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.
Evaluation of delayed hypersensitivity responses in normal horses and immunodeficient foals. Delayed hypersensitivity (DH) responses of normal and immunodeficient horses were evaluated with antigens [dinitrochlorobenzene (DNCB), keyhole limpet hemocyanin (KLH)] and phytolectins [phytohemagglutinin (PHA), concanavalin A (Con A)]. Immunologically normal horses sensitized with 5 daily applications of 2 mg of DNCB developed positive skin reactions upon challenge with 0.4 mg of DNCB. The delayed onset of the reaction and the predominately mononuclear cell infiltration at the test site indicated these were DH reactions. Normal horses sensitized with 500 microgram of KLH and challenged with ...
Maintenance of foals with combined immunodeficiency: causes and control of secondary infections. Sixty-six cases of combined immunodeficiency (CID) in foals were studied to determine the most prevalent causes of infection and death. Lesions of the respiratory system were observed in 59 of the foals and were attributable to infection with equine adenovirus. Pneumocystis carinii, and bacteria. Significant lesions were also observed in liver, pancreas, intestines, heart, and kidneys. Maintenance of foals with CID for experimental purposes is directed at the prevention and control of these secondary infections. Adenovirus can be controlled by administration of horse plasma containing high tit...
Failure to propagate equine infectious anemia virus in mosquitoes and Culicoides variipennis. Laboratory-colonized mosquitoes, Culex tarsalis, aedes aegypti, Culiseta inornata, and Anopheles free-borni, and the biting gnat, Culicoides variipennis, were exposed to equine infectious anemia virus. Exposure to the virus was by intrathoracic inoculation for mosquitoes and by oral ingestion of an infective blood meal through a membrane for C variipennis. After various intervals, groups of 15 to 20 insects were homogenized and inoculated into susceptible ponies. Positive immunodiffusion test results were used as criterion for equine infectious anemia infection in ponies. Virus was not detecte...
Measurement of neutralizing antibody to equid herpesvirus 1 by single radial hemolysis. Antibody to equid herpesvirus 1, which mediates single radial hemolysis, is that responsible for neutralization. Hemagglutination inhibition antibody is not necessarily involved in neutralization or hemolysis.
Equine rhinopneumonitis vaccine: immunogenicity and safety in foals. Immunogenicity and safety of an equine herpesvirus 1 (ehv-1) vaccine were studied in 111 foals varying in age from 1 to 122 days. Each of 88 principals was given 1 im injection of vaccine. Five of the 88 foals were revaccinated; 69 of the vaccinated principals and 23 nonvaccinated foals (serving as controls) were challenge exposed intranasally with virulent ehv-1.
The vaccine failed to cause adverse local or systemic reaction in 88 principals with serunirneutralization (sn) titers against ehv-1 varying between 0 to 1:256 at time of vaccination. After vaccination, the foals' body temperature...
Specific reaction of aloe extract with serum proteins of various animals. We found that aloe extract contains a lectin-like substance which reacts with serum proteins of various animals. Furthermore, in human serum 2 proteins, alpha2-macroglobulin and alpha1-antitrypsin, were shown to be reactive with aloe extract.
Some studies on equine strains of Escherichia coli. A detailed study was made of 194 equine strains of E. coli, involving biochemical and serological characters. In these, the equine strains closely resembled E. coli from other sources, and shared antigenic characters with strains isolated from different animal species.
Serological response in mares affected by contagious equine metritis 1977. A serum agglutination and antiglobulin test is described for the detection of antibodies to the contagious equine metritis organism. A provisional interpretation of the test is proposed and using this interpretation the results of 66 such tests are discussed.
Induction of a cell membrane antigen by equine infectious anemia virus. Equine fibroblasts persistently infected with equine infectious anemia virus acquire a new cell membrane antigen demonstrable by indirect radioimmunoassay, using infected horse serum as an antibody source.
Selection of a strain of Culex tarsalis highly resistant to infection following ingestion of western equine encephalomyelitis virus. After prolonged selection, two hybrid strains of Culex tarsalis were evolved that were highly resistant to infection following ingestion of western equine encephalomyelitis virus. These strains were greater than 25,000-fold more resistant than the most susceptible parental strain when fed on viremic chicks. Resistance was associated with a mesenteronal barrier since both refractory and parental strains were equally susceptible to infection by intrathoracic inoculation. Susceptibility was dominant, possibly incompletely dominant, over resistance. Inheritance was probably polyfactorial but this ...
Study of homologous and heterologous antibody response in California horses vaccinated with attenuated Venezuelan equine encephalomyelitis vaccine (strain TC-83). Of 359 horses vaccinated with attenuated Venezuelan equine encephalomyelitis (VEE) vaccine (strain TC-83), 87% developed hemagglutination-inhibition (HI) antibodies to VEE virus within 1 month. Blood from a subsample of 101 of the 359 horses was obtained over a 1-year period. Within 1 month after vaccination, 84% of the 101 horses had developed VEE HI antibodies, 87% had developed VEE-neutralizing (Nt) antibodies, and 78% had developed VEE complement-fixing (CF) antibodies. One year after vaccination, 58% of the horses had VEE HI antibodies and 73% had VEE Nt antibodies. The percentage of hors...
In vitro and in vivo effects of corticosteroids on peripheral blood lymphocytes from ponies. The in vitro and in vivo effects of corticosteroids on peripheral blood lymphocytes (PBL) from ponies were studied. Prednisolone inhibited lymphocyte stimulation by phytohemagglutin (PHA) in a dose-dependent manner, without inducing lysis even at large doses. The PBL from horses heterozygous for the combined immunodeficiency trait responded to corticosteroid treatment the same as did PBL from normal ponies. Removal of the corticosteroid after incubation with PBL from normal ponies partially restored responsiveness of these cells to PHA. Chronic in vivo treatment of ponies with corticosteroids ...
Role of intracranial [H+] receptor in physiologic regulation of ventilation in ponies. Numerous studies have demonstrated the existence of an intracranial [H+] chemoreceptor mechanism capable of stimulating ventilation. 1 Supposedly, this chemoreceptor is located 0.2 mm below the surface of the ventrolateral side of the medulla and is responsive to [H+] in the surrounding cerebral extracellular fluid (ECF). During chronic conditions, ECF [H+] is supposedly in equilibrium with CSF [H+]; hence, stimulus level can be established through sampling and analysis of CSF. In this presentation, we summarize data from studies on spontaneously breathing, unanesthetized ponies which suggests...
Microculture method for mixed lymphocyte cultures in the horse. A miniaturized method for the mixed lymphocyte culture test in the horse is described. The test is performed in either round- or flat-bottom microtitration tissue culture plates. Concentrations of responsing and stimulating cells are varied, depening on the experiment. Significant discrimination between isogeneic and allogenic mixtures is possible after 120 hours' culture when cells are labeled ([3H]thymidine) for the last 16 to 18 hours of the test.
Immunoglobulins and secretory component in the external secretions of foals with combined immunodeficiency. Nasal washings and tears were collected from seven Arabian foals with combined immunodeficiency and nine normal foals. The major immunoglobulin in the external secretions of normal foals over 2 months of age was secretory immunoglobulin A, whereas foals with combined immunodeficiency lacked this immunoglobulin. The external secretions of both normal and immunodeficient foals contained free secretory component at birth.
Listeriosis in an Arabian foal with combined immunodeficiency. A 1-month-old Arabian foal with signs of central nervous system disease was found to have combined (B- and T-lymphocyte) immunodeficiency. The foal died in spite of intensive antibiotic therapy. At necropsy, generalized lymphoid hypoplasia and acute necrotizing and granulomatous inflammation of the brain, heart, and adrenal glands were found. In addition, there were spinal meningitis and focal hepatic necrosis. Listeria monocytogenes was isolated on primary culture from the brain.
Mixed lymphocyte culture responses in combined immunodeficiency of horses. Combined immunodeficiency in horses is a genetic disorder in which there is a defect in the production of committed B and T lymphocytes. In this study, peripheral blood mononuclear leukocytes from foals with combined immunodeficiency were examined for their capacity to stimulate and respond in one-way mixed lymphocyte cultures. Irradiated cells from combined immunodeficient foals were uniformly capable of stimulating cells from unrelated horses. However, none were able to respond to allogeneic stimulation. Examination of cells from known carrier horses revealed no difference in capacity to sti...
[Immunochemical investigations on the gene expression of horse serum carboxylesterase (author’s transl)]. Immunochemical and enzymatic analyses of horse serum carboxylesterase were carried out with respect to the existence of a silent gene. Sera with positive phenotypic expression of esterase, both heterozygotes and presumed homozygotes, were compared with:--sera with positive phenotypic expression but genotypically +/O;--sera with a negative phenotypic expression, i. e. genotypically O/O;--sera of natural +/O "hemi-zygotes": mules (donkey lacking the esterase);--positive sera heated at 60 degrees C;--positive sera after specific inhibition of enzymatic activity. Titration by immunocompetition has...
Immunocytochemical demonstration of calcitonin-containing C-cells in the thyroid glands of different mammals. In the thyroid glands of the horse, pig, deer, mole, and rat, C-cells could be demonstrated by means of the immunocytochemical PAP-technique using rabbit antisera against human calcitonin. Only in ruminants, the cross-reaction between the intracellularly stored antigen and the antibodies used appeared to be incomplete.
Synthetic antigens. Horse “natural” antibodies against interpolymer of styrene and maleic acid (PSM). Properties of horse natural anti-PSM antibodies are described. The antibodies were of IgG class. Electrostatic forces were mainly involved in reaction of PSM with horse antibodies. The reaction was inhibited by low molecular compounds resembling structural unit of PSM. Studies of difference spectra and ORD and CD spectra showed no major conformational changes in horse antibodies after reaction with PSM.
Equine markers genes. Polymorphism for group-specific component (Gc). Polymorphism of equine Gc protein was demonstrated by immunofixation electrophoresis with a goat anti-human Gc antibody. Three different phenotypes, F, FS and S, were found. Family data supported the genetic theory of two autosomal codominant alleles, GcF and GcS. Both alleles occurred in Standardbred, Thoroughbred and Arabian horses and in Shetland ponies. A frequency of 0.23 for GcS in the American Standardbred horse indicates the system should be useful for problems of identification and parentage.