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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.
Transforming growth factor beta concentrations and interferon gamma responses in cerebrospinal fluid of horses with equine protozoal myeloencephalitis. The following experiment was performed to test the hypothesis that transforming growth factor beta (TGF-beta) concentration varies in the cerebrospinal fluid and serum of horses with EPM and to determine if cerebrospinal fluid (CSF) alters the interferon-gamma (IFN-gamma) rersponse of equine peripheral blood mononuclear cells (PBMCs). The concentration of transforming growth factor-beta (TGF-beta2) was investigated in the serum and cerebrospinal fluid (CSF) of 18 horses (9 normal, 9 affected with equine protozoal myeloencephalitis [EPM]). The TGF-beta2 assay was validated in a group of 6 norma...
Altered immune responses to a heterologous protein in ponies with heavy gastrointestinal parasite burdens. This study was performed to test the hypothesis that immunity to heterologous vaccination would improve when the parasites were removed. It was also expected that parasitised ponies would exhibit a biased Th2 cytokine response to KLH immunisation. Helminth parasites are common in horses even in the era of highly effective broad-spectrum antiparasiticides. These parasites have been shown to alter the outcome to heterologous immunisation in a number of host species. The effect of gastrointestinal parasites on heterologous vaccination has not been addressed in equids. In the current study, humora...
An immunodeficiency in Fell ponies: a preliminary study into cellular responses. A putative immunodeficiency, causing mortality in UK Fell pony foals (Fell pony syndrome), was studied in affected foals and compared with healthy, age-matched foals. Differential cell counts of peripheral blood indicated that the syndrome foals were lymphopenic (P<0.05). Flow cytometric analysis of circulating leucocytes showed a reduced MHC II expression (P<0.01) on lymphocytes but not on polymorphonuclear cells in affected foals. There were no changes in the percentages of CD4+ or CD8+ T cells. There was an increased (P<0.05) expression of CD11a/18 by the lymphocytes of the syndrom...
IgG antibody responses to an inhaled antigen in horses with “heaves” (recurrent airway obstruction). A controlled experimental system for the evaluation of pulmonary immune responses in horses with "heaves" (recurrent airway obstruction) has been developed. We hypothesized that the humoral immune response to an inhaled antigen in diseased horses would be different from that of healthy horses and that chronic pulmonary inflammation would bias the production of IgG isotypes in diseased horses as compared to healthy horses. Healthy and affected horses were housed in a natural challenge environment (stabled, fed dusty hay) and exposed by inhalation, to a nebulized solution of keyhole limpet hemoc...
Duration of immunity induced by an adjuvanted and inactivated equine influenza, tetanus and equine herpesvirus 1 and 4 combination vaccine. An adjuvanted vaccine containing inactivated equine influenza, herpesvirus antigens, and tetanus toxoid was administered to young seronegative foals of 8 months of age by deep intramuscular injection in the neck (Group A). The first two vaccinations were given 4 weeks apart. The third was administered 6 months later. Another group of foals (Group B) was vaccinated according to the same scheme at the same time with monovalent equine herpes virus (EHV) vaccine (EHV1.4) vaccine. Antibody responses to the equine influenza (single radial haemolysis; SRH) and tetanus (ToBi ELISA) components of the v...
Passive transfer of maternal immunoglobulin isotype antibodies against tetanus and influenza and their effect on the response of foals to vaccination. Influenza and tetanus-specific antibodies of the IgG sub-isotypes are posively transferred to foals via colostrum and inhibit their response to inactivated influenza vaccines and tetanus toxoid. High titres of influenza antibodies of IgGa and IgGb subisotypes and tetanus antibodies of the IgGa, IgGb and IgG(T) subisotypes were detected in postsucking serum samples collected from foals born to mares that had received booster doses of multicomponent vaccines during the last 2 months of gestation. Thereafter, titres declined in an exponential manner but were still detectable in all foals at age 2...
Exercise alters the immune response to equine influenza virus and increases susceptibility to infection. Equine influenza virus remains a major health concern for the equine industry in spite of ongoing vaccination programmes. Previous work has shown that the immune system of horses can be affected by strenuous exercise. The possible adverse consequence of exercise-induced alterations in lymphocyte responses measured in vitro was unknown. Here we demonstrate that subjecting vaccinated ponies to a 5 day strenuous exercise programme results in a significant suppression of their T cell-mediated immune response to equine influenza virus as measured by decreased lymphoproliferation and gamma interfero...
The mucosal humoral immune response of the horse to infective challenge and vaccination with equine herpesvirus-1 antigens. Equine herpesvirus-1 (EHV-1) remains a frequent cause of upper respiratory tract infection and abortion in horses worldwide. However, little is known about the local antibody response elicited in the upper airways of horses following exposure to EHV-1. This study analysed the mucosal humoral immune response of weanling foals following experimental infection with virulent EHV-1, or vaccination with either of 2 commercial vaccines. Twenty weanlings were assigned to 5 groups and were inoculated with, or vaccinated against, EHV-1 following different regimens. Finally, all weanlings were simultaneo...
Efficacy of a cold-adapted, intranasal, equine influenza vaccine: challenge trials. A randomised, controlled, double-blind, influenza virus, aerosol challenge of horses was undertaken to determine the efficacy of a cold-adapted, temperature sensitive, modified-live virus, intranasal, equine influenza vaccine. Ninety 11-month-old influenza-naïve foals were assigned randomly to 3 groups (20 vaccinates and 10 controls per group) and challenged 5 weeks, 6 and 12 months after a single vaccination. Challenges were performed on Day 0 in a plastic-lined chamber. Between Days 1 and 10, animals were examined daily for evidence of clinical signs of influenza. Nasal swabs for virus isol...
A new modified live equine influenza virus vaccine: phenotypic stability, restricted spread and efficacy against heterologous virus challenge. Flu Avert IN vaccine is a new, live attenuated virus vaccine for equine influenza. We tested this vaccine in vivo to ascertain 1) its safety and stability when subjected to serial horse to horse passage, 2) whether it spread spontaneously from horse to horse and 3) its ability to protect against heterologous equine influenza challenge viruses of epidemiological relevance. For the stability study, the vaccine was administered to 5 ponies. Nasal swabs were collected and pooled fluids administered directly to 4 successive groups of naïve ponies by intranasal inoculation. Viruses isolated from th...
Mice lacking the gene for inducible or endothelial nitric oxide are resistant to sporocyst induced Sarcocystis neurona infections. Equine protozoal myeloencephalitis (EPM) is a neurologic syndrome in horses from the Americas and is usually caused by infection with the apicomplexan parasite, Sarcocystis neurona. Little is known about the role of immunobiological mediators to this parasite. Nitric oxide (NO) is important in resistance to many intracellular parasites. We, therefore, investigated the role of inducible and endothelial NO in resistance to clinical disease caused by S. neurona in mice. Groups of interferon-gamma gene knockout (IFN-gamma-KO) mice, inducible nitric oxide synthase gene knockout (iNOS-KO) mice, endo...
Interaction between equine semen and the endometrium: the inflammatory response to semen. Insemination of mares with bacteria-free equine spermatozoa results in an influx of polymorphonuclear neutrophils (PMNs) into the uterine lumen. In vitro studies have demonstrated that equine spermatozoa activate complement, resulting in cleavage of factors C5a and C3b. Since uterine secretion is rich in complement, it is likely that an interaction between spermatozoa and uterine secretion results in C5a-mediated chemotaxis and migration of PMNs into the uterine lumen. Once in the uterine lumen, the PMNs phagocytize bacteria and spermatozoa, which is an important part of sperm elimination from...
Effects of age and recombinant equine somatotropin (eST) administration on immune function in female horses. Aging has been associated with declines in somatotropin and IGF-I levels as well as declines in immune function. To determine the effects of age and whether ST administration could reverse immunosenescence in horses, eight young and eight aged female standardbred horses were given 10 mg/d recombinant equine somatotropin (eST) or vehicle buffer for 49 d. Plasma IGF-I concentrations in both age groups were higher in eST-treated animals (P < 0.001), and higher in young eST-treated mares than in aged eST-treated mares during wk 4 to 7 (P < 0.001). There was a trend toward lower monocyte and ...
Measurement of serum amyloid A in the neonatal foal using a latex agglutination immunoturbidimetric assay: determination of the normal range, variation with age and response to disease. This paper describes the use of a latex agglutination assay to measure serum amyloid A (SAA) in the neonatal foal. The normal range and response to clinical disease was determined. This retrospective study evaluated SAA concentrations over the first 3 days postpartum of 226 Thoroughbred foals judged to be clinically healthy. The normal range for each day was determined; levels were found to be significantly highest on Day 2 (Day 1 vs. Day 2 P<0.0001). The 95th percentile for Days 1-3 was 27.1 mg/l. Clinical records of 133 foals, presented as first or second opinion cases, were evaluated. Fo...
Systemic antibodies to Clostridium botulinum type C: do they protect horses from grass sickness (dysautonomia)? The aetiology of equine grass sickness (EGS) is still unknown. There is increasing evidence that toxicoinfection with Clostridium botulinum type C is involved. Epidemiological evidence shows that resistance to EGS can occur in older horses and those that have been on a particular pasture for longer or have been in prior contact with the disease. This resistance may be in the form of an immune response to the aetiological agent. Levels of systemic antibodies to the surface antigens of C. botulinum type C (using the closely related and safe C. novyi type A as a phenotypic marker) and to the botu...
Neutrophilic airway inflammation in horses with heaves is characterized by a Th2-type cytokine profile. 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...
Intradermal testing in healthy horses and horses with chronic obstructive pulmonary disease, recurrent urticaria, or allergic dermatitis. 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...
Intradermal testing in healthy horses and horses with chronic obstructive pulmonary disease, recurrent urticaria, or allergic dermatitis. 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...
High-dose Borna disease virus infection induces a nucleoprotein-specific cytotoxic T-lymphocyte response and prevention of immunopathology. Experimental Borna disease virus (BDV) infection of rats and natural infection of horses and sheep leads to severe central nervous system disease based on immunopathological pathways. The virus replicates slowly, and the cellular immune response results in immunopathology. CD8(+) T cells exert effector cell functions, and their activity results in the destruction of virus-infected cells. Previously, Oldach and colleagues (D. Oldach, M. C. Zink, J. M. Pyper, S. Herzog, R. Rott, O. Narayan, and J. E. Clements, Virology 206:426-434, 1995) have reported protection against Borna disease after inocu...
The effect of aging on T cell responses in the horse. Horses greater than 20 years of age exhibit alterations in their immune responses similar to those observed in other aged individuals. The purpose of this study was to characterize immunosenescence in a population of aged ponies. The peripheral blood mononuclear cells (PBMC) from aged ponies exhibited a decreased proliferative response to various mitogens that was not overcome by the addition of interleukin 2 (IL-2) to the cultures. No difference in overall expression of the IL-2 receptor was seen between young and aged ponies, though CD8(+) cells from aged ponies exhibited increased levels of...
Specific antibody levels and antigenic recognition of Wistar rats inoculated with distinct isolates of Trypanosoma evansi. "Mal de Cadeiras", an enzootic disease caused by Trypanosoma evansi, is one of the most important trypanosomiases in the Brazilian Pantanal region. The disease affects mainly horses, which are widely used in extensive cattle production, an activity of greatest economical significance for the region. The parasite also infects sylvan (coatis and capybaras) and domestic (dogs) animals, respectively considered wild and domestic reservoirs of T. evansi. For a better understanding of the interaction of T. evansi with its rodent host, we evaluated the differences in the specific antibody level patter...
Immune reconstitution prevents continuous equine infectious anemia virus replication in an Arabian foal with severe combined immunodeficiency: lessons for control of lentiviruses. Acute infection with equine infectious anemia virus (EIAV), a lentivirus of horses, results in a persistent high-level viremia in Arabian foals affected with severe combined immunodeficiency (SCID). This observation argues against the idea that the transient nature of acute lentiviral viremia is solely a function of viral population dynamics. To extend these studies, EIAV-specific immune reconstitution was attempted prior to EIAV challenge in two SCID foals, using adoptively transferred virus-stimulated lymphocytes derived from persistently EIAV-infected half sibling donors. Following transfer...
A structural and immunological study of chorionic gonadotrophin production by equine trophoblast girdle and cup cells. Equine chorionic gonadotropin (eCG) production by the fetally derived endometrial cups appears to be necessary for the establishment and maintenance of normal equine pregnancy. Starting at about the 27th day of pregnancy, an equatorial band of trophectodermal cells on the surface of the spherical conceptus forms the chorionic girdle. This girdle consists initially of flat trophectodermal epithelium which corrugates into folds as the cells proliferate. The folds are then pressed against the uterine epithelium by expansion of the conceptus. The cells on the apices of the folds become binucleate ...
Bronchoconstrictive properties of inhaled 8-epi-PGF2alpha in healthy and heaves-susceptible horses. The 8-epi-PGF2alpha is a marker of oxidative stress which is increased in lungs of asthmatic humans and heaves-susceptible horses. 8-Epi-PGF2alpha has also been demonstrated to be an in vitro and in vivo bronchoconstrictor in humans and rodents. We hypothesised that inhaled 8-epi-PGF2alpha was a bronchoconstrictor in healthy and heaves-susceptible horses in clinical remission. The effect on ventilatory mechanics of nebulised 8-epi-PGF2alpha was compared to that of PGF2alpha and U46619, a thromboxane A2 agonist. Pulmonary resistance (R(L)) and dynamic compliance (Cdyn) were assessed in six heal...
Zinc and copper plasma levels in Icelandic horses with Culicoides hypersensitivity. Zinc concentration has been shown to have a potent immunomodulatory capacity, particularly influencing T helper cell organisation and cytokine secretion. Culicoides hypersensitivity (CHS) in horses resembles the early and late phase of type I hypersensitive reactions in man, characterised by a shift from T helper cell subtype 1 to T helper cell subtype 2 cytokine profile. In this pilot study, zinc and copper levels were measured in the plasma of 48 CHS-affected and 56 healthy Icelandic horses age 4-25 years (mean approximately 11 years) kept on 7 farms. Affected horses were divided into 3 grou...
Differences in wound contraction between horses and ponies: the in vitro contraction capacity of fibroblasts. The contribution of wound contraction to wound closure determines the speed of second intention wound healing and it has been shown that significant differences exist with regard to both contraction and inflammatory response between horses and ponies and between various areas of the body. In this study, the contraction capacity of fibroblasts from limbs and buttocks of 4 Dutch Warmblood horses and 4 Shetland ponies was studied in vitro, in order to determine whether differences in wound contraction are due to differences in the inherent contraction capacity of the fibroblasts or to differences...
Differential inhibition of equine neutrophil function by phosphodiesterase inhibitors. Neutrophils are recruited to the lungs of horses with chronic obstructive pulmonary disease (COPD) and exhibit increased activity after antigen challenge, which may contribute to inflammation and lung damage. Inhibition of phosphodiesterase isoenzymes (PDEs) has been shown to attenuate human neutrophil functions including superoxide production, leukotriene (LT)B4 biosynthesis, enzyme and chemokine release. As equine neutrophils contain predominantly the isoenzyme, PDE4, the present study was undertaken to investigate the effects of rolipram, a PDE4 inhibitor, on equine neutrophil function. For...
Allergic rhinoconjunctivitis, eczema, and sensitization in two areas with differing climates. In this 5-year follow-up study we compared the prevalence of allergic rhinoconjunctivitis, eczema, and sensitization, in relation to several background factors, in two Swedish regions (Göteborg and Kiruna). In Göteborg, a city on the southwest coast, the climate is mild and humid. Kiruna is a town north of the Arctic Circle. Questionnaire replies and results of interviews were collected from all 412 7-8-year-old children of a population-based sample (203 in Göteborg and 209 in Kiruna); in addition, 192 children from Göteborg and 205 from Kiruna were skin-prick tested for sensitization to c...
Immunohistochemical demonstration of chromogranin A in endocrine organs of the rat and horse by use of region-specific antibodies. Chromogranin A (CgA) is an acidic glycoprotein that is co-stored with hormones or neurotransmitters in granular components of endocrine cells and neurons, and released together with them in response to adequate stimulation. In addition to acting as a packaging protein, CgA functions as a precursor molecule that yields several bioactive peptides by proteolytic cleavage. The purpose of this study is to elucidate how different the processing of CgA is among endocrine tissues by immunostaining using multiple region-specific antisera, and to evaluate the availability of region-specific antisera. Wh...
