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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.
Identification of allergens in extract of horse hair and dandruff by means of crossed radioimmunoelectrophoresis. Sera from 26 patients and 4 normals were examined for specific IgE binding to antigens of extract of horse hair and dandruff by means of CRIE. 22 of the patients were RAST- and intracutaneous-positive to horse extract. 4 more of the patients were RAST-negative to horse allergens, but showed allergies to extract of allergens from sources other than horse. The remaining four sera from controls were RAST-negative to horse and had no history of allergy. Antigens of horse hair and dandruff showed a significantly higher degree of binding to specific IgE in the sera from the first group of patients t...
Immunization of man and animals against influenza by oral and intranasal routes. Live human and equine influenza virus strains modified by serial passage on allantois-on-shell system (AOS) in the presence of normal horse serum were administered orally or intranasally to volunteers or horses. Mostly mild clinical short-lasting reactions, replication in nasal mucosae, transmission to placebo recipients and significant local or circulating antibody rises were observed following administration to volunteers of strains modified by five or less serial passages on AOS in the presence of normal horse serum (NHS). Milder clinical reactions, no replication, no viral transmission and...
Recrudescence of equine infectious anemia by treatment with immunosuppressive drugs. Horses which had passed a few months to a few years asymptomatically after the last recurrence of equine infectious anemia (EIA) showed a typical febrile response after treatment with the immunosuppressive agent, dexamethasone (DM) or cyclophosphamide (CY). In horses showing a febrile response, EIA virus which had not been neutralized by neutralizing antibody previously produced was propagated. In DM-treated horses it disappeared from the blood soon after pyretolysis and antibody against the virus was produced promptly. In contrast, detectable viremia persisted in CY-treated horses for 10 to 8...
[Effect of ultraviolet ray-irradiated autogenous blood on hematological indices in horses]. Comparative clinical and experimental investigations were carried out on 18 clinically normal horses. It was found that the single transfusion of in vitro UV-treated autogenous blood, following a previously described method, was tolerated well by horses and did not lead to any deviations from the normal indices. Under the effect of the treated blood there was an increase in the hemoglobin content, rise in the erythrocyte and leukocyte count with slightly expressed hyperleukocytosis and weak neutrophilia (simple regeneration of the blood). The sedimentation of erythrocytes also showed higher ra...
Treatment of horses with chronic diarrhea: immunologic status. All chronically diarrheal horses given (orally) 2 series of treatments with normal horse serum recovered in 2 to 4 weeks. However, mild diarrhea sometimes persisted several months in the group of horses with severe diarrhea. Weight gains were approximately 35% in horses with severe diarrhea and approximately 10% in horses with mild diarrhea. Serum specimens from 12 diarrheal and 20 normal horses were examined for immunoglobulins by single radial immunodiffusion technique. Concentration of immunoglobulin A in serum of diarrheal horses was approximately 50% lower than that in serum of normal hor...
Suppression of synthesis of an IgG subclass in a persistent viral infection. Comparison of immunoglobulin levels of nine horses before and after infection with equine infectious anaemia (EIA) virus demonstrated a significant depression of serum IgG(T) at 2 months (P less than 0-001) and at 1 year (P less than 0-01) after infection. In contrast, the levels of IgGa were significantly increased at both times after infection. Another sixteen horses with EIA for 1-4 months were examined and there was also significant depression (P less than 0-001) of IgG(T) when compared to pre-infection levels. No significant changes in IgG(T), IgGa and IgM were noted in fourteen normal ho...
Equine toxoplasmosis: a survey for antibodies to Toxoplasma gondii in horses. A nationwide sample of horses was tested to determine the prevalence of toxoplasma antibodies in equine animals. Of 1,294 serum samples from horses tested by the microtitration indirect hemagglutin test, 20% were positive. Among the popular breeds of horses, the following antibody prevalences were found: Arabian, 19%; Paint, 22%; Quarter Horses, 13%; Thoroughbred, 24%; and Standardbred, 17%. The antibody prevalence increased from 2% in horses 1 year of age to 18% in 2-year-olds, and rose to 38% in horses 12 years of age. Significant differences were not evident by broad geographic locations ac...
Evidence of respiratory tract infection induced by equine herpesvirus, type 2, in the horse. Five horses were experimentally exposed to equine herpesvirus 2 strain LK. Two young foals developed chronic pharyngitis (98 and 232 days, respectively). Growth characteristics, cytopathic effects (CPE), inclusion body formation, ether sensitivity, and immunofluorescent analysis indicated that the virus recovered from infected animals was a herpesvirus serologically identical with, or at least antigenically related to EHV-2 strain LK. No significant complement-fixing (CF) or virus-neutralizing (VN) antibody responses were observed in adult horses while both foals demonstrated a rise in CF anti...
Monocyte activation in horses persistently infected with equine infectious anemia virus. The monocytes of horses infected with equine infectious anemia virus were shown by their failure to migrate from capillary tubes and their increased adherence to erythrocytes to be activated.
Isolation and partial characterization of the major glycoproteins of horse and swine erythrocyte membranes. The major glycoproteins of horse and swine erythrocyte membranes were isolated and examined chemically and immunologically. The major glycoprotein of horse erythrocyte membranes had a molecular weight of 33 000 and consisted of 46.2% protein and 53.8% carbohydrate, of which 9.4% was hexose, 10.1% hexosamine and 33.7% sialic acid. This glycoprotein was associated with activity for the infectious mononucleosis heterophile antigen. There were two different major glycoproteins in swine erythrocyte membranes. One major glycoprotein had a molecular weight of 46 200 and consisted of 34.2% protein and...
Some aspects of endometrial cup formation and PMSG production. Two females of heterosexual pairs of chimaeric horse twins were fertilized by their co-twin brother and PMSG production examined during gestation. Four pregnancies developed in one mare and two in the other. The levels of PMSG were high in both mares and remained detectable in the peripheral blood until 220 and 265 days of gestation. The fetal membranes of one mare contained remnants of cup secretion with PMSG activity at term. The findings support the thesis of Allen & Moor (1972) that the endometrial cups are of fetal origin and that they are destroyed by immunological mechanisms.
Comparison of the methods of rectal palpation and haemagglutination-inhibition assay for diagnosis of pregnancy in mares. The diagnostic value of rectal palpation and immunological assay of PMSG was tested at different stages of pregnancy in mares inseminated with frozen semen in three separate studies. The results were based on foaling success and particular attention was paid to the numbers of inconsistent results obtained by the two tests. Generally, the number of false positive diagnoses was lower for the immunological assay than for palpation in early pregnancy (Days 40 to 60) and the relationship became reversed later in gestation.
The contribution of the mule to scientific thought. The infertility of the mule has proved a continuing challenge to scientific thought. Since the chromosomal differences between the two parental species are so great as to render normal meiosis impossible, it is postulated that all mules and hinnies are sterile. The problem now is to explain how mules and hinnies can occasionally produce spermatozoa or ova. The appearance of the mule was sufficient to persuade the ancients that both parents, not just the male, must contribute to the make-up of the offspring. The mule has also taught us that, when the number of oocytes in the ovary is reduced, t...
The transfer of passive immunity to the foal and its relation to immune status after birth. The mechanism of transfer of maternal immunity to the foal is reviewed. Maximal efficiency of macromolecular absorption by specialized cells of the small intestine exists soon after birth. The absorptive cells are progressively replaced by more mature-looking cells incapable of taking up large molecules and the rate of absorption is reduced in a linear decline and ceases completely within 24 hr. Passive antibody levels fall rapidly in the first 4 weeks of life to less than half their original values and have usually completely disappeared by 6 months of age. The foal shows immunological compet...
The ultrastructure of endometrial cups in pregnant mares. Electron microscopy and immunofluorescence techniques were used to study the various epithelial cells in the endometrial cups of ten pregnant mares, and in the uterine epithelium of one non-pregnant mare. Evidence was obtained which suggested that epithelial gland cells within the endometrial cups, as distinct from the hypertrophied decidual-like cells in the cup, may synthesize PMSG. The suggestion does not agree with the findings of other workers in the fetal origin (chorionic girdle cells) of this gonadotrophin.
Immunoglobulin metabolism in the neonatal foal. The proteins IgG and IgG(T) are the predominant immunoglobulins in equine colostrum. Their distribution and catabolism were studied in the newborn foal using an isotopic tracer technique. More precise quantitation of the absorption of these immunoglobulins from colostrum is now possible.
Coital exanthema in stallions. Equine coital exanthema can be produced experimentally in stallions by inoculation with an equine herpesvirus (strain 65/61) and be transmitted during coitus with an infected mare. Serological responses to this infection include the production of complement-fixing and serum-neutralizing antibodies which reach maximum levels 14 to 21 days after infection. Complement-fixing antibodies decline rapidly and are usually not detectable by 60 days after infection, whereas serum-neutralizing antibody activity is maintained for at least 1 year. This disparity provides a useful method for the diagnosis o...
Identification of multiple equine infectious anemia antigens by immunodiffusion reactions. Equine infectious anemia (EIA) cell antigens prepared from infected equine spleen, equine leukocyte cultures or a persistently infected equine dermis cell line contained at least two serologically reacting components. For convenience one component was designated as soluble antigen (SA) and the other as cell-associated antigen (CAA). The SA appeared as a single component when it was prepared from EIA virus precipitated from infectious tissue culture fluid with polyethylene glycol and ether treated but it was mixed with CAA when the source was infected cells. Cytolytic or mechanical disruption o...
Antigenic relationship between the surface antigens of avian and equine influenze viruses. Influenza virus Equine 1 (A/equine/Prague/56) has a hemagglutinin which is antigenically related to the hemagglutinin of fowl plague virus strain Rostock (FPV) and a neuraminidase which cross-reacts with the enzyme of virus N (A/chick/Germany/49). After a single injection of chickens with Equine 1 virus no hemagglutination inhibiting (HI) and neutralizing antibodies against FPV can be demonstrated, although the birds are fully protected against a lethal dose of FPV. HI and neutralizing antibodies against FPV appear after a second injection of Equine 1 virus several weeks after the first one. L...
Studies in atypical Streptococcus equi. An atypical variety of Streptococcus equi is described. It was shown to be deficient in capsular material, to be very virulent for mice and to possess a cell-wall protein similar to the M-like protein of classical Str equi. Antiserum prepared against classical Str equi effectively opsonised the atypical strains, and induced the formation of long chains by these atypical strains. It is possible that this variant of Str equi can be used to overcome many of the current problems associated with the manufacture and use of strangles vaccines.
Investigation of equine infectious anaemia in Queensland using gel diffusion. An antigen for the gel diffusion test for equine infectious anaemia (EIA) was prepared from the spleen of a horse experimentally infected with the CQ strain of the virus. The antigen produced a single, distinct line of precipitation when tested against a range of known positive serums, and did not react with pre-inoculation and known negative serums. Extracts prepared from uninfected spleens displayed no reaction when similarly tested. Serum from 34 of 451 Queensland horses contained detectable levels of antibody to EIA virus. The positive serums were from horses in widely separated areas of t...
Digitoxin metabolism by rat liver microsomes. The chest roentgenographic findings in Takayasu's arteritis include widening of the ascending aorta, contour irregularities of the descending aorta, arotic calcifications, pulmonary arterial changes, rib notching, and hilar lymphadenopathy. The single most important diagnostic sign is a segmental calcification outlining a localized or diffuse narrowing of the aorta. The other signs may be suspicious or suggestive, but the diagnostic accuracy increases when several findings are present simultaneously. A routine screening of monoclonal gammopathies (M.G.) was performed in the serum from 36, 015 ...
Immunological and chemical correlation between alpha-fetoproteins from human and several mammalian species. Alpha-Fetoproteins of several animals were purified and their molecular weights, amino acid compositions and peptide maps were compared, demonstrating the close similarities. These data indicated that the alpha-fetoproteins of mammalian species have closely related antigenical and chemical structures. Rabbits and horses were immunized with human alpha-fetoprotein, and it was observed that the animals produced antibodies reaction not only with human alpha-fetoprotein but with their homologous alpha-fetoproteins. The results were interpreted as the breakdown of the tolerance to their own alpha-f...
Leucocyte myosin and its location in the cell. The intracellular location of the binding site of antibody against purified myosin prepared from equine leucocytes was investigated in neutrophils and lymphocytes by electron microscopy using peroxidase-labelled antibody method. The myosin extracted from equine leucocytes could bind skeletal muscle F-actin and the formed complex showed the biophysical and biochemical properties and electron microscopic appearance of actomyosin. On immunodiffusion, the leucocyte myosin formed a single precipitin line with its antibody prepared in rabbits. The antibody also formed single precipitin lines with my...
Differences in subunit composition and iron content of isoferritins. Horse spleen ferritin was fractionated into its constituent isoferritins by isoelectric focusing. Separated isoferritins were stable and showed no tendency to redistribute when re-examined by analytical gel focusing. All of the isoferritins were immunologically indistinguishable when tested with antibodies raised against unfractionated horse spleen ferritin. The separated isoferritins also had similar conformations as determined by circular dichroism. Iron distribution studies, however, revealed a wide disparity among the isoferritins. The most acidic components had the lowest iron content but...
