The immune response in horses involves a complex network of cells, tissues, and molecules that work together to protect the animal from pathogens and other harmful agents. This process includes both innate and adaptive immune mechanisms. Innate immunity provides the first line of defense and involves components such as physical barriers, phagocytic cells, and the complement system. Adaptive immunity, on the other hand, is characterized by the activation of lymphocytes and the production of antibodies, which provide a targeted response to specific antigens. Key components of the equine immune system include T cells, B cells, and various cytokines that facilitate communication between immune cells. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, regulation, and implications of immune responses in equine health.
Kydd JH, Wattrang E, Hannant D.In general, vaccines containing inactivated equine herpesvirus-1 (EHV-1) fail to prevent abortion in pregnant mares following infection with a virulent strain of EHV-1. We have tested the hypothesis that resistance to EHV-1-induced abortion in pregnant mares is associated with high frequencies of EHV-1 specific, major histocompatibility complex (MHC) class I-restricted, cytotoxic T lymphocytes (CTL) in the circulation. To test this theory, three groups of pregnant mares were assembled with varying backgrounds of infection or vaccination in an attempt to mimic the immune status of the general p...
Fischer L, Minke J, Dufay N, Baudu P, Audonnet JC.In order for DNA vaccines to become a practical alternative to conventional vaccines their ability to induce antibody responses in large mammals needs to be improved. We used DNA vaccination against rabies in the horse as a model to test the potential of two different strategies to enhance antibody responses in a large mammalian species. The administration of the DNA vaccine in the presence of aluminum phosphate improved both the onset and the intensity of serological responses but was not potent enough to achieve seroconversion in all vaccinated ponies. However, when the DNA vaccine was formu...
Kohler AK, Stone DM, Hines MT, Byrne BA, Alperin DC, Norton LK, Hines SA.Rhodococcus equi is an opportunistic pathogen in immunocompromised humans and an important primary pathogen in young horses. Although R. equi infection can produce life-threatening pyogranulomatous pneumonia, most foals develop a protective immune response that lasts throughout life. The antigen targets of this protective response are currently unknown; however, Mycobacterium tuberculosis is a closely related intracellular pathogen and provides a model system. Based on previous studies of M. tuberculosis protective antigens released into culture filtrate supernatant (CFS), a bacterial growth s...
Moore BD, Balasuriya UB, Watson JL, Bosio CM, MacKay RJ, MacLachlan NJ.Equine arteritis virus (EAV) infects endothelial cells (ECs) and macrophages in horses, and many of the clinical manifestations of equine viral arteritis (EVA) reflect vascular injury. To further evaluate the potential role of EAV-induced, macrophage-derived cytokines in the pathogenesis of EVA, we infected cultured equine alveolar macrophages (AMphi), blood monocyte-derived macrophages (BMphi), and pulmonary artery ECs with either a virulent (KY84) or an avirulent (CA95) strain of EAV. EAV infection of equine AMphi, BMphi, and ECs resulted in their activation with increased transcription of g...
Ainsworth DM, Grünig G, Matychak MB, Young J, Wagner B, Erb HN, Antczak DF.In horses prone to developing recurrent airway obstruction (RAO), we tested the hypotheses that the cytokine profile in the bronchoalveolar lavage (BAL) cells of affected horses would reflect a polarized Th-2 response; that cytokine and chemokine alterations would occur within 24 h of allergen exposure; and that allergen exposure would induce alterations in the expression of the transcription factor t-bet (t-box-expressed in T-cells). The expression levels of interleukin-4 (IL-4), IL-13, Interferon-gamma (IFN-gamma), t-bet, IL-8 and granulocyte-macrophage colony stimulating factor (GM-CSF) wer...
Fumuso E, Giguère S, Wade J, Rogan D, Videla-Dorna I, Bowden RA.Endometrial mRNA expression of the pro-inflammatory cytokines interleukin-1beta (IL-1beta), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-alpha) was assessed in mares resistant (RM) or susceptible (SM) to persistent post-breeding endometritis (PPBE). Eight RM and eight SM, were selected based on reproductive records and functional tests out of a herd of 2,000 light cross-type mares. Three experiments were done to study transcription patterns in (i) basal conditions; (ii) after artificial insemination (AI); and (iii) after administration of an immunomodulator at time of artificial ...
Wilmink JM, Veenman JN, van den Boom R, Rutten VP, Niewold TA, Broekhuisen-Davies JM, Lees R, Armstrong S, van Weeren PR, Barneveld A.Wound healing proceeds faster in ponies than in horses and complications during healing, such as wound infection, occur less frequently in ponies. Earlier studies suggested that this difference might be related to differences in the initial post traumatic inflammatory response. Objective: That polymorphonuclear leucocyte (PMN) function and profiles of humoral factors in local inflammatory processes are different in horses and ponies. Methods: PMNs were isolated from venous blood of horses and ponies. Chemotaxis and reactive oxygen species (ROS) production was determined. Tissue cages were impl...
Soboll G, Whalley JM, Koen MT, Allen GP, Fraser DG, Macklin MD, Swain WF, Lunn DP.Equine herpesvirus-1 (EHV-1) causes serious disease in horses throughout the world, despite the frequent use of vaccines. CTLs are thought to be critical for protection from primary and reactivating latent EHV-1 infections. However, the antigen-specificity of EHV-1-specific CTLs is unknown. The aim of this study was to identify EHV-1 genes that encode proteins containing CTL epitopes and to determine their MHC I (or ELA-A in the horse) restriction. Equine dendritic cells, transfected with a series of EHV-1 genes, were used to stimulate autologous CTL precursor populations derived from previous...
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...
Cunningham FM, Vandergrifft E, Bailey SR, Sepulveda MF, Goode NT, Horohov DW.The cytokine, interleukin (IL)-5 stimulates eosinophil differentiation, activation and survival and can prime these cells, increasing the response to other mediators. In view of its many effects on eosinophils, IL-5 has been implicated in the pathogenesis of allergic disease in man. Here we report the cloning of equine IL-5 and expression of the recombinant protein by transfection of Chinese hamster ovary (CHO) cells. The cloned cDNA sequence consisted of 405 nucleotides and encoded a protein of 135 amino acids. There is >85% identity with feline, bovine, ovine, canine, and human IL-5 sequence...
Pirie RS, Dixon PM, McGorum BC.Mould extract inhalation challenges have been used extensively in the investigation of heaves. Such challenges have induced pulmonary neutrophilic inflammation and dysfunction, consistent with, but less severe than the natural disease. However, the method of mould extract production is likely to result in endotoxin contamination. Objective: To investigate whether insufficient dose delivery was responsible for the shortfall in response to inhaled extract compared with natural disease, and whether endotoxin contamination of mould extract contributed to the pulmonary inflammation and dysfunction....
Mealey RH, Zhang B, Leib SR, Littke MH, McGuire TC.Equine infectious anemia virus (EIAV) is a lentivirus that causes persistent infections in horses. We hypothesized that high-avidity CTL specific for nonvariable epitopes might be associated with low viral load and minimal disease in EIAV-infected horses. To test this hypothesis, memory CTL (CTLm) responses were analyzed in two infected horses with high plasma viral loads and recurrent disease (progressors), and in two infected horses with low-to-undetectable viral loads and mild disease (nonprogressors). High-avidity CTLm in one progressor recognized an envelope gp90 epitope, and the data doc...
Kiku Y, Kusano K, Miyake H, Fukuda S, Takahashi J, Inotsume M, Hirano S, Yoshihara T, Toribio RE, Okada H, Yoshino TO.Cellular activation and functional cell surface markers were evaluated during experimentally-induced endotoxemia in healthy horses. Eight healthy adult horses were infused a low dose of endotoxin (lipopolysaccharide from Escherichia coli O26: B6, 30 ng/kg of body weight, IV) and five control horses were given an equivalent volume of sterile saline solution. Venous blood samples were collected for flow cytometric analysis of peripheral blood mononuclear cells (PBMCs) and to measure plasma endotoxin concentrations. Clinical signs of endotoxemia were recorded at 10, 20, 30, 40, 50 min, 1, 2, 3, 4...
Witonsky S, Gogal RM, Buechner-Maxwell V, Ahmed SA.To determine whether immune function can be accurately assessed in blood samples obtained from horses and refrigerated overnight and whether a nonradioactive lymphocyte proliferation assay can be used to evaluate samples obtained from horses. Methods: 224 blood samples from 28 clinically normal adult horses. Methods: Heparinized blood samples were collected. Each sample was divided into 2 equal aliquots. One aliquot was refrigerated overnight to simulate overnight shipping of blood samples, and the other aliquot was evaluated on the day of blood collection. Lymphocytes were isolated and enumer...
Lopez AM, Hines MT, Palmer GH, Knowles DP, Alperin DC, Hines SA.Rhodococcus equi remains one of the most important pathogens of early life in horses, yet conventional vaccines to prevent rhodococcal pneumonia have not been successful. DNA vaccination offers an alternative to conventional vaccines with specific advantages for immunization of neonates. We developed a DNA vaccine expressing the vapA gene (pVR1055vapA) that induced an anamnestic response characterized by virulence associated protein A (VapA)-specific IgG antibodies in sera and bronchoalveolar lavage fluid (BALF) as well as VapA-specific proliferation of pulmonary lymphocytes when tested in adu...
McGuire TC, Leib SR, Mealey RH, Fraser DG, Prieur DJ.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...
Soboll G, Horohov DW, Aldridge BM, Olsen CW, McGregor MW, Drape RJ, Macklin MD, Swain WF, Lunn DP.We have previously demonstrated that hemagglutinin (HA) gene vaccination and influenza virus infection generate protective antibody responses in equids. However, these antibody responses differ substantially in that particle mediated DNA vaccination does not induce an immunoglobulin A (IgA) response. A study was performed to investigate the regional immunoregulatory mechanisms associated with these different immune responses. Ponies were either vaccinated with equine HA DNA vaccines at skin and mucosal sites, infected with influenza virus or left untreated and influenza-specific antibody respo...
Li F, Craigo JK, Howe L, Steckbeck JD, Cook S, Issel C, Montelaro RC.Previous evaluations of inactivated whole-virus and envelope subunit vaccines to equine infectious anemia virus (EIAV) have revealed a broad spectrum of efficacy ranging from highly type-specific protection to severe enhancement of viral replication and disease in experimentally immunized equids. Among experimental animal lentivirus vaccines, immunizations with live attenuated viral strains have proven most effective, but the vaccine efficacy has been shown to be highly dependent on the nature and severity of the vaccine virus attenuation. We describe here for the first time the characterizati...
Soboll G, Nelson KM, Leuthner ES, Clark RJ, Drape R, Macklin MD, Swain WF, Olsen CW, Lunn DP.We have previously demonstrated that equine influenza virus hemagglutinin (HA) DNA vaccination protects ponies from challenge infection, and induces protective IgGa and IgGb responses. However, this approach does not induce a nasal IgA response. The objective of this study was to examine the value of cholera toxin (CT) administration as an adjuvant for intranasal HA DNA vaccination, and to measure protection 3 months after DNA vaccination. After an immunogenic dose of CT was determined, ponies were immunized on two occasions by intranasal administration of HA DNA and cholera toxin, or HA DNA a...
Mendoza L, Mandy W, Glass R.The immunotherapeutic properties of a new Pythium insidiosum-vaccine formulation (PIV), was evaluated in 18 horses and 6 dogs with proven pythiosis from different enzootic areas in the United States. All injected horses but one responded with a weak (=29 mm, n=3), a mild (30-90 mm, n=7) or a strong (=100 mm, n=7) inflammatory reactions at the site of injection. Three equines with weak or negative reactions at the injection site were not cured. Seven equines with strong reactions at their injection sites, however, were cured. Six of the eight horses with mild reactions were also cured. The rema...
Hanel RM, Crawford PC, Hernandez J, Benson NA, Levy JK.To determine whether passive transfer of IgG in neonatal kittens affects plasma opsonic capacity and neutrophil phagocytic and oxidative burst responses to bacteria in vitro. Methods: 22 kittens from 6 specific pathogen-free queens. Methods: Kittens were randomized at birth into the following treatment groups: colostrum-fed, colostrum-deprived, or colostrum-deprived supplemented with feline or equine IgG. Blood samples were collected at intervals from birth to 56 days of age. Plasma IgG concentrations were determined by radial immunodiffusion assay. Neutrophil function was assessed by a flow c...
Pirie RS, Collie DD, Dixon PM, McGorum BC.Equine heaves is a naturally occurring organic dust-induced asthma characterized by airway neutrophilia, mucus hypersecretion and obstructive lung dysfunction. However, the relative role of different dust components in disease severity remains unclear. Objective: This study investigated the relative contribution of inhaled endotoxin and organic dust particulates (mainly mould spores) in inducing heaves in heaves-susceptible horses. Methods: Control and heaves-susceptible horses received inhalation challenges with hay dust suspension (HDS) before and after lipopolysaccharide (LPS) depletion. He...
Martoriati A, Gérard N.A growing body of evidences suggests that the ovary is a site of inflammatory reactions, and thus, ovarian cells could represent sources and targets of the interleukin-1 (IL-1) system. The purpose of this study was to examine the IL-1 system gene expressions in equine granulosa cells, and to study the IL-1beta content in follicular fluid during the follicle maturation. For this purpose, granulosa cells and follicular fluids were collected from the largest follicle at the early dominance stage (diameter 24 +/- 3 mm) or during the preovulatory maturation phase, at T0 h, T6 h, T12 h, T24 h and T3...
Hooper-McGrevy KE, Wilkie BN, Prescott JF.Rhodococcus equi causes severe pyogranulomatous pneumonia in foals and in immunocompromised humans. Replication of virulent isolates within macrophages correlates with the presence of a large plasmid which encodes a family of seven virulence-associated proteins (VapA and VapC to VapH), whose functions are unknown. Although cell-mediated immunity is thought to be crucial in eliminating R. equi infection, antibody partially protects foals. The antibody response to both VapA and VapC was similar in six adult horses and six naturally exposed but healthy foals, as well as in eight foals with R. equ...
Wattrang E, Jessett DM, Yates P, Fuxler L, Hannant D.The production of interferon (IFN), interleukin-6 (IL-6), and tumor necrosis factor (TNF) was monitored in horses during the course of influenza A2 virus infections. The effects of two virus strains, Newmarket/2/93 and Sussex/89, were compared, of which the latter is considered the more pathogenic in terms of clinical signs. Ten naive ponies were infected with influenza A/equine/Sussex/89 and 10 with influenza A/equine/Newmarket/2/93, respectively. As expected ponies infected with Sussex/89 showed the most pronounced clinical signs but there was no notable difference in viral excretion compare...
Wagner HM, Balasuriya UB, James MacLachlan N.In an effort to further characterize the humoral immune response of horses to equine arteritis virus (EAV), direct and competitive enzyme-linked immunosorbent assays (c-ELISAs) were developed using monoclonal and polyclonal anti-sera to structural (G(L), N and M) and non-structural (nsp1) viral proteins. A nsp1-specific monoclonal antibody was produced to facilitate development of a c-ELISA to this protein. Data obtained using the various c-ELISAs confirm that the M protein is a major target of the antibody response of horses to EAV. However, none of the c-ELISAs that were developed were as se...
Solbrig MV, Koob GF.Borna Disease Virus (BDV) is a neurotropic RNA virus that is worldwide in distribution, causing movement and behavior disorders in a wide range of animal species. BDV has also been reported to be associated with neuropsychiatric diseases of humans by serologic study and by recovery of nucleic acid or virus from blood or brain. Natural infections of horses and sheep produce encephalitis with erratic excited behaviors, hyperkinetic movement or gait abnormalities; naturally infected cats have ataxic "staggering disease." Experimentally infected primates develop hyperactivity, aggression, disinhib...
Wagner IP, Rees CA, Dunstan RW, Credille KM, Hood DM.To determine whether systemic immunologic hyperreactivity exists in horses with chronic laminitis, compared with responses for nonlaminitic horses. Methods: 7 nonlaminitic horses and 7 CL horses. Methods: In experiment 1, intradermal testing (IDT) was performed on 7 nonlaminitic and 7 CL horses to evaluate the response to a combination of 70 allergens at 15 and 30 minutes and 4 and 24 hours after injection. Three nonlaminitic and 3 CL horses used in experiment 1 were used in experiment 2 to determine whether histologic differences existed between the 2 groups. The H&E-stained tissue sectio...
House JA.African horse sickness (AHS), which causes mortality up to 95%, is caused by orbiviruses and is transmitted by Culicoides. The goal of a control and eradication program for AHS is to prevent the spread of the virus via the biological vector. Control measures include slaughter of infected animals, housing of suspected infected animals in insect-proof stalls, and vaccination. Vaccination has played a key role in eradication when AHS occurred outside of Africa. Both modified live vaccines (MLV) and inactivated vaccines have been used to control AHS. An acceptable vaccine should be: safe, efficaci...
Lea RG, Bolton AE.Commercial preparations of equine chorionic gonadotrophin (eCG) and extracts of horse placenta taken at 80 days gestation were incorporated into mixed lymphocyte culture and mitogen stimulation assays of horse peripheral blood mononuclear cells. A dose-related inhibition of lymphocyte proliferation, indicative of immunosuppressive activity, was observed in both systems, both with commercial eCG preparations and tissue extracts. Negligible inhibitory activity was observed with an extract of term placenta. The inhibitory activity of the placental samples was not related to their eCG content as m...
Escribano BM, Castejón FM, Vivo R, Santisteban R, Agüera EI, Rubio MD.Using simple techniques, the neutrophil function, in its phagocytosis and oxidative metabolism stages, was evaluated in horses. This was done before and after moderate exercise at the aerobic-anaerobic threshold (standardized heart rate 150 beats/min and lactate level of 3.07 +/- 0.21 mmol/L). The objective was to determine whether regular training and moderate exercise improved the neutrophil function. A group of 19 horses was used; 11 of these were untrained and the remainder trained for national jumping events. The exercise test consisted of a 5 min trot followed by a 3 min gallop on a long...
Strzemienski PJ, Dyer RM, Sertich PL, Garcia MC, Kenney RM.The oestrous cycles of 20 mixed-breed mares were synchronized with daily injections of 10 mg oestradiol-17 beta and 150 mg progesterone given i.m. for 10 days. On the 10th day, 10-15 mg prostaglandin F-2 alpha was administered i.m. to induce oestrus. Neutrophils were isolated from jugular blood on the 2nd or 3rd day of oestrus, Days 5 and 7 after ovulation or during early pregnancy (Days 18-34 of pregnancy). Neutrophils were challenged with Staphylococcus aureus and their bactericidal activity examined after 30 and 120 min of incubation for a reduction of colony forming units. Bactericidal act...
Tomlinson JE, Blikslager AT.To determine whether ischemia and flunixin affect in vitro lipopolysaccharide (LPS) absorption in samples of the jejunum of horses. Methods: 12 horses. Methods: Horses were anesthetized, a midline celiotomy was performed, and the jejunum was located. Two 30-cm sections of jejunum (60 cm apart) were selected. One segment was designated as control tissue; ischemia was induced in the other segment for 120 minutes. Horses were then euthanatized. Mucosa from each jejunal segment was mounted on Ussing chambers and treated with or without flunixin. Tissues from 6 horses were used to assess permeabili...
Davidson AJ, Edwards GB, Proudman CJ, Cripps PJ, Matthews JB.The aim of this study was to investigate cytokine expression patterns in the large intestinal mucosa of horses, particularly in diseases associated with inflammation. Many cases of equine colitis remain without a definitive diagnosis and survival rates are poor. In humans, colitis is associated with increased expression of pro-inflammatory cytokines. To examine if similar responses occur in horses, we investigated il -2, il -4, il -5, il -10, tnfalpha, ifngamma and tgfbeta messenger rna expression in large intestinal mucosa. Samples were obtained from animals with large intestinal disease (n=1...
Idrissi Bougrine S, Fassi Fihri O, el Harrak M, Fassi Fehri MM.A vaccination protocol involving three horses, with five repeated injections of inactivated serotype 4 African horse sickness virus, was undertaken to determine a possible threshold for the appearance of antibodies against the non-structural protein NS3. Using an indirect enzyme-linked immunosorbent assay, with the recombinant NS3 protein as an antigen, the authors detected a response to NS3 as of the second injection for the first horse and after four injections for the second horse. No response to NS3 was detected for the third horse. The results show that the inactivated vaccine is insuffic...
Hetherington VJ, Kawalec JS, Dockery DS, Targoni OS, Lehmann PV, Nadler D.One means of treating osteoarthritis is with autologous or allogeneic osteochondral grafts. The purpose of this study was to evaluate the innate immunological response in humans toward xeno-derived osteochondral grafts that have been partially or entirely treated by the photooxidation process. Methods: The antigens tested included bovine, porcine, ovine and equine osteochondral samples that have been treated in successive steps of photooxidation. ELISPOT assays were used to evaluate the production of IL-1, IL-4, IL-6, IL-10, IL-12 and TNF-alpha by human monocytes in response to the antigens. R...
Stein RS, Means RT, Krantz SB, Flexner JM, Greer JP.The authors evaluated antilymphocyte serum prepared in rabbits (ALS-R) as an alternative to antilymphocyte serum prepared in horses (ALG-H) in the therapy of aplastic anemia. Between 1980 and 1993, 57 evaluable patients received ALS-R and prednisone +/- cyclosporine +/- androgens. Standard response criteria were used and patients were evaluated at 3 months from the start of therapy. Median age was 43 years. Disease was present for up to 2 months in 24 patients, 2-5 months in 14 patients, and 6 months or more in 19 patients. Disease was severe in 30 patients and moderate in 27. Responses occurr...
Krakowski L, Krawczyk CH, Wrona Z, Dabrowski R, Jarosz Ł.The objective of the present study was to analyse the immune status of mares in the early stages of pregnancy and mares which experienced early embryonic death (EED). Forty-eight fertile purebred Arabian mares were used for the study. The mares were divided into two groups. Group I was the control group composed of 32 mares in the early stages of a normal pregnancy. Group II was composed of 12 mares which had experienced EED. In both groups, subpopulations of T lymphocytes containing CD2(+), CD4(+) and CD8(+) were characterized using flow cytometry. The percentages of CD3(+) lymphocytes (addin...
Antczak DF, Allen WR.There is little evidence for maternal immunological recognition of pregnancy in most species with the striking exception of the members of the genus Equus. Almost all mares make strong cytotoxic antibody responses to paternally inherited fetal antigens by Day 60 of gestation. Most of these responses are directed against antigens of the Major Histocompatibility Complex (MHC), which constitutes the primary immunogenetic barrier to successful organ transplantation. The source of fetal MHC antigens in the pregnant mare appears to be the specialized trophoblast cells of the chorionic girdle region ...
Spann K, Barnum S, Pusterla N.EHV-1 vaccines are often administered intranasally during emergency situation such as outbreaks of equine herpesvirus myeloencephalopathy. However, there is currently no data available on the efficacy of such protocols, nor the diagnostic challenge when recently vaccinated horses become clinically infected and nasal secretions are collected to support a diagnosis of EHV-1 infection. Therefore, the objective of this study was to determine if two commercially available EHV-1 vaccines, a killed-adjuvanted (Calvenza) and a modified-live (Rhinomune) EHV-1 vaccine, could induce a measurable systemic...
van Hoogmoed LM, Harmon FA, Stanley S, White J, Snyder J.The objective of this study was to determine if a correlation exists between the presence of nitric oxide and prostaglandin release in the equine ventral colon smooth muscle, since this relationship may accentuate the inflammatory process during intestinal injury. Tissue was collected from the ventral colon, cut into muscle strips oriented along the circular, longitudinal and taenial layers, and mounted in a tissue bath system. Samples of the bath fluid were collected before, following electrical field stimulation (EFS), and following EFS in the presence of L-NAME, a nitric oxide synthase inhi...
Boger BL, Manfredi JM, Yob C, Weber PSD, Jacobs CC.Diagnosis of equine septic arthritis is not straightforward, and increasing time between onset, diagnosis, and treatment can have serious consequences for quality of life. Defensins are used in diagnosis of human joint infection. The presence of beta defensins (BDs) in equine synovial fluid and their utility as a biomarker of sepsis has not been investigated; therefore, our objectives were to (1) compare in vitro gene expression of lipopolysaccharide (LPS)-stimulated equine neutrophils to unstimulated neutrophils and (2) compare BD protein expression from normal, aseptically inflamed, and sept...
Willingham-Lane JM, Berghaus LJ, Berghaus RD, Hart KA, Giguère S.The soil-dwelling, saprophytic actinomycete is a facultative intracellular pathogen of macrophages and causes severe bronchopneumonia when inhaled by susceptible foals. Standard treatment for disease is dual-antimicrobial therapy with a macrolide and rifampin. Thoracic ultrasonography and early treatment with antimicrobials prior to the development of clinical signs are used as means of controlling endemic infection on many farms. Concurrently with the increased use of macrolides and rifampin for chemoprophylaxis and the treatment of subclinically affected foals, a significant increase in t...
Tallmadge RL, Miller SC, Parry SA, Felippe MJB.The value of prophylactic neonatal vaccination is challenged by the interference of passively transferred maternal antibodies and immune competence at birth. Taken our previous studies on equine B cell ontogeny, we hypothesized that the equine neonate generates a diverse immunoglobulin repertoire in response to vaccination, independently of circulating maternal antibodies. In this study, equine neonates were vaccinated with 3 doses of keyhole limpet hemocyanin (KLH) or equine influenza vaccine, and humoral immune responses were assessed using antigen-specific serum antibodies and B cell Ig var...
Benarafa C, Collins ME, Hamblin AS, Sabroe I, Cunningham FM.The chemokine eotaxin (CCL11) is a key player in the trafficking of eosinophils to normal tissues and in the tissue eosinophilia associated with human allergic disease. We have recently cloned equine eotaxin and here we report the production of rEq eotaxin, with and without a C-terminal fusion peptide, in a novel expression system utilising stably transfected insect cells. rEq eotaxin induced equine eosinophil migration and superoxide production in vitro. A shape change in human eosinophils that could be blocked by 7B11, a monoclonal antibody against human CCR3, was also observed. Biological a...
Bayless RL, Sheats MK, Jones SL.Neutrophils play a major role in many equine conditions, including equine asthma, laminitis, and intestinal ischemia and reperfusion injury, and therefore represent an attractive target for innovative therapeutic approaches. Novel strategies for reducing neutrophilic inflammation include modulation of neutrophil functions and lifespan. Withaferin A (WFA) is a phytochemical with well-established and anti-inflammatory properties, but its direct effects on neutrophils are largely unknown. We hypothesized that WFA would inhibit adhesion, migration, and respiratory burst by equine neutrophils and...
Vendrig JC, Fink-Gremmels J.Gastrointestinal defence in the new-born is limited in comparison to adults, due to an immature epithelial barrier function and deficits in both innate and adaptive immune responses. Consequently, neonates (including foals) are at increased risk of disturbance to mucosal homeostasis during initial intestinal colonisation that may lead to excessive inflammation and bacterial translocation into the bloodstream, resulting in septicaemia. Bacterial recognition by Pattern Recognition Receptors (PRRs) and their downstream regulation of cytokine release have been shown to be pivotal for gastrointesti...
Pickles KJ, Mair JA, Lopez-Villalobos N, Shaw DJ, Scott I, Pomroy W.Cyathostomins are the principal pathogenic nematode of equidae worldwide. In other species mast cell (MC) proteinases, in particular chymases, appear to have protective roles. Knowledge of the equine intestinal immune response to cyathostomins is limited. Objective: To investigate MC numbers and proteinase expression in equine cyathostomin-infected large intestine. Objective: MC populations in the large intestine are positively associated with cyathostomin burden and predominantly express chymase. Methods: The caecal cyathostomin burden of naturally infected horses (n = 25) was determined by l...
Targowski SP.Serum specimens from 12 sick and 20 normal horses were examined for levels of different classes of immunoglobulin (Ig) by a single radial immunodiffusion. The level of IgA in the sera of sick horses was about 50% lower than in the sera of normal horses. By contrast, the level of serum IgG was higher in sick than in normal horses. Phytohemagglutinin (PHA) responsiveness of blood lymphocytes showed transient suppression during the stage of severe diarrhea. The regaining of PHA responsiveness of lymphocytes was observed simultaneously with the recovery process. However, the responsiveness of lymp...
Christen G, Gerber V, van der Kolk JH, Frey CF, Fouché N.Pituitary pars intermedia dysfunction (PPID) has been associated with diminished immune response in aged horses. This prospective study hypothesised that this may result in increased strongyle egg shedding in affected animals and that horses treated with pergolide would have reduced fecal egg counts (eggs per gram, EPG) compared to placebo-treated animals. Adrenocorticotropic hormone (ACTH) concentrations and EPG were tested in 48 horses. There were no significant differences in baseline EPG between horses with pre-clinical PPID and healthy controls. There was no significant difference in EPG ...
Fairbairn SM, Marr KA, Lees P, Cunningham FM, Page CP.Antigen challenge is known to cause the recruitment of neutrophils to the lungs of horses with chronic obstructive pulmonary disease (COPD). To evaluate a possible role of platelet activating factor (PAF) in this process, the effects of PAF on the distribution of radiolabelled neutrophils were compared in normal horses and asymptomatic horses with COPD. Changes in lung function, heart rate and the distribution of platelets and eosinophils were also measured. PAF (5 ng kg-1 intravenously) caused immediate but transient increases in the number of radiolabelled neutrophils in the lungs and a conc...
Rütten S, Schusser GF, Abraham G, Schrödl W.Horses are much predisposed and susceptible to excessive and acute inflammatory responses that cause the recruitment and stimulation of polymorphnuclear granulocytes (PMN) together with peripheral blood mononuclear cells (PBMC) and the release of cytokines. The aim of the study is to develop easy, quick, cheap and reproducible methods for measuring tumor necrosis factor alpha (TNF-α) and interleukin-1 receptor antagonist (IL-1Ra) in the equine whole blood cultures ex-vivo time- and concentration-dependently. Results: Horse whole blood diluted to 10, 20 and 50 % was stimulated with lipopolysa...
Sellon DC, Walker KM, Russell KE, Perry ST, Fuller FJ.Equine infectious anemia virus (EIAV) is a lentivirus that replicates predominantly in mature tissue macrophages. Viral expression is strongly influenced by the state of differentiation of the host cell. While blood monocytes can be infected, viral transcription is limited until the cell differentiates into a mature macrophage. Activation of mature macrophages infected with EIAV might also alter viral expression, presumably through binding of cellular transcription factors to viral nucleic acid sequences within the long terminal repeat (LTR). Using DNA amplification techniques, we compared LTR...
Foster AP, McCabe PJ, Sanjar S, Cunningham FM.Eosinophils are believed to play an important part in the pathogenesis of equine diseases such as helminth infestation and the allergic skin disease, sweet itch. It has been shown that adherence of human eosinophils to the connective tissue matrix protein fibronectin enhances cell activation and survival time. If adherence causes similar changes in the properties of equine eosinophils, cell-induced tissue damage at a site of parasitic infestation or allergic response would be exacerbated. However, investigation of this hypothesis requires identification of mediators that cause equine eosinophi...
Kydd JH, Case R, Minke J, Audonnet JC, Wagner B, Antczak DF.Cytotoxic T-lymphocytes (CTLs) are associated with protective immunity against disease caused by equid herpesvirus type 1 (EHV-1). However, the EHV-1 target proteins for CTLs are poorly defined. This limits the development of vaccine candidates designed to stimulate strong CTL immunity. Here, classical CTL assays using lymphocytes from horses of three defined MHC class I types that experienced natural infection with EHV-1 and a modified vaccinia virus construct containing an EHV-1 gene encoding the immediate-early (IE) protein are reported. Horses homozygous for the equine leukocyte antigen (E...
Wagner IP, Rees CA, Dunstan RW, Credille KM, Hood DM.To determine whether systemic immunologic hyperreactivity exists in horses with chronic laminitis, compared with responses for nonlaminitic horses. Methods: 7 nonlaminitic horses and 7 CL horses. Methods: In experiment 1, intradermal testing (IDT) was performed on 7 nonlaminitic and 7 CL horses to evaluate the response to a combination of 70 allergens at 15 and 30 minutes and 4 and 24 hours after injection. Three nonlaminitic and 3 CL horses used in experiment 1 were used in experiment 2 to determine whether histologic differences existed between the 2 groups. The H&E-stained tissue sectio...
Farley J, Sirois J, MacFarlane PH, Kombé A, Laverty S.To characterize expression of cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase-1 (mPGES-1) and regulation of prostaglandin E2 (PGE2) production by equine articular chondrocytes. Methods: Articular cartilage from the metacarpophalangeal joints of 7 adult horses. Methods: Equine chondrocyte monolayer cultures were stimulated with different concentrations (2.5, 5, 10, and 20 ng/mL) of recombinant human interleukin-1beta (rhIL-1beta) for 24 hours and then with rhIL-1beta (5 ng/mL) for 3, 6, 9, 12, and 24 hours. Concentration of PGE2 in the media was measured via radioimmunoassay. T...
Kilcoyne I, Nieto JE, Watson JL, Galuppo LD, Borjesson DL.Endotoxemia is a leading cause of morbidity and mortality in the equine industry, with colic being the most common cause of endotoxemia in horses. The objective of this study was to evaluate the safety and potential efficacy of a single dose of allogeneic equine bone marrow derived mesenchymal stem cells (BM-MSCs) in horses after the IV administration of lipopolysaccharide (LPS). Six horses were administered an IV infusion of 30 ng/kg LPS (O55:B5 Escherichia coli) in 500 ml saline over 30 min. Immediately after infusion test horses (n = 3) were administered 100 × 10 allogeneic BM-MSCs diluted...
