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Topic:Immune Response
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.
Efficacy of an avirulent live vaccine against Lawsonia intracellularis in the prevention of proliferative enteropathy in experimentally infected weanling foals. To determine the efficacy of an avirulent Lawsonia intracellularis vaccine in preventing proliferative enteropathy in weanling foals. Methods: 12 healthy weanling foals. Methods: Foals were randomly assigned to a vaccinated, nonvaccinated, or control group. Vaccinated foals received an avirulent porcine L intracellularis frozen-thawed vaccine intrarectally 60 and 30 days prior to experimental challenge. On day 1, vaccinated and nonvaccinated foals were challenged via nasogastric intubation with a virulent heterologous isolate of L intracellularis. Control foals were not challenged. Clinical ob...
Infected dendritic cells are sufficient to mediate the adjuvant activity generated by Venezuelan equine encephalitis virus replicon particles. Replicon particles derived from Venezuelan equine encephalitis virus (VEE) are infectious non-propagating particles which act as a safe and potent systemic, mucosal, and cellular adjuvant when delivered with antigen. VEE and VEE replicon particles (VRP) can target multiple cell types including dendritic cells (DCs). The role of these cell types in VRP adjuvant activity has not been previously evaluated, and for these studies we focused on the contribution of DCs to the response to VRP. By analysis of VRP targeting in the draining lymph node, we found that VRP induced rapid recruitment of TNF-s...
Intestinal bacterial overgrowth includes potential pathogens in the carbohydrate overload models of equine acute laminitis. Carbohydrate overload models of equine acute laminitis are used to study the development of lameness. It is hypothesized that a diet-induced shift in cecal bacterial communities contributes to the development of the pro-inflammatory state that progresses to laminar failure. It is proposed that vasoactive amines, protease activators and endotoxin, all bacterial derived bioactive metabolites, play a role in disease development. Questions regarding the oral bioavailability of many of the bacterial derived bioactive metabolites remain. This study evaluates the possibility that a carbohydrate-induc...
Immunogenicity of two adjuvant formulations of an inactivated African horse sickness vaccine in guinea-pigs and target animals. Monovalent, inactivated and adjuvanted vaccines against African horse sickness, prepared with serotypes 5 and 9, were tested on guinea-pigs to select the formulation that offered the greatest immunity. The final formulation of the vaccines took into account the immune response in the guinea-pig and the inflammatory properties of two types of adjuvant previously tested on target animals. A pilot study was subsequently conducted on horses using a vaccine prepared with serotype 9. The vaccine stimulated neutralising antibodies from the first administration and, after the booster dose, 28 days lat...
Effect of strenuous exercise and ex vivo TLR3 and TLR4 stimulation on inflammatory gene expression in equine pulmonary leukocytes. The effects of strenuous exercise and ex vivo stimulation of TLR3 and TLR4 pathways on the expression of six inflammatory genes in equine pulmonary leukocytes were investigated. The genes tested were interferon-beta (IFN-β), interleukin-1-beta (IL-1β), interleukin-6 (IL-6), interferon gamma-induced protein 10 (IP-10), chemokine (c-c motif) ligand 5 (RANTES) and tumor necrosis factor-alpha (TNF-α). We hypothesized that strenuous exercise would modulate basal gene expression on one hand and modulate the response to bacterial lipopolysaccharide (LPS) and to polyinosinic:polycytidylic acid (Pol...
Hendra and Nipah viruses: why are they so deadly? 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 ...
IL-22 is expressed by the invasive trophoblast of the equine (Equus caballus) chorionic girdle. The invasive trophoblast cells of the equine placenta migrate into the endometrium to form endometrial cups, dense accumulations of trophoblast cells that produce equine chorionic gonadotropin between days 40 and 120 of normal pregnancy. The mechanisms by which the trophoblast cells invade the endometrium while evading maternal immune destruction are poorly defined. A gene expression microarray analysis performed on placental tissues obtained at day 34 of gestation revealed a >900-fold upregulation of mRNA encoding the cytokine IL-22 in chorionic girdle relative to noninvasive chorion. Quan...
Inflammatory responses to induced infectious endometritis in mares resistant or susceptible to persistent endometritis. The objective of the study was to evaluate the gene expression of inflammatory cytokines (interleukin [IL]-1β, IL-6, IL-8, IL-10, tumor necrosis factor [TNF]-α, IL-1 receptor antagonist [ra] and serum amyloid A (SAA) in endometrial tissue and circulating leukocytes in response to uterine inoculation of 105 colony forming units (CFU) Escherichia coli in mares. Before inoculation, mares were classified as resistant or susceptible to persistent endometritis based on their uterine inflammatory response to infusion of 109 killed spermatozoa and histological assessment of the endometrial quality. ...
Immunogenicity and clinical protection against equine influenza by DNA vaccination of ponies. Equine influenza A (H3N8) virus infection is a leading cause of respiratory disease in horses, resulting in widespread morbidity and economic losses. As with influenza in other species, equine influenza strains continuously mutate, often requiring the development of new vaccines. Current inactivated (killed) vaccines, while efficacious, only offer limited protection against diverse subtypes and require frequent boosts. Research into new vaccine technologies, including gene-based vaccines, aims to increase the neutralization potency, breadth, and duration of protective immunity. Here, we demons...
Association of adrenocorticotrophin and cortisol concentrations with peripheral blood leukocyte cytokine gene expression in septic and nonseptic neonatal foals. 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...
Miscellaneous vitreous-derived IgM antibodies target numerous retinal proteins in equine recurrent uveitis. In equine recurrent uveitis (ERU), immune reactions are directed toward known antigens like S-antigen, interphotoreceptor retinoid-binding protein, and cellular retinalaldehyde-binding protein, and anti-retinal antibodies were detected in vitreous samples. The aim of this study was the investigation of intraocular immunoglobulin M (IgM) reactivities to retinal proteome. Methods: Retina was separated by one- and two-dimensional gel electrophoresis and blotted semidry on PVDF membranes. To identify intraocular IgM antibody responses to retinal tissue, blots were incubated with vitreous samples o...
Intestinal barrier function in neonatal foals: options for improvement. Gastrointestinal defence in the new-born is limited in comparison to adults, due to an immature epithelial barrier function and deficits in both innate and adaptive immune responses. Consequently, neonates (including foals) are at increased risk of disturbance to mucosal homeostasis during initial intestinal colonisation that may lead to excessive inflammation and bacterial translocation into the bloodstream, resulting in septicaemia. Bacterial recognition by Pattern Recognition Receptors (PRRs) and their downstream regulation of cytokine release have been shown to be pivotal for gastrointesti...
Generation and characterization of monoclonal antibodies to equine CD16. The low-affinity Fc receptor CD16 plays a central role in the inflammatory and innate immune responses of many species, but has not yet been investigated in the horse. Using the predicted extracellular region of equine CD16 expressed as a recombinant fusion protein with equine IL-4 (rIL-4/CD16), we generated a panel of mouse monoclonal antibodies (mAbs) that recognize equine CD16. Nine mAbs were chosen for characterization based upon recognition of CD16, but not IL-4, in ELISA. All nine mAbs recognized full-length, cell-surface CD16 expressed as a GFP fusion protein by CHO cells, but not the c...
Monoclonal antibodies to equine CD23 identify the low-affinity receptor for IgE on subpopulations of IgM+ and IgG1+ B-cells in horses. CD23, also called FcεRII, is the low-affinity receptor for IgE and has first been described as a major receptor regulating IgE responses. In addition, CD23 also binds to CD21, integrins and MHC class II molecules and thus has a much wider functional role in immune regulation ranging from involvement in antigen-presentation to multiple cytokine-like functions of soluble CD23. The role of CD23 during immune responses of the horse is less well understood. Here, we expressed equine CD23 in mammalian cells using a novel IL-4 expression system. Expression resulted in high yield of recombinant IL-4/...
Cytokine production and proliferation upon in vitro oligodeoxyribonucleotide stimulation of equine peripheral blood mononuclear cells. Synthetic oligodeoxyribonucleotides (ODN) may prove useful immune modulators in equine medicine. It is however important to assess the effects of each specific ODN in the species it is intended to be used in. The present study therefore aimed to evaluate some ODN for induction of cytokine production; i.e. type I interferons (IFN), IFN-γ, tumor necrosis factor-α (TNF-α) and transforming growth factor-β (TGF-β), and proliferation of equine peripheral blood mononuclear cells (PBMC). A panel of four ODN containing unmethylated cytosine-guanosine sequences (CpG) was used: ODN 1 and ODN 8 repre...
Virus-specific CD8⁺ T-cells detected in PBMC from horses vaccinated against African horse sickness virus. African horsesickness (AHS) is an infectious but noncontagious viral disease affecting all species of Equidae. The recall immune response of AHSV naïve horses immunised with an attenuated African horsesickness virus serotype 4 (AHSV4) was characterised using immune assays including ELISPOT, real-time PCR (qPCR) and flow cytometry. The recall immune response detected in PBMC isolated from three inoculated horses showed an upregulation of circulating B lymphocytes that correlated with elevated IL-4 mRNA expression indicative of humoral immunity, but reduced frequency of CD4⁺ cells. In additio...
Systemic inflammation and priming of peripheral blood leukocytes persist during clinical remission in horses with heaves. To compare innate immune responses of peripheral blood leukocytes from healthy and asymptomatic heaves-affected horses. Methods: Heaves-affected horses (n=5-6) and healthy controls (n=4-5) kept under low dust environments (pasture or shavings and pellets). Methods: Blood neutrophil and neutrophil-depleted cell populations were isolated using MACS system. Cells were incubated with or without bacterial products (lipopolysaccharide (LPS), 100 ng/mL and fMLP, 5 ng/mL, 5 h). Cytokine (IL-1β, IL-8, TNF, IL-4, INFγ and IL-10) and receptor (TLR4) mRNA expression was assessed by qPCR. TNF concentrati...
Altered expression of talin 1 in peripheral immune cells points to a significant role of the innate immune system in spontaneous autoimmune uveitis. The molecular mechanism which enables activated immune cells to cross the blood-retinal barrier in spontaneous autoimmune uveitis is yet to be unraveled. Equine recurrent uveitis is the only spontaneous animal model allowing us to investigate the autoimmune mediated transformation of leukocytes in the course of this sight threatening disease. Hypothesizing that peripheral blood immune cells change their protein expression pattern in spontaneous autoimmune uveitis, we used DIGE to detect proteins with altered abundance comparing peripheral immune cells of healthy and ERU diseased horses. Among ...
Clinical and virological outcome of an infection with the Belgian equine arteritis virus strain 08P178. Equine viral arteritis (EVA) is an infectious disease with variable clinical outcome. Outbreaks, causing important economic losses, are becoming more frequent. Currently, there is a shortage of pathogenesis studies performed with European strains. In the present study, eight seronegative ponies were experimentally inoculated with the Belgian strain of equine arteritis virus (EAV) 08P178 (EU-1 clade) and monitored daily for clinical signs of EVA. Nasopharyngeal swabs, ocular swabs, bronchoalveolar cells and blood were collected for virological and serological testing. Two ponies were euthanized...
Inflammation and immune response of intra-articular serotype 2 adeno-associated virus or adenovirus vectors in a large animal model. Intra-articular gene therapy has potential for the treatment of osteoarthritis and rheumatoid arthritis. To quantify in vitro relative gene transduction, equine chondrocytes and synovial cells were treated with adenovirus vectors (Ad), serotype 2 adeno-associated virus vectors (rAAV2), or self-complementary (sc) AAV2 vectors carrying green fluorescent protein (GFP). Using 6 horses, bilateral metacarpophalangeal joints were injected with Ad, rAAV2, or scAAV2 vectors carrying GFP genes to assess the in vivo joint inflammation and neutralizing antibody (NAb) titer in serum and joint fluid. In vit...
Effect of corticotherapy on proteomics of endometrial fluid from mares susceptible to persistent postbreeding endometritis. The objective was to determine the effects of corticotherapy, in the presence and absence of uterine inflammation, on proteomics of endometrial fluid from mares susceptible to endometritis. In 11 mares, estrus was induced seven times with 5 mg PGF(2α) given at 14-day intervals. The first estrus was a control (no treatment). During the third estrus, mares received glucocorticoid (GC) treatment (20 mg isoflupredone acetate) every 12 h, for three consecutive days. The fifth estrus was the Infected treatment (intrauterine infusion of 1 × 10(9) colony-forming unit/mL Streptococcus equi subspecies...
Immunological correlates of vaccination and infection for equine herpesvirus 1. Equine herpesvirus 1 (EHV-1) induces a variety of disease manifestations, including respiratory disease, abortions, and myeloencephalopathy. Several vaccines are commercially available but could not previously be distinguished by serologic testing from infection with EHV-1 (or the closely related EHV-4). Currently available vaccines are not reliably protective against the severe manifestations of the disease, including fatal myeloencephalopathy. We determined immunological parameters that can differentiate vaccinated from previously infected animals by comparing humoral and cellular EHV-1-spec...
Effect of progesterone on the in vitro response of peripheral blood mononuclear cells stimulated by Escherichia coli in mares. Escherichia coli(E. coli) isolated from the uterus of a Thoroughbred mare with bacterial endometritis was used to evaluate the effect of progesterone (P(4)) on the immune response of mares. Peripheral blood mononuclear cells (PBMCs) were collected from 10 nonpregnant clinically healthy adult mares (range, 4-12 years) during diestrus, four Thoroughbreds and six Hokkaido native horses. Cell proliferation and expression of cytokine mRNA, including interferon (IFN)-γ, tumor necrosis factor (TNF)-α and interleukin (IL)-10, of PBMCs stimulated with E. coli and P(4) were examined in vitro. P(4) was...
Assessment of correlation between in vitro CD3+ T cell susceptibility to EAV infection and clinical outcome following experimental infection. In a recent study, we demonstrated that the virulent Bucyrus strain (VBS) of EAV could infect in vitro a small population of CD3(+) T lymphocytes from some but not all horses. Furthermore, we have shown that a common haplotype is associated with this in vitro CD3(+) T cell susceptibility/resistance phenotype to EAV infection. In this study, we investigated whether the differences in the susceptibility or resistance of CD3(+) T cells in vitro correlate with the outcome and severity of clinical signs in vivo. Thus, horses were divided into two groups based on their CD3(+) T cell susceptible or r...
Comparison of the response to experimentally induced short-term inflammation in the temporomandibular and metacarpophalangeal joints of horses. To investigate the relationship between inflammatory responses of the temporomandibular joint (TMJ) and the metacarpophalangeal (MCP) joint in clinically normal horses. Methods: 7 mature horses. Methods: In each horse, 1 TMJ and 1 MCP joint were injected with lipopolysaccharide (LPS; 0.0025 μg). The contralateral TMJ and MCP joint were injected with saline (0.9% NaCl) solution. Synovial fluid samples were collected from all 4 joints over 24 hours after injection. Concentrations of interleukin-6, tumor necrosis factor-α, transforming growth factor-β, and total protein were measured via immun...
ISCOM-matrix-based equine influenza (EIV) vaccine stimulates cell-mediated immunity in the horse. The humoral immune response induced by ISCOM-matrix (Immuno Stimulating COMplex-Matrix)-adjuvanted equine influenza virus (EIV) vaccine is well documented in horses. ISCOM-matrix adjuvanted vaccines against human influenza are strong inducers of cell-mediated immunity (CMI), including T cell proliferation and virus-specific cytotoxic T cell. In the horse, the CMI response to equine influenza vaccination is less well characterised. An ISCOM-based vaccine has been shown to induce interferon gamma (IFN-γ) synthesis, a CMI marker, in the horse, but this has not been shown for the ISCOM-matrix vac...
Neutrophil function of neonatal foals is enhanced in vitro by CpG oligodeoxynucleotide stimulation. Rhodococcus equi is an intracellular bacterium that causes pneumonia in foals and immunocompromised adult horses. Evidence exists that foals become infected with R. equi early in life, a period when innate immune responses are critically important for protection against infection. Neutrophils are innate immune cells that play a key role in defense against this bacterium. Enhancing neutrophil function during early life could thus help to protect foals against R. equi infection. The objective of our study was to determine whether in vitro incubation with the TLR9 agonist CpG 2142 would enhance d...
Neutrophil and cytokine dysregulation in hyperinsulinemic obese horses. Equine metabolic syndrome is characterized by obesity and regional adiposity coupled with evidence of recurrent laminitis. Although inflammation has been well characterized in several experimental models of acute laminitis, the inflammatory events associated with endocrinopathic laminitis are not well documented. The aim of this study was to characterize selected markers of inflammation in horses with clinical evidence of equine metabolic syndrome (EMS). Neutrophil phagocytosis and oxidative burst, as well as endogenous and stimulated cytokine expression were evaluated. A marked increase in ne...
