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.
Viraemia and abortions are not prevented by two commercial equine herpesvirus-1 vaccines after experimental challenge of horses. Eighteen horses, vaccinated on a number of occasions over a period of 12 to 20 months with either a live equine herpesvirus-1 (EHV-1) or an inactivated EHV-1 vaccine, were challenged by the intranasal instillation of the subtype 1 virus isolated from the 1983 outbreak of abortion and paralytic disease at the Lipizzan Stud, Piber, Austria. The prechallenge serum titres of all vaccinated horses were remarkably low, although most horses had received their last vaccine dose only 3 weeks before test-infection. Higher titres were obtained with the inactivated product than with the live virus vaccine...
Sequential mesenteric arteriography in pony foals during repeated inoculations of Strongylus vulgaris and treatments with ivermectin. Semiselective mesenteric arteriography was performed at regular intervals (inoculation weeks [IW] 0, 11, 18, and 24) in 9 of 10 pony foals raised to be free of parasites. Fifty infective larvae (L3) of Strongylus vulgaris were administered weekly for 4 weeks, then every 2 weeks through the 20th week. Three ponies were given ivermectin (oral paste, 0.2 mg/kg of body weight) treatment at IW 8, 16 and 24. Four ponies were inoculated, but did not receive ivermectin, and a third group of 2 ponies acted as uninoculated controls. Control ponies did not have gross or arteriographic lesions, whereas th...
Lysozyme, alkaline phosphatase and neutrophils in uterine secretions of mares with differing resistance to endometritis. A study was conducted to 1) determine differences in the inflammatory response following bacterial challenge between normal mares and mares with chronic endometritis and 2) to determine if enzyme activity in uterine fluid can be used to evaluate degree of inflammation in the equine uterus. Six normal mares (Group 1) and four mares with chronic endometritis (Group 2) received an intrauterine infusion of beta-hemolytic streptococci on the second day of estrus. Neutrophil concentration as well as lysozyme and alkaline phosphatase activity were determined in uterine secretions obtained by placing ...
One way protection between equid herpesvirus 1 and 4 in vivo. Two groups each of six sibling ponies were exposed to sequential infections with equid herpesvirus 1 or 4 (EHV-1 or EHV-4) at four or five month intervals. Two exposures to EHV-4 did not significantly reduce virus shedding or pyrexia when the ponies were subsequently exposed to EHV-1. However, two sequential infections with EHV-1 completely protected against challenge with EHV-4. Virus neutralising antibody in each group did not increase until 21 days after primary exposure and was subtype specific. However, complement fixing antibody rose within seven days after inoculation with EHV-1, and 14...
Induction of immune response and protection from equine viral arteritis (EVA) by formalin inactivated-virus vaccine for EVA in horses. Thirty-nine horses included 3 pregnant mares were examined by inoculating with formalin inactivated-virus vaccine for EVA. Antibody response of horses after one dose vaccination was somewhat poor and 50% effective inoculum dose of the vaccine should be included 10(8.4) pfu of virus before inactivation. After 2 doses given at an interval of 4 weeks, the horses developed such high titer of SN antibody as up to 1:5,120. The SN titer declined rather rapidly, but supplemental administration of the vaccine at an interval of more than 2 months elicited a prompt antibody response and SN titers persist...
[Allergic rhinitis in the horse: first case]. The responsibility of the artificial environment in the development of respiratory allergy in horses is well known as the most important factor for the development of asthma, chronic dry cough and pulmonary emphysema. One case of allergy to the natural environment could be observed. One allergic rhinitis with asthma could be explored. Pathology, cause, tests and specific immuno-therapy are presented.
The characterisation of equine interleukin-1. Equine interleukin-1 has been produced from peripheral blood monocytes by stimulation with E. coli lipopolysaccharide. Sephacryl S200 gel filtration revealed a molecular weight of 17-18 kD. Chromatofocusing of the 17-18 kD peak identified four active fractions. Two major peaks were detected at pH 6.7 and pH 7, with smaller peaks at pH 6.3 and pH 5.9. The pI 7 molecule is probably the equine form of IL-1 beta.
A preliminary study of uterine derived polymorphonuclear cell function in mares with chronic uterine infections. From 6 mares with chronic uterine infection, polymorphonuclear neutrophils (PMNs) were obtained from the uterus. In order to recover an adequate number of viable PMNs, 0.1% oyster glycogen was infused into the uterus as a mild irritant 12 h prior to the uterine flushing. Phagocytosis and chemotaxis of the uterine derived PMNs were determined. The supernatant from the uterine flushing was compared with autologous serum for its capacity as an opsonin and chemoattractant. There was a significant increase of both phagocytosis and chemotaxis when autologous serum was used compared with the supernat...
Effect of strenuous exercise stress on chemiluminescence response of equine alveolar macrophages. Bronchoalveolar lavage samples were collected using a fibreoptic endoscope from horses at specified times before and after single bouts of exercise. Lucigenin-dependent phagocytic chemiluminescence was used to assess the effect of exercise on the alveolar macrophage metabolic activity in response to stimulation by opsonised zymosan. A profound suppressive effect on the chemiluminescence production was present throughout the first three days after exercise. However, the cellular composition of lavage fluids was not altered by the exercise. It is suggested that strenuous exercise may jeopardize ...
Use of erythrocyte fragility profiles for monitoring immune-mediated haemolysis in horses. The fragility of erythrocytes is easily demonstrated by their ability to withstand osmotic swelling and lysis in solutions of increasingly hypotonic saline. In healthy animals a plot of percentage haemolysis against increasing hypotonicity produces a sigmoid curve. Using the same data a derivative curve calculated from haemolytic increments shows a normal distribution of fragility within samples. In enhanced fragility due to immune-mediated haemolytic anaemia, these profiles of haemolysis are markedly altered and the derivative curve becomes multiphasic, indicating the presence of subpopulatio...
Equine infectious anemia virus (EIAV) humoral responses of recipient ponies and antigenic variation during persistent infection. Three ponies were inoculated with plasma containing 10(4.8) TCID50 of equine infectious anemia virus (EIAV) and observed for 165 to 440 days. Each pony developed a febrile response within 3 weeks of infection during which a plasma viremia greater than or equal to 10(3.5) TCID50/ml was observed. Analyses of four isolates from sequential febrile episodes in a single pony were conducted by two-dimensional tryptic peptide maps and with monoclonal antibodies in immunoblots. Structural and antigenic alterations were observed in the envelope glycoproteins gp90 and gp45, with greatest variation in gp9...
Immunopathogenesis of equine infectious anemia lentivirus disease. Virus replication and subsequent viremia are clearly correlated with clinical disease in EIAV infected horses. Termination of viremia is the result of specific immune responses. Recurrences of viremia are associated with antigenic variation of neutralization-sensitive epitopes. Immunosuppression experiments indicate that the eventual control of EIAV and development of carriers is mediated by the immune system. Even though the immune response to EIAV has a protective effect, immune responses also cause some of the lesions. At least one part of the anemia, erythrocyte destruction, is caused by t...
[Clinico-pathological changes after intravenous administration of endotoxin in the horse]. The results of a study conducted to determine the clinico-pathological changes in 4 experimentally-induced cases of endotoxaemia in the horse are reported on. Endotoxaemia was induced by injecting commercially available E. coli 055:B5 lipopolysaccharide intravenously at a dose of 1 microgram kg-1. The haematocrit, red cell count, total and differential white cell counts, thrombocyte count, prothrombin time, partial thromboplastin time, fibrinogen level, level of fibrin degradation products, arterial acid-base status, serum lactate and blood glucose were determined repeatedly. Changes that occu...
Effect of dietary linolenic acid on endotoxin-induced thromboxane and prostacyclin production by equine peritoneal macrophages. In laboratory animals, the incorporation of alpha linolenic acid or other n-3 series fatty acids into the diet results in marked changes in cell membrane composition as well as arachidonic acid metabolism. The purpose of the present study was to determine whether endotoxin-induced thromboxane A2 (TxA2) and/or prostacyclin (PGI2) production by equine peritoneal macrophages was altered by feeding horses a diet containing 8% linseed oil as a source of alpha linolenic acid for 8 weeks. Peritoneal macrophages were cultured in vitro in the presence of endotoxin (LPS) (0.5-500 ng/ml) or calcium ionop...
Cross-neutralizing and subclass characteristics of antibody from horses with equine infectious anemia virus. Antibody responses in horses with equine infectious anemia virus (EIAV) were examined to determine their cross-neutralizing capacity. Antibodies induced by infection with any of six biologically cloned variants of EIAV cross-neutralized multiple variants from the group. Anti-EIAV antibody was found in both the IgG and IgG(T) subclasses in plasmas with virus-neutralizing activity and the majority of antiviral antibody was of the IgG(T) subclass. Depletion of IgG(T) did not increase the neutralization indexes of either neutralizing or non-neutralizing plasma samples.
Influence of technical parameters on the in vitro motility of equine neutrophils in the presence of streptococcal culture supernatant. To identify the influence of technical factors on the in vitro motility of equine neutrophils towards streptococcus culture supernatant in an under-agarose assay, we studied the changes in eight cell migration parameters. The distances the phagocytes travelled by directed, random and spontaneous migration increased with incubation time, cell concentration and the gelatin and serum contents of the migration plates. The contribution of chemotaxis to the phagocyte migrations, however, decreased simultaneously. The directed and random, though not the spontaneous, migrations of the phagocytes incre...
[The development of the anti-phospholipase A2 antibody response in horses inoculated with venom for the production of polyvalent antisnake serum in Costa Rica]. The development of antibody response against phospholipase A2 activity of Bothrops asper venom was studied in a group of adult and healthy horses used in the production of the polyvalent antivenom at the Instituto Clodomiro Picado. Simultaneously, the general condition of the animals during the immunization schedule was also studied. There was a great individual variability in the immune response, although most of the horses studied reached the highest neutralizing titer after injection of doses of venom of 30 mg and 50 mg. On the other hand, in horses that had been previously immunized and we...
Intradermal challenge of Icelandic horses with extracts of four species of the genus Culicoides. Twenty-three Icelandic horses were challenged with extracts of four species of biting midges: Culicoides pulicaris, C chiopterus, C obsoletus and C impunctatus. Fourteen of the tested horses were affected with summer eczema. The horses were challenged intradermally with 0.1 ml of whole-body extracts of midges at a concentration of 0.01 or 0.005 per cent weight/volume. The skin reactions were measured after 30 minutes, 60 or 180 minutes and four, 24 and 48 hours after injection. Antigen titration showed that the reaction was dependent on the antigen concentration. Eight of nine unaffected horse...
Localization of conserved and variable antigenic domains of equine infectious anemia virus envelope glycoproteins using recombinant env-encoded protein fragments produced in Escherichia coli. Previous characterizations of equine infectious anemia virus (EIAV) glycoprotein variation by DNA sequence analysis and epitope mapping using monoclonal antibodies (MAbs) have revealed the presence of conserved and variable regions within the EIAV env gene. To extend these studies, fragments of the EIAV envelope proteins gp90 and gp45 were expressed in Escherichia coli and used in Western blot analysis with a diverse panel of equine immune sera to identify antigenic segments. All sera from EIAV-infected animals reacted with the carboxyl terminal portion of gp90 and the amino terminal portion o...
Current views on the pathogenesis of bacterial endometritis in mares. Mares with persistent and recurrent endometritis are said to be susceptible to infection; in particular they are unable to resolve the acute endometritis that always follows mating. It is thought, therefore, that these mares have a local immunological defect in the uterus that impedes the elimination of bacteria. Studies on immunoglobulins, opsonins and the functional ability of neutrophils in the uterus of susceptible mares have not confirmed the presence of an impaired immune response. It is concluded that factors involved in the production and drainage of uterine fluid may be important in t...
An ongoing in vivo immune response affects the abundancy and differentiation of lymphokine-activated killer cell precursors, but does not influence their broad spectrum target reactivity. Using a model of local lymph node (LN) immunization, we investigated the effect of in vivo Ir on the generation of lymphokine-activated killer (LAK) cells or their precursors. Ag used for immunization were SRBC, horse RBC, OVA, keyhole limpet hemocyanin, or CFA. Ag-draining LN, in the acute phase of the Ir, did not contain detectable LAK effector activity, nor an enhanced NK activity. After culture for 3 to 5 days in the absence of exogenously added IL-2, immunized LN cells developed a spontaneous LAK-like cytotoxicity. This activity represented a substantial fraction of the IL-2-generated LAK...
Release of immunoreactive arachidonate metabolites by equine endometrium in vitro. The ability of equine endometrium to release prostaglandin (PG) F, PGE2, and leukotriene (LT) B4 was studied in vitro, using endometrial tissue from diestrous mares. Because of the high cross-reactivity of the PGF antiserum with PGF1 alpha and with PGF2 alpha, results were quoted as total immunoreactive PGF. Significant concentrations of these arachidonate metabolites were released into tissue culture medium between 1 and 24 hours of incubation. Significantly higher concentrations of PGE, but not of PGE2 or LTB4, were released from endometria of mares with chronic endometritis than from genita...
Immunologic and hematologic responses in ponies with experimentally induced Strongylus vulgaris infection. Immunologic and hematologic responses were examined in 4 ponies with experimentally induced Strongylus vulgaris infection and in 5 helminth-free ponies. Two ponies were inoculated with 200 larvae and 2 were inoculated with 700 larvae of S vulgaris and then were reinoculated with the same numbers of larvae 34 weeks later. Initial response of the ponies inoculated with S vulgaris was S vulgaris antigen-induced lymphocyte response that developed 1.5 to 3 weeks after inoculation and did not persist. Development of antigen-reactive lymphocytes was followed sequentially by a biphasic complement-fixi...
White-footed mice: tick burdens and role in the epizootiology of Potomac horse fever in Maryland. One hundred ten white-footed mice (Peromyscus leucopus) were captured on horse farms in south-central Maryland, examined for ticks, and tested for specific antibodies to Ehrlichia risticii, the causative agent of Potomac horse fever. Peromyscus leucopus were consistently infested with immature American dog ticks (Dermacentor variabilis), with monthly prevalences as high as 80%. Sera from all 97 P. leucopus tested for antibodies to E. risticii were negative. This indicates that P. leucopus is not a reservoir of E. risticii, and suggests that immature D. variabilis do not acquire E. risticii in ...
Cell mediated immune responses in ponies following infection with equine influenza virus (H3N8): the influence of induction culture conditions on the properties of cytotoxic effector cells. Cytotoxic cell precursors and/or cytotoxic memory cells were demonstrated in the peripheral blood of ponies after aerosol infection with influenza A/equine/Newmarket/79 (H3N8). In order to reveal their cytotoxic potential, peripheral blood mononuclear cells required a secondary antigenic stimulation. In vitro induced cytotoxic cells showed activity against influenza infected target cells in a 3-4 h 51Cr-release assay. The reactivity of cytotoxic cells was markedly influenced by the conditions of the secondary induction culture. If high concentrations of exogenous crude equine IL-2 were used, v...
The effect of immunity to core lipopolysaccharides (LPS) on the production of thromboxane and prostacyclin by equine peritoneal macrophages. An experiment was designed to determine whether a change in the ability of macrophages to respond to lipopolysaccharides (LPS) of gram-negative bacteria was involved in the development of cross-reactive immunity to endotoxemia. The endotoxin-induced production of thromboxane A2(TxA2) and prostacyclin (PGI2) by peritoneal macrophages from horses which were hyperimmunized against the common core region of LPS were compared to those in unimmunized horses. Bacterins used for induction of core LPS immunity were prepared from the J-5 mutant of Escherichia coli 0111:B4, and the R 595 mutant of Salmon...
Rhodococcus equi foal pneumonia: protective effects of immune plasma in experimentally infected foals. The immunoprophylactic capacity of specific immune plasma was evaluated in pony foals infected experimentally with Rhodococcus equi. Immune plasma, produced by repeated parenteral administration of viable R. equi to adult horses, was harvested and frozen. Group I (six control foals) and Group II (six principal foals) received lactated Ringers solution and immune plasma respectively at three and five days of age. R. equi were aerosolised into a caudal lung lobe of all foals at seven days of age. Clinical signs, haematological alterations, immune responses, thoracic radiographs and technetium99m...