
Causey RC.Equine uterine infections inflict major losses on the equine industry. Persistent inflammation of the oviduct and uterus leads to loss of the conceptus and mares susceptible to infection have weakened uterine defences partly due to retention of inflammatory exudate. Bacteria may trigger inflammation, resist phagocytosis, or adhere to the endometrium and types of infection range from genital commensals in susceptible mares to reproductive pathogens in normal mares. Uterine infections are diagnosed by history, detection of uterine inflammation, and isolation of typical organisms and susceptible ...
Holbrook TC, Tipton T, McFarlane D.Equine metabolic syndrome is characterized by obesity and regional adiposity coupled with evidence of recurrent laminitis. Although inflammation has been well characterized in several experimental models of acute laminitis, the inflammatory events associated with endocrinopathic laminitis are not well documented. The aim of this study was to characterize selected markers of inflammation in horses with clinical evidence of equine metabolic syndrome (EMS). Neutrophil phagocytosis and oxidative burst, as well as endogenous and stimulated cytokine expression were evaluated. A marked increase in ne...
Raidal SL, Bailey GD, Love DN.To evaluate the effect of transportation on lower respiratory tract contamination and peripheral blood neutrophil function in horses and to compare results from transported horses with those obtained in earlier experiments from horses confined with heads elevated. Methods: A prospective study. Methods: Six horses were transported by road for 12 h. Clinical and haematological examination, transtracheal aspiration and cell function studies were conducted before and after transportation. Results obtained after transportation were compared to pre-transportation values. Results: After transportatio...
Katavolos P, Ackerley CA, Clark ME, Bienzle D.Horses suffer from recurrent airway obstruction, an asthma-like condition induced by repeat inhalation of environmental substances present in barn air. Clara cell secretory protein (CCSP) is much reduced during active inflammation when neutrophils predominate in the airways, and in chronic asthmatics. We sought to investigate morphologic and functional interactions of CCSP with neutrophils. Bronchoalveolar and blood neutrophils from healthy control animals, and from animals with recurrent airway obstruction in remission and exacerbation, were evaluated by immuno-cytochemistry and immuno-electr...
Troedsson MH, Liu IK, Thurmond M.In vitro phagocytosis and chemotaxis of uterine and blood-derived polymorphonuclear neutrophils (PMNs) were compared in mares with different resistance to chronic uterine infection (CUI). Both the primary in vitro function of PMNs and the role of uterine environmental factors on PMN function were investigated. The uteri of mares susceptible to (n = 6) and resistant to CUI (n = 5) were inoculated with 5 x 10(6) Streptococcus zooepidemicus when the mares were in estrus. Uterine secretions in addition to uterine and blood-derived PMNs were sampled at 5 and 24 h later. During a subsequent estrus, ...
Ambawat HK, Malhotra DV, Kumar S, Dhar S.Equine babesiosis, caused by Babesia equi and transmitted by ticks is of major economic importance in India. The adverse effects which B. equi organism and its metabolites inflict on red blood cells have not been reported. Erythrocytes were analysed for red cell membrane phospholipids, proteins and haemoglobin (Hb) concentration and plasma for malondialdehyde (MDA) in B. equi carrier donkeys before splenectomy (50% parasitaemia. Before splenectomy the mean values of membrane protein, phospholipids, plasma MDA and Hb were found to be 1.63 +/- 0.12 mg/ml PCV, 2.28 +/- 0.9 mg/ml PCV, 3.63 +/- 0.3...
Espinosa G, Plaza A, Schenffeldt A, Alarcón P, Gajardo G, Uberti B, Morán G, Henríquez C.Polymorphonuclear neutrophils (PMN) are the largest leukocyte population in the blood of most mammals including horses, and play an important defensive role in many infectious diseases. However, the mechanisms that increase PMN as one of the main cellular subsets in the defense against pathogens could also be involved in the pathophysiology of dysregulated inflammatory conditions. Mesenchymal stem/stromal cells (MSCs) are a heterogeneous population with a modulatory potential on the inflammatory response and are known to interact with nearly all cells of the immune system, including PMN. In th...
Anzai T, Timoney JF, Kuwamoto Y, Fujita Y, Wada R, Inoue T.The glossy non-encapsulated strain of Steptococcus equi, NCTC 9682, was compared with the matt strain Hidaka/95/2 which expresses a medium sized capsule and with the mucoid CF32 which expresses a large sized capsule in phagocytosis assays and for virulence in inoculated horses. The three strains, NCTC 9682, Hidaka /95/2 and CF32 produced 2.0, 3.1, and 5.3 mg/g wet cells respectively after 3 h incubation, but similar amounts of M-like proteins, cytotoxin and mitogen. NCTC 9682 showed no resistance to phagocytosis by equine neutrophils regardless of the presence of opsonin while strains Hidaka /...
Boschwitz JS, Timoney JF.The antiphagocytic property of equine fibrinogen for Streptococcus equi subsp. equi strain CF32 was examined in vitro. The results of bactericidal assays demonstrated that the presence of fibrinogen enhanced the ability of overnight and early log-phase cultures of strain CF32 to resist killing by equine neutrophils by 12-fold and seven-fold, respectively (p > 0.01). In addition, fibrinogen-coated bacteria treated with fibrinogen specific F(ab')2 fragments were 32% more susceptible to killing by equine neutrophils after opsonization in serum (p > 0.05), indicating that specific epitopes o...
Jörg A, Portmann P, Fellay G, Dreyer JL, Meyer J.An improved and short method is described for the isolation of intact eosinophilic leukocytes from horse blood with high yield (1--1.5 g/20 l). Viability and purity of the preparations were verified by light and electron microscopy and by the trypan blue exclusion test. Isolated eosinophils were 98--100% pure, intact and viable, and they could be shown to phagocytise immune-complexes.
Yoshikawa H, Yasu T, Ueki H, Oyamada T, Oishi H, Anzai T, Oikawa M, Yoshikawa T.To evaluate the possibility that Streptococcus equi subsp. zooepidemicus (S.z) the causative bacterial agent of equine shipping fever pneumonia (ESFP), as well as to investigate its pathogenesis, 10 horses (seven Thoroughbreds and three Anglo-Arab species, ranging from 2-4 years in age) were experimentally inoculated, via an endoscope, into bronchus of the lung lobe with a dose of 30 ml of 1-7 x 10(8) CFU/ml of S.z. After inoculation, autopsy and pathological examinations were sequentially conducted 30 min, 1, 2, 3, 4, 17, 20 hr and 2 weeks later. Pneumonia induced by the intrapulmonary inocul...
Borlone C, Morales N, Henriquez C, Folch H, Olave C, Sarmiento J, Uberti B, Moran G.Neutrophils participate in innate immunity as the first line of host defense against microorganisms. However, exacerbated neutrophil activity can be harmful to surrounding tissues; this is important in a range of diseases, including allergic asthma and chronic obstructive pulmonary disease in humans, and equine asthma (also known as recurrent airway obstruction (RAO). Tamoxifen (TX) is a non-steroidal estrogen receptor modulator with effects on cell growth and survival. Previous preliminary studies showed that TX treatment in horses with induced acute pulmonary inflammation promoted early apop...
Franchini M, Gilli U, Akens MK, Fellenberg RV, Bracher V.Chronic obstructive pulmonary disease (COPD) is defined as a chronic obstructive inflammatory disease affecting the small airways associated with hay dust exposure (Lowell, F.C., 1964. Observation on heaves. An asthma like syndrome in the horse, J. Allergy 35, 322-330). The disease corresponds histopathologically to a chronic bronchiolitis (Gerber, H., 1973. Chronic pulmonary disease in the horse, Equine Vet. J. 5, 26-33; Winder, N.C., Grünig, G., Hermann, M., Howald, B., von Fellenberg, R., 1989. Comparison of respiratory secretion cytology and pulmonary histology in horses, J. Vet. Med., A3...
Hart KA, Barton MH, Vandenplas ML, Hurley DJ.Low-dose hydrocortisone (LDHC) therapy modulates inflammatory responses in adults and improves outcomes in some septic adults and neonates, but its immunologic effects have not been evaluated in neonates. The objective of this study was to evaluate effects of LDHC therapy on ex vivo immune function in neonatal horses (foals). We hypothesized that LDHC treatment would dampen proinflammatory responses without impairing neutrophil function. Hydrocortisone (1.3 mg/kg/d i.v.) was administered to foals in a tapering 3.5 d course. Peripheral blood leukocytes were collected from foals before, during, ...
Theoret CL, Barber SM, Moyana T, Townsend HG, Archer JF.The reparative ability of equine synovium was determined by gross, histological, and ultrastructural examination. The functional potential of the synovium was estimated by examination of synovial cell organelles with transmission electron microscopy. Results from rested and exercised horses were compared to determine the effect of exercise on synovial healing. The response of synovectomized joint to exercise was evaluated with a standardized lameness examination and by gross, histological, and histochemical observations of the articular cartilage. A 7-mm diameter motorized synovial resector wa...
