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.
Evaluation of immune complexes and collagen type-specific antibodies in sera and synovial fluids of horses with secondary osteoarthritis. Thirty-one horses with secondary osteoarthritis as a sequel of trauma (chip fractures) or osteochondritis dissecans were screened for immune complexes (IC) and anticollagen antibodies. Eighty-two percent of horses with joint disease had circulating C1q-binding IC; 77% of those horses had IC in synovial fluids of affected joints. Although only a few horses had anticollagen type-II antibodies, anticollagen type-I antibodies were found in sera of 25% of the horses and in 41% of their synovial fluids. This correlated well with the clinical data and suggested that antibodies might have been elicite...
Equine neonatal isoerythrolysis: evidence for prevention by maternal antibodies to the Ca blood group antigen. Foals with the Ca blood group antigen on their RBC were given colostrum with anti-Ca antibodies (6 foals) or colostrum without anti-Ca antibodies (6 foals). The PCV were determined at birth and 2, 4, and 6 days after birth for the foals in each group. Significant differences were not observed for the PCV between the 2 groups, indicating that foals were not adversely affected by ingesting colostrum with the anti-Ca antibody. Standardbred mares without the Aa blood group antigen were evaluated to determine whether production of anti-Ca antibodies influenced production of anti-Aa antibodies. Of 2...
Factors affecting the composition of mare uterine fluid. The influx of protein and polymorphonuclear leucocytes (PMN) into the uterine lumen was examined at different intervals after intrauterine infusion of fluids. The intrauterine infusion of both phosphate buffered saline (PBS) and a solution of lipopolysaccharide (LPS) derived from Escherichia coli resulted in a biphasic influx of protein in the uterine flushings peaking three and six hours after infusion. LPS infusion caused an additional influx of protein at 24 hours. The initial influx of protein preceded a biphasic influx of PMN which peaked six and 24 hours after both infusions. Uterine flu...
The effect of various antibacterial preparations on the in vitro morphology and chemotactic response of equine neutrophils. Two independent assay systems were used to study the effect of three antibacterial preparations on in vitro morphology and chemotaxis of equine neutrophils. Incubation of neutrophils with high (200 micrograms/ml) and medium (20 micrograms/ml) concentrations of neomycin impaired their response to standard chemoattractants. Trimethoprim/sulfadoxine (0.4/2.0 micrograms/ml-40/200 micrograms/ml) and benzylpenicillin (0.25-25 micrograms/ml) had no effect. Neutrophils collected from geldings 2 and 24 h after neomycin (5 mg/kg) administration had impaired responses to standard chemoattractants. Benzyl...
Immune-mediated polysynovitis in four foals. The deposition of immune complexes in the synovial membrane resulted in polysynovitis in 4 foals. All 4 foals had an infection at a site other than the joints. The polysynovitis was characterized by marked effusions of affected joints and joint stiffness. Bacterial and mycoplasmal cultures of the joints did not yield growth. Staining of synovial membrane biopsy specimens with fluorescein-labeled anti-equine IgG revealed immune complexes in the synovial membrane. Immune-mediated polysynovitis might develop in foals with bacterial infections. We propose that deposition of immunoglobulin in the s...
Endotoxaemia in racehorses following exertion. Endotoxins (lipopolysaccharides-LPS) and anti-endotoxin IgG antibodies were measured in racehorses before and after races of 1,000, 2,000 and 2,800 m. Results show that the mean plasma concentration of endotoxin increased significantly (p less than 0.02) while the anti-LPS IgG concentration decreased significantly (p less than 0.005) in all horses following the races. Pre-race and post-race anti-LPS IgG levels in racing-fit racehorses were significantly higher than in untrained horses (p less than 0.05). The possibility therefore exists that training-induced stress leads to leakage of LPS into...
Aerosolized Micropolyspora faeni antigen as a cause of pulmonary dysfunction in ponies with recurrent airway obstruction (heaves). Ponies with recurrent airway obstruction (principal ponies) and their controls were given aerosolized Micropolyspora faeni antigen via endotracheal tube during a period when the principal ponies were in disease remission. In both groups of ponies, we performed bronchoalveolar lavage (BAL) and measured pulmonary function at base line, and 5 hours after aerosol administration of 30 ml of 0.9% NaCl solution or 30 ml of 1% w/v particulate M faeni antigen in 0.9% NaCl solution. In both groups of ponies, aerosolized M faeni antigen increased WBC count, neutrophil numbers, and albumin concentration i...
Protection against experimental infection with influenza virus A/equine/Miami/63 (H3N8) provided by inactivated whole virus vaccines containing homologous virus. Thirty-one ponies immunized with inactivated virus vaccine containing A/equine/Miami/63 (H3N8) virus and six seronegative ponies were experimentally challenged with the homologous virus strain. All 6 unvaccinated ponies and 11 out of 31 vaccinated ponies became infected. A clear relationship between pre-challenge antibody, measured by single radial haemolysis (SRH), and protection was demonstrated as judged by virus excretion, febrile responses and antibody responses. Those ponies with SRH antibody levels greater than 74 mm2 were completely protected against challenge infection by the intranas...
ADCC and complement-dependent lysis as immune mechanisms against EHV-1 infection in the horse. Immunity to equine herpesvirus type 1 (EHV-1) was evaluated using sera collected from yearling horses involved in a trial of a commercial vaccine. Measurement of the ability of these sera to mediate antibody-dependent cellular cytotoxicity and complement-dependent lysis revealed that these mechanisms, although potentially important in recovery from EHV-1 infection, do not play a role in protection following vaccination.
Immunoassay detection of drugs in racing horses. IV. Detection of fentanyl and its congeners in equine blood and urine by a one step ELISA assay. We have developed and evaluated a one step enzyme-linked immunosorbent assay (ELISA) test for fentanyl as part of a panel of pre- and post-race tests for narcotic analgesics in racing horses. This ELISA test detects fentanyl with an I-50 of about 100 pg/ml. The test is economical in that it can be read with an inexpensive spectrophotometer, or even by eye. The test is rapid, and ten samples, a normal pre-race complement, can be analyzed in about twenty minutes. The test readily detects the presence of fentanyl or its metabolites in equine blood and urine from two and twenty-four hours respecti...
Rhodococcus (Corynebacterium) equi: bactericidal capacity of neutrophils from neonatal and adult horses. The capacity of hematogenous polymorphonuclear neutrophilic leukocytes (PMNL) to kill Rhodococcus equi was compared in horses of various ages. A radioisotope bactericidal assay was used to determine the capacity of PMNL to kill R equi. Assays were conducted on PMNL from horses in 3 groups: group I, 13 foals with a mean age of 3.3 days; group II, 10 group-I foals at a mean age of 35.7 days; and group III, adult dams of group-I foals. Bacteria were obtained from the lungs of a foal with R equi pneumonia and opsonized with fresh adult equine serum that contained R equi specific antibody. The mean...
Chronic small airway disease in the horse: immunohistochemical evaluation of lungs with mild, moderate and severe lesions. The peroxidase anti-peroxidase technique was used to demonstrate free and intracellular immunoglobulin (Ig) within the lungs of 23 horses with chronic small airway disease. Histologically, all the horses had chronic bronchiolitis; however, the lesions varied in degree from mild in eight horses, to moderate in nine horses and severe in six horses. Lungs from three horses which had no gross or histopathological lesions were used as controls. In comparison with control horses, horses with mild chronic bronchiolitis had increased numbers of Ig A-containing and non-immunoglobulin staining cells aro...
Duration of circulating antibody and immunity following infection with equine influenza virus. The duration of immunity as measured by virological, serological and clinical responses following infection with influenza A/equine/Newmarket/79 (H3N8) was assessed in repeated challenge experiments in which ponies were infected by exposure to aerosols of infectious virus. Previous infection stimulated complete clinical protection which persisted for at least 32 weeks as demonstrated by the absence of febrile responses and coughing in two groups of ponies infected 16 weeks or 32 weeks after the first infection. Partial clinical protection persisted for over a year as demonstrated by the absenc...
Influenza virus ISCOMs: antibody response in animals. A monovalent experimental ISCOM vaccine has been prepared with the envelope glycoproteins haemagglutinin and neuraminidase of the equine virus strain A/Solvalla/79 (H3N8). In vaccination trials on BALB/c mice the ISCOM vaccine induced more than ten times higher serum antibody titres measured in ELISA than a corresponding experimental micelle vaccine. Similarly, in guinea-pigs the ISCOMs induced about tenfold higher haemagglutination inhibition (HI) and neuraminidase inhibition (NI) titres than a micelle vaccine or a conventional killed influenza whole virus vaccine. Horses vaccinated with a di...
Equine ehrlichial colitis: effect of oxytetracycline treatment during the incubation period of Ehrlichia risticii infection in ponies. Equine ehrlichial colitis was experimentally induced in 18 ponies, using Ehrlichia risticii-infected blood. Four ponies (group 1) were treated with oxytetracycline (6.6 mg/kg of body weight, IV, q 12 h), beginning 14 hours before inoculation and continuing for 5 days after inoculation. Four additional ponies (group 2) were treated similarly for 10 days after inoculation. The remaining 10 ponies were used as nontreated, infected controls. Clinical disease was delayed in 3 group-1 ponies and in 4 group-2 ponies. Protective immunity developed in the remaining pony that did not develop clinical di...
Intradermal challenge of Icelandic horses in Norway and Iceland with extracts of Culicoides spp. A skin test survey was carried out in Icelandic horses in Norway and Iceland using extracts of Culicoides spp. as antigen. Eleven horses with recurrent seasonal dermatitis reacted with an immediate hypersensitivity response to intradermal challenge with antigen. All except one of thirty-three clinically normal horses in Norway showed a negative response in skin tests. These findings indicate that Culicoides spp. may be the major cause of the disease in Norway. Only one of the 110 horses tested in Iceland showed any skin test reaction (weak), demonstrating that the horses were not sensitized to...
Plasma lysozyme activity of Polish primitive horses under physiological conditions and in experimental fever. The normal level of plasma lysozyme of 9 Tarpane-like horses was 0.922pg/ml. This was
calculated from determinations performed 5 times in a period of 14 months. Observations on the
normal plasma level of lysozyme in the horse revealed marked variations in individual animals, as well
as in the whole group and in the mean values calculated for individual horses. The model for the
subsequent studies was an experimental fever evoked by the administration of E. colz LPS in a dose of
0.1 pg/kg body weight. Blood samples from the jugular vein were taken just before LPS injection, and
then for 8...
Role of the host immune response in selection of equine infectious anemia virus variants. Equine infectious anemia virus was isolated from peripheral blood leukocytes collected during two early febrile cycles of an experimentally infected horse. RNase T1-resistant oligonucleotide fingerprint analyses indicated that the nucleotide sequences of the isolates differed by approximately 0.25% and that the differences appeared randomly distributed throughout the genome. Serum collected in the interval between virus isolations was able to distinguish the isolates by membrane immunofluorescence on live cells. However, no neutralizing antibody was detected in the interval between virus isola...
Assessment of neutrophil migration, phagocytosis and bactericidal capacity in neonatal foals. Comparison of neutrophil function was made between 8 clinically normal pony foals (3 to 7 days of age), and their dams. Random migration, stimulated migration to zymosan-activated serum, bacterial phagocytosis and bactericidal capacity of neutrophils were determined in vitro. Random migration was greater (P less than 0.01) and stimulated migration was less (P less than 0.01) in foals than in their dams. Bacterial phagocytosis and bactericidal capacity of neutrophils were not different (P greater than 0.05) between foals and mares. Results of this study suggested that neonatal foals have altere...
Effect of estradiol and progesterone on antistaphylococcal activity of neutrophils from ovariectomized mares. Neutrophils isolated from jugular blood of ovariectomized mares were studied for the effect of estradiol and progesterone on bactericidal activity against Staphylococcus aureus. In experiment 1, neutrophils obtained from 4 mares were tested for bactericidal activity by adding estradiol (43 pg/ml) or progesterone (6.4 ng/ml) to the bactericidal assay. In experiment 2, 3 of the 4 ovariectomized mares were given 2 mg of estradiol, IM, daily for 3 days. Eighteen days after the initial estradiol injection, mares were given 300 mg of progesterone, IM, for 6 days. Neutrophils from these mares were te...
Genetic restriction of cytolysis during equid herpesvirus 1 subtype 2 infection. Six Welsh Mountain pony foals were experimentally infected with a subtype 2 isolate of Equid Herpesvirus 1 (EHV-1) and subsequently examined for T cell mediated cytotoxicity against both subtypes. Cytotoxicity was not observed at 3 or 7 days after primary exposure but virus-specific, and genetically restricted, cytotoxicity of EHV-1-labelled autologous skin fibroblasts could be demonstrated 7 and 21 days after the animals were given a second exposure to live virus. Killing of subtype 2 antigen-labelled targets was more efficient than subtype 1 coated cells. This finding was paralleled by the o...
Protection of foals against experimental Rhodococcus equi pneumonia by oral immunization. Two groups of three one to three week old foals were immunized orally on four occasions over five weeks with two strains of Rhodococcus equi, a clinical isolate from a pneumonic foal and a laboratory passaged Congo red negative variant of this strain. Three nonimmunized foals of similar age acted as controls. Three weeks after the last immunization, all foals were challenged on five occasions over seven days by aerosol infection with about 10(10) of the pneumonic foal isolate on each occasion. Control foals became seriously ill and were euthanized. Immunization with either strain protected foa...
Serum neutralizing antibody titers in dairy cattle administered an inactivated vesicular stomatitis virus vaccine. Two doses of a formalin-killed, cell culture-derived vesicular stomatitis virus (vsv)-New Jersey serotype vaccine were administered intramuscularly, 30 days apart, to all lactating and nonlactating cows in a 350-cow dairy herd. Serum specimens were obtained serially from 96 cows before vaccination and at 30, 52 and 80 days after vaccination and from 24 of these cows 175 days after vaccination. Serum neutralizing antibody titers to vsv-New Jersey serotype were determined from serum-dilution, plaque-reduction tests. Serum neutralizing antibody titers also were determined during the same period f...
Influence of arachidonic acid metabolites in vitro and in uterine washings on migration of equine neutrophils under agarose. The influence of arachidonic acid metabolites on migration of equine neutrophils under agarose was investigated. Leukotriene B4 (LTB4) was chemotactic at concentrations between 0.1 and 1000 ng ml-1 and prostaglandin E2 (PGE2) at 1 and 10 ng ml-1 but not at higher or lower concentrations. Prostaglandin F2 alpha (PGF2 alpha) was not chemotactic for equine neutrophils at any concentration. Random migration was significantly inhibited (P less than 0.05) by suspension of neutrophils in LTB4 (0.1 to 1000 ng ml-1) and PGF2 alpha (0.1 ng ml-1) but not at high concentrations. There was a significant po...
Effects of a specific thromboxane synthetase inhibitor in equine endotoxaemia. Thromboxane A2 may play a major role in circulatory shock. In some species, thromboxane synthetase inhibitors have a beneficial effect on shock induced by endotoxin, trauma, sepsis and administration of arachidonate. In some shock models, however, results with thromboxane synthetase inhibitors have been conflicting. The effect of UK-38,485, a selective thromboxane inhibitor, was evaluated in ponies injected with endotoxin intraperitoneally. Four groups of ponies were used to compare the effects of endotoxin alone, UK-38,485 alone, treatment with UK-38,485 before endotoxin challenge and treatme...
Cellular and humoral defence mechanisms in mares susceptible and resistant to persistent endometritis. Both random and directional migration of blood neutrophils from 9 mares susceptible to persistent endometritis were significantly less (p less than 0.05) than neutrophils from 8 resistant mares. Serum from susceptible mares had significantly more (p less than 0.01) chemotactic activity than serum from resistant mares. Although phagocytosis of yeast blastospores by blood neutrophils from 4 resistant and 3 susceptible mares was similar, uterine neutrophils from susceptible mares were significantly worse (p less than 0.01) at phagocytosis than uterine neutrophils from resistant mares. Uterine was...
The immunological response of foals to Rhodococcus equi: a review. Normal horses of all ages regularly show evidence of having responded immunologically to R. equi, thus adding serological support to epidemiological evidence that this organism is a normal intestinal inhabitant. More animals from "diseased" farms show a stronger antibody response when compared with foals from "healthy" farms. Various serological tests have been used to detect evidence of infection and to relate antibody level to severity of disease. Anti-R. equi IgG antibody levels, as measured by ELISA, are raised significantly during natural infection. Clinical severity of pneumonia can be c...
Humoral immune response of foals to experimental infection with Rhodococcus equi. Humoral immune response to Rhodococcus equi in experimentally infected foals was studied with the enzyme-linked immunosorbent assay (ELISA) method. Class-specific antibodies were measured by ELISA in the sera of foals after intratracheal or oral inoculation with R. equi ATCC 6939 or T 48 and in the lung washings of a foal after intratracheal inoculation or of normal horses. After intratracheal or oral inoculation with R. equi, serum antibodies were first detected in immunoglobulin G (IgG) followed by IgM and IgA classes, but significant levels of IgM and IgA developed only in the foal infected...