T cells are a type of lymphocyte that play a significant role in the adaptive immune system of horses. They are involved in identifying and responding to pathogens, such as viruses and bacteria, by recognizing specific antigens. T cells can be categorized into various subsets, including helper T cells (CD4+), cytotoxic T cells (CD8+), and regulatory T cells, each with specific functions in immune regulation and response. The study of T cells in horses encompasses their development, activation, and the mechanisms by which they mediate immune responses. This research area includes investigations into how T cells contribute to equine health, their response to vaccinations, and their involvement in immune-mediated diseases. This page compiles peer-reviewed research studies and scholarly articles that explore the biology, function, and clinical relevance of T cells in equine immunology.
Sellon DC, Knowles DP, Greiner EC, Long MT, Hines MT, Hochstatter T, Hasel KM, Ueti M, Gillis K, Dame JB.Sarcocystis neurona is an apicomplexan parasite that is the primary etiologic agent of equine protozoal myeloencephalitis in horses. Protective immune responses in horses have not been determined, but interferon-gamma (IFN-gamma) is considered critical for protection from neurologic disease in mice. The role of adaptive and innate immune responses in control of parasites was explored by infecting BALB/c, IFN-gamma knockout (GKO), and severe combined immune deficient (SCID) mice with S. neurona (10(4) sporocysts/mouse). Immune competent BALB/c mice eliminated parasites within 30 days, with no s...
Chung C, Mealey RH, McGuire TC.Cytotoxic T lymphocytes (CTL) are important for controlling equine infectious anemia virus (EIAV). Because Gag matrix (MA) and capsid (CA) are the most frequently recognized proteins, the hypothesis that CTL from EIAV-infected horses with diverse MHC class I alleles recognize epitope clusters (EC) in these proteins was tested. Four EC were identified by CTL from 15 horses and 8 of these horses had diverse MHC class I alleles. Two of the eight had CTL to EC1, six to EC2, five to EC3, and four to EC4. Because EC2-4 were recognized by CTL from >50% of horses with diverse alleles, the hypothesi...
Deeg CA, Reese S, Gerhards H, Wildner G, Kaspers B.To investigate the uveitogenic potential of retinal S-antigen (S-Ag) in horses. Methods: Horses were immunized subcutaneously with S-Ag or BSA as control antigen, emulsified in complete Freund's adjuvant. Simultaneously, Bordetella pertussis was given intravenously. Antigen specific T- and B-cell responses were analyzed in a 3-day interval. Disease development was judged clinically and histopathologically. Two identical booster immunizations were given every 4 weeks to test induction of recurrences. Results: T- and B-cell responses specific for S-Ag were observed in all immunized horses but we...
Chaffin MK, Cohen ND, Martens RJ, Edwards RF, Nevill M, Smith R.Rhodococcus equi causes severe pyogranulomatous pneumonia in foals and in immunocompromised people. In mice, both CD4+ and CD8+ T lymphocytes contribute to host defense against R. equi, but CD4+ T lymphocytes are required for pulmonary clearance of the bacteria. In this prospective study of 208 foals at two equine breeding farms with endemic R. equi infections, we collected peripheral blood samples at 2 and 4 weeks of age and at the time of diagnosis of R. equi pneumonia. Samples were analyzed for concentrations of total and differential leukocytes, EqCD4+ and EqCD8+ T lymphocytes, and B lymph...
Taouji S, Nomura I, Giguère S, Tomomitsu S, Kakuda T, Ganne V, Takaï S.Amino acid 65-78 of membrane protein VapA of the facultative intracellular Rhodococcus equi contained an immunodominant N-terminal B-cell epitope (N15Y peptide). Safety and immunogenecity of a synthetic peptide consisting of the amino acid 65-78 of VapA (peptide N15Y) were evaluated first in mice and in healthy adult horses. A single dose of a peptide-VapA vaccine induced and only in presence of adjuvant, specific IgG antibodies in sera of mice. After challenge with virulent R. equi 3 weeks after immunization, tissue clearance was more delayed in immunized mice than in control mice. An antibod...
Takahashi T, Yawata M, Raudsepp T, Lear TL, Chowdhary BP, Antczak DF, Kasahara M.In rodents, the Ly49 family encodes natural killer (NK) receptors interacting with classical MHC class I molecules, whereas the corresponding receptors in primates are members of the killer cell immunoglobulin-like receptor (KIR) family. Recent evidence indicates that the cattle, domestic cat, dog, and pig have a single LY49 and multiple KIR genes, suggesting that predominant NK receptors in most non-rodent mammals might be KIR. Here, we show that the horse has at least six LY49 genes, five with an immunoreceptor tyrosine-based inhibition motif (ITIM) and one with arginine in the transmembrane...
Mérant C, Bonnefont C, Desbos A, Greenland T, Cadoré JL, Monier JC.The recognition of equine lymphocyte antigens by monoclonal antibodies (mAbs) directed against human CD11a, CD18, CD21, CD23, CD29 and DR, as well as mouse CD23 was studied by flow cytometry. Unlike anti-CD11a, -CD21, -CD23 and DR mAbs, anti-CD18 and CD29 mAbs labelled the same percentage of horse peripheral blood lymphocytes (PBL) as human PBL. Double-staining with anti-horse immunoglobulin antibodies showed that anti-CD21 and -CD23 mAbs are mainly bound to peripheral blood B lymphocytes. The seven mAbs were also tested on the lymph node and thymus cells. The molecular targets of anti-CD11a, ...
Roberto Da Costa RP, Carvalho H, Agrícola R, Alpoim-Moreira J, Martins C, Ferreira-Dias G.The purpose of this study was to evaluate different parameters of the immune status in the mare, during the follicular and the luteal phases of the oestrous cycle, in two consecutive years. Functional competence of peripheral blood neutrophils, such as chemotaxis, phagocytosis and oxidative burst was assessed under physiological cyclic conditions (Exp. I). In the second year of this study (Exp. II), besides peripheral blood neutrophil phagocytosis and oxidative burst analysis, circulating lymphocyte subsets were also characterized. The reproductive status in a total of 17 adult cycling mares w...
Kydd JH, Wattrang E, Hannant D.In general, vaccines containing inactivated equine herpesvirus-1 (EHV-1) fail to prevent abortion in pregnant mares following infection with a virulent strain of EHV-1. We have tested the hypothesis that resistance to EHV-1-induced abortion in pregnant mares is associated with high frequencies of EHV-1 specific, major histocompatibility complex (MHC) class I-restricted, cytotoxic T lymphocytes (CTL) in the circulation. To test this theory, three groups of pregnant mares were assembled with varying backgrounds of infection or vaccination in an attempt to mimic the immune status of the general p...
Soboll G, Whalley JM, Koen MT, Allen GP, Fraser DG, Macklin MD, Swain WF, Lunn DP.Equine herpesvirus-1 (EHV-1) causes serious disease in horses throughout the world, despite the frequent use of vaccines. CTLs are thought to be critical for protection from primary and reactivating latent EHV-1 infections. However, the antigen-specificity of EHV-1-specific CTLs is unknown. The aim of this study was to identify EHV-1 genes that encode proteins containing CTL epitopes and to determine their MHC I (or ELA-A in the horse) restriction. Equine dendritic cells, transfected with a series of EHV-1 genes, were used to stimulate autologous CTL precursor populations derived from previous...
Mealey RH, Zhang B, Leib SR, Littke MH, McGuire TC.Equine infectious anemia virus (EIAV) is a lentivirus that causes persistent infections in horses. We hypothesized that high-avidity CTL specific for nonvariable epitopes might be associated with low viral load and minimal disease in EIAV-infected horses. To test this hypothesis, memory CTL (CTLm) responses were analyzed in two infected horses with high plasma viral loads and recurrent disease (progressors), and in two infected horses with low-to-undetectable viral loads and mild disease (nonprogressors). High-avidity CTLm in one progressor recognized an envelope gp90 epitope, and the data doc...
Mendoza L, Mandy W, Glass R.The immunotherapeutic properties of a new Pythium insidiosum-vaccine formulation (PIV), was evaluated in 18 horses and 6 dogs with proven pythiosis from different enzootic areas in the United States. All injected horses but one responded with a weak (=29 mm, n=3), a mild (30-90 mm, n=7) or a strong (=100 mm, n=7) inflammatory reactions at the site of injection. Three equines with weak or negative reactions at the injection site were not cured. Seven equines with strong reactions at their injection sites, however, were cured. Six of the eight horses with mild reactions were also cured. The rema...
Hines SA, Stone DM, Hines MT, Alperin DC, Knowles DP, Norton LK, Hamilton MJ, Davis WC, McGuire TC.Rhodococcus equi is a gram-positive bacterium that infects alveolar macrophages and causes rhodococcal pneumonia in horses and humans. The virulence plasmid of R. equi appears to be required for both pathogenicity in the horse and the induction of protective immunity. An understanding of the mechanisms by which virulent R. equi circumvents protective host responses and by which bacteria are ultimately cleared is important for development of an effective vaccine. Six adult horses were challenged with either virulent R. equi or an avirulent, plasmid-cured derivative. By using a flow cytometric m...
Montes LF, Abulafia J, Wilborn WH, Hyde BM, Montes CM.Histopathologic studies of vitiligo have been rather limited in number, thus the microscopic features of this common disorder are not very well known. Methods: Skin specimens from 20 human vitiligo patients and skin specimens from five equine vitiligo patients were studied by light and transmission electron microscopy. Conclusions: Absence of melanocytes, increased number of Langerhans' cells, epidermal vacuolization, thickening of the basement membrane, T-cell inflammatory infiltrate, and neural alterations were noted in the vitiligo lesions. These results may explain the development of depig...
Rappocciolo G, Birch J, Ellis SA.There is good evidence that cytotoxic T lymphocytes play an important role in the clearance of equine herpesvirus-1 (EHV1) in horses. We have demonstrated that, in common with other alphaherpesviruses, EHV1 infection can lead to dramatic down-regulation of MHC class I expression at the cell surface, a common strategy for pathogen evasion of the host immune response. This down-regulation is specific for MHC class I and does not reflect a general shut-off of host-cell protein synthesis. The use of monoclonal antibodies that recognize different MHC class I epitopes has demonstrated that the effec...
Lopez AM, Hines MT, Palmer GH, Alperin DC, Hines SA.Rhodococcus equi infects and causes pneumonia in foals between 2 and 4 months of age but does not induce disease in immunocompetent adults, which are immune and remain clinically normal upon challenge. Understanding the protective response against R. equi in adult horses is important in the development of vaccine strategies, since those mechanisms likely reflect the protective phenotype that an effective vaccine would generate in the foal. Twelve adult horses were challenged with virulent R. equi and shown to be protected against clinical disease. Stimulation of cells obtained from bronchoalve...
European journal of immunologySeptember 11, 2002
Volume 32, Issue 9 2598-2606 doi: 10.1002/1521-4141(200209)32:93.0.CO;2-#
Deeg CA, Thurau SR, Gerhards H, Ehrenhofer M, Wildner G, Kaspers B.Equine recurrent uveitis (ERU) is an inflammatory eye disease with high similarity to uveitis in man. It is the only spontaneous animal model for uveitis and the most frequent eye disease in horses affecting up to 10% of the population. To further investigate the pathophysiology of ERU we now report the establishment of an inducible uveitis model in horses. An ERU-like disease was elicited in seven out of seven horses by injection of interphotoreceptor retinoid-binding protein (IRBP) in complete Freund's adjuvant. Control horses did not develop uveitis. The disease model is characterized by a ...
Deeg CA, Ehrenhofer M, Thurau SR, Reese S, Wildner G, Kaspers B.Equine recurrent uveitis (ERU) is the most serious eye disease in horses worldwide. Despite the fact that ERU is generally considered to be immune mediated, a detailed description of the histopathology of the posterior part of ERU eyes is lacking. Here, we examined sections of paraffin-embedded eyes using histological and immunhistological methods. Twenty seven eyes of 20 horses with ERU and 30 eyes of 15 healthy control horses were included in this study. We could consistently demonstrate an involvement of the retina and the choroid in all examined eyes of horses with spontaneous ERU. In eyes...
Gilger BC, Yang P, Salmon JH, Jaffe GJ, Allen JB.To determine whether a chemokine (RANTES)-like protein expressed by ciliary epithelium plays a role in uveitis. Methods: 3 clinically normal horses intradermal, 5 eyes from 5 horses with recurrent uveitis, and 10 normal eyes from 5 age- and sex-matched horses. Methods: Cross-reactivity and sensitivity of recombinant human (rh)-regulated upon activation, normal T-cell expressed and secreted (RANTES) protein were evaluated in horses by use of intradermal hypersensitivity reactions and a chemotaxis assay. Aqueous humor and ciliary body of eyes from clinically normal horses and horses with uveitis...
Beadle RE, Horohov DW, Gaunt SD.We hypothesised that horses affected with summer pasture-associated obstructive pulmonary disease (SPAOPD) react to an allergen or allergens in their summer environment that is either absent or present at lower levels in their winter environment; and that such allergens stimulate SPAOPD-affected horses to produce a different T helper lymphocyte cytokine profile from that of control horses. The primary objective of this study was to determine the cytokine mRNA profile of T helper lymphocytes obtained from summer pasture-associated obstructive pulmonary disease (SPAOPD) affected horses when 1) t...
Henson KL, Alleman AR, Kelley LC, Mahaffey EA.Immunohistochemical techniques were used to examine 29 cases of equine lymphoma for estrogen receptor (ER) and progesterone receptor (PR) expression. The lymphomas examined included T-cell-rich large B-cell lymphomas, B-cell neoplasms, and T-cell lymphomas. The individual cases were also classified according to the anatomic location of the tumors. One normal equine lymph node was also examined for ER and PR expression. All of the cases of equine lymphoma and the normal lymph node were negative for Er. A total of 16/29 (55%) PR-positive lymphomas were identified. Seven of the 12 (58%) T-cell-ri...
Baker JM, Stidworthy M, Gull T, Novak J, Miller JM, Antczak DF.Serological and cellular assays and molecular techniques were used to define features of the major histocompatibility complex (MHC) of the donkey With this information in hand, immune recognition of MHC determinants within and between donkeys and horses was compared. An antibody-mediated, complement-dependent, microcytotoxicity assay using a variety of antisera to donkey histocompatibility antigens, including those induced as a result of intraspecies or interspecies pregnancy in horse mares and jenny donkeys, delineated five donkey leukocyte antigen (DoLA) specificities. Antisera raised across...
Pinkerton ME, Bailey KL, Thomas KK, Goetz TE, Valli VE.A 17-year-old Quarterhorse gelding with a clinical diagnosis of protein-losing enteropathy was submitted for necropsy following a 4-5-month duration of weight loss, decreased appetite, and hypoproteinemia. Gross findings included multiple 1-2-cm diameter ulcers on the luminal surfaces of the duodenum and ileum. Histologic examination revealed individual large, round cells infiltrating much of the mucosal epithelium of the duodenum, jejunum, ileum, and colon in addition to multifocal areas of ulceration. Similar round cells infiltrated Brunner's glands and expanded the submucosa beneath the foc...
Fraser DG, Oaks JL, Brown WC, McGuire TC.Equine infectious anaemia virus (EIAV) is a horse lentivirus causing lifelong, persistent infection. During acute infection, CD8(+) cytotoxic T lymphocytes (CTL) are probably involved in terminating plasma viraemia. However, only a few EIAV CTL epitopes, restricted to fewer horse major histocompatibility complex (MHC) class I alleles, are known. As interferon-gamma (IFN-gamma)-secreting CD4(+), T helper 1 (Th1) lymphocytes promote CTL activity and help maintain memory CTL, identifying broadly recognized EIAV Th1 epitopes would contribute significantly to vaccine strategies seeking to promote s...
Ridgely SL, McGuire TC.The immunogenicity of equine infectious anemia virus (EIAV) Gag and Env equine leukocyte alloantigen (ELA)-A5.1, -A9, and -A1 restricted cytotoxic T lymphocyte (CTL) epitopes synthesized on multiple antigenic peptide (MAP) system coupled to tripalmitoyl-S-glycerylcysteine (P3C) was evaluated in vitro. P3C-MAP-peptide-stimulated peripheral blood mononuclear cells (PBMCs) from horses, chronically infected with EIAV, had memory CTL (CTLm) similar to that of PBMCs stimulated with either the minimal CTL epitopes, longer peptides containing the CTL epitopes, or EIAV. The stimulated CTL lysed EIAV-in...
Macintyre AR, Dixon JB.To determine whether living hydatid tissue can, like hydatid fluid, regulate leukocyte growth, T-cell, B-cell, and macrophage lines were cocultured with protoscoleces of Echinococcus granulosus and their growth was compared with that of control cultures by thymidine uptake estimates and chemiluminescent assays of cell number. Protoscoleces supported mitosis of IL-1-deprived D10 T cells, but did not increase D10 count. The action of protoscoleces was affected by the species and organ of their origin and the length of time in culture. Unusually marked mitotic reaction, unaffected by parasite age...
Steinbach F, Mauel S, Beier I.Interferons (IFNs) are important mediators of the immune system. Their antiviral activity is an integral part of the innate immune defence, but all IFNs have immune regulatory functions also. Besides rec.eq.IFN-beta detailed descriptions on other rec.IFNs were lacking and none of the proteins was available. To compare the equine IFNs and allow detailed studies on proteins and bioactivity, we performed the expression cloning of rec.eq.IFN-alpha, -beta and -gamma. To achieve maximal expression, a bacterial expression system was chosen. Additionally, rec.eq.IFN-beta and -gamma were expressed in m...
Kleiber C, Grünig G, Jungi T, Schmucker N, Gerber H, Davis WC, Straub R.A panel of specific antibodies against CD3, CD4, CD5, CD8, MHC I and II was used in single and two colour flow cytometry to define T cell subpopulations in bronchoalveolar lavage fluid of horses affected with chronic obstructive pulmonary disease and of healthy controls. According to the results of the clinical examination including bronchoscopy and cytology of the tracheal aspirate the horses were divided into four groups (healthy, subclinically to mildly affected; moderately affected, and severely affected). All groups of horses had a similar percentage of CD3+ cells in the BALF. Compared to...
Banks EM, Kyriakidou M, Little S, Hamblin AS.Leucocytes in the lung epithelium play an important role in the ability of an animal to respond appropriately to inhaled pathogens. The distribution of lymphoid and myeloid cells associated with the lung epithelium was examined immunohistochemically throughout the respiratory tract of four horses, comprising two adults from an abattoir, one pregnant mare, and her fetus (in the final stage of gestation). Cross and tangential cryosections were labelled with monoclonal antibodies against T-cell, B-cell, macrophage/dendritic myeloid cell, and major histocompatibility Class (MHC) II surface antigen...
Wilson AD, Hicks C.Bovine papillomavirus (BPV) infections of equine species have a central role in the aetiology of equine sarcoids; a common benign skin tumour of horses, zebras and donkeys. Within the lesions, all of the early papillomavirus genes are expressed and promote the excessive replication of fibroblasts which characterise these tumours. Equine sarcoids differ from BPV induced fibro-papillomas of cattle (the natural host of BPV), in that they do not produce high amounts of virus particles, do not usually regress spontaneously and do not sero-convert to BPV; features which suggest that affected horses ...
Hines MT, Palmer GH, Byrne KM, Brassfield AL, McGuire TC.Bronchoalveolar lavage fluid (BALF) and peripheral blood were obtained from each of 17 adult Arabian mares and absolute numbers and relative lymphocyte proportions were determined for total T lymphocytes, using CD2 as a marker, CD4 + T lymphocytes, CD8 + T lymphocytes, CD5 + lymphocytes, and sIgM + B lymphocytes. The marked variation in BALF cell recovery resulted in wide variation in absolute values for each lymphocyte subset. The relative proportions of gated BALF lymphocytes were much less variable and provided a basis for comparison of lymphocyte subsets between the BALF and peripheral blo...
Broström H, Bredberg-Rådén U, England J, Obel N, Perlmann P.Cell-mediated immunity in horses with sarcoid tumor against sarcoid antigens was studied in vitro by means of mixed lymphocyte tumor cell culture assay and lymphocyte-mediated cytotoxicity of 52Cr-labeled target cells. When Mc-1 sarcoid cells were used as stimulatory cells for peripheral blood lymphocytes in the mixed lymphocyte tumor cell assay, a clear difference in the kinetics of the generated lymphocytic proliferative response could be detected between sarcoid and control horses. With sarcoid horses, their proliferative maximum was reached 3 days earlier than that of the control horses, a...
Tschetter JR, Davis WC, Perryman LE, McGuire TC.Eight murine monoclonal antibodies (mAb) were used to identify the equine CD8 alpha or CD8 beta chains and to define the expression of these chains on lymphocytes from various lymphoid tissues. CD8 alpha was a 39 kDa protein and CD8 beta was a 32 kDa protein. Both chains were expressed on most of the CD8+ T lymphocytes in the peripheral blood, spleen, thymus, mesenteric lymph nodes and ileal intraepithelial lymphocytes (IEL), however, in each lymphoid compartment a percentage of lymphocytes expressed only the CD8 alpha chain. The largest percentage of CD8 alpha alpha expressing T lymphocytes w...
Kamm JL, Riley CB, Parlane NA, Gee EK, McIlwraith CW.Mesenchymal stromal cells (MSCs) are believed to be hypoimmunogeneic with potential use for allogeneic administration. Bone marrow was harvested from Connemara (n = 1), Standardbred (n = 6), and Thoroughbred (n = 3) horses. MSCs were grouped by their level of expression of major histocompatibility factor II (MHC II). MSCs were then sub-grouped by those MSCs derived from universal blood donor horses. MSCs were isolated and cultured using media containing fetal bovine serum until adequate numbers were acquired. The MSCs were cultured in xenogen-free media for 48 h prior to use and d...
Platt R, Sponseller BA, Chiang YW, Roth JA.The cell-mediated immune (CMI) response of foals to virulent equine herpesvirus-1 (EHV-1) infection was evaluated by multi-parameter flow cytometry (FCM). Ten 7-8-month-old EHV-1 seronegative foals were infected intranasally with virulent EHV-1 and 10 foals served as uninfected controls. Blood samples were collected 6 and 7 weeks after infection to test for specific CMI responses to live heterologous EHV-1 recall antigen. The activation markers included major histocompatibility complex class II (MHC II), intracellular interferon gamma (IFN-gamma) and interleukin 4 (IL-4). The results from both...
Wu F, Zhang S, Zhang Y, Mo R, Yan F, Wang H, Wong G, Chi H, Wang T, Feng N, Gao Y, Xia X, Zhao Y, Yang S.Ebola virus infections lead to severe hemorrhagic fevers in humans and nonhuman primates; and human fatality rates are as high as 67%-90%. Since the Ebola virus was discovered in 1976, the only available treatments have been medical support or the emergency administration of experimental drugs. The absence of licensed vaccines and drugs against the Ebola virus impedes the prevention of viral infection. In this study, we generated recombinant baculoviruses (rBV) expressing the Sudan virus (SUDV) matrix structural protein (VP40) (rBV-VP40-VP40) or the SUDV glycoprotein (GP) (rBV-GP-GP), and SUDV...
Magnuson NS, Perryman LE, Wyatt CR, Ishizaka T, Mason PH, Namen AE, Banks KL, Magnuson JA.Peripheral blood mononuclear cells (PBMC) from 14 foals with hereditary severe combined immunodeficiency (SCID) were studied to determine the extent of lymphocyte differentiation that occurs in this disorder. PBMC from all 14 horses had the morphologic characteristics of large granular lymphocytes (LGL). Cells from only one of 14 horses were responsive to phytolectin stimulation in a standard blastogenesis assay; however, PBMC from all 14 horses proliferated in continuous culture in the presence of partially purified interleukin 2. Furthermore, there were differences in the growth patterns of ...
Montes LF, Abulafia J, Wilborn WH, Hyde BM, Montes CM.Histopathologic studies of vitiligo have been rather limited in number, thus the microscopic features of this common disorder are not very well known. Methods: Skin specimens from 20 human vitiligo patients and skin specimens from five equine vitiligo patients were studied by light and transmission electron microscopy. Conclusions: Absence of melanocytes, increased number of Langerhans' cells, epidermal vacuolization, thickening of the basement membrane, T-cell inflammatory infiltrate, and neural alterations were noted in the vitiligo lesions. These results may explain the development of depig...
Watson ED, Thomson SR.The density and distribution of MHC Class II positive cells and subpopulations of lymphocytes were studied in the endometrium of genitally normal mares and mares susceptible to endometritis. In genitally normal mares, more MHC Class II positive cells were present in the epithelium and stratum compactum during oestrus than dioestrus. Significantly more CD4+ and CD8+ lymphocytes were present in the stratum compactum than in the stratum spongiosum. CD4+ lymphocytes were present in greater numbers than CD8+ lymphocytes in the stratum compactum but approximately equal numbers were present in the st...
Fernandez C, Möller G.After a primary immune response to the alpha 1-6 epitope of dextran B512, dextran high responder strains exhibit a specific inability to produce IgM and IgG antibodies against this epitope, although they gave an expected secondary response to horse erythrocytes. Spleen cells from dextran-primed and-suppressed mice responded well to dextran after transfer to lethally irradiated previously untreated mice, indicating that tolerance or exhaustive proliferation of dextran reactive B cells is not responsible. Thymus-dependent dextran-protein conjugates also induced specific suppression. Suppression ...
Saad B, Corradin G, Bosshard HR.The antigenic determinants for two monoclonal antibodies directed against horse apo-cytochrome c, a protein of disordered structure, as judged by spectroscopic and hydrodynamic criteria, have been studied by a combination of methods: antigen competition in solution by radio immunoassay and enzyme-linked immunoassay, and differential acetylation of free and antibody-bound antigen. In the latter method the accessibility of lysine residues of the antigen in the antigen-antibody complex is compared to the accessibility in the free antigen. The two antibodies against the heme-free protein do not re...
Jelìnek F, Faldyna M, Jasurkova-Mikutova G.Five days after birth of a viable Fell pony filly, yellow watery diarrhoea appeared without any signs of systemic disease. Four days later the diarrhoea ceased. On 11th day, the animal showed apathy, and a few days later, the foal was very lethargic, suffered from muscular weakness and severe watery diarrhoea that reappeared. The illness did not respond to therapy. At the age of 21 days the filly spontaneously died under symptoms of intestinal colic and pneumonia. Haematological examinations revealed lower numbers of erythrocytes as well as non-selective lymphopenia. Phagocytic activity was sl...
Watson RE, Larson KA.Indirect immunofluorescence and lymphocyte cytotoxicity experiments demonstrated the presence of a tumor-specific antigen(s) on the surface of cells from an equine sarcoid cell line (Mc1). Autologous serum (taken from the horse from which the Mc1 cells were derived) and sera from three other sarcoid-bearing horses revealed a similar membrane immunofluorescence when reacted with Mc1 cells, indicating the existence of cross-reacting antibodies. Results of serum colony inhibition experiments indicate that these antibodies are not cytotoxic. Incubation of Mc1 cells with autologous lymphocytes resu...
Geisshüsler H, Marti E, Stoffel MH, Kühni K, Stojiljkovic A, von Tscharner C, Vidondo B, Gerber V, Koch C.Sarcoids are the most frequently observed skin tumours in equids and consist of cutaneous accumulations of transformed fibroblasts. Their aetiopathogenesis is closely linked to a presumably abortive infection by bovine papillomavirus (BPV) types 1 and 2. In cattle, dermal fibropapillomas induced by BPV1/2 usually regress spontaneously due to a local, cell-mediated, immune response; however, equids appear to lack an effective immune response to BPV1/2 and mechanisms of immune evasion have been postulated. As a consequence, equine sarcoids tend to persist and are prone to recur. In this study, c...
Weldon AD, Zhang C, Antczak DF, Rebhun WC.Selective IgM deficiency was diagnosed in a 3-month-old Standardbred colt that was referred for chronic respiratory tract disease. Immunoglobulin quantification revealed normal IgG and IgA concentrations, but undetectable IgM concentration. Stimulation of blood lymphocytes with the T-cell mitogens concanavalin A and phytohemagglutinin yielded results within the normal range. However, stimulation with the B-cell mitogen lipopolysaccharide produced no response. A B-cell defect similar to that associated with several immunodeficiency disorders in people was suggested as the cause of the IgM defic...
Pargass IS, Wills TB, Davis WC, Wardrop KJ, Alperin DC, Hines SA.There is a distinct age-associated susceptibility of horses to Rhodococcus equi infection. Initial infection is thought to occur in the neonatal and perinatal period, and only foals less than 6 months of age are typically affected. R. equi is closely related and structurally similar to Mycobacterium tuberculosis, and causes similar pathologic lesions. Protective immune responses to M. tuberculosis involve classical major histocompatibility complex (MHC)-restricted T cells that recognize peptide antigen, as well as MHC-independent T cells that recognize mycobacterial lipid antigen presented by ...
Mottironi VD, Perryman LE, Pollara B, Mickey MR, Swift R, McGrath P.Combined immunodeficiency disease (CID) is a genetic disorder of T and B lymphocyte production which results in a nonfunctional immune system. It is inherited as an autosomal recessive trait and has been reported in humans and in horses of the Arabian breed. Arabian horses known to have the CID gene and horses of unknown carrier status were tested using a microlymphocytotoxicity technique. Computer chi 2 analysis distinguished six serologically defined specificities. The study of unrelated horses and a limited number of families showed that the specificities behave as codominant alleles segreg...
Studdert MJ.Set in a context of immunodeficiency diseases in general this paper provides a brief, illustrated review of a primary, severe, combined immunodeficiency (PSCID) disease of Arabian foals. Affected foals are clinically normal at birth but beginning at about 10 days of age they develop a range of clinical signs particularly bronchopneumonia and diarrhoea with which adenoviruses are peculiarly associated. Despite intensive therapy foals invariably die by about 3 months of age. Affected foals are profoundly lymphopagenic (greater than 1000 lymphcoytes per mm3). There is thymic and lymph node hypopl...
Banerjee DP, Singh B, Gautam OP, Sarup S.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...
Ostevik L, de Souza GA, Wien TN, Gunnes G, Sørby R.Two horses with chronic uveitis and histological lesions consistent with equine recurrent uveitis (ERU) were examined. Microscopical findings in the ciliary body included deposits of amyloid lining the non-pigmented epithelium, intracytoplasmic, rod-shaped, eosinophilic inclusions and intraepithelial infiltration of T lymphocytes. Ultrastructural examination of the ciliary body of one horse confirmed the presence of abundant extracellular deposits of non-branching fibrils (9-11 nm in diameter) consistent with amyloid. Immunohistochemistry revealed strong positive labelling for AA amyloid and m...
Dominguez-Medina CC, Rash NL, Robillard S, Robinson C, Efstratiou A, Broughton K, Parkhill J, Holden MTG, Lopez-Alvarez MR, Paillot R, Waller AS.Bacterial superantigens (sAgs) are powerful activators of the immune response that trigger unspecific T cell responses accompanied by the release of proinflammatory cytokines. () and () produce sAgs that play an important role in their ability to cause disease. Strangles, caused by , is one of the most common infectious diseases of horses worldwide. Here, we report the identification of a new sAg of , SpeS, and show that mutation of the putative T cell receptor (TCR)-binding motif (YAY to IAY) abrogated TCR-binding, whilst maintaining interaction with major histocompatibility complex (MHC) c...
Vairo S, Favoreel H, Scagliarini A, Nauwynck H.Currently, little is known on the cellular pathogenesis of equine arteritis virus (EAV). The purpose of the present study was to identify the target cells in ponies experimentally inoculated with EAV 08P178 (EU, clade-1). EAV-target organs (respiratory tissues with associated lymphoid tissues and large intestines), collected at 3 and 7 days post inoculation (dpi) and with virus titers≥10(5.0) TCID50/g, were processed with double immunofluorescence staining for the simultaneous detection of EAV N-protein and one of the following cell markers: CD172a (myeloid cells), CD3 (T lymphocytes), IgM (...
Swiderski CE.Hypersensitivity is an exaggerated immunologic response to a foreign agent that results in inflammation and organ dysfunction. Hypersensitivity disorders are broadly divided into antibody-mediated and T-cell-mediated reactions. The inflammatory pathways that result in disease are initiated in an antigen-specific manner through Fab portions of antibodies or the T-cell receptor, causing the up-regulation of effector mechanisms designed to clear the offending agent. Effector mechanisms include the generation of inflammatory chemicals such as cytokines and chemokines and the attraction of leukocyt...
Baker JM, Bamford AI, Carlson ML, Mcculloch CE, Antczak DF.A cytotoxic T-lymphocyte assay was used to determine whether equine chorionic girdle cells are susceptible to lysis by CD8+ cytotoxic T cells primed in vitro against allogeneic lymphocytes. Classical cytotoxic T-lymphocyte activity against fresh or cultured trophoblast targets was demonstrated using peripheral blood lymphocytes from nonpregnant mares. Lysis of allogeneic (horse) and xenogeneic (donkey) lymphocyte targets was used as a control for trophoblast lysis. The major histocompatibility complex (MHC) class I specificity of the cytotoxic T-lymphocyte reactions was determined using panels...
Ridgely SL, McGuire TC.The immunogenicity of equine infectious anemia virus (EIAV) Gag and Env equine leukocyte alloantigen (ELA)-A5.1, -A9, and -A1 restricted cytotoxic T lymphocyte (CTL) epitopes synthesized on multiple antigenic peptide (MAP) system coupled to tripalmitoyl-S-glycerylcysteine (P3C) was evaluated in vitro. P3C-MAP-peptide-stimulated peripheral blood mononuclear cells (PBMCs) from horses, chronically infected with EIAV, had memory CTL (CTLm) similar to that of PBMCs stimulated with either the minimal CTL epitopes, longer peptides containing the CTL epitopes, or EIAV. The stimulated CTL lysed EIAV-in...
Agrícola R, Carvalho H, Barbosa M, Pereira M, Medeiros JA, Ferreira-Dias G.The aim of this study was to evaluate peripheral blood lymphocyte subpopulations, neutrophil phagocytic capacity and proteinogram characteristics in mares, during the last trimester of pregnancy and in postpartum. Measurement of phagocytosis and quantification of T-lymphocyte subsets were done by flow cytometry. Quantification of T-lymphocyte subsets was performed with monoclonal antibodies specific for CD2, CD3, CD4 and CD8 cell markers. Natural killer and B-cell counts were estimated mathematically. Serum proteinogram was obtained by electrophoresis. No significant differences were observed ...
Kumar P, Timoney JF.The stratified squamous epithelium of the lingual tonsil of five young horses was infiltrated with CD4 and CD8 positive cells, which were very numerous in the crypt reticular epithelium along with macrophages and IgGb and IgA positive cells. Lymphoid follicles of the lamina propria mucosae consisted of a parafollicular area, corona and germinal centre. The parafollicular area was populated by large numbers of CD4 and CD8 positive lymphocytes as well as macrophages, inter-digitating cells, and a few B-lymphocytes. The germinal centre contained mainly IgGb and IgG(T) positive cells, plasma cells...
