Topic:Immunology
The equine immune system is a complex network of cells, tissues, and organs that work collaboratively to defend against pathogens and maintain homeostasis. It consists of innate and adaptive components, each with distinct functions and mechanisms. The innate immune system provides the first line of defense through physical barriers, phagocytic cells, and the complement system. The adaptive immune system involves lymphocytes, such as B cells and T cells, which generate specific responses to antigens and provide immunological memory. Research in equine immunology explores the interactions between these components, the impact of genetic and environmental factors on immune function, and the development of vaccines and therapeutics. This page gathers peer-reviewed studies and scholarly articles focusing on the mechanisms, regulation, and clinical applications of the equine immune system in health and disease.
Antigenic relationship between the Tokyo and the Miami strains of equine influenza subtype 2 virus. The first outbreak of equine influenza (EI) infection in Japan was recognized during the period December 1971 to January 1972 [1, 6]. No evidence of the disease had been found before then [2,6]. The etiological agent of this epizootic was identified by hemagglutination-inhibition (HI) and neutralization tests with chicken or ferret antiserum as the subtype 2 of EI virus (6, 7). However, the isolate, A/equine/Tokyo/71 (Tokyo) strain, was not completely identical to the prototypic A/equine/Miami /63 (Miami) strain of the subtype 2, since antibody responses of convalescent horses were 2 to 16 tim...
Immunological properties of two related fragments from human and equine growth hormones. The immunological properties of a synthetic human growth hormone fragment comprising the amino acids 73 through 128 and of the homologous natural horse growth fragment formed by amino acids 73 through 123, have been comparatively studied. Antisera obtained in rabbits inoculated with the native human hormone or with the fragments, were used. By hemagglutination experiments both fragments have the same reactivity toward the anti-human growth hormone serum, but complement fixation curves detect the existence of at least two populations of antibodies presumably originated against the sequence 73-1...
Effect of age and pregnancy on the antibody and cell-mediated immune responses of horses to equine herpesvirus 1. The cell-mediated immune response and antibody response of horses of varying ages and of pregnant horses to equine herpesvirus 1 antigen were examined. Six to eight month old horses showed either no increase or slight increases in anti-equine herpesvirus 1 serum neutralizing antibody following vaccination and revaccination with a modified live equine herpesvirus 1 vaccine. However, these same horses showed a marked increase in the cell-mediated immune response to equine herpesvirus 1 as measured by the lymphocyte transformation test. Eighteen to 21 month old horses showed four to 64-fold incre...
Practical methods of determining serum immunoglobulin M and immunoglobulin G concentrations in foals. Serum concentrations of immunoglobulin M (IgM) and immunoglobulin G (IgG) can be determined in the horse with a satisfactory degree of accuracy, using commercially available reagents. Selected lots of anti-human IgM can be used in precipitation tests to detect and quantitate equine IgM. Commercially available anti-equine IgG tended to overestimate the amount of IgG in single radial immunodiffusion tests. Even with these limitations, commercial reagents can be used to differentiate immunodeficiency disorders of foals, including combined immunodeficiency and failure of passive transfer of colost...
RAST in the diagnosis of hypersensitivity to horse allergens. A comparison with clinical history and in vivo tests. Case history, skin tests and RAST were compared in a group (n = 40) of children with a history suggesting allergy to horses and in a group (n = 43) in whom there was no suspicion of hypersensitivity to horses. There was an agreement of 91% between case history and prick test. The same magnitude of agreement was found between case history and RAST (89%), and the agreement between RAST and prick test was 90%. The results of this investigation are clearly in contrast to earlier earlier reports, in that there was a very good correlation between prick test, RAST and case history. The results sugges...
Inhibition of the growth of some strains of Mycoplasma mycoides subsp mycoides by the blood of certain horses. When incorporated in solid medium at a concentration of 15 per cent, the defibrinated blood of certain horses strongly suppressed the growth of some, but not all, strains of Mycoplasma mycoides subsp mycoides so that many colonies failed to develop to a visible size. Blood from a single rabbit was tested and found to exert a similar effect. There was striking variation in the degree of inhibition produced by different samples of horse blood and, of five strains of the organism examined, the T1 vaccine strain was the most susceptible. The results suggested that the effect was not due to antibod...
Cell-mediated immune response in equine babesiosis. An intradermal skin test, to demonstrate a delayed cutaneous hypersensitivity reaction in Babesia equi infection in donkeys, was developed. A skin reaction to B. equi antigen was elicited in vaccinnated, infected and carrier intact and splenectomised donkeys. The histopathological examination of the skin biopsy revealed infiltration of mononuclear cells and accumulation of oedematous fluid in the deeper layers of the dermis. A leucocyte migration inhibition test was developed and its specificity as an in vitro measure of cell-mediated immunity to B. equi antigen was established. The results of...
Studies on the antigenicity of an inactivated, aluminum hydroxide adjuvant equine influenza vaccine. An inactivated, aluminum hydroxide adjuvant equine influenza vaccine was tested in horses and guinea pigs to determine the levels of antigen that would elicit maximum serological responses. Vaccine containing serial twofold increments of A/Equi-1/Prague and A/Equi-2/Miami strains of equine influenza virus was administered to random groupings of both types of test animals. The hemagglutination inhibition antibody response for each group was then measured. Results in horses and guinea pigs were compared to determine if the equine serological values could be related to a potency test in laborator...
Bovine reaginic antibody III. Cross-reaction of antihuman IgE and antibovine reaginic immunoglobulin antisera with sera from several species of mammals. Using antisera specific for the heavy chain of human IgE and bovine reaginic immunoglobulin, the degree of cross-reaction amongst sera from pig, rat, rabbit, guinea pig, goat, cow, horse, dog, cat and human was tested. Antihuman IgE antiserum gave strong reactions with pig, rabbit, cow, goat and human sera (100% to 15.1%) and weak reactions with rat, guinea pig, horse, dog and cat sera (10.1% to 3.22%). Antibovine reagin antiserum produced a considerable amount of cross-reaction with sera from pig, rat, rabbit, goat, horse and human (43.6% to 20.1%) with limited reactions with guinea pig, dog ...
A three-year evaluation of four commercial equine influenza vaccines in ponies maintained in isolation. Ponies held in isolation for 40 months were vaccinated and revaccinated with four commercial equine influenza vaccines. Little or no HI antibody was detected after the first inoculation; second and subsequent annual revaccinations produced peak HI antibody titres between 7 and 14 days. Titres fell quickly between 14 and 28 days and less quickly thereafter. The decline of HI antibody appeared to be related more to the initial titre attained and to the period after vaccination than to the composition of the vaccine. The response to a first annual revaccination was superior to that produced by a ...
Failure of colostral immunoglobulin transfer as an explanation for most infections and deaths of neonatal foals. Failure in colostral immunoglobulin G (IgG) transfer was found in 9 of 87 Thoroughbred foals. Seven (78%) of these 9 foals acquired infections requiring therapy. Twelve of the foals had partial failure in colostral IgG transfer, and 3 of these had infections requiring therapy. The remaining 66 foals had normal transfer of colostral IgG, and only 2 had detectable infections. The failure of colostral IgG transfer was attributable to nursing problems in only one case. When presuckle postpartum colostrum was collected, 2 of 4 failures of colostral IgG transfer and 4 of 6 partial failures of colost...
Intrathecal antitetanus serum (horse) in the treatment of tetanus. In a two-year study of 322 conservatively treated, consecutive cases of tetanus in a rural hospital (all over twelve months old), intrathecal administration of 200 units of antitetanus serum (A.T.S.) (horse) reduced the overall mortality of 4-5% (5/110) compared with 14-5% (16/111) in the control series. 200 units intrathecal A.T.S. (horse) gave better results than 1500 units A.T.S. (horse). The results with lumbar and cisternal administration did not differ. It is suggested that tetanus is a polysystemic condition requiring polysystemic therapy. A regimen in which intrathecal A.T.S. is given ...
Laboratory methods of equine pregnancy diagnosis. Rectal examination is a reliable method of diagnosing pregnancy in the mare. Also, test kits are available for the simple quick detection of pregnant mare serum gonadotrophin. Nevertheless there is a considerable demand by practitioners for an independent laboratory service in equine pregnancy diagnosis, particularly during the gestational phase when placental gonadotrophin is concentrated in the blood. An initial attempt to provide a service by means of the agar gel diffusion test was disappointing and alternatives were sought. The primary requirements for an ideal alternative technique were ...
Electron-microscopic study of the development of an equine adenovirus in cultured fetal equine kidney cells. Sequential changes induced by an equine adenovirus in cultured fetal equine kidney cells were studied by electron microscopy. The first morphological change was the appearance of type I inclusions. These inclusions developed to type II inclusions which appeared as ring forms. Type III inclusions were formed within the central part of type II inclusions and finally filled up most of the nuclear space. As the infection proceeded, type IV inclusions which appeared as dense dark-staining spheres were formed at the center of the type III inclusions and also inside the cytoplasm. These dark-staining...
Immunoglobulin G subclass [IgG and IgG(T)] interaction with the P26 group specific antigen of equine infectious anemia virus: immunodiffusion and complement-fixation reactions. Isolated equine immunoglobulin (Ig)G(T) antibodies to equine infectious anemia virus P26 antigen did not precipitate with antigen when the ratio of antibody to antigen was high. However, at lower ratios of antibody to antigen precipitation occurred. In addition, complement-fixation by IgG and P26 antigen was inhibited by high concentrations of IgG(T). The unusual reaction pattern noted with IgG(T) antibodies was still detectable by the immunodiffusion test for equine infectious anemia virus. In situations of nonprecipitability by IgG(T), the adjacent positive control line was inhibited, and th...
RNA-dependent DNA polymerase associated with equine infectious anemia virus. Equine infectious anemia (EIAV) is shown to have an associated RNA-instructed DNA polymerase similar in its cofactor requirements and reaction conditions to the RNA tumor virus DNA polymerases. Demonstrating this DNA polymerase activity requires a critical concentration of a nonionic detergent, all four deoxyribonucleoside triphosphates, and a divalent metal ion. The reaction is sensitive to RNase, and a substantial fraction of the FNA synthesized is complementary to viral RNA. The detection of a complex of tritium-labeled polymerase product DNA-template RNA, which sedimented at 60S to 70S, pr...
[Long-term therapy using horse anti-dog lymphocyte globulin without sensitization against horse protein]. Eight mongrel dogs received a standard daily i.v. infusion of 20 mg/kg b.w. deaggregated horse-anti-dog-lymphocyte-globulin (ALG) and additional prednisolone (1 mg/kg b.w. daily i.v.) over a maximum period of 82 days following pretreatment with deaggregated normal horse IgG. No sensitization against horse protein was observed during therapy of afterwards as proved by lack of humoral antibodies against horse antigens, maintained lymphopenia, good compatibility, longterm prolongation of xenogeneic skin graft survival (85.6+/-20.6 days, n=8' untreated controls 12.5+/-1.3 days, n=4) and longterm s...
The activity of purine salvage pathway enzymes in murine and horse models of congenital and acquired dysimmunity. Previous studies of human congenital immunodeficiency states and in vitro observations of lymphocyte response to mitogens have implicated two purine salvage pathway enzymes, andenosine deaminase (ADA) and nucleoside phosphorylase (NP), as critical in the normal maturation and/or function of the immune system. Based on this information, ADA and NP activities were examined in a variety of congenital and acquired animal models of dysimmunity. The animals studied herein included: congenitally athymic (nude) mice; congenitally asplenic mice; congenitally athymic-asplenic mice; motheaten mice; New Z...
IgM antibody–I. Heterogeneity of the component chains of equine anti-lactose antibody. The heterogeneity of the IgM response has been studied with anti-lactose antibody purified from the sera of seven horses. The IgM antibody was induced with a bacterial vaccine and the sera were obtained during a one-year period of immunization. L and H chain preparations were derived from separate bleedings of each horse and examined by analytical isoelectric focusing. All of the L chain preparations were complex and similar and, under optimum conditions, exhibited about 45 bands. Their similarity included almost identical concentration distributions over the entire pH gradient. Isoelectric ba...
Corynebacterium equi enteritis in foals. Corynebacterium equi is a pathogen associated with respiratory disease in the foal. This paper discusses two cases of Corynebacterium equi infection, one acute and one chronic, in which the major damage was intestinal. Necrosis of Peyer's patches was the only lesion seen in the small intestine of both foals. The foal with acute disease had distinct green-tan focal necrosis and thickened mucosa of the large intestine. In the foal with chronic disease, the mucosa of the large intestine was thickened, rugose, and mottled red-tan. Histologically, the predominant lesions were villous atrophy, mucos...
Equine antibody to bovine serum induced by several equine vaccines as a source of extraneous precipitin lines in the agar gel immunodiffusion test for equine infectious anemia. Precipitin lines not associated with equine infectious anemia (EIA) were observed in routine agar gel immunodiffusion (AGID) testing for the infection. The serums which produced these lines were obtained from horses which had been given multiple vaccinations with commercially available cell culture-origin equine virus vaccines as part of a comprehensive herd health program. The lines formed against cell culture-derived, but not spleen-derived EIA viral antigens. Investigation revealed that bovine serum proteins in the vaccines induced precipitating antibodies which reacted with bovine serum pr...
Selective immunoglobulin M deficiency in foals. Selective immunoglobulin M deficiency was diagnosed in 5 foals, on the basis of reduced serum immunoglobulin M concentrations (more than 2 standard deviations below the normal mean). All 5 foals had clinical signs or lesions involving the respiratory tract. Lkebsiella sp was isolated from joint fluids, bronchial lymph nodes, or tracheal washings from the 3 foals in which such samples were available for microbiologic evaluation.