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.
INGRAM DG.A method is described for the quantitative measurement of the reactions between sensitized cells and horse complement and between alexinated cells and conglutinin. The method is laborious but its application has allowed the determination of the optimal times of the reactions at various temperatures. The results obtained in these experiments indicate that the alexinated configuration with which conglutinin and immuno-conglutinin react is not one of the recognized intermediates formed during the process of immune haemolysis.
REBERS PA, HURWITZ E, HEIDELBERGER M.Rebers, Paul A. (Rutgers University, New Brunswick, N. J.), Esther Hurwitz, and Michael Heidelberger. Immunochemistry of pneumococcal types II, V, and VI. II. Inhibition tests in the type VI precipitating system. J. Bacteriol. 82:920-926. 1961.-As in other immune systems involving polysaccharides, rabbit antibodies but not those engendered in the horse were found sensitive to degradation of type VI pneumococcal (Pn) polysaccharide (SVI), and were readily inhibited by fragments of SVI. Large amounts, 30 to 111 mumoles, of most sugars gave up to 15% inhibition, while sugar and polyol phosphates ...
HETRICK FM, YANCEY FS, HANSEN PA, BYRNE RJ. Four horses inoculated with EEE virus remained asymptomatic following injection but did develop measurable HI and neutralizing antibodies as a result of infection. HI antibodies were detectable earlier than neutralizing antibodies but the levels tended to drop more rapidly. 2. Of 14 horses and ponies having significant levels of neutralizing antibody, 5 to 9 had measurable HI antibody depending on number of units of antigen employed in the test. 3. Sera from 3 clinical cases of EEE were positive on the HI test while only one of these animals had a significant neutralizing antibody level.
Todd EW.Antiproteinase sera were prepared by immunizing horses with filtrates from a selected strain of group A streptococcus. This strain, which produced high titred proteinase but no erythrogenic toxin, was selected from forty-two strains of group A streptococci which produced varying amounts of proteinase. A few strains belonging to groups B, C, and G were also tested; they were all proteinase-negative. Methods are described for titrating streptococcal proteinase in crude culture filtrates and for measuring the antiproteinase activity of serum. The antiproteinase titres of sera from immunized horse...
Olitsky PK, Harford CG.Young (12 to 15 day old) mice are approximately as susceptible to the virus of equine encephalomyelitis, Eastern or Western strain, when it is given intraperitoneally as are adult mice when the virus is injected intracerebrally. With this susceptibility by the intraperitoneal route as a basis, the injection of immune serum-virus mixtures intraperitoneally was found to result in protection in dilutions which give rise to infection after intracerebral inoculation. The difference of protective power by the two indicated routes was shown not to depend on the amount of inoculum nor on the age of th...
Inada R, Ido Y, Hoki R, Ito H, Wani H.Horses immunized with cultures of Spirochaeta icterohaemorrhagiae yield an immune serum having therapeutic properties. With rare exceptions the serum destroys completely the spirochetes contained in the circulating blood. The development of antibodies is promoted by the serum injections. The number of spirochetes in the organs is reduced by the treatment. Secondary manifestations due to the serum are slight and disappear promptly. The ultimate effects of the serum treatment on the symptoms and final outcome of the disease have still to be determined.
Smith T.The foregoing and earlier data taken together demonstrate that an active immunity lasting several years can be produced in guinea-pigs, by the injection of toxin-antitoxin mixtures which have no recognizable harmful effect either immediate or remote. They also show, what might have been anticipated, that under the same conditions mixtures which produce local lesions and which, therefore, contain an excess of toxin produce a much higher degree of immunity than the neutral mixtures, and that an excess of antitoxin reduces the possibility of producing an active immunity, and may extinguish it alt...
McKenzie HC, Funk RA, Trager L, Werre SR, Crisman M.Potomac horse fever (PHF) is a potentially fatal enterocolitis of horses caused by Neorickettsia risticii. The disease was originally recognised almost 40 years ago in the state of Maryland in the US. It is now known to occur in many areas of North America, as well as having been described in South America and Europe. Monocomponent PHF vaccines are available, but clinical protection with vaccination has been reported to be inconsistent. Objective: This study was designed to assess the immunogenicity of a commercially available Potomac Horse Fever (PHF) vaccine when administered as either a mo...
Van Crombrugge E, Vanbeylen E, Van Cleemput J, Van den Broeck W, Laval K, Nauwynck H.Respiratory disease in horses is caused by a multifactorial complex of infectious agents and environmental factors. An important pathogen in horses is equine herpesvirus type 1 (EHV-1). During co-evolution with this ancient alphaherpesvirus, the horse's respiratory tract has developed multiple antiviral barriers. However, these barriers can become compromised by environmental threats. Pollens and mycotoxins enhance mucosal susceptibility to EHV-1 by interrupting cell junctions, allowing the virus to reach its basolateral receptor. Whether bacterial toxins also play a role in this impairment ha...
Velineni S, Timoney JF, Artiushin SC, Donahue JM, Steinman M.Foals of mares infected with Leptospira interrogans serovar Pomona type kennewicki (Lk) may be aborted/stillborn or delivered as healthy foals. Is fetal survival explained in part by the immune response of the fetus to Leptospira antigens? Objective: To describe an outbreak of Leptospira abortion in which infected mares delivered dead/sick or normal foals and determine specificities of antibody in a collection of 54 fetuses from similar outbreaks. Methods: Outbreak investigation in combination with a case-control study of a larger set of samples from aborted fetuses. Methods: Serology and poly...
Rossi SL, Guerbois M, Gorchakov R, Plante KS, Forrester NL, Weaver SC.Venezuelan equine encephalitis virus (VEEV) is an arbovirus that causes periodic outbreaks that impact equine and human populations in the Americas. One of the VEEV subtypes located in Mexico and Central America (IE) has recently been recognized as an important cause of equine disease and death, and human exposure also appears to be widespread. Here, we describe the use of an Internal Ribosome Entry Site (IRES) from encephalomyocarditis virus to stably attenuate VEEV, creating a vaccine candidate independent of unstable point mutations. Mice infected with this virus produced antibodies and wer...
Tatarov G, Martinov S, Panova M.It was established that the complement binding reaction (CBR) is a suitable and very fast method for horse rhino-pneumonitis diagnostics. Cell cultural virus produced in cell cultures of pig kidneys was used as antigen. The antigen lots tested have no anticomplementary properties. Highest complement binding activity was evident in the non-diluted antigen, which discovered specific antibodies in immune serums. The CBR specificity was tested by the aid of homologous and heterologous serums and antigens. The titers of complement binding antibodies in the serums of 255 horses recovered from the di...
Löfgren M, Svala E, Lindahl A, Skiöldebrand E, Ekman S.Osteoarthritis is an inflammatory and degenerative joint disease commonly affecting horses. To identify genes of relevance for cartilage pathology in osteoarthritis we studied the time-course effects of interleukin (IL)-1β on equine articular cartilage. Articular cartilage explants from the distal third metacarpal bone were collected postmortem from three horses without evidence of joint disease. The explants were stimulated with IL-1β for 27 days and global gene expression was measured by microarray. Gene expression was compared to that of unstimulated explants at days 3, 9, 15, 21 and 27...
Bonin CP, Baccarin RY, Nostell K, Nahum LA, Fossum C, de Camargo MM.Engagement of Toll-like receptor 4 (TLR4) by lipopolysaccharide (LPS) is a master trigger of the deleterious effects of septic shock. Horses and humans are considered the most sensitive species to septic shock, but the mechanisms explaining these phenomena remain elusive. Analysis of tlr4 promoters revealed high similarity among LPS-sensitive species (human, chimpanzee, and horse) and low similarity with LPS-resistant species (mouse and rat). Four conserved nuclear factor kappa B (NFκB) binding sites were found in the tlr4 promoter and two in the md2 promoter sequences that are likely to be t...
Mckelvie J, Foster AP, Hamblin AS, Cunningham FM.Intradermal injection of a Culicoides antigen extract (CAgX) induces T lymphocyte and eosinophil accumulation in the skin of horses with sweet itch. Blood mononuclear (BMN) cells from normal ponies proliferate when stimulated by mitogen (phytohaemagglutinin, PHA) or antigen (tetanus toxoid, TT) and, as shown here, release soluble factor(s) that induce eosinophil adherence. CAgX also caused concentration dependent proliferation of BMN cells from sweet itch and normal ponies [stimulation index: 29 (13) and 17 (7) for BMN cells from sweet itch and normal ponies, respectively during the active pha...
Merl J, Deeg CA, Swadzba ME, Ueffing M, Hauck SM.Most autoimmune diseases are multifactorial diseases and are caused by the immunological reaction against a number of autoantigens. Key for understanding autoimmune pathologies is the knowledge of the targeted autoantigens, both initially and during disease progression. We present an approach for autoantigen identification based on isolation of intact autoantibody-antigen complexes from body fluids. After organic precipitation of high molecular weight proteins and free immunoglobulins, released autoantigens were identified by quantitative label-free liquid chromatography mass spectrometry. We ...
Sánchez MD, Pierson TC, Degrace MM, Mattei LM, Hanna SL, Del Piero F, Doms RW.A major neutralizing epitope (here referred to as the T332 epitope) located on the lateral surface of domain III (DIII) of the West Nile virus (WNV) envelope protein has been identified based on the analysis of murine monoclonal antibodies. However, little is known about the humoral immune response against WNV in a natural host or whether DIII in general or the T332 epitope in particular are important targets of neutralizing antibodies in vivo. To characterize the types of antibodies produced during infection with WNV, we studied a group of naturally infected horses. Using immune adsorption as...
Giacominelli-Stuffler R, Frangipane di Regalbono A, Traversa D, Geurden T, Marcer F, Di Francesco A, Angelini C, di Cesare A, Storelli MM....Leukotrienes are products of the arachidonic acid metabolism and act as potent inflammatory mediators modulating the immune response and various physiological processes. This study evaluated the expression and activity of 5-lipoxygenase (5-LOX), the enzyme that catalyzes the first two steps in the biosynthesis of leukotrienes, in horses infected by larval cyathostomins. Tissue samples from dorsal and ventral colon, and from the cecum were collected from 16 horses slaughtered for human consumption. Samples were analyzed to estimate the burdens of encysted cyathostomin larvae and adult luminal s...
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...
Phumoonna T, Barton MD, Vanniasinkam T, Heuzenroeder MW.Rhodococcus equi remains a significant bacterial pathogen, causing severe pyogranulomatous pneumonia in foals aged 1-3 months. There is no effective vaccine currently available for the prevention of R. equi pneumonia. DNA vaccines are known to offer specific advantages over conventional vaccines. The aim of this study was to demonstrate efficacy of our recombinant DNA vaccine candidates, namely pcDNA3-Re1, pcDNA3-Re3 and pcDNA3-Re5 by combining a heat shock protein GroEL2 to a virulence-associated protein A (VapA) from R. equi to protect C3H/He mice against the R. equi infection. VapA was show...
Sánchez-Matamoros A, Beck C, Kukielka D, Lecollinet S, Blaise-Boisseau S, Garnier A, Rueda P, Zientara S, Sánchez-Vizcaíno JM.African horse sickness (AHS) is a viral disease that causes high morbidity and mortality rates in susceptible Equidae and therefore significant economic losses. More rapid, sensitive and specific assays are required by diagnostic laboratories to support effective surveillance programmes. A novel microsphere-based immunoassay (Luminex assay) in which beads are coated with recombinant AHS virus (AHSV) structural protein 7 (VP7) has been developed for serological detection of antibodies against VP7 of any AHSV serotype. The performance of this assay was compared with that of a commercial enzyme-l...
Widders PR, Stokes CR, David JS, Bourne FJ.Antibody in serum, uterine and vaginal secretions was measured following local immunisation and experimental infection with the organism of contagious equine metritis (Taylorella equigenitalis). Intrauterine immunisation with killed T equigenitalis stimulated a systemic IgG titre and a uterine IgA and IgM response. Subsequent challenge with the organism, however, resulted in a characteristic metritis in both control and vaccinated mares. Antibody in serum and secretions was increased following challenge infection, dwarfing the response to immunisation. The local response was restricted to the ...
Craig NM, Munguia NS, Trujillo AD, Wilkes R, Dorr M, Marsella R.Preliminary evidence supports a role for IL-31 in equine insect bite hypersensitivity (IBH) and pruritus. Our studies investigated IL-31 and IL-31 receptor-α (IL-31RA) transcription in leukocytes from normal and IBH horses in response to Culicoides nubeculosus. 19 normal and 15 IBH horses were recruited in the summer of 2019 (low-dose study) and 8 normal and 10 IBH horses in the winter of 2022 to 2023 (high-dose study). Normal horses had no history or signs of allergic skin disease, while IBH horses had a history and clinical signs compatible with IBH. Pruritus was scored using a visual analo...
Roth TL, White KL, Thompson DL, Horohov DW.It has been proposed that PGE2 is an important immunosuppressant acting at the fetal-maternal interface during pregnancy. We have previously shown that horse conceptus-conditioned medium suppresses lymphocyte proliferation. This experiment was designed to determine if horse conceptus-derived immunosuppressive activity could be attributed to PGE2 production by the trophoblast tissue. Trophoblast tissue from 21-day-old conceptuses was cut into equal sections and cultured in the presence or absence of the prostaglandin inhibitor, indomethacin. Following culture, immunosuppressive activity and the...
Smith EJ, Beaumont RE, McClellan A, Sze C, Palomino Lago E, Hazelgrove L, Dudhia J, Smith RKW, Guest DJ.Tendon injuries occur commonly in both human and equine athletes, and poor tendon regeneration leads to functionally deficient scar tissue and an increased frequency of re-injury. Despite evidence suggesting inadequate resolution of inflammation leads to fibrotic healing, our understanding of the inflammatory pathways implicated in tendinopathy remains poorly understood, meaning successful targeted treatments are lacking. Here, we demonstrate IL-1β, TNFα and IFN-γ work synergistically to induce greater detrimental consequences for equine tenocytes than when used individually. This includes ...
Rhiner T, Fettelschoss V, Schoster A, Birkmann K, Fettelschoss-Gabriel A.Previously, virus-like particle (VLP)-based self-vaccinations targeting interleukin (IL)-5 or IL-31 have been suggested to treat equine insect bite hypersensitivity (IBH), a seasonal recurrent allergic dermatitis in horses. The IL-5-targeting equine vaccine significantly reduced blood eosinophil counts in horses, similar to human monoclonal antibodies targeting IL-5 or the IL-5 receptor alpha (IL-5Rα). Previous studies in humans have also reported an additional effect on reduction of basophil counts. The aim of the present study was to evaluate whether an equine anti-IL-5 vaccine affected blo...
Durán-Ferrer M, Agüero M, Zientara S, Beck C, Lecollinet S, Sailleau C, Smith S, Potgieter C, Rueda P, Sastre P, Monaco F, Villalba R....The laboratory diagnosis of African horse sickness (AHS) is important for: (a) demonstrating freedom from infection in a population, animals or products for trade (b) assessing the efficiency of eradication policies; (c) laboratory confirmation of clinical diagnosis; (d) estimating the prevalence of AHS infection; and (e) assessing postvaccination immune status of individual animals or populations. Although serological techniques play a secondary role in the confirmation of clinical cases, their use is very important for all the other purposes due to their high throughput, ease of use and good...
Gold JR, Cohen ND, Welsh TH.The hypothalamic-pituitary-adrenal (HPA) is influenced by the proinflammatory cytokines IL-6, IL-1β, and TNF-α in critically ill humans. Information about the association of cytokines with the HPA axis in neonatal foals is lacking. Objective: The objectives were to describe for hospitalized septic and nonseptic foals (1) temporal changes in blood concentrations of ACTH, and cortisol, and leukocyte cytokine gene expression, and (2) coassociation of these HPA axis hormones with blood leukocyte cytokine gene expression. Methods: Hospitalized septic foals (N = 15) and hospitalized nonseptic foal...
Velineni S, DeNegri R, Artiushin SC, Timoney JF.Streptococcus zooepidemicus (Sz) and its clonal derivative Streptococcus equi (Se) share greater than 96% DNA identity and elicit immune responses to many shared proteins. Identification of proteins uniquely targeted by the immune response to each infection would have diagnostic value. Objective: The aim of the study was to compare serum antibody responses of horses infected by Se or Sz. Methods: Antibody levels were measured to panels of recombinant proteins of Sz and Se in sera of horses and ponies before and after experimental and naturally occurring invasive infections by these organisms. ...
Rinnovati R, Romagnoli N, Gentilini F, Lambertini C, Spadari A.Platelet-rich plasma (PRP) commonly refers to blood products which contain a higher platelet (PLT) concentration as compared to normal plasma. Autologous PRP has been shown to be safe and effective in promoting the natural processes of soft tissue healing or reconstruction in humans and horses. Variability in PLT concentration has been observed in practice between PRP preparations from different patients or from the same individual under different conditions. A change in PLT concentration could modify PRP efficacy in routine applications. The aim of this study was to test the influence of envi...
Kunanusont N, Taesuji M, Kulthonggate U, Rattanamas K, Mamom T, Thongsri K, Phannithi T, Ruenphet S.African horse sickness (AHS) has become a newly emerging disease after an outbreak in northeastern Thailand in March 2020. Mass vaccination in horses with live-attenuated AHS virus (AHSV) vaccine is essential for AHS control and prevention. This study aimed to monitor the longitudinal humoral immune response before and after a single vaccination using a live-attenuated vaccine against AHS in stallions, mares, and pregnant mares, including maternal immunity in foals born from pregnant mares during the outbreak in Thailand. Unassigned: A total of 13 stallions and 23 non-pregnant and 21 pregnant ...
Herrmann I, Sanchez AJ.Allergen-specific immunotherapy (AIT) is the only current intervention that has the ability to modify the immune response toward a tolerogenic state. This study aimed to assess the efficacy and safety of AIT in horses with allergic diseases in a systematic manner. Three databases were searched to identify articles reporting clinical outcomes and adverse events associated with AIT. The articles were evaluated for beneficial responses to AIT, defined as a ≥50% reduction in clinical signs, and clinical remission. Horses with respiratory diseases, urticaria, and pruritic dermatitis receiving ins...
Sage SE, Leeb T, Jagannathan V, Gerber V.Severe equine asthma (SEA) is a complex respiratory condition characterized by chronic airway inflammation. It shares many clinical and pathological features with human neutrophilic asthma, making it a valuable model for studying this condition. However, the immune mechanisms driving SEA have remained elusive. Although SEA has been primarily associated with a Th2 response, there have also been reports of Th1, Th17, or mixed-mediated responses. To uncover the elusive immune mechanisms driving SEA, we performed single-cell mRNA sequencing (scRNA-seq) on cryopreserved bronchoalveolar cells from 1...
Degroote RL, Schmalen A, Hauck SM, Deeg CA.The perception of circulating granulocytes as cells with a predetermined immune response mainly triggered by pathogens is evolving, recognizing their functional heterogeneity and adaptability, particularly within the neutrophil subset. The involvement of these cells in the pathophysiology of autoimmune uveitis has become increasingly clear, yet their exact role remains elusive. We used an equine model for autoimmune-mediated recurrent pan-uveitis to investigate early responses of granulocytes in different inflammatory environments. For this purpose, we performed differential proteomics on gran...
Lacerenza MD, Arantes JA, Reginato GM, Passarelli D, Balieiro JCC, Amaral AR, Vendramini THA, Brunetto MA, Dória RGS.β-glucan is part of the cell wall of fungi and yeasts and has been known for decades to have immunomodulating effects on boosting immunity against various infections as a pathogen-associated molecular pattern that is able to modify biological responses. β-glucan has been used in rat models and in vitro studies involving sepsis and SIRS with good results, but this supplement has not been evaluated in the treatment of endotoxemia in horses. This study aims to evaluate the effects of preventive supplementation with β-glucan in horses submitted to endotoxemia by means of inflammatory response m...
Moroni R, Fanelli D, Camillo F, Rota A, Cantile C, Marmorini P, Salamone G, Ori M, Panzani D.Endometritis is a major cause of subfertility in mares. Multiparous old mares are more susceptible to developing endometritis given that ageing is associated with an altered immune response and with inadequate physiological uterine clearance after breeding, which can lead to degenerative changes in the endometrium. Molecules such as antimicrobial peptides (AMPs) have been proposed as endometritis markers in the equine species. Methods: Cross-sectional. Objective: To investigate the endometrial expression of defensin-beta 4B (DEFB4B), lysozyme (LYZ) and secretory leukocyte peptidase inhibitor (...
Carlier S, Depuydt E, Van Hecke L, Martens A, Saunders J, Spaas JH.Mesenchymal stem cells provide a valuable treatment option in orthopedic injuries in horses. Unassigned: The aim of this study was to evaluate the hematological, biochemical, immunological and immunomodulatory parameters following intralesional treatment with tenogenic primed equine allogeneic peripheral blood-derived mesenchymal stem cells (tpMSCs) in client-owned horses with naturally occurring superficial digital flexor tendon (SDFT) and suspensory ligament (SL) injuries. Unassigned: The immunogenicity and immunomodulatory capacities of tpMSCs were assessed in a modified mixed lymphocyte re...
