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 determinants of acylphosphatase from porcine skeletal muscle. Analysis of the quantitative precipitin reaction of acylphosphatase from porcine skeletal muscle with rabbit antiserum indicated the presence of at least two antigenic determinants on the porcine enzyme molecule. Immunological cross-reactivities of acylphosphatases from equine and rabbit skeletal muscles were examined. In double immunodiffusion with the antiserum, the precipitin lines of the porcine and equine enzymes completely fused, while the rabbit enzyme gave no precipitin line. The reaction between the 125I-labeled porcine enzyme and its antibody was inhibited to the same extent by the p...
Turbidimetric measurement of IgG(T) in the serum of healthy Thoroughbreds and ponies. The turbidimetric analysis of IgG(T) in the serum of horses is described. Reference values are provided for 'worm-free' ponies (2.6 +/- 0.7 g/litre), stabled Thoroughbreds two years old and over (4.1 +/- 1.3 g/litre), grazing Thoroughbred broodmares (7.1 +/- 2.4 g/litre) and regularly wormed adult and young ponies grazing pasture contaminated with intestinal parasite eggs and larvae.
Onchocerca cervicalis in horses: dermal histopathology. A histopathological study of ventral midline skin from midwestern U.S. horses with and without onchocerciasis due to Onchocerca cervicalis found perivascular mononuclear dermatitis as the most consistent difference between the two groups. Seasonal variation in parasite numbers or cellular influxes was not observed. Eosinophilic dermatitis was observed in horses with onchocerciasis and dermatitides of unknown etiology.
[Comparative characteristics of the vitreous body proteins in vertebrates]. Using disc-electrophoresis in polyacrylamide gel and immunochemical methods, studies have been made on proteins from the vitreous body of mammals (albino mouse, rat, guinea pig, pig, dog, cat), birds (hen), amphibians (the frog Rana ridibunda) and fish (the perch Perca fluviatilis). It was found that vitreous body proteins in man and animals include both the specific proteins and those of the blood serum. During evolution, specific antigens of the vitreous body attained strict species specificity, although some of them preserved the initial properties.
Mucosal nasopharyngeal immune responses of horses to protein antigens of Streptococcus equi. Mucosal nasopharyngeal immunoglobulin A (IgA) and IgG responses to proteins of Streptococcus equi were studied in horses after the experimental production of strangles. S. equi-specific IgA and IgG titers in nasopharyngeal mucus were much higher in samples from animals 1 to 2 weeks after challenge than in samples from control animals. Although IgA was the major immunoglobulin in nasal mucus, there was more antibody activity associated with IgG as measured by radioimmunoassay. Great differences between the specificities of antibodies in nasal mucus and in serum were detected. IgA and IgG of muc...
Production and biological properties of M-protein of Streptococcus equi. The production of M-protein antigen of Streptococcus equi was studied during in vitro growth in equine blood and in various media. Of 11 S equi strains studied, seven which had initially possessed 0.04 mg or less M-protein per 10 mg of streptococcal cell extract showed an increase in M-protein content after successive culture in heparinised horse blood. Maximum proliferation occurred in Todd-Hewitt (TH) medium with added 0.2 per cent w/v glucose when compared with TH medium alone or TH medium with 2 per cent w/v sucrose, starch, neopeptone or normal horse serum. The M-protein of these strains ...
Amino acid sequences of haemagglutinins of influenza viruses of the H3 subtype isolated from horses. The amino acid sequence of the haemagglutinin of A/equine/Miami/63 (H3N8), the prototype influenza virus of the H3 subtype from horses, is deduced from the nucleotide sequence of virus RNA and compared with the sequences of haemagglutinins of viruses of this subtype isolated from humans [X-31 (H3N2)] and from birds [A/duck/Ukraine/63 (H3N8)] and with the sequence of the haemagglutinin of A/equine/Fontainebleau/79 (H3N8) a virus isolated from a recent outbreak of equine influenza. The amino acid sequence differences detected are discussed with reference to the structure of the molecules, their ...
Variant specific opsonization of Trypanosoma evansi measured by luminol-dependent chemiluminescence. Using luminol-dependent chemiluminescence (LCL), the specificity of antibodies to variable antigen type (VAT)-populations of Trypanosoma evansi was studied in four infected ponies. Trypanosomes of each wave of parasitemia were isolated and multiplied in irradiated mice. Their opsonization by serum collected during the infection was investigated with LCL and results for isolated VAT-populations are shown in the paper. Antibodies specific to each VAT-population were first found three days after the maximum of a parasitemic wave. There was no cross reactivity between different VAT-populations. LC...
Natural cytotoxicity of human lymphocytes against equine target cells in vitro. Human lymphocytes displayed a frequent natural cytotoxicity (NK) in vitro against normal equine dermal fibroblasts (ED) and against equine tumour cells of a virus-containing cell line (Mc-1). Similarly, human normal sera contained antibodies that induced antibody-dependent cellular cytotoxicity (ADCC) by normal human lymphocytes against the same target cells. Both NK and ADCC varied for different donors. For individual donors, however, cytotoxicity against the two target cells was significantly correlated both in NK and ADCC. For ED there was also a significant correlation between ADCC and NK ...
Measurement of IgG in equine blood by immunoturbidimetry and latex agglutination. This paper describes the quantitative measurement of IgG concentrations in equine blood/serum by turbidimetric analysis and the qualitative assessment using latex agglutination. The concentration of IgG in foal serum measured by turbidimetry correlated well with the results obtained by radial immunodiffusion (r = 0.91) and the gamma-globulins estimated from the electrophoresis of serum on cellulose acetate (r = 0.92). The method, using antibody-coated latex beads, to detect foals with serum IgG concentrations of less than 4 g/litre (whole blood less than 2 g/litre) proved to be accurate in 96 ...
Depression of lymphocyte reactivity by granulocytes in equine whole blood culture. Tritiated thymidine uptake in response to Concanavalin A was recorded as stimulated counts per minute (SCPM) in equine whole blood cultured with an optimum concentration of 3 X 10(4) mononuclear cells/culture. A significant negative correlation was found between log10 SCPM and granulocyte level in culture, in a group of 27 adult horses (r = -0.745, P less than 0.001). Addition of isolated autologous granulocytes to such cultures resulted in a reduction of log10 SCPM of a magnitude similar to that predicted by the gradient of the log10 SCPM/granulocyte level regression line in the group of adul...
Susceptibility of equine bacterial isolates to antimicrobial agents. In vitro antimicrobic susceptibility patterns of commonly isolated aerobic gram-positive and gram-negative bacterial pathogens of equine origin were determined, using the agar-plate dilution method. All organisms were recent clinical isolates and included Corynebacterium (Rhodococcus) equi, Corynebacterium pseudotuberculosis, (coagulase positive) Staphylococcus sp, Streptococcus equi, Streptococcus zooepidemicus, Actinobacillus sp, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Salmonella. In vitro susceptibility levels were outlined for 14 antimicro...
Nocardia asteroides infection in horses: a review. From 1965 to 1983, Nocardia asteroides infection was diagnosed in 16 horses at the Veterinary Medical Teaching Hospital, University of California, Davis. In 2 of the cases, the infection was traumatic in origin and local in extent; the horses recovered without relevant antimicrobial therapy. Fourteen horses had pulmonary or disseminated infections that ended fatally. All 14 had various degrees of immunosuppression. Of these, 8 were Arabian foals with combined immunodeficiency disease and 3 were aged horses with hyperadrenocorticism secondary to ACTH-secreting pituitary tumors. Of the other 3, ...
[The economic evaluation of vaccination against infectious cough in horses using the cost-benefit analysis]. Approximately 40% of all horses in the Federal Republic of Germany had infectious respiratory disease in 1982. Although an expert vaccine prophylaxis confers a reliable protection, conventional therapy is preferred over vaccination because of the cost. The cost/effect analysis carried out in this investigation demonstrates that vaccination should be favoured also for economic reasons. Based on the individual animal immune prophylaxis saves the horse owner at least 415 DM per year. This analysis did not take into account the danger of a transmission to man and related infection chains of viruse...
Immunohistological studies of the local immune system in the reproductive tract of the mare. The immunoperoxidase technique was adapted for the identification of free immunoglobulin and immunoglobulin producing cells in equine tissues. Staining specific for free IgG, IgA and IgM was detected at all levels of the reproductive tract, and secretory component staining was present in the uterine epithelium but not in the oviduct, cervix or vagina. Immunoglobulin producing cells were present at all levels of the tract, with IgG and IgA cells at equivalent concentrations, but with fewer IgM cells. There was no cyclical trend in free immunoglobulin staining, or plasma cell numbers. IgG and Ig...
Equine lymphocyte antigens in four major Belgian horse populations. Contribution to serology and antigen distribution. 158 Belgian Saddlebreds, 130 Belgian Trotters, 108 Belgian Draft horses and 92 Shetland ponies have been typed for serologically defined antigens at the ELA and ELY systems. Gene frequencies were estimated in each breed for the internationally established ELA, ELY-1 and ELY-2 alleles as well as for locally assigned additional ELA markers and for subtypes of ELA-W3, W9 and W11. The distribution of ELA alleles was in agreement with the expected Hardy-Weinberg equilibrium for the 4 horse breeds described here. Differences in gene frequencies between these main Belgian horse populations were obser...
Detection of Corynebacterium equi-specific antibody in horses by enzyme-linked immunosorbent assay. An enzyme-linked immunosorbant assay was developed to measure naturally occurring Corynebacterium equi specific antibody in horse serum. Antibody against C equi was demonstrated in normal adults and was passively transferred to foals. Adult levels of specific antibody were reached by 5 to 6 months of age in healthy foals. Decreased early antibody levels were demonstrated in a limited number of foals with confirmed C equi infection.
Seasonal changes in the white blood cell system, lyzozyme activity and cortisol level in Arabian brood mares and their foals. In 34 pure-breed Arabian horses divided into four groups (Gr. I, ten pregnant mares; Gr. II, seven barren mares; Gr. III, ten foals born in 1981; Gr. IV, seven foals born in 1982) seasonal changes in the white blood cell system, cortisol level and lyzozyme activity were studied. Seasonal periodicity was found in all groups for the number of lymphocytes, segmented neutrophils and eosinophils and cortisol level. Leukocyte periodicity was found in three groups, but not in the barren mares. In lyzozyme activity there was periodicity in three groups but not in the youngest foals. In the stab neutro...
Precipitating antibodies against Micropolyspora faeni in equines in north-western India. Prevalence of serum precipitins against Micropolyspora faeni, Thermoactinomyces vulgaris and Aspergillus fumigatus, employing the counterimmunoelectrophoresis (COIE) and Ouchterlony's double diffusion (DD) techniques, is reported in 162 of the equines stationed at two military installations in north-western India. M. faeni specific precipitins were demonstrable in 58 of 112 mules from site I in the mountainous region whereas the results were negative for all of the 50 horses examined from site II located in the plains. Of the 58 M. faeni positive mules, 45 (78%) had signs and symptoms suggesti...
Equine infectious anemia virus: immunopathogenesis and persistence. Equine infectious anemia (EIA) is a chronic, relapsing infectious disease of horses caused by a nononcogenic retrovirus. Virus persists in infected animals for life and can be reliably detected by serologic tests that measure levels of antibody to the major structural protein of the virus. Periodic virus replication in macrophages leads to an immunologically mediated acute disease characterized primarily by severe anemia. Recrudescence of acute EIA is the result of antigenic variation of the surface glycoprotein of EIA virus. The frequency and severity of clinical episodes of EIA decrease in m...
Metabolic investigations of fibroblasts from horses, Equus caballus, with hereditary severe combined immunodeficiency. In an attempt to determine the metabolic defect causing severe combined immunodeficiency (SCID) in horses in which altered purine metabolism has been observed, various parameters of purine and pyrimidine metabolism were evaluated. The activities of nine purine enzymes (adenosine kinase, purine nucleoside phosphorylase, deoxyadenosine kinase, deoxycytidine kinase, 5'-nucleotidase, AMP deaminase, hypoxanthine-guanine phosphoribosyl transferase, and adenine phosphoribosyl transferase were measured in fibroblasts. All activities determined for SCID horses were normal. Uptake of 10 microM adenosine...
Endotoxin-induced eicosanoid production by equine vascular endothelial cells and neutrophils. Dispersed equine vascular endothelial cells grown in tissue culture, and freshly isolated neutrophils were used to determine direct effects of endotoxin on cyclooxygenase and lipoxygenase products. Endothelial cells (10(7)/ml) or neutrophils (2 X 10(6)/ml) were incubated with (a) buffer, (b) endotoxin (10 micrograms/ml), (c) endotoxin + flunixin meglumine (10 micrograms/ml), or (d) calcium ionophore, A23187 (10 micrograms/ml). Thromboxane (TxB2), prostacyclin (6-keto-PGF1 alpha), and leukotriene C4 (LTC4) were determined in the incubation fluid by radioimmunoassay. Thromboxane and prostacyclin...