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.
DiSilvestro AN, Wesolowski LT, Williams BD, Warren LK, Athrey G, White-Springer SH.Energy-dense feeds commonly provided to equine athletes may be high in starch, which alter gastrointestinal microbiota and could promote systemic inflammation. Objective: To test the hypothesis that exercise-induced inflammation would be greater in horses receiving a starch- versus fiber-based concentrate. Methods: Quarter Horses (mean±SD 16±1mo; 337±30kg) received either a fiber-based control (CON; 7 fillies, 8 geldings) or an isocaloric, isonitrogenous starch concentrate (STARCH; 8 fillies, 7 geldings) for 24d. Fecal metagenomics were evaluated on d0 and 21. Blood inflammatory mediators w...
Mulcahy G, Byrne O, Walshe N.Cyathostomins (also known as small strongyles or small redworms) are ubiquitous parasites of equids. They are found in a wide range of climatic regions, and inhabit the large intestine of their hosts. While infections are often sub-clinical, clinical consequences ranging from chronic to acute, and most notably, acute larval cyathostominosis, can occur in specific circumstances. Control of cyathostomin infection is complicated by widespread drug resistance. This Chapter provides a broad review of cyathostomin biology and host-parasite relationships, and also highlights significant knowledge gap...
Baillou A, Botos M, Oberhaensli S, Cvitas I, Jonsdottir S, Ziegler A, Brito F, Summerfield A, Marti E, Talker SC.Detailed classification of equine dendritic cells (DC) is necessary to address various research questions, such as the role of DC subsets in immune-mediated diseases of horses. Unassigned: We applied single-cell RNA sequencing (scRNA-seq) on DC enriched from the blood of two horses. Unassigned: All main DC subsets were detected by key gene expression, including conventional DC type 1 (cDC1; ) and type 2 (cDC2; , ), as well as plasmacytoid DC (pDC; ). In addition, we detected a small cluster of hematopoietic progenitors, as well as transitional DC (tDC; , ) and putative DC type 3 (DC3; , ). Our...
Jehle MC, Reinthaler B, Patan-Zugaj B, Schwendenwein I, Licka TF.To evaluate an ex vivo model of synovitis induced by IA lipopolysaccharide (LPS) and IL-1β in isolated, perfused equine forelimbs. Unassigned: Forelimbs and blood were collected from 12 clinically unremarkable horses following slaughter at a licensed abattoir. In 8 limbs, 2 of 3 phalangeal joints were injected with LPS (0.5 to 5 ng, 4 limbs) or IL-1β (100 ng, 4 limbs) diluted in 1 mL of distilled water. All limbs were perfused with autologous perfusate for 8 hours. Synovial fluid cytology and synovium sample histology scores for synovitis (0 = no changes and 3 = marked changes) were assessed...
Długopolska D, Siwińska N, Noszczyk-Nowak A, Niedźwiedź A, Żak-Bochenek A.Equine Asthma (EA) is a common, lower airway disease. Yet current diagnostic standards rely on bronchoalveolar lavage fluid (BALF) cytology, which is moderately invasive and not always feasible in field conditions. This review aimed to synthesize current evidence on candidate biomarkers of EA, with a primary focus on blood-based matrices and BALF, while also including data on biomarkers measured in tracheal wash (TW), saliva and exhaled breath condensate (EBC), where available. Searches were performed in PubMed, Scopus and Google Scholar, and original studies in horses with mild-to-moderate or...
Musoles-Cuenca B, de la Cuesta-Torrado M, Álvarez AV, Vitale V, Lorenzo-Bermejo T, Ballester B, Rubio-Guerri C, Álvarez L, Maiques E.Equine herpesvirus type 1 (EHV-1) outbreaks associated with international equestrian events have demonstrated the capacity of this virus for rapid transboundary dissemination. However, detailed longitudinal data integrating viral shedding across multiple biological matrices within the same animals during naturally occurring outbreaks remain limited. In this study, ten horses hospitalized during a naturally occurring EHV-1 outbreak linked to an international jumping competition were monitored for 10-12 days, from which 306 nasal, ocular, urine and faecal samples were obtained and analysed by qu...
Chow L, Contino E, Seabaugh K, Goodrich L, McIlwraith CW, Impastato R, Singer J, Das S, Dow S, Pezzanite LM.To determine differential gene expression in synovial tissues following injection of IA 2.5% polyacrylamide hydrogel (2.5% iPAAG), a biocompatible nondegradable synthetic polymer, to treat osteoarthritis (OA). Unassigned: Osteoarthritis was induced in 1 middle carpal joint of 16, 2- to 5-year-old horses (7 mares and 9 geldings) via surgical osteochondral fragment creation in combination with exercise on a high-speed treadmill; the contralateral limb underwent a sham operation. Horses were exercised 5 days per week, beginning on day 16 postoperatively. The osteochondral fragment joint was injec...
Wierzbicka M, Samsel A, Siemieniuch-Tartanus M.Equine asthma is a chronic inflammatory disease of the lower respiratory tract, primarily associated with inhalation of organic dust, microbial particles and environmental aeroantigens. Although the inflammatory and immunological mechanisms underlying equine asthma have been extensively investigated, the potential contribution of neuroimmune pathways remains poorly understood. In humans and rodent models, asthma is increasingly recognised as a disorder involving complex bidirectional interactions between the nervous and immune systems. Sensory nerve activation, neuropeptide release, autonomic ...
De Heus P, Maute J, Huber N, Tichy A, Palme R, Steinmann E, Volz A, Cavalleri J-V, Trachsel DS.Stress is an umbrella term indicating increased allostatic load with the potential to reach a pathological state of the organism. In this context, cortisol concentration and neutrophil granulocytes-to-lymphocyte ratio (NEU: LYM) are expected to increase. On the functional pathway, stress reduces the oxidative burst capacity of neutrophils and therefore, the leucocyte coping capacity (LCC) quantifying this oxygen radical generation of neutrophils. Therefore, we hypothesized that in ponies subjected to repetitive handling, LCC will decrease and will be negatively correlated with cortisol concent...
Bindi F, Cingottini D, de Marchi L, Sala G, Vitale V, Sgorbini M.Oxidative stress both contributes to and results from sepsis pathophysiology, but its role in ill foals remains poorly characterized. Objective: Ill foals will exhibit decreased antioxidant defense activity and increased oxidative products compared with healthy foals, and these changes will be associated with higher sepsis scores, lower survival scores, and non-survival. Methods: Twenty-six foals < 14 days old: 16 hospitalized foals (11 sick non-septic, 5 septic; median age, 1.5 days; range 1-13) and 10 healthy Standardbred foals (2 days old). Nine of 16 ill foals survived to discharge...
Armonaitė A, Olivier M, Kerzienė S, Picandet V.The treatment for failure of transfer of passive immunity (FTPI) in foals with hyperimmune plasma has substantial variability of efficacy. Objective: The aims of the study were to assess the safety and efficacy of plasma transfusion and to investigate factors that may predict transfusion results, thereby allowing estimation of plasma volume requirements prior to transfusion. Methods: A retrospective review was conducted of foals admitted to an equine hospital that received a plasma transfusion for FTPI. Results: The study included 110 foals and 150 hyperimmune plasma transfusions. The median i...
Concha D, Azocar-Aedo L, Ricardo T, Rodriguez A, Ramirez R, Paffetti MG.Leptospirosis is a bacterial zoonotic disease with clinical consequences and potential sequelae in horses. Objective: To estimate the pooled global seroprevalence of anti-Leptospira antibodies in horses, detected with the Microscopic Agglutination Test, the frequency by serogroups and serovars, the geographical distribution of studies and the main reported clinical signs and organic manifestations through a systematic review and meta-analysis. Methods: A bibliographic search was conducted for cross-sectional epidemiologic studies published between 2015 and 2025. The risk of bias was determined...
Brown KA, Max LNF, Struble SE, Linardi RL, Ortved KF.Determine the acute effects of xylazine and detomidine on concentrations of selected growth factors, cytokines, and α2-macroglobulin (A2M) in platelet-rich plasma (PRP) and autologous protein solution (APS) and the long-term effects of these sedatives on serum A2M. We hypothesized that sedative administration would decrease concentrations of all bioactive proteins in PRP and APS acutely and A2M in serum for 6 days following sedative administration. Unassigned: 6 horses were randomized to receive IV xylazine (200 mg) or detomidine (10 mg). Blood was collected before and 5 minutes after sedativ...
Paillot R, Newton JR, Gonzalez Medina S, Frosth S, Frykberg L, Flock M, Guss B, Flock JI, Waller AS.Streptococcus equi subspecies zooepidemicus is a highly diverse opportunistic pathogen of horses, associated with respiratory disease and endometritis. Objective: To characterise S. zooepidemicus isolates recovered from young ponies during a natural episode of respiratory disease, and to determine if vaccination with Strangvac®, a vaccine against Streptococcus equi subspecies equi, conferred cross-protection. Methods: Retrospective analysis of a double-blinded placebo-controlled study involving 32 ponies (16 vaccinates and 16 placebo controls) that experienced a natural episode of respiratory...
Yoshida S, Takeyama A, Maeda Y, Nambo Y.Maternal cells and antibodies are present in equine colostrum, but their relationship with immune cells in foals after colostrum ingestion remains unclear. This study longitudinally analyzed immune cells in the peripheral blood of neonatal foals at short intervals and investigated their relationship with colostral immune cells. Eleven clinically healthy draft mares and their foals were examined. Foal blood was collected before colostrum intake (0 hr) and at 2-3, 6, 12, 36-48 hr, and 3 and 7 days after ingestion. Mare blood and milk (0, 36-48 hr; 0 hr milk defined as colostrum) were also collec...
Jin F, Shi Y, Wang L, Kuang T, Ren K, Xu J, Zhang Y, Niu C, Cheng J, Pan S.Colitis is a chronic relapsing inflammatory disorder characterized by persistent mucosal inflammation, epithelial barrier disruption, oxidative stress, immune dysregulation, and gut microbiota imbalance. Although current therapies have improved disease management, their long-term use is still limited by incomplete response, relapse, adverse effects, and high cost. Natural products have attracted increasing attention as promising candidates for colitis intervention because of their structural diversity, broad bioactivity, and multitarget regulatory potential. In veterinary medicine, colitis and...
Khan FA, Caissie MD, Wagner B, Scholtz EL, Chenier TS.Persistent breeding-induced endometritis (PBIE) is a major cause of infertility in mares. Recent research has shown that PBIE-affected mares treated with intrauterine N-acetyl cysteine (NAC) 12 hours before breeding showed no improvement in clinical signs at 12- and 60-hours post-breeding. Objective: The present study was designed to examine the effects of NAC treatment on the uterine inflammatory cytokine and chemokine profiles in PBIE-affected mares. Methods: Using a randomized, blinded, cross-over design, mares susceptible to PBIE (n=9) were allocated to Control and Treatment cycles with at...
Van Reusel Y, Broeckx SY, Carolo A, Patruno M, Steenbrugge J, Saunders J, Gugliandolo E, Spaas JH.Orthobiologics such as platelet-rich plasma (PRP) and alpha-2-macroglobulin (A2MG) are increasingly used for equine musculoskeletal injuries. However, their composition and safety with repeated allogeneic intra-articular administration remain poorly investigated. Objective: To characterise orthobiological preparations with or without 1 h incubation at 37°C (PRP, PRP + Inc, A2MG, A2MG + Inc) and evaluate immunological safety following repeated intra-articular administration (autologous and allogeneic) of PRP combined with A2MG + Inc in healthy horses. Methods: In vivo experiments...
Tanner K, Mays M, Nguyen TA, Lugo T.Multisystemic eosinophilic epitheliotropic disease (MEED) is a rare and severe equine disorder characterized by chronic eosinophilic inflammation, epithelial disruption, and multi-organ involvement, with an undefined genetic basis. We performed the high-depth (~40×) whole-genome sequencing of an affected horse and compared it to 40 control genomes. Over 6.3 million variants were identified, with moderate- and high-impact variants enriched in low-frequency categories, including rare and private variants absent from the controls. The affected horse was dominated by missense mutations, with rela...
Ren H, Chen K, Zhou B, Zhang W, Wang XF, Wang X.Type I interferons (IFNs) play a pivotal role in antiviral defence by inducing interferon-stimulated genes (ISGs) that target multiple stages of viral replication. Equine infectious anemia virus (EIAV) is an ancient lentivirus that establishes long-term asymptomatic infections in equids, suggesting its exceptional immune evasion capabilities. However, the mechanisms by which EIAV modulates IFN responses remain unclear. Here, we demonstrate that EIAV infection attenuates ISG expression at the post-transcriptional level. The viral Rev protein plays a central role by interacting with the stress g...
Pinto JEL, Gervásio JHB, Ng JC, Gomes-Silva A, de Matos Guedes HL, Cunha L, Castilho LR, da Silva JL, Franco GR, Navas C, Felicori LF.The humoral immune response relies on a diverse antibody repertoire, which is expanded through processes such as somatic hypermutation, class-switch recombination and gene conversion. These processes are primarily mediated by activation-induced cytidine deaminase (AID). Gene conversion generates diversity in immunoglobulin heavy and light chains (IGHVs) in species such as chickens and rabbits, though it has not been widely studied. Since 80% of the equine IGHV repertoire originates from only three functional gene segments, we examined gene conversion events in horses to assess their role in an...
Zhou B, Chen K, Liang H, Qi T, Guo X, Wen Y-J, Du C, Wang X.Equine arteritis virus (EAV) is a positive-sense, single-stranded RNA virus that belongs to the family , which also includes porcine reproductive and respiratory syndrome virus (PRRSV). EAV is the causative agent of equine viral arteritis (EVA), an economically important systemic, reproductive, and respiratory disease of equids. EAV infection triggers host innate immunity, yet the precise strategies employed by the virus to evade immune defenses and achieve productive infection are poorly characterized. In this study, it was observed that EAV infection can induce a cellular IFN response; howev...
Geng A, Wang X, Li L, Cowie S, Bai D, Dugarjaviin M, Zhang X.The scientific evidence regarding the use of plant-derived extracts to alleviate exercise-induced muscle damage in horses remains limited. Mulberry leaf flavonoids (MLFs) are the primary bioactive constituents of a traditional medicinal plant and are potent antioxidants. The aim of this study was to investigate the protective effects of MLFs against exercise-induced muscle damage. In this study, twelve Mongolian horses were used in a 3 × 3 Latin square design to investigate the protective effects of MLFs. Our results showed that high-intensity exercise negatively impacted the immune status, m...
Valero-Cedeño N, Durán A, Mosquera JA.Venezuelan equine encephalitis virus (VEEV) is an alphavirus vectored by mosquitos. It can cause disease in equines and humans characterised by a febrile illness that may progress into encephalitis. Replication of VEEV in the central nervous system induces activation of glial cells and neurons, compromising the blood-brain barrier (BBB) and inducing a state of neuroinflammation. This inflammation can lead to symptoms such as confusion, seizures, and coma, and sustained inflammation contributes to neurodegeneration. C-reactive protein (CRP) is a biomarker that has previously been associated wit...
Gago P, Cruz-Lopez F, Dorrego A, Rivera B, de Juan L, Lorente-Leal V.Equine viral arteritis (EVA) remains a relevant health and economic concern due to the ability of some infected stallions to establish long-term persistent infection with equine arteritis virus (EAV). Allelic variation in the CXCL16 gene has been identified as a determinant of susceptibility or resistance to the carrier state, positioning genotyping as a useful tool for risk-based reproductive and health management. Objective: To characterise the distribution of CXCL16 genotypes in export-bound horses from Spain and to assess the utility of CXCL16 genotyping for EVA prevention and control. Met...
Eertink LG, Jacob O, Adam EN, Page AE, Wang D, Li F.Despite a monovalent G3P[12] ('G3') vaccine being available for horses, equine rotavirus A (ERVA) is still the predominant infectious pathogen causing diarrhea in foals in the United States of America (U.S.). Previous research has shown that maternal neutralizing antibody (NAb) titers are too high and will interfere with the vaccination of foals at 30 and 45 days of age. We aimed to determine if it is possible to increase NAb titers in foals through vaccination before they are vulnerable to ERVA infection. We immunized two foals with the commercially available vaccine (G3) at solely three mont...
Magalhães VLP, Pinho FA, Souza FN, Santos KR, Santos AS, Hlavac N, Libera AMPD, Massoco CO, Barrouin-Melo SM.There are diverse uses for equine peripheral blood mononuclear cells (PBMC) in research. Studies have shown that PBMC isolation protocols can affect immune parameters of diagnostic and research assays. We aimed to assess the impact of equine blood handling techniques on cell yield, viability, and proliferation under mitogen stimulation. Whole blood (WB) samples were collected from eight healthy adult horses into heparinized tubes for PBMC isolation by comparing method 1 (M1) where freshly collected WB was layered directly over a density gradient medium for centrifugation, followed by PBMC harv...
Cooper BL, O'Donnell K, Hickman E, Bayless R, Sheats MK.To determine the impact of a commercially available docosahexaeonic acid (DHA) supplement (DHA, methylslfonylmethane, and mushroom blend) on equine alveolar macrophage metabolism and lipid and protein profiles in bronchoalveolar lavage (BAL) supernatant. Unassigned: This was a prospective, sequential, placebo-controlled study using 10 healthy adult horses. Bronchoalveolar lavage fluid was collected at baseline, following 45 days of oral placebo administration, and following 45 days of oral commercially available DHA supplement, with a 14-day washout. Whole blood was collected following placebo...
Yalavarthi G, Sabbinen H, Kosuri P, Amalaradjou M, Govoni K, Nadeau J.Strongyles are parasitic roundworms that cause significant gastrointestinal infections in equines, primarily through contact with infected soil. Worldwide, strongylosis affects nearly 90% of horse populations. Objective: The objectives of our study were to determine if there was a relationship between fecal egg count (FEC) and housing types on interleukin IL-4 and IL-13. Methods: Horses (N=25) were separated into two groups based on housing conditions: pasture (housed on pasture 24/7; PS, N=13) and semi-intensive (housed in stalls with turnout overnight; SI, N=12). Within each housing group, t...
Espinosa MA, Lack A, Kenney D, Arroyo LG.Equine herpesvirus type 1 (EHV-1) is an important viral pathogen in horses, associated with diverse clinical manifestations including fever, upper and lower respiratory disease, neurological signs, ocular disease, and abortion. Currently, EHV-1 variants (genotypes) are classified based on a single nucleotide polymorphism mutation of the open reading frame 30 (ORF30). Unassigned: The aim of this retrospective study was to evaluate the EHV-1 genotypes present in horses with various clinical presentations, including respiratory disease, abortion, and neurological disease, at a referral center in ...
Lewis NS, Daly JM, Russell CA, Horton DL, Skepner E, Bryant NA, Burke DF, Rash AS, Wood JL, Chambers TM, Fouchier RA, Mumford JA, Elton DM, Smith DJ.Equine influenza virus is a major respiratory pathogen in horses, and outbreaks of disease often lead to substantial disruption to and economic losses for equestrian industries. The hemagglutinin (HA) protein is of key importance in the control of equine influenza because HA is the primary target of the protective immune response and the main component of currently licensed influenza vaccines. However, the influenza virus HA protein changes over time, a process called antigenic drift, and vaccine strains must be updated to remain effective. Antigenic drift is assessed primarily by the hemagglu...
Guest DJ, Smith MR, Allen WR.Autologous mesenchymal progenitor cells (MPCs) purified from bone marrow aspirates are being used in the treatment of superficial digital flexor tendon (SDFT) injuries in the horse with promising results. In this study the fate of autologous and allogeneic MPCs following injection into the SDFT was monitored by stable transfection of MPCs with green fluorescent protein (GFP). Small lesions were created manually in one forelimb SDFT of 2 horses and injected with autologous MPCs, allogeneic MPCs or bone marrow supernatant alone. Post mortem examinations performed after 10 or 34 days revealed GFP...
Bowen RA, Nemeth NM.West Nile virus emerged recently in North America as a serious human and animal pathogen. This review summarizes the use of experimental infections with West Nile virus in diverse vertebrate species that have been used to answer fundamental questions about the host response, pathogenesis of West Nile virus infection and virus evolution. Results: West Nile virus has an extremely broad vertebrate host range. Infection of common species of birds has defined those with high vs. low potential to serve as amplifying hosts for the virus. In general, mammals (primates, horses, companion animals) are d...
Vargas A, Boivin R, Cano P, Murcia Y, Bazin I, Lavoie JP.Severe neutrophilic asthma is poorly responsive to glucocorticosteroids (GC). Neutrophil extracellular traps (NETs) within the lungs have been associated with the severity of airway obstruction and inflammation in asthma, and were found to be unaffected by GC in vitro. As IL-17 is overexpressed in neutrophilic asthma and contributes to steroid insensitivity in different cell types, we hypothesized that NETs formation in asthmatic airways would be resistant to GC through an IL-17 mediated pathway. Six neutrophilic severe asthmatic horses and six healthy controls were studied while being treated...
Marsh GA, Wang LF.Henipavirus, including Hendra and Nipah viruses, is a group of emerging bat-borne paramyxoviruses which were responsible for severe disease outbreaks in humans, horses and pigs. The mortality rate of human infection varies between 50 and 100%, making them one of the most deadly viruses known to infect humans. Its use of highly conserved cell surface molecules (ephrin) as entry receptors and its highly effective replication and fusion strategies are believed to be important characteristics responsible for its high pathogenicity. Henipavirus also encodes multiple accessory proteins which play a ...
Carrade Holt DD, Wood JA, Granick JL, Walker NJ, Clark KC, Borjesson DL.Mesenchymal stem cells (MSCs) are used in both human clinical trials and veterinary medicine for the treatment of inflammatory and immune-mediated diseases. MSCs modulate inflammation by decreasing the cells and products of the inflammatory response. Stimulated equine MSCs from bone marrow (BM), adipose tissue (AT), cord blood (CB), and umbilical cord tissue (CT) inhibit lymphocyte proliferation and decrease inflammatory cytokine production. We hypothesized that equine MSCs inhibit T cell proliferation through secreted mediators and that MSCs from different tissue sources decrease T cell proli...
Scheel TK, Kapoor A, Nishiuchi E, Brock KV, Yu Y, Andrus L, Gu M, Renshaw RW, Dubovi EJ, McDonough SP, Van de Walle GR, Lipkin WI, Divers TJ....Nonprimate hepacivirus (NPHV) is the closest known relative of hepatitis C virus (HCV) and its study could enrich our understanding of HCV evolution, immunity, and pathogenesis. High seropositivity is found in horses worldwide with ∼ 3% viremic. NPHV natural history and molecular virology remain largely unexplored, however. Here, we show that NPHV, like HCV, can cause persistent infection for over a decade, with high titers and negative strand RNA in the liver. NPHV is a near-universal contaminant of commercial horse sera for cell culture. The complete NPHV 3'-UTR was determined and consists...
Katila T.This review attempts to summarize the current knowledge on uterine inflammatory response after mating in horses, pigs and cattle. Post-mating endometritis has been extensively studied in horses as it has been considered to cause infertility. The inflammation is known to occur also in cattle, but it has not been investigated to a similar extent. There are a number of publications about mechanisms of post-mating uterine inflammation in pigs, which seem to resemble those in horses. The major focus of this review is the horse, but relevant literature is presented also on swine and cattle. Spermato...
Grieder FB, Vogel SN.To investigate the role of type I interferon (IFN) and its regulatory transacting proteins, interferon regulatory factors (IRF-1 and IRF-2), in early protection against infection with virulent Venezuelan equine encephalitis virus (VEE), we utilized mice with targeted mutations in the IFN-alpha/beta receptor, IRF-1, or IRF-2 genes. IFN-alpha/beta-receptor knockout mice are highly susceptible to peripheral infection with virulent or attenuated VEE, resulting in their death within 24 and 48 h, respectively. Treatment of normal macrophages with anti-IFN-alpha/beta antibody prior to and during infe...
Ramsay JD, Evanoff R, Wilkinson TE, Divers TJ, Knowles DP, Mealey RH.Equine hepacivirus (EHCV; nonprimate hepacivirus) is a hepatotropic member of the Flaviviridae family that infects horses. Although EHCV is the closest known relative to hepatitis C virus (HCV), its complete replication kinetics in vivo have not been described, and direct evidence that it causes hepatitis has been lacking. In this study, we detected EHCV in 2 horses that developed post-transfusion hepatitis. Plasma and serum from these horses were used to experimentally transmit EHCV to 4 young adult Arabian horses, two 1-month-old foals (1 Arabian and 1 Arabian-pony cross), and 2 foals (1 Ara...
Carrade DD, Affolter VK, Outerbridge CA, Watson JL, Galuppo LD, Buerchler S, Kumar V, Walker NJ, Borjesson DL.BACKGROUND AIMS. The use of allogeneic mesenchymal stem cells (MSC) to treat acute equine lesions would greatly expand equine cellular therapy options; however, the safety and antigenicity of these cells have not been well-studied. We hypothesized that equine allogeneic umbilical cord tissue (UCT)-derived MSC would not elicit acute graft rejection or a delayed-type hypersensitivity response when injected intradermally. METHODS. Six Quarterhorse yearlings received 12 intradermal injections (autologous MSC, allogeneic MSC, positive control and negative control, in triplicate) followed by the sam...
Stewart AS, Pratt-Phillips S, Gonzalez LM.All species, including horses, suffer from alterations that increase intestinal permeability. These alterations, also known as "leaky gut," may lead to severe disease as the normal intestinal barrier becomes compromised and can no longer protect against harmful luminal contents including microbial toxins and pathogens. Leaky gut results from a variety of conditions including physical stressors, decreased blood flow to the intestine, inflammatory disease, and pathogenic infections, among others. Several testing methods exist to diagnose these alterations in both a clinical and research setting....
Nara PL, Garrity RR, Goudsmit J.The production of immunoglobulin capable of neutralizing the infectivity of a virus represents one of the most remarkable molecular accomplishments of the host's available immune defenses. It should be no surprise that a virus that has existed in the parenchyma of the immune system has evolved as an equally dynamic molecule (i.e., viral envelope) for survival. Neutralizing immunoglobulin (Ig) can best serve the host under conditions where the invading pathogen requires a well-defined cell-free state for establishing an infection or transmission. Evidence for a controlling and therefore protect...
Edington N, Bridges CG, Patel JR.Eight mares were infected with equid herpesvirus-1 subtype 1 isolated from a case of equine paresis. In two mares killed at 4 d.p.i. immunofluorescence showed endothelial cell infection together with thrombosis in the rete arteriosus of the nasal mucosa and also in the spinal cord of one of these mares. Circulating platelet counts in the other six mares fell as early as 2 d.p.i. and remained depressed for seven days. Circulating immune complexes started to appear at 2 d.p.i., reached maximum levels at 10 d.p.i., but were undetectable at 28 d.p.i. Three of the six remaining mares developed vary...
Berglund AK, Schnabel LV.Allogeneic mesenchymal stem cells (MSCs) are a promising cell source for treating musculoskeletal injuries in horses. Controversy exists, however, over whether major histocompatibility complex (MHC)-mismatched MSCs are recognised by the recipient immune system and targeted for death by a cytotoxic antibody response. Objective: To determine if cytotoxic anti-MHC antibodies generated in vivo following MHC-mismatched MSC injections are capable of initiating complement-dependent cytotoxicity of MSCs. Methods: Experimental controlled study. Methods: Antisera previously collected at Days 0, 7, 14 an...
Pigott JH, Ishihara A, Wellman ML, Russell DS, Bertone AL.Mesenchymal stem cells have demonstrated immunomodulatory capabilities as well as modest efficacy in animal models of joint injury, warranting further study as a potential treatment of joint disease. The goal of the study was to investigate the blood and synovial immune and histologic response to intra-articular injection of autologous, allogeneic, and xenogeneic bone marrow-derived mesenchymal stem cells (MSC) in horses. The study group consisted of 6 five-year-old Thoroughbred mares that had been injected previously with 15 million, genetically modified autologous, allogeneic, or xenogeneic ...
Jacobsen S, Kjelgaard-Hansen M, Hagbard Petersen H, Jensen AL.The aim of the present study was to evaluate whether equine serum amyloid A (SAA) concentrations could be measured reliably with a turbidometric immunoassay (TIA) developed for use with human serum. Intra- and inter-assay imprecision were evaluated by multiple measurements on equine serum pools. Assay inaccuracy was determined by linearity under dilution. The assay was subsequently used for measuring SAA concentrations in clinically healthy horses, horses with inflammatory diseases, horses with non-inflammatory diseases, and in horses before and after castration. In pools with low, intermediat...
Leclere M, Lavoie-Lamoureux A, Joubert P, Relave F, Setlakwe EL, Beauchamp G, Couture C, Martin JG, Lavoie JP.Recent studies suggest that airway smooth muscle remodeling is an early event in the course of asthma. Little is known of the effects of long-term antigen avoidance and inhaled corticosteroids on chronically established airway remodeling. We sought to measure the effects of inhaled corticosteroids and antigen avoidance on airway remodeling in the peripheral airways of horses with heaves, a naturally occurring asthma-like disease. Heaves-affected adult horses with ongoing airway inflammation and bronchoconstriction were treated with fluticasone propionate (with and without concurrent antigen av...
Ma G, Azab W, Osterrieder N.The equine herpesviruses type 1 (EHV-1) and 4 (EHV-4) are ubiquitous pathogens that affect horse populations on all continents. Despite widespread vaccination, EHV-1 and EHV-4 infections remain a permanent risk. While the two viruses share a high degree of genetic and antigenic similarity, they differ significantly in host range and pathogenicity. Compared to EHV-4, which mainly infects horses and causes respiratory disease, EHV-1 has a broader host range and can result in respiratory disease, abortions, neonatal death, and equine herpesvirusmyeloencephalopathy (EHM). Recent studies have eluci...
Meijer WG, Prescott JF.Rhodococcus equi is an important cause of subacute or chronic abscessating bronchopneumonia of foals up to 3-5 months of age. It shares the lipid-rich cell wall envelope characteristic of the mycolata, including Mycobacterium tuberculosis, as well as the ability of pathogenic members of this group to survive within macrophages. The possession of a large virulence plasmid in isolates recovered from pneumonic foals is crucial for virulence. The plasmid contains an 27 kb pathogenicity island (PI) that encodes seven related virulence-associated proteins (Vaps), including the immunodominant surface...
Giguère S, Prescott JF.Since the 1986 Rhodococcus equi workshop, there have been major breakthroughs in understanding the epidemiology of, the virulence of, and the immune response to, this intriguing pathogen. However, with the exception of the use of hyperimmune plasma for the prevention of the disease (Martens et al., 1989; Madigan et al., 1991) the clinical aspects of R. equi infections have essentially remained unchanged. This article reviews the various clinical manifestations and summarizes recent advances in diagnosis, treatment and prevention of R. equi infections in foals.
El Garch H, Minke JM, Rehder J, Richard S, Edlund Toulemonde C, Dinic S, Andreoni C, Audonnet JC, Nordgren R, Juillard V.Successful vaccination against West Nile virus (WNV) requires induction of both neutralizing antibodies and cell-mediated immune responses. In this study, we have assessed the ability of a recombinant ALVAC-WNV vaccine (RECOMBITEK WNV) to elicit neutralizing antibodies and virus-specific cell-mediated immune responses in horses. In addition, we examined whether prior exposure to ALVAC-WNV vaccine would inhibit B and cell-mediated immune responses against the transgene product upon subsequent booster immunizations with the same vaccine. The results demonstrated that the recombinant ALVAC-WNV va...
H A Morris L, M McCue P, Aurich C.Endometritis in the mare begins as a normal physiological inflammatory response to breeding that involves both a mechanical and immunological response pathway activated to rid the uterus of semen and bacteria. With successful resolution of this inflammation, the mare's uterus will provide a hospitable environment for the development of the semi-allogenic conceptus. If the mare fails to resolve this inflammatory response within 48 h of breeding, she will become susceptible to persistent breeding-induced endometritis (PBIE) which will have detrimental effects on her fertility. This condition can...
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...
Afable MG, Shaik M, Sugimoto Y, Elson P, Clemente M, Makishima H, Sekeres MA, Lichtin A, Advani A, Kalaycio M, Tiu RV, O'Keefe CL, Maciejewski JP.A combination of horse anti-thymocyte globulin and cyclosporine produces responses in 60-70% of patients with severe aplastic anemia. We performed a phase II study of rabbit anti-thymocyte globulin and cyclosporine as first-line therapy for severe aplastic anemia. Methods: Twenty patients with severe aplastic anemia treated with rabbit anti-thymocyte globulin were compared to 67 historical control cases with matched clinical characteristics treated with horse anti-thymocyte globulin. Results: Response rates at 3, 6 and 12 months were similar for patients treated with rabbit anti-thymocyte glob...
Perryman LE, O'Rourke KI, McGuire TC.Six normal and four immunodeficient horses were injected with a cloned variant of equine infectious anemia virus (EIAV). The six normal horses had detectable EIAV in their plasma by 7 days postinjection. During their primary viremic episode, which was accompanied by fever and anemia, maximum titers of EIAV in plasma ranged from 10(3.8) to 10(4.8) 50% tissue culture infective doses per ml. All six normal horses cleared detectable virus from their plasma by 21 to 35 days after injection. Horses with combined immunodeficiency became viremic by 9 days postinjection and also developed anemia. In co...
Muscatello G, Leadon DP, Klayt M, Ocampo-Sosa A, Lewis DA, Fogarty U, Buckley T, Gilkerson JR, Meijer WG, Vazquez-Boland JA.Infection with Rhodococcus (Corynebacterium) equi is a well-recognised condition in foals that represents a consistent and serious risk worldwide. The condition manifests itself primarily as one of pulmonary abscessation and bronchitis, hence the terminology of 'rattles' derived from its most obvious clinical sign, frequently terminal when first identified. This review addresses the clinical manifestation, bacteriology and pathogenesis of the condition together with recent developments providing knowledge of the organism in terms of virulence, epidemiology, transmission and immune responses. E...
Lavoie JP, Maghni K, Desnoyers M, Taha R, Martin JG, Hamid QA.Heaves in horses shares many similarities with human asthma, including lower airway inflammation, reversible airway obstruction, and bronchial hyperresponsiveness. Extrinsic asthma is an allergic response to environmental allergens and a similar immunologic mechanism may be implicated in heaves. It is now recognized that a Th2 subset of CD4+ lymphocytes is associated with allergic diseases such as atopic asthma. The purpose of this study was to determine whether airway inflammation in heaves is associated with a pattern of expression of cytokine suggestive of a Th2 type response. The expressio...
Lewis MJ, Wagner B, Woof JM.Recombinant versions of the seven equine IgG subclasses were expressed in CHO cells. All assembled into intact immunoglobulins stabilised by disulphide bridges, although, reminiscent of human IgG4, a small proportion of equine IgG4 and IgG7 were held together by non-covalent bonds alone. All seven IgGs were N-glycosylated. In addition IgG3 appeared to be O-glycosylated and could bind the lectin jacalin. Staphylococcal protein A displayed weak binding for the equine IgGs in the order: IgG1>IgG3>IgG4>IgG7>IgG2=IgG5>IgG6. Streptococcal protein G bound strongly to IgG1, IgG4 and IgG...
Goodman LB, Wagner B, Flaminio MJ, Sussman KH, Metzger SM, Holland R, Osterrieder N.Equine herpesvirus type 1 (EHV-1) is a ubiquitous alphaherpesvirus of horses which causes rhinopneumonitis, abortion and myeloencephalopathy. To test the efficacy of commercial vaccines in protection against neurological EHV-1 challenge, groups of five horses were immunized with modified-live virus or an inactivated vaccine, or received placebo. Horses were challenged by aerosol with a recent virus isolate obtained from a case of paralytic EHV-1. The duration of fever decreased significantly in the modified-live virus vaccine group. Three animals in each of the inactivate and control groups sh...
