Macrophages are a type of white blood cell found in horses that play a significant role in the immune system. They are involved in the detection, phagocytosis, and destruction of bacteria and other harmful organisms. Additionally, macrophages contribute to tissue homeostasis and repair by removing dead cells and stimulating tissue regeneration. In horses, macrophages are distributed throughout various tissues, including the liver, lungs, and lymph nodes, where they help orchestrate the body's response to infection and injury. This page compiles peer-reviewed research studies and scholarly articles that explore the function, regulation, and clinical implications of macrophages in equine health.
Perron Lepage MF, Gerber V, Suter MM.Subacute interstitial pneumonia with diffuse alveolar damage, marked macrophage infiltration, and intracellular Pneumocystis carinii cysts is described in a 3-month-old Swiss warmblood foal. Clinically, the disease was characterized by sudden onset of respiratory distress with fatal outcome. Based on serum immunoglobulin G (IgG), IgA, and IgM values, no humoral immunosuppression was detected. Spleen, thymus, and bronchial lymph nodes did not reveal lymphoid depletion, as assessed by immunohistochemical staining of CD-3-positive cells. Immunopathogenesis of pulmonary infections with intracellul...
Murabayashi H, Hondo E, Kitamura N, Furuoka H, Taguchi K, Nambo Y, Yamada J.One of the most attractive characteristics of a horse testis is the change of the weight during development. As the testicular weight changes and the number of Leydig cells decreases, pigments appear in interstitial tissues. In the present study, the characteristics of the pigments found in the interstitial tissues were examined histochemically and ultrastructurally. Specific stainings indicated that the pigmented granules showed almost all of the histological and histochemical characteristics of ceroid or ceroid-like pigment. The cells showed positive reaction for acid phosphatase while the p...
Pérez J, Mozos E, Martín MP, Day MJ.The distribution of T (CD3), B (CD79) lymphocytes, immunoglobulin (IgG, IgM and IgA)-producing plasma cells, macrophages (lysozyme, Mac387) and MHC Class II antigen was analysed in the inflammatory infiltrate associated with 19 equine squamous cell carcinomas (SCCs) and six cases of precancerous lesions (actinic keratosis). The SCCs came from the penis (11 cases), conjunctiva (four), skin (two), nasal cavity (one) and oral cavity (one). Seven cases were well-differentiated and 12 moderately differentiated. Nine cases showed no invasion of peritumoral deep tissues (locally invasive), whereas th...
Oaks JL, Ulibarri C, Crawford TB.Equine infectious anaemia virus (EIAV) infection of horses is characterized clinically by recurrent episodes of fever, thrombocytopenia and anaemia. In vivo, the only site of virus replication that has been previously demonstrated for EIAV is the tissue macrophage. In this study, in situ hybridization for EIAV was combined with immunohistochemistry for cell-type-specific markers to identify infected endothelial cells. EIAV-infected endothelial cells and macrophages were detected in horses infected with either virulent wild-type or with weakly virulent tissue culture-adapted strains of EIAV. Th...
Shikichi M, Kitamura HP, Yanase H, Konno A, Takahashi-Iwanaga H, Iwanaga T.The synovial membrane displays a superficial cellular lining composed of two types of synoviocytes: "absorptive" macrophages (type A cells) and "secretory" fibroblast-like cells (type B cells). The types are intermingled and extend a variety of processes, rendering the cellular architecture of the synovial membrane difficult to visualize. Previous electron microscopic and histochemical studies failed to demonstrate the entire shape of synoviocytes, except our immunohistochemical study for protein gene product 9.5 in the horse joint. The present SEM study is the first to demonstrate the three-d...
Raabe ML, Issel CJ, Montelaro RC.We have previously demonstrated a high propensity for enhancement of virus replication and disease resulting from experimental immunization of ponies with a baculovirus recombinant envelope (rgp90) vaccine from equine infectious anemia virus (EIAV). The current studies were undertaken to examine the correlation between the observed in vivo vaccine enhancement and in vitro assays for antibody-dependent enhancement (ADE) of EIAV replication. Toward this goal an optimized EIAV in vitro enhancement assay was developed using primary equine macrophage cells and used to evaluate the enhancement prope...
Furuoka H, Hasegawa M, Kobayashi Y, Matsui T.A male 14-year-old Arab horse was pathologically diagnosed as equine motor neuron disease (EMND), which was kept as a breeding horse on a farm in Tokachi district of Hokkaido in Japan. On examination of the peripheral nerves, the most characteristic feature was Wallerian-type degeneration revealed by myelinoclasis associated with myelin ovoids which were sometimes infiltrated by macrophages. The other abnormalities were axonal swellings which were surrounded by thin myelin sheaths. Ultrastructurally, the axonal swelling was due to an accumulation of neurofilaments, and was accompanied by a thi...
Carrasco L, Sánchez C, Gómez-Villamandos JC, Laviada MD, Bautista MJ, Martínez-Torrecuadrada J, Sánchez-Vizcaíno JM, Sierra MA.African horse sickness (AHS) is a disease of equids, characterized by severe pulmonary oedema and caused by an orbivirus. To determine the role of pulmonary intravascular macrophages (PIMs) in the development of pulmonary microvascular changes in this disease, five horses were given an intravenous inoculation of 10(6)TCID50of serotype 4 of AHS virus. Viral replication was detected in endothelial cells, PIMs, interstitial macrophages and fibroblasts. Alveolar and interstitial oedema, and changes in pulmonary microvasculature, consisting mainly of the sequestration of neutrophils and the formati...
Hammond RA, Hannon R, Frean SP, Armstrong SJ, Flower RJ, Bryant CE.To determine the amount of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) enzymes induced in vitro in equine alveolar macrophages in response to lipopolysaccharide (LPS). Sample Population-Alveolar macrophages obtained from 12 horses. Methods: Alveolar macrophages were collected by bronchoalveolar lavage from 12 horses and incubated for 6 hours with LPS (0.001 to 10 microg/ml) or vehicle. Total RNA was extracted and purified. After first-strand cDNA synthesis, mRNA induction was measured, using a polymerase chain reaction (PCR) technique for COX-2, iNOS, and glyceraldehyde...
Banks EM, Kyriakidou M, Little S, Hamblin AS.Leucocytes in the lung epithelium play an important role in the ability of an animal to respond appropriately to inhaled pathogens. The distribution of lymphoid and myeloid cells associated with the lung epithelium was examined immunohistochemically throughout the respiratory tract of four horses, comprising two adults from an abattoir, one pregnant mare, and her fetus (in the final stage of gestation). Cross and tangential cryosections were labelled with monoclonal antibodies against T-cell, B-cell, macrophage/dendritic myeloid cell, and major histocompatibility Class (MHC) II surface antigen...
Franchini M, Gilli U, Akens MK, Fellenberg RV, Bracher V.Chronic obstructive pulmonary disease (COPD) is defined as a chronic obstructive inflammatory disease affecting the small airways associated with hay dust exposure (Lowell, F.C., 1964. Observation on heaves. An asthma like syndrome in the horse, J. Allergy 35, 322-330). The disease corresponds histopathologically to a chronic bronchiolitis (Gerber, H., 1973. Chronic pulmonary disease in the horse, Equine Vet. J. 5, 26-33; Winder, N.C., Grünig, G., Hermann, M., Howald, B., von Fellenberg, R., 1989. Comparison of respiratory secretion cytology and pulmonary histology in horses, J. Vet. Med., A3...
Kalsow CM, Albrecht TR, Steinberg NP, Lunn DP.Immunohistochemical evaluation of equine tissue necessitates the use of antibodies reactive with cells from a heterogeneous population. Lymphoid tissues from 12 horses were fixed in Bouin's fluid, ethanol or formalin and examined for immunohistochemical reactivity with anti-equine and anti-human monoclonal antibodies (MAbs) specific for MHC Class II antigens, T and B lymphocytes, and macrophages. Only a few of the anti-equine MAbs tested were reactive with fixed, paraffin wax-embedded tissue. Anti-human MAbs expanded the desired range of reactivity and increased the consistency in different an...
Raidal SL, Bailey GD, Love DN.Flow cytometric techniques were developed for the evaluation of oxidative burst activity in equine peripheral blood neutrophils and lymphocytes, as well as bronchoalveolar lavage derived pulmonary alveolar macrophages and lymphocytes. The oxidation of dichlorofluorescin was measured by the increased fluorescence of cells stimulated with phorbol myristate acetate or a variety of other stimulants. Flow cytometry was a suitable method for the evaluation of the intracellular oxidation in all cell populations evaluated. Analysis was rapid and cell separation before analysis was not required. Hetero...
Raidal SL, Bailey GD, Love DN.Flow cytometry was used to assess the phagocytosis of fluorescent-labelled bacteria by equine peripheral blood neutrophils and pulmonary alveolar macrophages. Cell populations were prepared from venous blood following ammonium chloride lysis and from washed bronchoalveolar lavage derived samples. Discrete clusters of cells, corresponding to different leucocyte groups, were readily identified on the basis of differing light scattering properties and could thus be discriminated, negating the need for prior cell separation. Cells able to associate with fluorescent-labelled bacteria (by attachment...
Wohlsein P, Pohlenz JF, Salt JS, Hamblin C.African horse sickness virus (AHSV) antigen was demonstrated immunohistochemically in formalin-fixed, paraffin-embedded sections of tissues collected from three ponies suffering from the peracute form of the disease and from one pony affected by the fever form. The pattern of the antigen distribution indicated a particular organ tropism characterised by an accumulation of AHSV antigen in cardio-pulmonary tissues of the animals with the peracute disease and in the spleen of the pony with the fever form. AHSV antigen was identified in endothelial cells of small blood vessels, particularly capill...
Li F, Puffer BA, Montelaro RC.Equine infectious anemia virus (EIAV) contains the simplest genome among lentiviruses in that it encodes only three putative regulatory genes (S1, S2, S3) in addition to the canonical gag, pol, and env genes, presumably reflecting its limited tropism to cells of monocyte/macrophage lineage. Tat and Rev functions have been assigned to S1 and S3, respectively, but the specific function for the S2 gene has yet to be determined. Thus, the function of S2 in virus replication in vitro was investigated by using an infectious molecular viral clone, EIAVUK. Various EIAVUK mutants lacking S2 were constr...
Meyer TS, Fedde MR, Gaughan EM, Langsetmo I, Erickson HH.Exercise-induced pulmonary haemorrhage (EIPH) causes serious economic losses in the horse racing industry. Endoscopic examination indicates that 40-90% of horses exhibit EIPH following sprint exercise, but the limitations of the endoscope prevent diagnosis in many horses. Bronchoalveolar lavage (BAL) was utilised to detect red blood cells (RBCs) in the terminal airways in 6 horses. Two lavages were performed at weekly intervals prior to exercise, one within 90 min after exercise, and 5 at weekly intervals after exercise. The horses were exercised strenuously at 12.5-14.6 m/s on a treadmill (3 ...
Oaks JL, McGuire TC, Ulibarri C, Crawford TB.The equine infectious anemia virus (EIAV) often results in lifelong subclinical infection following early episodes of clinical disease. To identify the cellular reservoirs of EIAV during subclinical infection, horses were infected with EIAV and allowed to develop subclinical infections. Horses with acute disease served as a basis for comparison. The tissue distribution, replication status, location of infected cells, and viral load were characterized by PCR for proviral DNA and reverse transcriptase PCR for viral RNA, in situ hybridization, and in situ PCR. Proviral DNA was widespread in tissu...
Hills BA, Ethell MT, Hodgson DR.This study was undertaken to determine whether glucocorticosteroids promote the secretion of lubricating surfactant, i.e. surface-active phospholipid (SAPL), into the joint. A standard clinical dose (100 mg) of methylprednisolone acetate (MPA) in 2.5 ml of saline was injected into the load-bearing right radiocarpal joint of five horses and 2.5 ml of saline injected into each of the contralateral joints used as controls. Synovial fluid (SF) was aspirated from all 10 joints before injection and at intervals of 16 and 32 h after injection, and then analysed by standard methods. All test joints sh...
Raabe MR, Issel CJ, Montelaro RC.Equine infectious anemia virus (EIAV) has been shown to infect cells of monocyte/macrophage lineage. These primary cells are intrinsically difficult to obtain, to purify and to culture in vitro for extended periods of time. As a result, most in vitro studies concerning this lentivirus make use of primary equine fibroblasts or transformed canine or feline cell lines. We describe methods that yield reproducibly pure cultures of equine blood monocytes from peripheral blood mononuclear cells. The in vitro differentiation of these cells into mature equine macrophage was verified using various cytoc...
Caplazi P, Ehrensperger F.Borna disease (BD) has been recognized as a virally induced T-cell dependent immunopathological disorder of the central nervous system (CNS), as shown by experimental infection of rats with Borna disease virus (BDV). In contrast to the rat model, little is known about the pathogenesis of spontaneous BD in sheep and horses. The present study describes the brain lesions of 12 ovine and 11 equine cases of naturally occurring BD. A set of monoclonal and polyclonal antibodies was used in order to determine the cells operative in encephalitic lesions and to detect expression of MHC-I and MHC-II prod...
Smith TA, Davis E, Carpenter S.Lentiviruses replicate in cells of the immune system, and activation of immune cells has been shown to modulate virus replication. To determine the effects of macrophage activation on replication of equine infectious anaemia virus (EIAV), primary horse macrophage cultures (HMCs) were established from 20 different horses, infected with an avirulent strain of EIAV, and stimulated with 5 microg/ml of bacterial endotoxin. Supernatants collected from HMCs were assayed for the presence of tumour necrosis factor (TNF-alpha) and for production of infectious virus. Results indicated that EIAV replicati...
Siedek E, Little S, Mayall S, Edington N, Hamblin A.Despite their important role in initiating T-cell responses in other species, dendritic cells have not been studied in the horse. A method for isolating blood dendritic cells by adherence and metrizamide gradients was adapted to equine cells. A number of monoclonal antibodies (mAbs), including some which label dendritic cells in other species, were tested for immunochemical reactivity with the isolated blood dendritic cells, and sections of lymph node and spleen. 62 +/- 6% of the isolated blood cells were MHC Class II positive and had typical dendritic cell morphology and only 4 +/- 2% contain...
Swardson CJ, Lichtenstein DL, Wang S, Montelaro RC, Kociba GJ.To characterize infection of bone marrow-derived macrophages (BMDM) with equine infectious anemia virus (EIAV) by determining virus production, effects on viability, and induction of cytokines. Methods: BMDM obtained from bone marrow of 6 clinically normal adult horses. Methods: BMDM were infected with EIAV at a multiplicity of infection of 8. Cell viability, percentage of cells with detectable viral protein, reverse transcriptase activity, and concentrations of infective virus (focus-forming units/ml), interleukin 6, and tumor necrosis factor-alpha were measured in culture supernatant samples...
Wohlsein P, Pohlenz JF, Davidson FL, Salt JS, Hamblin C.The distribution of viral antigen was studied in various tissues of three ponies, aged 3-4 years, infected experimentally with a virulent strain of African horse sickness virus (AHSV) serotype 4. Tissues were collected from the animals in the terminal stage of the peracute form of the disease and from one noninfected horse, included as a control. A polyclonal antibody with specificity for AHSV, plus the nonstructural protein NS2, was used in a sensitive avidin-biotin-peroxidase-complex (ABC) method performed on formalin-fixed, paraffin-embedded tissue sections. AHSV antigen was located primari...
Hondalus MK.Inhalation of the soil-borne organism, Rhodococcus equi, can lead to a chronic and severe pyogranulomatous pneumonia in young horses and immunocompromised people. In addition, ulcerative colitis is a common sequela to infection in foals, and dissemination from the lung to other body sites is not uncommon in either the horse or man. Although the facultative intracellular bacterium is susceptible to neutrophil-mediated killing, it is able to resist innate macrophage defenses and establish residence within the intracellular environment of that phagocyte. Definitive virulence factors of R. equi ha...
Longworth KE.Pulmonary intravascular macrophages are an important part of the mononuclear phagocyte system in some species of mammals, mainly sheep and other ruminants, pigs, and horses. These cells phagocytize foreign particles, cell debris and pathogens that pass through the pulmonary circulation. Species with intravascular macrophages localize intravenously injected tracer particles and bacteria predominantly in the lung rather than the liver, and exhibit pulmonary hypertension when these cells are activated. Both in vivo and in vitro studies show that pulmonary intravascular macrophages have distinct s...
Shao H, Robek MD, Threadgill DS, Mankowski LS, Cameron CE, Fuller FJ, Payne SL.The macrophage tropic lentivirus, equine infectious anemia virus (EIAV), encodes a dUTPase in the pol gene that is required for efficient replication in macrophages. Two naturally occurring variants of the enzyme were expressed as recombinant proteins in Escherichia coli; metal chelate affinity chromatography was used to purify histidine-tagged recombinant enzymes to greater than 80% homogeneity in a single chromatographic step. Biochemical and enzymatic analyses of these preparations suggest that this method yields dUTPase that is suitable for detailed mutational analysis. Specific activities...
Koivunen AL, Maisi P, Konttinen YT, Sandholm M.The gelatinolytic activity in tracheal aspirates (TA) of horses with chronic obstructive pulmonary disease (COPD) was analyzed using SDS-PAGE-gelatin-gel electrophoresis (zymography) and compared to TAs from healthy controls. The 110-90 kD MMP-9 type gelatinase was high in symptomatic disease phases (permanent disease 0.46 +/- 0.15, p < 0.001; or intermittent disease 0.47 +/- 0.12, p < 0.001) compared to healthy controls (0.10 +/- 0.07). Similarly, the overall gelatinolytic activity, the activity in high-mw gelatinolytic bands (210-190 and 150 kD) and in proteolytically processed fragments in ...
Liu C, Cook FR, Cook SJ, Craigo JK, Even DL, Issel CJ, Montelaro RC, Horohov DW.Distinct from human lentivirus infection, equine infectious anemia virus (EIAV)-infected horses will eventually enter an inapparent carrier state in which virus replication is apparently controlled by adaptive immune responses. Although recrudescence of disease can occur after immune suppression, the actual immune correlate associated with protection has yet to be determined. Therefore, EIAV provides a model for investigating immune-mediated protective mechanisms against lentivirus infection. Here, we have developed a method to monitor EIAV-envelope specific cellular immunity in vivo. An EIA c...
Lapsina S, Riond B, Hofmann-Lehmann R, Stirn M.Bronchoalveolar lavage (BAL) is a diagnostic method for the assessment of the lower respiratory airway health status in horses. Differential cell count and sometimes also total nucleated cell count (TNCC) are routinely measured by time-consuming manual methods, while faster automated methods exist. The aims of this study were to compare: 1) the Sysmex XN-V body fluid (BF) mode with the manual techniques for TNCC and two-part differential into mononuclear and polymorphonuclear cells; 2) the Olympus VS200 slide scanner and software generated deep-learning-based algorithm with manual techniques f...
Lowe J, Clifford L, Julian A, Koene M.The data presented in this paper are derived from an in vivo study performed to characterize the nature of the synovial integration process of a 2.5% synthetic cross-linked injectable polyacrylamide hydrogel (2.5 iPAAG) injected IA in horses. Methods: 10 healthy horses not suffering from OA or signs of joint disease were administered 50 or 100 mg 2.5 iPAAG in a total of 13 metacarpophalangeal or middle carpal joints. Methods: Injected joints were examined at 0, 14, 42, and/or 90 days postinjection. Parameters investigated included clinical examination, synoviocentesis, gross pathology, histolo...
Sponseller BA, Clark SK, Gilbertie J, Wong DM, Hepworth K, Wiechert S, Chandramani P, Sponseller BT, Alcott CJ, Bellaire B, Petersen AC, Jones DE.Reactive intermediates contribute to innate immunity by providing phagocytes with a mechanism of defense against bacteria, viruses and parasites. To better characterize the role of CD154 in the production of reactive intermediates, we cloned and expressed recombinant equine CD154 (reqCD154) in Chinese Hamster Ovary (CHO). In co-culture experiments, CHO cells ectopically expressing reqCD154 elicited superoxide production in monocyte-derived macrophages (MDM). Collectively, our results indicate that regulation of CD154 expression plays a role in innate host defenses.
Pargass IS, Wills TB, Davis WC, Wardrop KJ, Alperin DC, Hines SA.There is a distinct age-associated susceptibility of horses to Rhodococcus equi infection. Initial infection is thought to occur in the neonatal and perinatal period, and only foals less than 6 months of age are typically affected. R. equi is closely related and structurally similar to Mycobacterium tuberculosis, and causes similar pathologic lesions. Protective immune responses to M. tuberculosis involve classical major histocompatibility complex (MHC)-restricted T cells that recognize peptide antigen, as well as MHC-independent T cells that recognize mycobacterial lipid antigen presented by ...
Karagianni AE, Summers KM, Couroucé A, Depecker M, McGorum BC, Hume DA, Pirie RS.Mild-to-moderate equine asthma is prevalent in young racehorses, particularly early in their training period. Although the precise etiopathogenesis remains undetermined, it is possible that the susceptibility of this population might partly reflect an exercise-associated immune derangement at the level of the airway. We performed a genome-wide basal gene expression scan on alveolar macrophages (AMs) isolated from Standardbred racehorses before and after commencement of competition race training with a view to identifying any exercise-associated gene expression modulation consistent with functi...
Anderson NV, DeBowes RM, Nyrop KA, Dayton AD.Twelve horses comprised 3 treatment groups; all horses in 2 of the groups had recently been transported and had clinical and laboratory evidence of respiratory tract infection, with equine influenza type 2 virus being the principal pathogen. Mononuclear phagocytes and other leukocytes from blood, lung, and peritoneal cavity were studied in phagocytosis and erythrocyte-antibody (EA) rosette assays. Total numbers of pulmonary alveolar macrophages were increased over control values in bronchoalveolar lavage (BAL) fluid of group 3 horses after recovery from influenza (P less than 0.02), whereas th...
Ramsey DT, Whiteley HE, Gerding PA, Valdez RA.An 11-year-old Quarter Horse gelding was evaluated because of a persistent, raised band of 1- to 2-mm subepithelial plaques of the left cornea. Cytologic examination of corneal scrapings revealed numerous eosinophils and segmented neutrophils, with few mast cells, plasma cells, and lymphocytes. Bacteriologic culture yielded sparse growth of alpha-hemolytic Streptococcus and Staphylococcus spp. Histologically, the plaques consisted of subepithelial foci of fragmented and degenerated collagen fibers infiltrated by eosinophils and neutrophils, with few lymphocytes, plasma cells, and macrophages. ...
Schlocker N, Gerber-Bretscher R, von Fellenberg R.In a search of viral agents in pulmonary macrophages of horses with chronic pulmonary disease, equine herpesvirus 2 was found to be unique. In 8 of 9 horses with chronic pulmonary disease, antigens of equine herpesvirus 2 were detected by indirect immunofluorescence staining of scattered foamy macrophages immediately after harvesting by bronchoalveolar lavage and fractionation on metrizamide gradients. In a healthy horse, antigens were not found. After 1 week of cultivation of bronchoalveolar lavage cells from a second group of 9 horses with chronic pulmonary disease, viral antigens were detec...
Aleman M.Inflammatory myopathies or myositis encompass diseases characterized by the presence of inflammatory cellular infiltrates, mainly polymorphonuclear cells and/or lymphocytes, in muscle. This is in contrast to most forms of muscle disease characterized by myodegeneration that results in macrophage infiltration. Inflammatory myopathies could have infectious or noninfectious causes. Noninfectious causes consist of primary (genetic, autoimmune) or acquired immune-mediated disease. Focal, multifocal or diffuse, acute or recurrent forms of disease can occur. This article will mainly review immune-med...
Arrighi S, Romanello MG, Domeneghini C.Following previous studies about the ultrastructure of male genital tract in parental species, a comparative study of epididymis of one of the possible hybrids, the mule, has been undertaken. Apart from small differences, general features of epididymal epithelium in the mule are similar to those of parental species. However, extension of our studies from the donkey to the horse to the hybrid permits a deeper insight into the morphology of this tract of excurrent duct. In the meantime, it is possible to evidence some features, sometimes shared with other species if taken separately, which in th...
Sano Y, Matsuda K, Okamoto M, Takehana K, Hirayama K, Taniyama H.In horse, the characterizations of hyalocytes under the steady state are still unclear. Therefore, we investigated characterizations of hyalocytes in normal equine eyes by their immunohistochemical phenotype, histomorphology and distribution. Thirty-one eyes from 18 horses, divided into 4 groups (G) by age, were used: early (G1) and late gestation (G2) fetuses, 1- to 3-year-old (G3) and 8- to 24-year-old (G4) horses. Equine hyalocytes were histologically classified into 4 types, and they immunohistochemically expressed MHC II and CD163. Hyalocytes were detected on and/or around ciliary process...
Winder NC, Grünig G, Hermann M, von Fellenberg R.The concentration of soluble fibrinogen derivatives (SFD) and protease and procoagulant activities were determined in cell-free supernatants of equine respiratory secretions obtained from horses with chronic pulmonary disease. The concentration of neutrophils was estimated from direct smears of the secretions. Lung specimens and smears of the secretions were evaluated for the presence of fibrin or fibrinogen by use of immunohistochemical methods. Thirty-five of 80 specimens tested contained SFD. Respiratory secretions from horses with moderate or severe chronic pulmonary disease contained SFD ...
Dyer RM, Leid RW.Isolated equine alveolar macrophages were shown to generate a luminol-dependent light response when challenged with a phagocytic stimulus. The chemiluminescent response was not detected with luminol prepared at 1.0 x 10(-5) or 1.0 x 10(-4) molar concentrations, but was readily quantitated when used at a 1.0 x 10(-3) molar concentration. Challenge of the alveolar macrophages with latex particles or with equine IgG-coated sheep red blood cells elicited the luminol-dependent light response, whereas unchallenged equine alveolar macrophages or those challenged with unopsonized erythrocytes failed t...
Nixon AJ, Stashak TS, Smith FW, Norrdin RW.Carbon fibre-polylactic acid composites and monofilament non-absorbable suture material were compared for the repair of surgically transected superficial digital flexor tendons in 10 horses. All surgical wounds healed by first intention. The repaired tendons were enlarged, the carbon implanted tendons being larger than those sutured. The horses were killed at six, eight, 12,20 or 24 weeks. Greater fibrous thickening occurred in tendons repaired with carbon fibre, especially at 12 weeks postoperatively. Carbon fibre incited a greater histological response with macrophages, lymphocytes, plasma c...
Kumar P, Timoney JF.The stratified squamous epithelium of the lingual tonsil of five young horses was infiltrated with CD4 and CD8 positive cells, which were very numerous in the crypt reticular epithelium along with macrophages and IgGb and IgA positive cells. Lymphoid follicles of the lamina propria mucosae consisted of a parafollicular area, corona and germinal centre. The parafollicular area was populated by large numbers of CD4 and CD8 positive lymphocytes as well as macrophages, inter-digitating cells, and a few B-lymphocytes. The germinal centre contained mainly IgGb and IgG(T) positive cells, plasma cells...
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...
Chen Q, Tong Q, Ge H, Li W, Liu J, Wang Y, Guo Z, Quan F, Zhang Y.SP110 has previously shown to be a genetic determinant of host resistance to the intracellular pathogen infection in mouse and human. However, its relevant biological information in large non-primate animals still remains unknown. Here we report the novel discovery and characterization of three transcript variants of horse SP110. The transcript variant 1 (Tv1) of horse SP110 with the longest open reading frame has four domains (Sp100, SAND, PHD and Bromo domain). Tv2 and Tv3 share the same N-terminal sequence as Tv1, which contains Sp100 and SAND. We show that Tv2 is generated from alternative...
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...
Jaworska J, Ropka-Molik K, Kowalczyk-Zięba I, Boruszewska D, Wocławek-Potocka I, Siemieniuch M.Physiological parturition is characterized by sterile, inflammatory-like processes. During parturition, the placenta expresses various proinflammatory mediators, such as chemokines and IL-17. Nevertheless, inflammatory processes present in the parturient mare are poorly characterized. The aim of this study was to investigate the expression of selected chemokines and IL-17 in the allantochorion and the endometrium of mares that retained fetal membranes (RFM) and expelled them physiologically. We hypothesized that the expression of these mediators may be altered in the placenta of mares with RFM...
Wohlsein P, Pohlenz JF, Davidson FL, Salt JS, Hamblin C.The distribution of viral antigen was studied in various tissues of three ponies, aged 3-4 years, infected experimentally with a virulent strain of African horse sickness virus (AHSV) serotype 4. Tissues were collected from the animals in the terminal stage of the peracute form of the disease and from one noninfected horse, included as a control. A polyclonal antibody with specificity for AHSV, plus the nonstructural protein NS2, was used in a sensitive avidin-biotin-peroxidase-complex (ABC) method performed on formalin-fixed, paraffin-embedded tissue sections. AHSV antigen was located primari...
Sledge DG, Miller DL, Styer EL, Hydrick HA, Baldwin CA.Granulomatous dermatitis in horses has been linked to many etiologies, including various parasites, fungi, and bacteria. Idiopathic forms of granulomatous inflammation-producing diseases, some of which are localized to the skin, also have been reported in horses. Herein we describe a case of recurrent equine granulomatous skin disease characterized by intranuclear viral inclusions within macrophages and giant cells. The histologic changes were primarily noted in the deep dermis and included multifocal to coalescing areas of necrosis marked by histiocytic cell infiltration and presence of giant...
Harada K, Kanemitsu S, Akioka K, Fujita K, Nishi Y, Taura Y, Sasaki N.Fifty-four slaughtered horses were classified into groups having adipose tissue in the crest of the neck with or without hemorrhage (AH and NH groups, respectively). Blood biochemical tests (Alb, TP, T-bil, GOT, GPT, LDH, T-cho, and BUN) and an epidemiological survey (age, gender, weight, origin, breed, BCS, CNS, and hoof disease) were performed. T-bil tended to be high, while the other parameters were normal. Weight, BCS, and CNS were higher in the AH group (P<0.05). GOT was lower in the AH group (P<0.05). It was suspected that the horses in the AH group had lipomatosis. It was assumed ...
Lisowski ZM, Sauter KA, Waddell LA, Hume DA, Pirie RS, Hudson NPH.Intestinal macrophages are the largest group of mononuclear phagocytes in the body and play a role in intestinal innate immunity, neuroimmune interactions and maintaining intestinal homeostasis. Conversely, they also are implicated in numerous pathologies of the gastrointestinal tract, such as postoperative ileus and inflammatory bowel disease. As a result, macrophages could be potential therapeutic targets. To date, there are limited studies on the morphology and distribution of macrophages in the equine gastrointestinal tract (GIT). The aim of this study was to identify the location and abun...
Longworth KE, Jarvis KA, Tyler WS, Steffey EP, Staub NC.Seven horses (4 anesthetized and 3 awake) and 2 ponies (anesthetized) were studied to evaluate the high sensitivity of the pulmonary circulation of the horse to various blood-borne particles, and to establish the presence of intravascular macrophages in the lung. Pulmonary and systemic pressures and cardiac output before and during particle injection were measured in some animals. An anesthetized foal had a large increase in pulmonary arterial pressure (32 and 34 mm of Hg) within 1 minute of IV administration of small test doses of radioactively labeled liposomes (2.5 mumol/kg of body weight) ...
Laan TT, Bull S, van Nieuwstadt RA, Fink-Gremmels J.Beta-agonists have been shown to display anti-inflammatory properties in several experimental models. The aim of this study was to investigate the anti-inflammatory properties of clenbuterol (CB), administered either intravenously or by aerosol, in comparison with fluticasone propionate (FP) in recurrent airway obstruction (RAO)-susceptible horses. Eight horses, of which five were known to be susceptible to RAO, underwent an inhalation challenge with Aspergillus fumigatus (AF) antigen and were treated with CB intravenously, CB by aerosol, or FP by aerosol. Twenty-four hours after the challenge...
Lapointe JM, Vrins A, Lavoie JP.Bronchoalveolar lavages (BAL) were performed for 6 healthy horses and 8 horses with lower airway diseases (LAD). Total cell and differential counts were performed before and after centrifugation and resuspension of the BAL cells in a small volume of fluid; there was no difference in the total cell counts, but mast cell percentages were significantly (P < 0.05) lower, after centrifugation, in the LAD group. The two specimen preparation techniques compared were cytocentrifugation and centrifugation on microscope glass covers. For both groups of horses, lymphocyte percentages were significantl...
Tanaka Y, Adilbish A, Koyama K, Bayasgalan MO, Horiuchi N, Uranbileg N, Watanabe K, Purevdorj B, Gurdorj S, Banzragch B, Badgar B, Suganuma K....Dourine is a deadly protozoan disease in equids caused by infection with Trypanosoma equiperdum. Neurological signs in the later stage of infection may be caused by peripheral polyneuritis and related axonal degeneration. This neuritis involves T lymphocytes, B lymphocytes, and macrophages, and is observed in cases without obvious neurological signs. However, the pathogenesis of neuritis remains unclear. We identified M2 macrophages and CD8 T cells as the predominant phenotypes in neuritis of dourine-affected horses with or without neurological signs. In contrast, the populations of M1 macroph...
