The equine immune system is a complex network of cells, tissues, and organs that work collaboratively to defend against pathogens and maintain homeostasis. It consists of innate and adaptive components, each with distinct functions and mechanisms. The innate immune system provides the first line of defense through physical barriers, phagocytic cells, and the complement system. The adaptive immune system involves lymphocytes, such as B cells and T cells, which generate specific responses to antigens and provide immunological memory. Research in equine immunology explores the interactions between these components, the impact of genetic and environmental factors on immune function, and the development of vaccines and therapeutics. This page gathers peer-reviewed studies and scholarly articles focusing on the mechanisms, regulation, and clinical applications of the equine immune system in health and disease.
KAPLAN MM, PAYNE AM.In 1957 the World Health Organization arranged a survey of horse and swine sera in a number of countries in order to gain information on the role and importance of animals in the epidemiology of influenza. The veterinary services of the countries concerned were requested to obtain blood specimens from these animals, if possible both before and after the human pandemic of Asian influenza. This paper reports on the results of haemagglutination-inhibition and complement-fixation tests performed on these sera in WHO Influenza Centres and other collaborating laboratories.It is apparent from these r...
FEEMSTER RF.This research focuses on the first recognized human infection of equine encephalomyelitis, a disease mostly found in horses, which occurred in Massachusetts in the summer of 1938. The study dives […]
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...
Kalemkerian PB, Metz GE, Peral-García P, Lopez-Gappa J, Echeverría MG, Giovambattista G, Díaz S.We investigated the association of equine arteritis virus (EAV) infection and three short tandem repeat (STR) polymorphisms located within or in close proximity to equine lymphocyte antigen (ELA) region. We used a case-control design as a first approach before proceeding to select candidate genes. One hundred and sixty-five Silla Argentino horses were taken in 2002 from positive serological detections of EAV in Argentina, to determine whether STR genotypes were correlated to genetic susceptibility to EVA. Allele frequency distribution did not show significant differences between both groups (P...
Dagleish MP, Pemberton AD, McAleese SM, Thornton EM, Miller HR, Scudamore CL.Equine alpha-1-proteinase inhibitor (API) consists of three, occasionally four, serum glycoproteins. This study investigated the immunohistochemical localisation of equine API in paraformaldehyde fixed, paraffin embedded equine tissue samples of liver, lung, stomach, pancreas, jejunum and colon in five horses using affinity purified sheep polyclonal and protein A purified mouse monoclonal antibodies, whose specificities were verified by Western blotting. Exposing tissue sections to boiling citrate buffer greatly enhanced antigen recovery and improved immunostaining with both antibodies, result...
Nichani AK, Sharma RD, Sarup S.Efficacy of medium RPMI-1640 (supplied by Gibco USA, Centron and Hi-media) supplemented with horse, donkey, sheep and goat sera was evaluated for in vitro propagation of Theileria annulata (Hisar) infected bovine mononuclear cells. The results were compared with the growth rate in RPMI-1640 supplemented with foetal bovine serum (Gibco). RPMI-1640 (Gibco) proved to be the best medium for in vitro cultivation of the parasite infected cells. Foetal bovine serum could be easily, safely and reliably substituted with goat and sheep sera in the growth medium. Horse and donkey sera also gave comparabl...
Wollstein M.The parameningococci of Dopter are culturally indistinguishable from true or normal meningococci, but serologically they exhibit differences as regards agglutination, opsonization, and complement deviation. Because of the variations and irregularities of serum reactions existing among otherwise normal strains of meningococci it does not seem either possible or desirable to separate the parameningococci into a strictly definite class. It appears desirable to consider them as constituting a special strain among meningococci not, however, wholly consistent in itself. The distinctions in serum rea...
Borchers K, Frölich K, Ludwig H.In blood samples of seven captive equid species from four German zoos EHV-1 specific antibodies were detected in 76% and EHV-4 specific antibodies in 73% of the 55 animals, whereas 93% were tested positive for EHV-2 and EHV-5, respectively. In only one blood sample from a Przewalski's wild horse EHV-4 DNA was amplified by PCR. From seven Przewalski's wild horses EHV-2, and from another one EHV-5 was isolated by cocultivation. The identity of the virus isolates was verified by PCR and restriction enzyme digestion.
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...
Hoshiba H, Sinowatz F.Spermadhesins are proteins with various functions in sperm capacitation and zona pellucida binding. In this study the cellular localization of the spermadhesin AWN-1 has been examined in the equine male genital tract. Results obtained by immunohistochemical methods reveal that in the horse AWN-1 is synthesized in spermatogonia, in the rete testis, the ductus epididymidis and the seminal vesicles. These findings indicate that the cellular origin of spermadhesins is species-specific.
Marquardt J, Heymer J, Heinz H, Adolf GR, Deegen E.Recombinant equine interferon-beta 1 (reqIFN-beta 1) induces an antiviral state in blood mononuclear cells (BMC) of horses. Maximal protection against replication of vesicular stomatitis virus is achieved 6 hours after treatment with IFN in vitro and in vivo. Duration of the protective effect depends on the dose of IFN in vitro and in vivo. Availability of reqIFN-beta 1 in cultures of BMC for up to 48 hours does not prolong the antiviral state. The protective effect on BMC after treatment with IFN has similar duration in vivo and in vitro. Monitoring of the effect of IFN in vivo is, thus, simp...
Uzal FA, Diab SS, Blanchard P, Moore J, Anthenill L, Shahriar F, Garcia JP, Songer JG.Clostridium perfringens type C is one of the most important agents of enteric disease in newborn foals. Clostridium difficile is now recognized as an important cause of enterocolitis in horses of all ages. While infections by C. perfringens type C or C. difficile are frequently seen, we are not aware of any report describing combined infection by these two microorganisms in foals. We present here five cases of foal enterocolitis associated with C. difficile and C. perfringens type C infection. Five foals between one and seven days of age were submitted for necropsy examination to the Californi...
Kudrimoti S, Machin J, Arojojoye AS, Awuah SG, Eisenberg R, Fenger C, Maylin G, Lehner AF, Tobin T.Based on structural similarities and equine administration experiments, Barbarin, 5-phenyl-2-oxazolidinethione from Brassicaceae plants, is a possible source of equine urinary identifications of aminorex, (R,S)-5-phenyl-4,5-dihydro-1,3-oxazol-2-amine, an amphetamine-related US Drug Enforcement Administration (DEA) controlled substance considered illegal in sport horses. We now report the synthesis and certification of d -barbarin to facilitate research on the relationship between plant barbarin and such aminorex identifications. D -barbarin synthesis commenced with production of d -2-oxo-2-phe...
Boussetta M, Chabchoub A, Ghram A, Jomaa I, Ghorbel A, Aouina T, Ben Amor H.Using the haemagglutination inhibition and immunodiffusion tests, a national serological survey was carried out to detect antibodies to equine influenza (EI) (A/equi/1/Prague 56 and A/equi/2/Miami 63) and equine infectious anaemia (EIA) in horse sera collected in northeastern Tunisia. 533 samples were analysed for EIA antibodies. All were negative. 13.6% of 433 equine sera tested for EI antibodies were positive. These results are discussed and compared with others obtained in Tunisia and bordering countries.
Tåmová B, Stumpa A, Zakopal J, Vĕzníková D, Mensík J.Equine influenza occurred in Czechoslovakia 14 years after the last epizootic in horses that had returned from abroad. Six strains A (Heq1Neq1) antigenically related to, but not identical with, strain A/eq/Praha/56 were isolated from 10 washings. Seroconversion was demonstrated with paired sera, but the antibody increase was more marked against the newly isolated strain.
Sanz MG.Foals become infected shortly after birth; most develop subclinical pneumonia and 20% to 30% develop clinical pneumonia that requires treatment. It is now well established that the combination of screening programs based on thoracic ultrasonography and treatment of subclinical foals with antimicrobials has led to the development of resistant Rhodococcus equi strains. Thus, targeted treatment programs are needed. Administration of R equi-specific hyperimmune plasma shortly after birth is beneficial as foals develop less severe pneumonia but does not seem to prevent infection. This article provi...
Rabinovsky ED, Yang TJ.A tumor antigen (TA) associated with murine leukemia-lymphoma L5178Y cells has been identified by the enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence (IIF) techniques. The antigen was present in both non-solubilized and 0.5% NP-40 solubilized membrane extracts. Rabbit anti-L5178Y lymphoma serum (RALS), extensively absorbed with normal mouse tissues, identified TA in extracts of L5178Y lymphoma and L5178Y leukemia cells grown in horse serum (L5178Y/HS), but not in extracts of L5178Y cells grown in fetal calf serum (L5178Y/FCS). Similarly, absorbed rabbit anti-L5178Y/HS...
Bocking T, Singh B.The lung is a complex organ, and its physiology and immunology are regulated by various immune molecules and cells. Lung surfactant, a mixture of phospholipids and proteins produced by the bronchiolar and type II alveolar epithelial cells, is one such important player in lung physiology. Compared to knowledge about the biology of the surfactant in rodents and humans, only limited data are available on the surfactant in the horse. Although there are data linking levels of surfactant proteins with respiratory disease in the horse, there are no data on the cellular localization of surfactant prot...
Sharma AK, Karthikeyan S, Sharma S, Yadav S, Srinivasan A, Singh TP.Lactoferrin (Lf), an iron binding glycoprotein found in the external secretions and neutrophilic leucocytes of mammals, is thought to be responsible for primary defence against microbial infection, mainly as a result of lactoferrin sequestration of iron required for microbial growth (Weinberg, 1978). Many other functions have been attributed to lactoferrin, including immunomodulation and cell growth regulation (Lbnnerdal & lyer, 1995). The lactoferrin has molecular mass of 80 kDa. The protein folds into two globular lobes, the N-lobe comprising the N-terminal half of the polypeptide chain ...
Lection J, Wagner B, Byron M, Miller A, Rollins A, Chenier T, Cheong SH, Diel de Amorim M.Endometrial biopsy is required to diagnose mares with chronic endometritis and endometrial degenerative fibrosis. An increase in understanding of equine reproductive immunology could be utilised to create less-invasive, time-efficient diagnostic tools especially when evaluating mares for chronic endometritis. Objective: To evaluate inflammatory cytokine and chemokine concentrations in uterine fluid samples collected by low-volume lavage (LVL) as a potential screening diagnostic biomarker for endometritis. Methods: Prospective cross-sectional clinical study. Methods: Forty-six mares underwent a...
May A, Gerhards H, Wollanke B.During hospitalization horses may develop gastrointestinal conditions triggered by a stress-associated weak local immune system. The prospective, clinical trial was conducted to find out whether fecal immunoglobulin A (IgA) concentrations could be determined in hospitalized horses and how they changed during hospitalization and in response to various stressors. Samples were obtained from 110 horses and a control group (n = 14). At arrival in the hospital, horses were categorized into pain grades (1-5), and elective versus strenuous surgery (> 2 hours, traumatic and emergency procedures). Feces...
Vaske A, Gautier C, Winter J, Aurich C.We followed the hypothesis that equine neonates with reduced transfer of tumor necrosis factor-α (TNFα) are at increased risk of neonatal infection. We investigated TNFα concentrations in colostrum of healthy mares and blood of their neonates in a non-hospitalized population of Warmblood mares where delivery, neonatal adaptation and health was closely monitored by veterinarians. Concentration of TNFα and IgG was determined in colostrum respective milk and in neonatal blood collected immediately after delivery and 18 h thereafter in 97 foals that were assigned to groups failure of passive ...
Holmes CM, Babasyan S, Wagner B.The end of gestation, ensuing parturition, and the neonatal period represent highly dynamic phases for immunological changes in both mother and offspring. The regulation of innate immune cells at the maternal-fetal interface during late term pregnancy, after birth, and during microbial colonization of the neonatal gut and other mucosal surfaces, is crucial for controlling inflammation and maintaining homeostasis. Innate immune cells and mucosal epithelial cells express antileukoproteinase (SLPI), which has anti-inflammatory and anti-protease activity that can regulate cellular activation. Unas...
Mattei DN, Harman RM, Van de Walle GR, Smith R, Grivel JC, Abdelalim EM, Vinardell T.Mesenchymal stromal cells (MSCs) have regenerative and immunomodulatory potential and may be used to treat injured tissues. Pregnancy has been associated with increased MSCs in the peripheral circulation in multiple species, but to date, there are no reports on this matter in horses. This study aimed to evaluate the effect of pregnancy on isolation efficiency and proliferation capacity of equine MSCs derived from the peripheral blood (PB) of mares. Venous blood samples were collected at the 11th month of gestation and 1 month after delivery from clinically healthy Arabian mares that presented ...
Giessler KS, Goehring LS, Jacob SI, Davis A, Esser MM, Lee Y, Zarski LM, Weber PSD, Hussey GS.Herpesviruses establish a well-adapted balance with their host's immune system. Despite this co-evolutionary balance, infections can lead to severe disease including neurological disorders in their natural host. In horses, equine herpesvirus 1 (EHV-1) causes respiratory disease, abortions, neonatal foal death and myeloencephalopathy (EHM) in ~10 % of acute infections worldwide. Many aspects of EHM pathogenesis and protection from EHM are still poorly understood. However, it has been shown that the incidence of EHM increases to >70 % in female horses >20 years of age. In this study we use...
Jose-Cunilleras E, Kohn CW, Hillier A, Saville WJ, Lorch G.To compare responses to a variety of intradermally injected allergens among healthy horses and horses with chronic obstructive pulmonary disease (COPD), recurrent urticaria (RU), and atopic dermatitis-insect hypersensitivity (allergic dermatitis [AD]). Methods: Case-control study. Methods: 86 horses. Methods: Results of intradermal testing for horses with COPD, RU, or AD were compared with results for healthy horses. Results: Compared with healthy horses, horses with COPD, RU, and AD were significantly more likely to have positive (> or = 3+) reactions to intradermal allergens (molds, weeds, t...
Wood JM, Baum HP, Bews JP, Wachsmuth ED, Heusser C, Hofbauer KG.In this study, the hypotensive efficacy of R-3-36-16, a monoclonal antibody against human kidney renin, was investigated during chronic administration to a primate. R-3-36-16 was given by continuous intraperitoneal infusion with osmotic minipumps to normotensive marmosets fed a low-sodium diet in doses of 30 or 300 micrograms/kg/day for 14 days. The lower dose had no effect on blood pressure (BP) or plasma renin activity (PRA). After two days of treatment, the higher dose reduced PRA by 57% and lowered BP by 13 +/- 7 mm Hg. Although the hypotensive response persisted after 14 days of treatment...
Rasmussen N, Karlsen P, Otten ND, Fjeldborg J, Hansen S.Bronchoalveolar lavage (BAL) cytology results from 1 lung might not be representative of both lungs. Objective: To determine whether the lung site sampled would influence the horse's BAL cytology profile, and if a pooled BAL sample would be superior with regard to BAL cytology diagnosis in a cohort of healthy and subclinical asthmatic warmblood horses. Methods: Fifty-nine horses in 2021 and 70 horses in 2022, the follow-up included 53 of the same in each year. Methods: A cross-sectional study with follow-up included BAL cytology samples from individual lungs and from pooled BAL samples. The BA...
Hamond C, Adam EN, Stone NE, LeCount K, Anderson T, Putz EJ, Camp P, Hicks J, Stuber T, van der Linden H, Bayles DO, Sahl JW, Schlater LK, Wagner DM....Equine leptospirosis can result in abortion, stillbirth, neonatal death, placentitis, and uveitis. Horses can also act as subclinical reservoir hosts of infection, which are characterized as asymptomatic carriers that persistently excrete leptospires and transmit disease. In this study, PCR and culture were used to assess urinary shedding of pathogenic Leptospira from 37 asymptomatic mares. Three asymptomatic mares, designated as H2, H8, and H9, were PCR-positive for lipL32, a gene specific for pathogenic species of Leptospira. One asymptomatic mare, H9, was culture-positive, and the recovered...
Mullen KR, Felippe MJB.Equine common variable immunodeficiency (CVID) is a rare, late-onset, nonfamilial humoral deficiency characterized by B-cell depletion and/or dysfunction resulting in inadequate antibody production and predisposition to recurrent infections. Serum immunoglobulin concentration and peripheral blood lymphocyte immunophenotyping are required to diagnose and characterize CVID in horses. Early recognition of the disease by the equine practitioner is paramount to managing the quality of life for these patients, for whom specific treatment is not yet available and long-term prognosis remains poor. An ...
Bozorgmanesh R.Immune-mediated vasculopathies occur secondary to infection or another noninfectious stimulus. Potential triggers include heterologous antigens including viruses, injected proteins and drugs; or auto-antigens including immunoglobulins or other endogenous proteins. Although these conditions are rare in horses, immune-mediated vasculopathies can cause considerable morbidity, with variable clinical signs depending on severity and organ system affected. Examples include purpura hemorrhagica, systemic lupus erythematosus, drug-induced vasculitis, paraneoplastic vasculitis, and idiopathic immune-med...
