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.
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...
Monahan CM, Taylor HW, Chapman MR, Klei TR.Protection from Strongylus vulgaris infection through immunization with radiation-attenuated third-stage larvae (L3) or crude soluble homogenates from larval or adult stages was examined. Yearling ponies raised parasite-free were divided into 3 immunization groups: radiation-attenuated L3; soluble adult somatic extracts; larval somatic extracts with excretory/secretory products (E/S) from in vitro culture; and 1 medium control group. Ponies were immunized twice; attenuated larvae were administered orally and somatic extracts or controls injected intramuscularly with adjuvant. Approximately 6 w...
Otten N, Marti E, Söderström C, Amtmann E, Burger D, Gerber H, Lazary S.A xanthate compound with antiviral and antitumoural activities, tricyclodecan-9-yl-xanthogenate (D609) in combination with the potassium salt of the lauric acid (KC12) and, in a further investigation, the above-mentioned substances together with recombinant human TNF alpha (rh-TNF alpha), were tested on equine sarcoid tumours for therapeutic efficacy. A pilot investigation on 5 healthy horses showed that the compounds were well-tolerated; apart from a local, temporary oedema at the injection site, no other clinical symptoms were observed after subcutaneous administration of volumes from 0.1 to...
Barton MH, Moore JN.Whole blood from 10 healthy horses was aseptically collected into heparin or citrate anticoagulant and incubated in vitro for 6 hr in the absence (saline control) or presence of 1 ng endotoxin/ml blood. Pentoxifylline (0.1, 1, 10, or 100 micrograms/ml blood) was added 1 hr before, at the same time, or 1 hr after endotoxin. As compared to saline controls, pentoxifylline alone had no effect on mediator production, with the exception of significantly increasing 6-ketoprostaglandin F1 alpha concentration. Pentoxifylline inhibited endotoxin-induced increases in tumor necrosis factor (TNF) and inter...
Kydd JH, Smith KC, Hannant D, Livesay GJ, Mumford JA.Twelve adult ponies and 2 conventional foals were exposed intranasally to EHV-1, strain Ab4 (TCID50 10(-6.6) and samples of respiratory tract associated lymphoid tissues were recovered between 12 h and 13 days after infection. Infectious virus was detected in tissue homogenates using susceptible cell monolayers and expression of viral antigens was monitored using indirect immunoperoxidase histochemistry on paraffin sections. The results showed both infectious EHV-1 and viral antigens in respiratory tract associated lymph nodes 12 h after exposure. Infected leucocytes were identified morphologi...
Bauer JE.The metabolism and clinical potential for dietary polyunsaturated fatty acids (PUFAs) modifications using oil supplements containing n-3 and n-6 fatty acids are reviewed. Their use in such disorders as renal disease, inflammatory and immune-related disorders, and dermatological conditions in dogs and cats is discussed. The influence of n-3 fatty acid-rich rations on the endotoxin response in horses is described. Progress has been made toward understanding the clinical potential for PUFAs in these species. However, they have not yet been shown to be efficacious in any of the conditions investig...
Kluciński W, Winnicka A, Olszewski M, Sikora J, Sitarska E, Niemiałtowski M, Muzylak M, Bylinka G, Wyszyński M.The aim of this study was to compare phagocytic activity of polymorphonuclear cells (PMNs) from the bronchoalveolar lavage of clinically healthy horses and those with severe chronic bronchiolitis. Research was carried out on 28 horses. Chronic inflammation of the lower airways was diagnosed in nine horses. Cells from the respiratory tract were lavaged according to accepted methods. For comparison, PMNs were isolated from peripheral blood of all investigated horses. The phagocytic activity of PMNs was determined in relation to two standard strains of Staphylococcus aureus, Staph, aureus Smith w...
Crans WJ, Caccamise DF, McNelly JR.Eastern equine encephalomyelitis virus (EEEV) is perpetuated in eastern North America in a mosquito-wild bird maintenance cycle that involves Culiseta melanura (Coquillett) as the principal enzootic vector and passerine birds as the primary amplifying hosts. We examined the role of birds in the EEEV cycle at a site in southern New Jersey where EEEV cycles annually at high levels. Birds and mosquitoes were sampled during three epiornitics and one season of limited virus activity. We examined antibody prevalence in birds in relation to eight physical and natural history characteristics. Our goal...
Cobbold S, Holmes M, Willett B.There is now a wide range of immunological reagents that can be used in the diagnosis and treatment of diseases in the companion animals (dogs, cats and horses). Many of these diseases are the veterinary equivalents of human conditions, and may therefore provide good models to study basic pathogenic mechanisms.
Burrage TG, Laegreid WW.African horsesickness (AHS) is a serious, non-contagious disease of horses and other solipeds caused by an arthropod-borne orbivirus of the family Reoviridae. In horses, AHS causes three distinct clinicopathologic syndromes, the pulmonary, cardiac and fever forms of the disease. Recent work has shown that the primary determinant of the form of disease expressed by naive horses is the virulence of the virus inoculum. Horses which recover from AHS exhibit solid humoral immunity against homologous challenge. Protective antibodies appear to be directed towards neutralizing epitopes on AHS virus VP...
MacDonald MH, Stover SM, Willits NH, Benton HP.The metabolic responses of equine articular cartilage to incubation with bacterial lipopolysaccharide (LPS) were studied, using explant cultures of articular cartilage obtained from the metatarsophalangeal joints of 15 horses, age of which ranged from 3 months to 20 years. For comparison, explants were also established from the metatarsophalangeal joints of 3 calves. Explants were cultured for 3 days in medium containing various concentrations of LPS from 0 (control) to 100 micrograms/ml. Glycosaminoglycan (GAG) released during the 3-day incubation was determined by a spectrophotometric assay,...
Bernoco MM, Liu IK, Willits NH.Six foals were deprived of colostrum for the first 36 hours after birth and, instead, received reconstituted powdered milk. Five control foals suckled their dams naturally. Blood samples were obtained from all the foals after birth and at approximately weekly intervals until at least 5.5 months of age. Sera were analyzed for hemolytic complement activity, complement component C3, and correlating IgG concentration. Hemolytic complement (P = 0.0145) and C3 (P = 0.0002) values were significantly higher in colostrum-deprived foals (CDF) than in naturally nursed foals at 2 to 5 days of age. In addi...
Zhang CH, Donaldson WL, Antczak DF.A surface antigen of equine B lymphocytes was identified using the Equine Leucocyte Antigen Workshop antibody WS 65. This marker was expressed on almost all equine B cells, but not on T cells, granulocytes or thymocytes. WS 65 strongly stained cells in the follicular areas of lymph nodes and cells in the splenic nodules when tested on frozen tissue sections by immunohistochemistry. Equine leukemic T cells were not labeled by WS 65, and neither were the cells from a horse with B cell leukemia, although these latter cells carried surface immunoglobulin. Immunoprecipitation of lymphocyte membrane...
Platt D, Bayliss MT.The effect of human recombinant interleukin-1 beta (rhIL-1 beta) on proteoglycan metabolism was investigated in cultures of full thickness explants of articular cartilage from horses 3-21 years of age. Proteoglycan synthesis was inhibited at all ages but no alteration in the hydrodynamic size or electrophoretic heterogeneity was observed in proteoglycan isolated from rhIL-1 beta stimulated cartilage. The sulphation pattern of the newly synthesised proteoglycan molecules was, however, significantly affected by the presence of the peptide regulatory factor. Interleukin-1 had no effect on the rat...
Fukunaga Y, Matsumura T, Sugiura T, Wada R, Imagawa H, Kanemaru T, Kamada M.Serum cross neutralisation tests were conducted with a recent American isolate (84KY-A1) and a European isolate, (Wroclaw-2) and compared with the prototype and modified viruses of the Bucyrus strain of equine arteritis virus by using virus specific immune horse sera. The modified Bucyrus strain was neutralised and showed high neutralisation titres with all the immune sera. The prototype Bucyrus strain was also substantially neutralised, followed by the 84KY-A1 strain. As a result of the tests with the modified Bucyrus strain as the antigen, 20 seropositive horses were discovered among home-br...
Tumas DB, Hines MT, Perryman LE, Davis WC, McGuire TC.The immune control of chronic equine infectious anaemia (EIA) lentiviral infection was investigated by specifically depleting CD5+ T lymphocytes in vivo with monoclonal antibody (MAb) or by immunosuppression with corticosteroids. MAb was given at 25 to 50 mg/day intravenously for 11 days. Murine IgG1 anti-equine CD2 MAb (n = 2 horses) or IgG1 (n = 2) and IgG2a control MAb (n = 2 normal; 2 EIA-infected) did not deplete CD2+ T lymphocytes in horses. Horses given murine IgG2a anti-CD5 MAb HB19A (n = 4 normal; 5 EIA-infected) had depletion of peripheral blood CD5+ T lymphocytes during treatment. T...
Knowles DP, Kappmeyer LS, Perryman LE.Horses possessing a normal immune system and spleen often control infection caused by Babesia equi. However, splenectomized horses are unable to control B. equi infection and usually succumb to the infection. To investigate the role of the spleen in the control of B. equi infection in the absence of specific immune responses, two 1-month-old foals with severe combined immunodeficiency (SCID) and two age-matched normal foals were inoculated with B. equi. The SCID foals became febrile seven days postinoculation and developed terminal parasitemias of 41 and 29%. The SCID foals had greater than 50...
Mumford JA, Wilson H, Hannant D, Jessett DM.Equine influenza vaccines containing inactivated whole virus and Carbomer adjuvant stimulated higher levels and longer lasting antibody to haemagglutinin in ponies than vaccines of equivalent antigenic content containing aluminium phosphate adjuvants. Five months after the third dose of vaccine containing Carbomer adjuvant, ponies were protected against clinical disease induced by an aerosol of virulent influenza virus (A/equine/Newmarket/79, H3N8). In contrast ponies which received vaccine containing aluminium phosphate adjuvant were susceptible to infection and disease. There was an inverse ...
Hamlen HJ, Timoney JF, Bell RJ.A 2-phase study was performed to characterize the effects of Streptococcus equi infection in unexposed and previously exposed foals. In phase I, 22 weanling foals involved in a naturally occurring S equi epizootic were studied, along with a comparison group of 11 unexposed foals, matched for age, sex, and breed. Six months later (phase II), an epizootic was experimentally induced in previously exposed and unexposed foals from phase I. The prevalence and duration of clinical signs, the relative risk of developing disease, bacteriologic culture results, hematologic responses, and mucosal and ser...
Maddison JE.Fifty-nine reports of suspected adverse drug reactions (ADRs) were received by the Adverse Drug Reaction Subcommittee of the Australian Veterinary Association from April 1992-March 1993 inclusive. The number of reports received/number of animals involved per species was: dogs (30/43); cats (11/14); horses (8/10); cattle (9/30); ferret (1/1). Of these, 37 (63%) were classified as definite ADRs and 12 (20%) as probable ADRs. In 10 (17%) reports an ADR could not be substantiated or there was insufficient information available to make a decision. Twenty-three reports involved apparent hypersensiti...
Curran JA, Argyle DJ, Cox P, Onions DE, Nicolson L.Interferon gamma, a cytokine produced by T-lymphocytes and natural killer cells, plays a central role in the modulation of the immune response, and its antiviral and antitumourigenic properties have made it a potential candidate for use in immunoprophylactic and therapeutic regimes. We have cloned the equine IFN gamma cDNA to facilitate production of this cytokine for clinical evaluation in the horse. The predicted equine IFN gamma amino acid sequence is 67% identical to that of the human equivalent and 78% to the bovine equivalent.
Wilkins PA, Dewan-Mix S.The efficacy intravenous plasma to transfer passive immunity to clinically healthy colostrum-deprived and clinically ill foals with failure of passive transfer was investigated. Efficacy of transfer was evaluated by the elevation of serum IgG per gram of IgG administered as a function of body weight. Colostrum deprived healthy foals had a significantly greater increase in serum IgG than did clinically ill foals with failure of passive transfer. Knowledge of the IgG content of plasma to be administered and the health status of a foal with failure of passive transfer should allow more accurate p...
Blunden AS, Hannant D, Livesay G, Mumford JA.Welsh Mountain ponies were inoculated with an isolate of Streptococcus pneumoniae, SPE 1618 (capsular type 3) recovered from the equine respiratory tract: 10 ml of a suspension of 10(8) or 10(9) cfu/ml were instilled intratracheally. Fever was observed after either dose but the greater concentration also produced coughing, ocular and nasal discharge, depression and enlargement of submandibular lymph nodes. Cytological evidence of infection was also observed in tracheal washings during the first week after inoculation and corresponded with isolation of S. pneumoniae from the washes. Morbid anat...
Fairbairn SM, Lees P, Page CP, Cunningham FM.Antigen-induced airway hyperresponsiveness in allergic horses has previously been demonstrated when clinical signs of acute airway obstruction were apparent, as a consequence of exposure of animals to hay and straw for variable periods of time, and repeat measurements of hyperresponsiveness have been made no earlier than 1 week after challenge. In the present study airway responsiveness to methacholine has been measured in normal horses and allergic horses in clinical remission before and 24, 48 and 72 h after a hay and straw challenge of fixed, short, duration (7 h). Correlations between earl...
Troedsson MH, Liu IK, Ing M, Pascoe J, Thurmond M.The electrical myometrial activity of three mares with a documented increased susceptibility to chronic uterine infection (CUI) and three mares considered to be resistant to CUI was investigated. Electrodes were surgically implanted in the myometrium of the mares and electrical activity was monitored by a Grass polygraph. Oestrus was determined by transrectal ultrasonography of the reproductive tract and teasing of the mares with a stallion. Findings were confirmed by blood progesterone concentrations 35 mm was detected, the uterus was infused with a genital strain of 5 x 10(6) Streptococcus ...
Dirscherl P, Grabner A, Buschmann H.As basophils are the major effector cells of allergic reactions, confirmation of the allergic etiology of chronic obstructive pulmonary disease (COPD) was sought by the demonstration of a specific in vitro response of equine basophilic blood cells to some potential allergens (Aspergillus, Cladosporidium, Mucor, Penicillium, extracts of dust particles of hay and straw). The allergen induced degranulation of basophils and the histamine and protease release from basophils during incubation with the allergens were tested. By evaluating the results obtained from 14 COPD horses and eight controls it...
Marr KA, Lees P, Cunningham FM.Adherence to vascular endothelium and extracellular matrix proteins is a pre-requisite for neutrophil accumulation at sites of inflammation. In this study, equine neutrophil adherence to fibronectin and autologous serum-coated plastic in response to PAF, hrIL-8, hrC5a and PMA has been measured. In addition, the mechanisms involved have been investigated using monoclonal antibodies (MoAbs) against the beta2 integrin CD18. PAF and hrC5a caused similar, concentration dependent, increases in adherence to fibronectin- and serum-coated plastic (maximum responses 19 +/- 4% and 19 +/- 3% for PAF and 1...
Harkiss GD, Brown DL, Smith DJ, Nagington J.Circulating immune complexes were isolated from the sera of cardiac allograft recipients by bovine conglutinin/anti-conglutinin co-precipitation, or by gel filtration and protein A-Sepharose affinity chromatography. The antibody moieties within these isolated immune complexes were tested for specificity against heterologous anti-thymocyte globulins by solid phase radioimmunoassay, and bacterial and viral antigens by indirect immunofluorescence. The results showed that in addition to possessing specific anti-equine anti-thymocyte globulin antibodies, immune complexes also contained cross-reacti...
Whalley JM, Love DN, Tewari D, Field HJ.A series of recombinant baculoviruses containing genes for glycoproteins C, D, H and L of equine herpesvirus 1 (EHV-1) have been constructed, and the EHV-1 products characterised by gel electrophoresis and immunoblotting. The EHV-1 glycoproteins expressed in insect cells were similar but not identical in apparent sizes to those expressed in EHV-1 infected mammalian cells. Each of the EHV-1 products was recognised by convalescent equine sera, indicating that they were all targets for an equine immune response. Mice immunised with baculovirus-expressed EHV-1 gD and gC acquired an enhanced abilit...
Recknagel S, Snyder A, Blanke A, Uhlig A, Brüser B, Schusser GF.Knowledge of tetanus immunity in equine patients is crucial in cases of injuries, elective surgeries, or when effective vaccination protocols are to be designed. The Fassisi® TetaCheck is a stall-side rapid test which was developed to address these issues. The purpose of the present study was to evaluate its performance parameters. To this end, the qualitative test results obtained by two blinded observers were compared to tetanus toxoid antibody levels from 99 serum samples, measured with a double antigen ELISA. Additionally the colour intensities of the test window were quantified using a c...
MacKay RJ, King RR, Dankert JR, Reis KJ, Skelley LA.Blood monocytes and alveolar macrophages (AM) were harvested from foals (aged 46 days to 6 months) and cultured in either medium alone or medium containing 10 micrograms/ml bacterial lipopolysaccharide (LPS). After 24 h, culture supernates were collected and analyzed for cytotoxic activity on sensitized L929 cells. Both monocytes and AM that had been treated with LPS produced significantly more cytotoxic activity than the same cell type exposed to medium lacking LPS. LPS-treated macrophages secreted significantly more cytotoxic activity (120 +/- 17.8 U/ml) than did LPS-treated monocytes (47.3 ...
Simmons EJ, Bertone AL, Hardy J, Weisbrode SE.To quantitate nitric oxide synthase (NOS) activity in healthy and interleukin 1beta (IL-1beta)-exposed equine synovial membrane. Methods: 6 healthy horses, 2 to 8 years old. Methods: Recombinant human IL-1beta (0.35 ng/kg of body weight) was injected intra-articularly into 1 metacarpophalangeal joint of each horse. The contralateral joint served as an unexposed control. All horses were euthanatized 6 hours after injection of IL-1beta, and synovial membrane specimens were assayed for NOS activity by measuring conversion of arginine to citrulline. Severity of inflammation was semiquantitated by ...
Millican AA, Leatherwood JL, Coverdale JA, Arnold CE, Bradbery AN, Larson CK, Lamprecht ED, White SH, Paulk CB, Welsh TH, Wickersham TA.Sixteen weanling Quarter Horses (255 ± 22 kg) were utilized in a 56-d trial to evaluate the effects of trace mineral (TM) source on intra-articular inflammation following a single acute inflammatory insult. Horses were stratified by age, sex, and BW and then randomly assigned to dietary treatment: concentrate formulated with Zn, Mn, Cu, and Co as inorganic sources (CON; n = 8) or complexed TMs (CTM; n = 8). Added TM were formulated at iso-levels across treatments and intakes met or exceeded NRC requirements. Horses were offered 1.75% BW (as-fed) of treatment concentrate and 0.75% BW (as-fed) ...
Lopez KM, Fleming GJ, Mylniczenko ND.Reports of equine herpesvirus (EHV) 1 and EHV-9 causing clinical disease in a wide range of species have been well documented in the literature. It is thought that zebras are the natural hosts of EHV-9 both in the wild and in captive collections. Concerns about potential interspecies transmission of EHV-1 and EHV-9 in a mixed species savannah exhibit prompted serologic and polymerase chain reaction surveys. Eighteen Burchell's zebras ( Equus quagga ), 11 Hartmann's mountain zebras ( Equus zebra hartmannae), and 14 Thomson's gazelles ( Eudorcas thomsonii ) cohabitating the same exhibit were exa...
Rommel FA, Sahu SP.Intrauterine inoculation of pony mares with the bacterium that is the causative agent of contagious equine metritis (CEM) resulted in clinical disease. A humoral immune response could be detected by agglutination and complement fixation (CF), and in some cases precipitating antibody was found by immunodiffusion tests. Agglutinating antibody was the most reliable serological indicator of overt infection and was detected in 8 ot 28 mares after initial intrauterine inoculation of 3-4 x 10(5) bacteria. Seventy percent of mares given a second inoculation and all mares given a third inoculation of 3...
Holmes MA, Lunn DP.As part of a project to raise specific pathogen free (SPF) Welsh Mountain Pony foals, free from exposure to Equid herpesvirus type 1, foals were removed from their dams at birth and fed bovine colostrum. This study characterises the uptake of bovine colostral immunoglobulin and production of endogenous immunoglobulin, in 10 SPF foals. An enzyme-linked immunoadsorbent assay was developed to measure serum concentrations of bovine IgG1 (boIgG1) to assess the efficiency of transfer, and rate of elimination of boIgG1 by the foal. The endogenous production of equine IgG was studied using a single ra...
Pietra M, Cinotti S, Ducci A, Giunti M, Peli A.During an 18 day test, we measured the cytokine mRNA expression (Interleukin-1beta [IL-1beta], Interleukin-8 [IL-8], Interferon-gamma [IFN-gamma], Tumor Necrosis Factor-alpha [TNF-alpha]) of cells from bronchoalveolar lavage fluid [BALF] in five horses previously diagnosed with RAO, before and during challenge exposure, and after the desensitization phase which involved dexamethasone treatment and environmental modification. Simultaneously, the same cytokine mRNA expression of cells from BALF in four asymptomatic RAO-affected horses maintained outdoors was analyzed. An evident respiratory dist...
Siegel RC, Cathou RE.Complexes of IgM equine anti-dansyl antibodies and different dansyl substituted carriers were tested for their ability to fix complement (C). Only dansyl92-Ficoll and dansyl12-poly-L-lysine were found to be effective. Dansyl13-bovine serum albumin, dansyl127-keyhole limpet hemocyanin, and reduced and alkylated dansyl10-ribonuclease were all ineffective. Lack of C fixation by the dansyl-ribonuclease was not due to lack of antibody-antigen complex formation, since binding at the concentrations employed for C fixation was established. However, in contrast, polymerized dansyl-ribonuclease (polydis...
Ramsay JD, Evanoff R, Mealey RH.Hepacivirus A (also known as nonprimate hepacivirus and equine hepacivirus) is a hepatotropic virus that can cause both transient and persistent infections in horses. The evolution of intrahost viral populations (quasispecies) has not been studied in detail for hepacivirus A, and its roles in immune evasion and persistence are unknown. To address these knowledge gaps, we first evaluated the envelope gene (E1 and E2) diversity of two different hepacivirus A strains (WSU and CU) in longitudinal blood samples from experimentally infected adult horses, juvenile horses (foals), and foals with sever...
Dunkel B, Rickards KJ, Werling D, Page CP, Cunningham FM.To determine whether expression of equine platelet activation-dependent surface markers is influenced by phospodiesterase (PDE) isoenzyme activity and whether antigen challenge alters platelet PDE activity in horses with recurrent airway obstruction (RAO). Methods: 16 horses. Methods: 7 healthy horses were used for in vitro experiments, 6 horses with RAO were used for antigen challenge, and 6 healthy horses were used as control animals. Three of the healthy horses had also been used in the in vitro experiments. Effects of PDE inhibition and activation of adenylyl cyclase on CD41/61 and CD62P e...
Sykes BW, Furr M, Giguère S.Twelve healthy horses were assigned to treatment or control groups. Treated horses received PGG-Glucan[ED-1] (1 mg/kg, IV) 24 hours prior to peripheral blood mononuclear cell (PBMC) isolation. PBMCs were isolated and incubated in the presence of lipopolysachharide (LPS). At 0, 6, 12, 24 and 48 hours messenger RNA (mRNA) was extracted. Reverse transcription polymerase chain reaction (PCR) was performed and cytokine mRNA expression for tumor necrosis factor alpha (TNFalpha), interleukin 1beta (IL-1beta), interleukin 10 (IL-10) and interferon gamma (IFN-gamma) determined using real time PCR. A si...
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...
Skaggs JS, Reed Holyoak G, Montelongo M, Ayalew S, Confer AW.The immune responsiveness of mice (without prior natural exposure) and mares (with naturally acquired antibodies) was determined following vaccination with Actinobacillus equuli outer membrane proteins (OMPs) and/or recombinant A. equuli toxin (rAqx). Mice were vaccinated subcutaneously on days 0 and 21 with one of three doses (5, 25 or 50μg) of A. equuli OMPs, rAqx or both, together with Freund's incomplete adjuvant (FIA). Antibodies against formalin-killed whole bacterial cells (WBCs), OMPs and Aqx were determined on days 0, 21 and 42. Mares were vaccinated subcutaneously on days 0 and 21 w...
Perryman LE, Magnuson NS.Significant contributions to understanding the role of lymphocyte subpopulations in the immune response and to the characterization of immunodeficiencies in children have been achieved through study of animal models of immunodeficiency. Additional contributions can be made in two important areas. One is through identification of relevant, naturally-occurring models of adenosine deaminase deficiency and purine nucleoside phosphorylase deficiency. The second, and potentially more important contribution, would be the identification of the metabolic basis for existing immune deficiencies. The nece...
Rosypal AC, Lindsay DS, Duncan R, Ahmed SA, Zajac AM, Dubey JP.Equine protozoal myeloencephalitis (EPM) is a neurologic syndrome in horses from the Americas and is usually caused by infection with the apicomplexan parasite, Sarcocystis neurona. Little is known about the role of immunobiological mediators to this parasite. Nitric oxide (NO) is important in resistance to many intracellular parasites. We, therefore, investigated the role of inducible and endothelial NO in resistance to clinical disease caused by S. neurona in mice. Groups of interferon-gamma gene knockout (IFN-gamma-KO) mice, inducible nitric oxide synthase gene knockout (iNOS-KO) mice, endo...
Zhang CH, Donaldson WL, Antczak DF.A surface antigen of equine B lymphocytes was identified using the Equine Leucocyte Antigen Workshop antibody WS 65. This marker was expressed on almost all equine B cells, but not on T cells, granulocytes or thymocytes. WS 65 strongly stained cells in the follicular areas of lymph nodes and cells in the splenic nodules when tested on frozen tissue sections by immunohistochemistry. Equine leukemic T cells were not labeled by WS 65, and neither were the cells from a horse with B cell leukemia, although these latter cells carried surface immunoglobulin. Immunoprecipitation of lymphocyte membrane...
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...
Hurwitz A, Finci-Yeheskel Z, Dushnik M, Milwidsky A, Shimonovitz S, Yagel S, Adashi EY, Mayer M.This study examines the effects of interleukin-1 (IL-1) on plasminogen activator (PA) activity and prostaglandin (PG) E production in pregnant mare serum gonadotropin (PMSG)-primed granulosa cells and the potential involvement of PGE in the regulation of ovarian plasminogen activation. Methods: Granulosa cells were obtained from PMSG-primed rat (27-day-old) ovaries and cultured in serum-free conditions for 48 hours in the absence or presence of IL-1 beta (10 ng/mL) with and without transforming growth factor-beta 1 (10 ng/mL). Cellular PA activity was measured through the conversion of plasmin...
McCandless EE, Rai SK, Mwangi D, Sly L, Franz LC.Hydrocortisone is widely accepted as an anti-inflammatory agent and there are many products available containing hydrocortisone as an active ingredient. Surprisingly, there is little data available specifically on the immunological effects of hydrocortisone in large animals. Glucocorticoids are well-characterized for their ability to repress inflammation via a wide variety of mechanisms including suppression of cytokine production. In this study the effects of hydrocortisone on IFN-γ production by equine, bovine, and ovine PBMCs were assessed using flow cytometric or ELISpot analysis. Hydroco...
Bauquier JR, Tudor E, Bailey SR.Despite the severity and common occurrence of equine endotoxaemia, the available anti-endotoxic treatments do not effectively target key inflammatory mechanisms such as leucocyte activation and cytokine production. In this study, four compounds with potential anti-endotoxic effects, namely rolipram, azithromycin, ethyl pyruvate and metformin, were investigated in vitro using equine whole blood stimulated with bacterial lipopolysaccharide. TNF-α and IL-1β production were measured in plasma. Rolipram was the most potent inhibitor of cytokine production (IC50 0.84 and 4.68 μm for TNF-α and IL...
Cocco R, Rizzo M, Carta C, Arfuso F, Piccione G, Luridiana S, Crovace A, Passino ES, Sechi S.Among infection diseases transmitted by arthropods, the equine vector-borne diseases transmitted by ticks represent an emerging problem worldwide due to their morbidity and mortality and, in some cases, to their zoonotic relevance. Understanding the host immune/inflammatory response to the pathogens is crucial to develop effective methods of diagnosis, control and treatment. This study aimed to evaluate red blood cells (RBC), hematocrit (Hct), hemoglobin concentration (Hb), mean cell volume (MCV), mean cell hemoglobin content (MCH), mean cell hemoglobin (MCHC), platelets (PLT), white blood cel...
Foster AP, McKelvie J, Cunningham FM.A whole-body extract of Culicoides impunctatus induced a biphasic increase in oedema formation in ponies with insect hypersensitivity, with maxima after one and eight hours. The Culicoides antigen did not induce similar responses in ponies with no previous history of the disease. In insect-hypersensitive ponies the local administration of chlorpheniramine (12 micrograms) completely inhibited oedema formation in response to histamine (0.04 microgram) and to Culicoides antigen (0.5 microgram) at one hour, and the response to Culicoides antigen at eight hours was inhibited by 63 per cent. Chlorph...
Hammond SA, Issel CJ, Montelaro RC.Equine immunological research is hindered by the lack of a simple yet reliable general protocol by which to assay CTL activity specific for viral or parasitic antigens. We present here the first comprehensive analysis of the parameters necessary to reliably culture equine T cells and to analyze the antigen specific cytolytic activity of T lymphocytes utilizing the equine infectious anemia virus (EIAV) infection of outbred ponies as a source for in vivo primed T lymphocytes. Effective long-term in vitro culture of equine T cells was determined to require minimally 200 U/ml of recombinant human ...
Muko R, Sunouchi T, Urayama S, Toishi Y, Kusano K, Sato H, Muranaka M, Shin T, Oikawa MA, Ojima Y, Ali M, Nomura Y, Matsuda H, Tanaka A.Histidine-rich glycoprotein (HRG) is abundant plasma protein with various effects on angiogenesis, coagulation, and immune responses. Previously, we identified the base and amino acid sequences of equine HRG (eHRG) and revealed that eHRG regulates neutrophil functions. In this study, we first conducted a large-scale gene analysis with DNA samples extracted from 1700 Thoroughbred horses and identified unique insertion/deletion polymorphisms in the histidine-rich region (HRR) of eHRG. Here we report two types of polymorphisms (deletion type 1 [D1] and deletion type 2 [D2]) containing either a 45...
Zhang XY, Li HM, Liang H, Shen T, Ma Y, Xiang WH, Shen RX, Shao YM.To elucidate cellular immune protective mechanism of EIAV. Methods: Four horses were immunized with (DLV) by subcutaneous injection and 2 horses with 0.85% sodium chloride as the negative control. Rectal temperatures and clinical features were recorded daily. Whole blood samples were collected, from which PBMC were separated and used for CTL assay and lymphocyte proliferation assay. Results: The target cells were activated by PWM and treated with DLV or recombinant vaccinia vectors expressing DLV and LN Gag or Env separately. The percentage of EIAV-specific CTL lysis was under 5% in the negati...
Jefcoat AM, Wagner JG, Robinson NE.The research article involves an in-depth exploration of the role of neutrophils, a type of immune cell, in inflammation, especially in relation to horse diseases. The study discusses the historical […]
