Lymphocytes are a type of white blood cell found in horses that are integral to the immune system. They are involved in the body's defense mechanisms against infections and other diseases. Lymphocytes are primarily categorized into T cells, B cells, and natural killer (NK) cells, each playing distinct roles in immune responses. T cells are involved in cell-mediated immunity, B cells are responsible for antibody production, and NK cells contribute to the destruction of infected or cancerous cells. The study of lymphocytes in horses includes their development, function, and response to various pathogens. This page compiles peer-reviewed research studies and scholarly articles that explore the biology, regulation, and clinical relevance of lymphocytes in equine health.
Faramarzi B, Rich L.Foals' haematological values change constantly during their first year of life. The use of updated age-based reference intervals (RIs) is imperative for providing accurate diagnosis and optimum care for sick foals. The authors' objective was to provide updated RIs for 13 haematological values in 2, 7, 14, 30, 90, 180 and 365-day-old foals and to investigate the changes over time in each measured value. Venous blood was collected at those ages from clinically healthy foals. Thirteen haematological values were analysed. The 95% RIs were reported using a bootstrapping method. Differences over tim...
Rowland AL, Xu JJ, Joswig AJ, Gregory CA, Antczak DF, Cummings KJ, Watts AE.We recently demonstrated that intracellular xenogen-contaminated autologous MSCs (FBS) and non-xenogen-contaminated allogeneic (ALLO) MSCs caused an adverse clinical response after repeated intra-articular injection in horses, whereas autologous (AUTO) MSCs did not. Our current objective was to use clinical data from the previous study to compare MSC stemness against adverse response indicated by synovial total nucleated cell count (TNCC) following intra-articular MSC injection. Stemness, quantified by a trilineage differentiation (TLD) score; immunomodulation, quantified by mixed lymphocyte ...
Chikhaoui M, Smail F, Adda F.The Barb horse this famous Maghreb horse, symbol of the pride of the Berber peoples It is particularly significant in the Algerian history, tradition and culture. This study consists in establishing the hematologic values specific to the Barb horse in the national stud farm "Chaou-Chaoua" in Tiaret. Algeria. Age of the study animals varied between 1 and 23 years. The effects of age and sex were analyzed by dividing animals into four groups, A (1 - 2 years, n=5), B (3-5 years, n=5), C (5-10 years, n=5) and D (11-23 years, n=5); for females and E (2 - 3 years, n=5), F (5-7, n=5), G (10, n=5) and...
Schauer M, Kleinwort KJH, Degroote RL, Wiedemann C, Kremmer E, Hauck SM, Deeg CA.The GTP-binding protein septin 7 is involved in various cellular processes, including cytoskeleton organization, migration and the regulation of cell shape. Septin 7 function in lymphocytes, however, is poorly characterized. Since the intracellular signaling role of septin 7 is dependent on its interaction network, interaction proteomics was applied to attain novel knowledge about septin 7 function in hematopoietic cells. Our previous finding of decreased septin 7 expression in blood-derived lymphocytes in ERU, a spontaneous animal model for autoimmune uveitis in man, extended the role of sept...
Fielding CL, Rhodes DM, Howard EJ, Mayer JR.OBJECTIVE To identify clinical or clinicopathologic variables that can be used to predict a positive PCR assay result for Anaplasma phagocytophilum infection in equids. ANIMALS 162 equids. PROCEDURES Medical records were reviewed to identify equids that underwent testing for evidence of A phagocytophilum infection by PCR assay between June 1, 2007, and December 31, 2015. For each equid that tested positive (case equid), 2 time-matched equids that tested negative for the organism (control equids) were identified. Data collected included age, sex, breed, geographic location (residence at the tim...
Hartmann C, Gerner W, Walter I, Saalmüller A, Aurich C.In the mare, early pregnancy loss is common, but involvement of the maternal immune system in the pathogenesis of this condition has not been investigated in detail so far. In the present study, we assessed effects of exposure of the endometrium to semen or seminal plasma in oestrous mares on the response of regulatory T lymphocytes (Tregs) in the peripheral circulation as well as in the endometrium. Raw semen, seminal plasma or PBS (control) were introduced into the uterus of oestrous mares (n = 12). Blood was collected immediately before insemination or PBS infusion (time 0), and 12, 24 ...
Winter JC, Sponder G, Merle R, Aschenbach JR, Gehlen H.Equine metabolic syndrome (EMS) is a worldwide disease in horses that parallels human diabetes mellitus type 2. In both diseases, patients show an altered peripheral insulin sensitivity as a key feature. In humans, multiple studies have demonstrated the beneficial effect of magnesium supplementation on insulin sensitivity. However, serum magnesium levels vary and are therefore not a reliable indicator of the patients' magnesium status. Determining the intracellular free magnesium concentration appears to be a more sensitive diagnostic indicator. In this study, the free intracellular magnesium ...
Tomlinson JE, Wagner B, Felippe MJB, Van de Walle GR.Immune phenotyping of equine peripheral blood mononuclear cells (PBMC) is commonly described by single or double marker labeling, which limits complex phenotypic descriptions and subpopulation identification. Our objective was to develop a new multispectral flow cytometry protocol to identify and sort equine lymphocyte subpopulations using commercially available, pre-conjugated monoclonal antibodies to cell surface markers. Two clones of anti-equine CD8 (CVS8 and CVS21) were compared in combination with CD3. Clone CVS21 bound non-T CD3 cells in addition to CD8 T cells. Further analysis using c...
Mißbach S, Aleksic D, Blaschke L, Hassemer T, Lee KJ, Mansfeld M, Hänske J, Handler J, Kammerer R.The CEA gene family is one of the most rapidly evolving gene families in the human genome. The founder gene of the family is thought to be an ancestor of the inhibitory immune checkpoint molecule CEACAM1. Comprehensive analyses of mammalian genomes showed that the CEA gene family is subject to tremendous gene family expansion and contraction events in different mammalian species. While in some species (e.g. rabbits) less than three CEACAM1 related genes exist, were in others (certain microbat species) up to 100 CEACAM1 paralogs identified. We have recently reported that the horse has also an e...
Hauck SM, Lepper MF, Hertl M, Sekundo W, Deeg CA.Equine recurrent uveitis is the only spontaneous model for recurrent autoimmune uveitis in humans, where T cells target retinal proteins. Differences between normal and autoaggressive lymphocytes were identified in this study by analyzing peripheral blood derived lymphocytes (PBL) proteomes from the same case with interphotoreceptor retinoid binding protein induced uveitis sampled before (Day 0), during (Day 15), and after uveitic attack (Day 23). Relative protein abundances of PBL were investigated in a quantitative, label-free differential proteome analysis in cells that were kept frozen for...
Cooper CJ, Keller SM, Arroyo LG, Hewson J, Kenney D, Bienzle D.Leukemia is broadly divided into acute and chronic lymphocytic and myeloid types based on the proportion of blasts, morphology of cells, and expression of specific antigens on neoplastic cells. Classifying leukemia in horses can be challenging if blasts predominate and since few antibodies to identify cell types are available. The objective of this study was to describe in detail the clinical and pathologic features of acute leukemia in horses. Twelve horses ranging from 0.2 to 25.9 years of age were diagnosed with acute leukemia. Six cases were classified as acute lymphocytic leukemia (ALL) b...
Carossino M, Loynachan AT, Canisso IF, Cook RF, Campos JR, Nam B, Go YY, Squires EL, Troedsson MHT, Swerczek T, Del Piero F, Bailey E, Timoney PJ....Equine arteritis virus (EAV) has a global impact on the equine industry as the causative agent of equine viral arteritis (EVA), a respiratory, systemic, and reproductive disease of equids. A distinctive feature of EAV infection is that it establishes long-term persistent infection in 10 to 70% of infected stallions (carriers). In these stallions, EAV is detectable only in the reproductive tract, and viral persistence occurs despite the presence of high serum neutralizing antibody titers. Carrier stallions constitute the natural reservoir of the virus as they continuously shed EAV in their seme...
Léguillette R, Tohver T, Bond SL, Nicol JA, McDonald KJ.Airway hyperresponsiveness (AWHR), expressed as hypersensitivity (PC R ) or hyperreactivity (slope of the histamine dose-response curve), is a feature of inflammatory airway disease (IAD) or mild equine asthma in horses. Glucocorticoids are used empirically to treat IAD. Objective: To determine whether dexamethasone (DEX) (0.05 mg/kg IM q24h) and inhaled fluticasone (FLUT) (3,000 μg q12h) administered by inhalation are effective in decreasing AWHR, lung inflammation, and clinical signs in horses with IAD. Methods: A randomized crossover study design was used. Eight horses with IAD were assign...
Henríquez C, Morán G, Carrasco C, Sarmiento J, Barría M, Folch H, Uberti B.It is accepted that T regulatory cells (Treg) control different types of immune responses. In connection with this role, we have recently described an important increase in CD4+, CD25, Foxp3+ lymphocytes in the airway system of horses coursing with an exacerbation of severe equine asthma (EA). To explore the potential role of this population in the resolution of EA inflammation, we used a murine experimental model in which airway neutrophilic inflammation, which is similar to that observed in EA, is induced in mice by continual exposure to Aspergillus fumigatus contaminated hay. This model has...
Mekuria ZH, El-Hage C, Ficorilli NP, Washington EA, Gilkerson JR, Hartley CA.Equine herpesvirus 5 (EHV5) is a commonly detected gammaherpesvirus, which, along with the closely related EHV2, constitute the only two known percaviruses that infect horses. Apart from detection in horse populations worldwide and the recent publication of the whole genome, there is little known about the biology and pathogenesis of this virus, with many assumptions made by parallels with EHV2. The long-term survival of gammaherpesviruses within infected hosts involves the establishment and maintenance of latency in selected cell and tissues types, particularly lymphocytes. A latent gammaherp...
Colbath AC, Dow SW, Phillips JN, McIlwraith CW, Goodrich LR.The use of allogeneic bone marrow-derived mesenchymal stem cells (BMDMSCs) may provide an effective alternative to autologous BMDMSCs for treatment of equine musculoskeletal injuries. However, concerns have been raised regarding the potential safety and effectiveness of allogeneic BMDMSCs. We conducted studies to assess the immunological properties of equine allogeneic BMDMSCs compared with those of autologous BMDMSCs. For assessment of inherent immunogenicity, the relative ability of allogeneic and autologous BMDMSCs to stimulate spontaneous proliferation of equine lymphocytes was compared. T...
Sarkar S, Bailey E, Go YY, Cook RF, Kalbfleisch T, Eberth J, Chelvarajan RL, Shuck KM, Artiushin S, Timoney PJ, Balasuriya UB.Equine arteritis virus (EAV) is the causative agent of equine viral arteritis (EVA), a respiratory, systemic, and reproductive disease of horses and other equid species. Following natural infection, 10-70% of the infected stallions can become persistently infected and continue to shed EAV in their semen for periods ranging from several months to life. Recently, we reported that some stallions possess a subpopulation(s) of CD3+ T lymphocytes that are susceptible to in vitro EAV infection and that this phenotypic trait is associated with long-term carrier status following exposure to the virus. ...
Grau-Roma L, Peckham R, Paton J, Stahel A, de Brot S.The postmortem examination of a 14-y-old Appaloosa gelding with clinically diagnosed pituitary pars intermedia dysfunction showed a unique finding of moderate multifocal lymphocytic hypophysitis (LH). The pituitary glands of 24 horses submitted for postmortem examination were examined grossly and examined histologically for the presence of lymphocytes. Of these 23 horses, 1 additional case suffered from moderate LH. The 2 cases with LH tested negative for Equid herpesvirus 1 and 4 by polymerase chain reaction and immunohistochemistry (IHC), and no viral particles were observed by electron micr...
Wernersson S, Riihimäki M, Pejler G, Waern I.Mast cells are known for their detrimental effects in various inflammatory conditions. Regimens that induce selective mast cell apoptosis may therefore be of therapeutic significance. Earlier studies have demonstrated that murine- and human-cultured mast cells are highly sensitive to apoptosis induced by the lysosomotropic agent LeuLeuOMe (LLME). However, the efficacy of lysosomotropic agents for inducing apoptosis of in vivo-derived airway mast cells and the impact on mast cells in other species have not been assessed. Here we addressed whether lysosomotropic agents can induce cell death of ...
Williams LB, Co C, Koenig JB, Tse C, Lindsay E, Koch TG.Equine mesenchymal stromal cells (MSC) are commonly transported, chilled or frozen, to veterinary clinics. These MSC must remain viable and minimally affected by culture, transport, or injection processes. The safety of two carrier solutions developed for optimal viability and excipient use were evaluated in ponies, with and without allogeneic cord blood-derived (CB) MSC. We hypothesized that neither the carrier solutions nor CB-MSC would elicit measurable changes in clinical, hematological, or biochemical parameters. In nine ponies (study 1), a bolus of HypoThermosol(®) FRS (HTS-FRS), CryoSt...
Durward-Akhurst SA, Finno CJ, Barnes N, Shivers J, Guo LT, Shelton GD, Valberg SJ.Major histocompatibility complex (MHC) I and II expression is not normally detected on sarcolemma, but is detected with lymphocytic infiltrates in immune-mediated myositis (IMM) of humans and dogs and in dysferlin-deficient muscular dystrophy. Objective: To determine if sarcolemmal MHC is expressed in active IMM in horses, if MHC expression is associated with lymphocytic subtype, and if dysferlin is expressed in IMM. Methods: Twenty-one IMM horses of Quarter Horse-related breeds, 3 healthy and 6 disease controls (3 pasture myopathy, 3 amylase-resistant polysaccharide storage myopathy [PSSM]). ...
Aoki T, Kimura Y, Oya A, Chiba A, Ishii M, Nambo Y.Heavy draft mares potentially have a higher risk of suffering from postpartum fever (PF) than light breed mares. The purpose of this study was to compare hematological and biochemical features between clinically healthy mares (n=40) and PF-affected mares (n=16). Mares were classified as having PF when their rectal temperature rose to >38.5°C within 96 hr of foaling. The numbers of leukocytes, lymphocytes, and neutrophils and the serum magnesium level were significantly lower in PF-affected mares. The serum SAA and NEFA levels were significantly higher in PF-affected mares. Strong inflammation...
Razzaq F, Khosa T, Ahmad S, Hussain M, Saeed Z, Khan MA, Shaikh RS, Ali M, Iqbal F.The present study was designed to optimize a PCR-RFLP protocol for the molecular detection of Anaplasma sp. and to compare its prevalence in blood samples of equines from Southern Punjab (Pakistan) and to find out the risk factors involved in the spread of anaplasmosis. A total of 210 blood samples were collected from equines from 2 sampling sites (Dera Ghazi Khan and Khanewal districts). Data on the animals' characteristics (age, species and gender) were collected through survey. PCR amplified the 577bp product specific for 16S rRNA gene of Anaplasma spp. in 9 blood samples (4.3% of total), [...
Clark KC, Kol A, Shahbenderian S, Granick JL, Walker NJ, Borjesson DL.Mesenchymal stem cell (MSC) therapy is being increasingly used to treat dogs and horses with naturally-occurring diseases. However these animals also serve as critical large animal models for ongoing translation of cell therapy products to the human market. MSC manufacture for clinical use mandates improvement in cell culture systems to meet demands for higher MSC numbers and removal of xeno-proteins (i.e. fetal bovine serum, FBS). While serum-free media (SFM) is commercially available, its affects on MSC phenotype and immunomodulatory functions are not fully known. The objective of this study...
Witkowski L, Cywinska A, Paschalis-Trela K, Crisman M, Kita J.Equine recurrent uveitis (ERU) has various etiologies, with Leptospira infection and genetic predisposition being the leading risk factors. Regardless of etiology, expression of ocular proteins associated with maintenance of the blood-ocular barrier is impaired in ERU. The recurring-remitting cycle of ERU repeatedly disrupts the blood-ocular barrier, allowing the previously immune-privileged ocular environment to become the site of a progressive local autoimmune pathology that ultimately results in tissue destruction and vision loss. The immune-mediated process involves humoral and cellular me...
Kol A, Wood JA, Carrade Holt DD, Gillette JA, Bohannon-Worsley LK, Puchalski SM, Walker NJ, Clark KC, Watson JL, Borjesson DL.Intravenous (IV) injection of mesenchymal stem cells (MSCs) is used to treat systemic human diseases and disorders but is not routinely used in equine therapy. In horses, MSCs are isolated primarily from adipose tissue (AT) or bone marrow (BM) and used for treatment of orthopedic injuries through one or more local injections. The objective of this study was to determine the safety and lymphocyte response to multiple allogeneic IV injections of either AT-derived MSCs (AT-MSCs) or BM-derived MSCs (BM-MSCs) to healthy horses. Methods: We injected three doses of 25 × 10(6) allogeneic MSCs fro...
Ranera B, Antczak D, Miller D, Doroshenkova T, Ryan A, McIlwraith CW, Barry F.Recently, it has been shown that mesenchymal stem cells (MSCs) do not express the major histocompatibility complex (MHC) II antigen and are able to inhibit proliferation of MHC-mismatched stimulated lymphocytes, enabling their use as in vivo allogeneic transplants. However, prior to clinical application of allo-MSCs, in vitro tests are required to confirm the safety of treatment protocols. Objective: To evaluate the immunosuppressive capabilities of equine bone-marrow-derived MSCs (BM-MSCs) on MHC-mismatched lymphocytes. Methods: In vitro experiment. Methods: Phytohaemagglutinin-stimulated per...
Valle E, Zanatta R, Odetti P, Traverso N, Furfaro A, Bergero D, Badino P, Girardi C, Miniscalco B, Bergagna S, Tarantola M, Intorre L, Odore R.The aim of the study was to evaluate markers of the acute phase response (APR) in eventing horses by measuring acute phase proteins (APP) (haptoglobin, Hp, and serum amyloid A, SAA), lysozyme, protein adducts such as pentosidine-like adducts (PENT), malondialdehyde adducts (MDA), hydroxynonenal adducts (HNE) and total advanced glycation/glycoxidation end products (AGEs), complete blood count and lymphocyte subpopulations (CD4+, CD8+ and CD21+) both at rest and at the end of an eventing competition. Blood samples were collected from eight Warmblood horses (medium age 10 ± 3) during an offici...
Iwaszko-Simonik A, Niedzwiedz A, Graczyk S, Slowikowska M, Pliszczak-Krol A.Recurrent airway obstruction (RAO) is an allergic disease of horses similar to human asthma, which is characterized by airway inflammation and activation of neutrophils, lymphocytes and platelets. Platelet activation and an increase in circulating platelet-leukocyte aggregates may lead to airway remodeling. The aim of this study was to investigate platelet status in RAO-affected horses based on the platelet morphology and platelet surface expression of CD41/61 and CD62P. Ten RAO-affected horses and ten healthy horses were included in this study. Blood samples were obtained to determine the pla...
Williams LB, Tessier L, Koenig JB, Koch TG.Multipotent mesenchymal stromal cells (MSC) are receiving increased attention for their non-progenitor immunomodulatory potential. Cryopreservation is commonly used for long-term storage of MSC. Post-thaw MSC proliferation is associated with a lag-phase in vitro. How this lag-phase affect MSC immunomodulatory properties is unknown. We hypothesized that in vitro there is no difference in lymphocyte suppression potential between quick-thawed cryopreserved equine cord blood (CB) MSC immediately included in mixed lymphocyte reaction (MLR) and same MSC allowed post-thaw culture time prior to inclus...
Vineyard KR, Warren LK, Kivipelto J.To determine the effect of different sources of dietary n-3 fatty acids (FA) on plasma and red blood cell (RBC) FA composition and immune response, 18 Quarter Horse yearlings were randomly and equally assigned to 1 of 3 treatments: encapsulated fish oil (n = 6), milled flaxseed (n = 6), or no supplementation (control, n = 6). Fish oil contained 15 g of eicosapentaenoic acid (C20:5n-3) and 12.5 g of docosahexaenoic acid (C22:6n-3), and flaxseed contained 61 g of alpha-linolenic acid (C18:3n-3) per 100 g of FA. Horses had free access to bahiagrass pasture during the active growing season and wer...
Mair TS, Batten EH, Stokes CR, Bourne FJ.The distribution of mucosa-associated lymphoid tissue along the equine respiratory tract was surveyed in light microscopical sections. Intra-epithelial lymphocytes and similar cells scattered in the lamina propria were identified in all sites from the nasal vestibule to bronchioles of 2 to 4 mm diameter. Isolated lymphoid patches, occasionally with nodules, were common in bronchioles, but the density of this bronchiole-associated lymphoid tissue (BRALT) varied between individual horses. Bronchus-associated lymphoid tissue (BALT) was infrequently encountered. In the upper respiratory tract, nod...
Prescott JF, Markham RJ, Johnson JA.Transformation of peripheral blood lymphocytes from pony foals vaccinated and subsequently infected with Corynebacterium equi was studied. Three foals were vaccinated on two occasions using a formalinized C. equi vaccine with aluminum hydroxide as an adjuvant. Three nonvaccinated foals served as controls. Foals were challenged intratracheally with 9 x 10(9) C. equi six weeks after the initial vaccination. Foals survived this infection for one to two weeks. Significant lymphocyte transformation in response to C. equi antigens was detected in two vaccinated foals at the third week after initial ...
Drummer HE, Reubel GH, Studdert MJ.Peripheral blood leukocytes were collected from 5 Thoroughbred horses and examined for the presence of EHV2 in sub-populations of mononuclear cells. Peripheral blood mononuclear cells were separated on Percoll gradients and then enriched for plastic adherent cells (predominantly monocytes), surface immunoglobulin positive (sIg+) B lymphocytes and T lymphocytes, using panning techniques. The purity of each cell population was assessed by fluorescence activated cell scanning. In an infectious centre assay, each cell population was inoculated onto equine foetal kidney monolayer cell cultures whic...
Stull CL, Spier SJ, Aldridge BM, Blanchard M, Stott JL.Little information exists on the immunological effects of transport or the use of supplements to minimise transport stress. Objective: To establish baseline ranges and evaluate immunophenotypic and functional changes associated with transport and a nutritional 'adaptogen' supplement. Methods: Horses received either supplement (n = 10) or placebos (n = 9) during the 30 day study. After 28 days in stalls, 12 horses (6 supplement; 6 placebo) were transported for 24 h, then unloaded and recovered. Venous blood samples were collected on Days 1, 14 and 28 to establish baselines, and on Days 28, 29 a...
Stull CL, Morrow J, Aldridge BA, Stott JL, McGlone JJ.Thirty-eight mature horses were assigned to one of two equal groups to evaluate two treatments consisting of either 24 hours of continuous road transport (24T) or two 12-hour periods of transport separated by off-loading, resting and feeding the horses for 12 hours (12/12T). A subset of six horses from each group served as controls for the other group. The horses were loaded into a commercial straight-deck trailer and travelled loose in one of two standard-sized compartments. After the journeys the horses were put back into their paddocks for a 24-hour recovery period. Venous blood samples wer...
Holcomb KE, Tucker CB, Stull CL.Housing recommendations for horses invariably include providing access to shade on hot, sunny days, but the potential benefits have not been scientifically studied. This experiment measured physiological, behavioral, and serological responses of horses confined individually to completely shaded (SH) or completely unshaded (SUN) drylot pens during the summer in Davis, CA. Twelve healthy adult horses in a crossover design experienced both treatments for 5 d each. Rectal temperature, respiration rate, skin temperature, and sweat scores were recorded hourly from 1230 to 1730 h daily. Observations ...
Noronha LE, Huggler KE, de Mestre AM, Miller DC, Antczak DF.To identify equine orthologs of major NK cell marker genes and utilize them to determine whether NK cells are present among the dense infiltration of lymphocytes that surround the endometrial cup structures of the horse placenta during early pregnancy. Methods: PCR primers were developed to detect the equine orthologs of NKP46, CD16, CD56, and CD94; gene expression was detected in RNA isolated from lymphocytes using standard 2-step reverse transcriptase (RT) PCR and products were cloned and sequenced. Absolute real-time RT-PCR was used to quantitate gene expression in total, CD3+, and CD3- per...
Naylor JM, Clark EG, Clayton HM.We examined 18 horses with clinical signs of chronic obstructive pulmonary disease (COPD) using physical examination, cytological and bacteriological evaluation of bronchoalveolar fluid, and percutaneous lung biopsy. In 16 cases, histological examination of lung tissue confirmed the diagnosis of COPD. Two horses were excluded: one had uncomplicated bacterial pneumonia and in the other a satisfactory lung biopsy could not be obtained. In horses with COPD, the most common historical complaint was coughing, which was reported in 88%. The most frequently detected abnormal finding on physical exami...
Tumas DB, Brassfield AL, Travenor AS, Hines MT, Davis WC, McGuire TC.Murine monoclonal antibodies, HB88A, B29A and DH59B separately identify the CD2 T lymphocyte molecule, a unique pan-B lymphocyte surface marker and a pan-granulocyte/monocyte surface molecule, respectively, in the horse. Specificity was shown by two-color immunofluorescent flow cytometry and immunofluorescent microscopy. MAb HB88A reacted with a 52 kDa pan-T lymphocyte molecule present on 75% +/- 7 of peripheral blood lymphocytes (PBL) (n = 15 horses). It also reacted with lymphocytes restricted to T lymphocyte dependent areas of lymph node and spleen. Specificity of mAb HB88A to CD2 was demon...
Mekuria ZH, El-Hage C, Ficorilli NP, Washington EA, Gilkerson JR, Hartley CA.Equine herpesvirus 5 (EHV5) is a commonly detected gammaherpesvirus, which, along with the closely related EHV2, constitute the only two known percaviruses that infect horses. Apart from detection in horse populations worldwide and the recent publication of the whole genome, there is little known about the biology and pathogenesis of this virus, with many assumptions made by parallels with EHV2. The long-term survival of gammaherpesviruses within infected hosts involves the establishment and maintenance of latency in selected cell and tissues types, particularly lymphocytes. A latent gammaherp...
Degroote RL, Hauck SM, Amann B, Hirmer S, Ueffing M, Deeg CA.Equine recurrent uveitis is a spontaneous, lymphocyte-driven autoimmune disease. It affects horses worldwide and presents with painful remitting-relapsing inflammatory attacks of inner eye structures eventually leading to blindness. Since lymphocytes are the key players in equine recurrent uveitis, we were interested in potential changes of their protein repertoire which may be involved in disease pathogenesis. To create a reference for differential proteome analysis, we first unraveled the equine lymphocyte proteome by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis ...
Bailey E.336 Standardbred mares and 334 Thoroughbred mares in the vicinity of Lexington, Kentucky, were lymphocyte typed for 11 allelic antigenic specificities of the equine lymphocyte antigen (ELA) system. The Standardbred mares were divided into a population of pacers and a population of trotters. Substantial differences in ELA gene frequencies were found between the 3 groups. When the distribution of antigens within populations were compared to Hardy-Weinberg equilibrium expectations, relatively good agreement was found.
Taylor SD, Leib SR, Carpenter S, Mealey RH.Vaccines preventing HIV-1 infection will likely elicit antibodies that neutralize diverse strains. However, the capacity for lentiviruses to escape broadly neutralizing antibodies (NAbs) is not completely understood, nor is it known whether NAbs alone can control heterologous infection. Here, we determined that convalescent immune plasma from a horse persistently infected with equine infectious anemia virus (EIAV) neutralized homologous virus and several envelope variants containing heterologous principal neutralizing domains (PND). Plasma was infused into young horses (foals) affected with se...
Lewis SS, Valberg SJ, Nielsen IL.Although immune-mediated myositis (IMM) is commonly reported in other species, this condition is poorly described in horses. Objective: IMM occurs in horses. Methods: Thirty-seven horses with suspected IMM were included in the study. Methods: The database of the Neuromuscular Diagnostic Laboratory was reviewed to identify 37 horses with muscle biopsies characterized by lymphocytic infiltrates. A retrospective standardized questionnaire regarding clinical signs and response to treatment was answered by horse owners. Results: Horses with suspected IMM were predominantly of Quarter Horse bloodlin...
Alexander AJ, Bailey E, Woodward JG.Fourteen Standardbred horses homozygous for one of six equine lymphocyte antigen (ELA) specificities (A1, A3, A4, A5, A6, or A10) were analyzed by Southern blot hybridization using DNA probes derived from the mouse major histocompatibility complex (MHC). Total genomic DNA from peripheral lymphocytes was digested with the restriction enzymes Hind III, Pvu II, or Eco RI. Twenty-three to thirty-three bands were generated for individual horses with the class I cDNA probe. The resulting band patterns revealed 12-14 nonpolymorphic fragments, which is consistent with the highly conserved Qa/Tla genes...
McFarlane D, Sellon DC, Gaffney D, Hedgpeth V, Papich M, Gibbs S.To compare hematologic and serum biochemical variables and plasma ACTH concentration between healthy horses 5 to 12 years old and those more than 20 years old. Methods: 30 healthy horses 5 to 12 years old and 30 healthy horses more than 20 years old. Methods: Venous blood was collected from all horses, and CBC and serum biochemical analysis were performed for each horse. Plasma ACTH concentration was determined by radioimmunoassay. Student's paired t-test or the Mann-Whitney rank sum test was used to compare values between control and aged horse groups. Results: Compared with values for contro...
Pacheco AP, Paradis MR, Hoffman AM, Hermida P, Sanchez A, Nadeau JA, Tufts M, Mazan MR.Despite the increasing number of geriatric horses attended by veterinarians, there is a lack of understanding of aging-related changes on the respiratory system of horses. Objective: To identify aging-related changes on the respiratory function and bronchoalveolar lavage fluid (BALF) cytology of horses. Methods: Fifteen healthy young adult (2-11 years) and 16 healthy aged (≥20 years) horses. Methods: The respiratory system was examined by measurement of arterial blood gases (ABG), use of respiratory inductive plethysmography (RIP) for assessment of breathing pattern and ventilatory paramet...
Antczak DF, Miller JM, Remick LH.Evidence is presented for a reproducible maternal immune response to histocompatibility antigens during equine pregnancy. Mares were stimulated as a result of pregnancy to produce cytotoxic antibodies to paternal lymphocyte alloantigens. The majority of these antibodies were directed against antigens of the equine lymphocyte antigen (ELA) system, which is the major histocompatibility complex (MHC) of the horse. In 16 experimental pregnancies produced using 12 mares and 4 stallions which had been typed for ELA antigens, there was correlation between ELA incompatibility between sire and dam and ...
Kakhniashvili I, Filicko J, Kraft WK, Flomenberg N.Antithymocyte globulins (ATG) are purified, concentrated preparations of polyclonal immunoglobulin G from hyperimmune serum of horses or rabbits immunized with human thymus lymphocytes. Both the horse and the rabbit products induce immunosuppression as a result of lymphocyte depletion and immune modulation. The exact mechanism of action is unknown but may include T-cell clearance from the circulation and modulation of T-cell activation, homing, and cytotoxic activities. Both horse and rabbit ATG include multiple antibodies against T-cell surface antigens and have been used extensively in allog...
Razzaq F, Khosa T, Ahmad S, Hussain M, Saeed Z, Khan MA, Shaikh RS, Ali M, Iqbal F.The present study was designed to optimize a PCR-RFLP protocol for the molecular detection of Anaplasma sp. and to compare its prevalence in blood samples of equines from Southern Punjab (Pakistan) and to find out the risk factors involved in the spread of anaplasmosis. A total of 210 blood samples were collected from equines from 2 sampling sites (Dera Ghazi Khan and Khanewal districts). Data on the animals' characteristics (age, species and gender) were collected through survey. PCR amplified the 577bp product specific for 16S rRNA gene of Anaplasma spp. in 9 blood samples (4.3% of total), [...
Steinbach T, Bauer C, Sasse H, Baumgärtner W, Rey-Moreno C, Hermosilla C, Damriyasa IM, Zahner H.The study was undertaken to evaluate adverse effects of larvicidal treatment in horses naturally infected with cyathostomins. Out of 24 ponies kept on pasture, four animals were housed in September and anthelmintically cured to serve as worm-free controls (group C-0). The others were housed in December. Eight animals each were treated 8 weeks later with 5 x 7.5mg/kg fenbendazole (FBZ) or 1 x 0.4 mg/kg moxidectin (MOX). Four animals remained untreated (group C-i). Two, 4, 6 and 14 days after the end of treatment two animals of each of the treated groups were necropsied together with group C-0 a...
Guerriero V, Raynes DA.Cultured bovine, equine, ovine and chicken lymphocytes responded to heat stress by the increased synthesis of a specific set of proteins known as heat stress proteins (HSP). Proteins with molecular weights of 70 and 90 kDa were synthesized in all species. Additional proteins were found in bovine, ovine and chicken lymphocytes. A time course of induction showed an increased synthesis of some of these proteins with only 30 min of heat stress and of several proteins with 60 min of heat stress. A specific monoclonal antibody was used to identify HSP70 as one of the stress proteins in bovine lympho...
Ryan C, Giguère S.The objectives of this study were to compare relative vaccine-specific serum immunoglobulin concentrations, vaccine-specific lymphoproliferative responses, and cytokine profiles of proliferating lymphocytes between 3-day-old foals, 3-month-old foals, and adult horses after vaccination with a killed adjuvanted vaccine. Horses were vaccinated intramuscularly twice at 3-week intervals with a vaccine containing antigens from bovine viral respiratory pathogens to avoid interference from maternal antibody. Both groups of foals and adult horses responded to the vaccine with a significant increase in ...
Prescott JF, Johnson JA, Markham RJ.Four month-old foals were infected orally with 75 mL of a suspension of 5.0 x 10(8)Corynebacterium equi per mL. Two foals were killed after ten days and had scanty number of C. equi in the caeco-colic lymph nodes. No C. equi were recovered from the other two foals, killed 20 days after infection. No gross pathological change was detected in these four foals, although mild microscopic lesions were seen in the ileum of one foal. Results of lymphocyte blastogenesis using peripheral blood lymphocytes and C. equi antigens showed, however, that lymphocytes became sensitized to C. equi following this...
McGuire TC, O'Rourke KI, Perryman LE.Virus replication and subsequent viremia are clearly correlated with clinical disease in EIAV infected horses. Termination of viremia is the result of specific immune responses. Recurrences of viremia are associated with antigenic variation of neutralization-sensitive epitopes. Immunosuppression experiments indicate that the eventual control of EIAV and development of carriers is mediated by the immune system. Even though the immune response to EIAV has a protective effect, immune responses also cause some of the lesions. At least one part of the anemia, erythrocyte destruction, is caused by t...
Henry MM, Moore JN.Increasing evidence has demonstrated the importance of monocyte procoagulant activity (PCA) in the pathogenesis of coagulopathies in a variety of diseases. Because endotoxin precipitated coagulopathies are common sequelae to intestinal ischemia/endotoxemia in the equine species, we investigated the ability of equine peripheral blood monocytes to express PCA. Monocytes isolated from five healthy adult horses were incubated in vitro with Escherichia coli endotoxin (10 micrograms), and the PCA was measured by the ability of cellular lysates to accelerate the clotting times of equine plasma in a m...
Jacks S, Giguère S, Prescott JF.Rhodococcus equi is a facultative intracellular pathogen that causes pneumonia in foals but does not induce disease in adult horses. Virulence of R. equi depends on the presence of a large plasmid, which encodes a family of seven virulence-associated proteins (VapA and VapC to VapH). Eradication of R. equi from the lungs depends on gamma interferon (IFN-gamma) production by T lymphocytes. The objectives of the present study were to determine the relative in vivo expression of the vap genes of R. equi in the lungs of infected foals, to determine the recall response of bronchial lymph node (BLN)...
Montgomery JB, Wichtel JJ, Wichtel MG, McNiven MA, McClure JT, Markham F, Horohov DW.The effects of selenium (Se) supplementation and source on equine immune function have not been extensively studied. This study examined the effects of oral Se supplementation and Se source on aspects of innate and adaptive immunity in horses. Fifteen horses were assigned to 1 of 3 groups (5 horses/group): control, inorganic Se (sodium selenite), organic Se (Se yeast). Immune function tests performed included: lymphocyte proliferation in response to mitogen concanavalin A, neutrophil phagocytosis, antibody production after rabies vaccination, relative cytokine gene expression in stimulated lym...
Valle E, Zanatta R, Odetti P, Traverso N, Furfaro A, Bergero D, Badino P, Girardi C, Miniscalco B, Bergagna S, Tarantola M, Intorre L, Odore R.The aim of the study was to evaluate markers of the acute phase response (APR) in eventing horses by measuring acute phase proteins (APP) (haptoglobin, Hp, and serum amyloid A, SAA), lysozyme, protein adducts such as pentosidine-like adducts (PENT), malondialdehyde adducts (MDA), hydroxynonenal adducts (HNE) and total advanced glycation/glycoxidation end products (AGEs), complete blood count and lymphocyte subpopulations (CD4+, CD8+ and CD21+) both at rest and at the end of an eventing competition. Blood samples were collected from eight Warmblood horses (medium age 10 ± 3) during an offici...
