Topic:B cells
B cells are a type of white blood cell found in horses that are integral to the adaptive immune system. They originate from the bone marrow and are responsible for producing antibodies, which are proteins that bind to specific antigens to neutralize pathogens such as bacteria and viruses. B cells also play a role in antigen presentation and the activation of other immune cells. In equine health, the study of B cells includes understanding their development, function, and response to infections and vaccinations. This page compiles peer-reviewed research studies and scholarly articles that explore the biology, regulation, and clinical implications of B cells in horses, contributing to a deeper understanding of equine immunology.
Recognition of a B-cell epitope of the VapA protein of Rhodococcus equi in newborn and experimentally infected foals. The aim of this study was to evaluate the usefulness of the previously identified B-cell epitope TSLNLQKDEPNGRASDTAGQ of the VapA protein of Rhodococcus equi and its association with R. equi pneumonia. A modified peptide designated PN11-14 corresponding to the epitope was recognized by all sera from experimentally infected foals with virulent R. equi ATCC103+ containing the virulence plasmid but not by its plasmid-cured derivative ATCC103- strain. Marked levels of VapA-specific immunoglobulin (Ig)G were detected in all sera from the ATCC103+ infected foals at 2 weeks after the infection. One c...
Immunologic disorders in neonatal foals. Foals live in an environment heavily populated by bacteria, many of which are capable of causing disease. Development of infection,however, is the exception rather than the rule. The ability of the foal to prevent infection by most pathogens is the result of a sophisticated set of defense mechanisms. These defense mechanisms can be divided into adaptive and innate immunity. Innate immunity encompasses defense mechanisms that pre-exist or are rapidly induced within hours of exposure to a pathogen. Conversely, adaptive or acquired immunity represents host defenses mediated by T and B lymphocytes...
Common variable immunodeficiency in three horses with presumptive bacterial meningitis. Three adult horses were evaluated for signs of musculoskeletal pain, dullness, ataxia, and seizures. A diagnosis of bacterial meningitis was made on the basis of results of CSF analysis. Because primary bacterial meningitis is so rare in adult horses without any history of generalized sepsis or trauma, immune function testing was pursued. Flow cytometric phenotyping of peripheral blood lymphocytes was performed, and proliferation of peripheral blood lymphocytes in response to concanavalin A, phytohemagglutinin, pokeweed mitogen, and lipopolysaccharide was determined. Serum IgA, IgM, and IgG co...
Histology, immunohistochemistry and ultrastructure of the equine palatine tonsil. The palatine tonsils of five young horses formed 10-12 cm elongated follicular structures extending from the root of the tongue on either side to the base of the epiglottis and lateral to the glossoepiglottic fold. The stratified squamous non-keratinized epithelium of the outer surface was modified into crypts as reticular epithelium by heavy infiltration of lymphoid cells from underlying lymphoid follicles. In places, lymphoid tissue reaching almost to the surface and with only one to two cell layers intact was identified as the lymphoepithelium. Langerhans cells with Birbeck granules were in...
PNA-binding glycans are expressed at high levels on horse mature and immature T lymphocytes and a subpopulation of B lymphocytes. In mammals, the binding of peanut agglutinin (PNA) on the plasma membrane defines subpopulations among lymphocytes from peripheral blood and lymphoid organs. PNA binds Galbeta 1,3GalNAc residues provided that they are not sialylated. Here, we studied the expression of PNA-binding glycans on healthy horse peripheral blood, thymus, lymph node and spleen lymphocytes. We first demonstrated the binding specificity of PNA for galactose residues by competition experiments and the inhibitory role of sialic acids in PNA binding by sialidase digestion. Unlike human and murine lymphocytes, all equine lym...
Histology and ultrastructure of the equine lingual tonsil. II. Lymphoid tissue and associated high endothelial venules. 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...
Influence of Ganoderma lucidum on blood biochemistry and immunocompetence in horses. The characteristic ingredients of Ganoderma lucidum, such as polysaccharides, triterpenoids, nucleic acids and small proteins, have been found and proved to have many special pharmacological properties. Mice and rats have been extensively used to investigate the effects of G. lucidum. Experiments with horses as an animal model for investigating the effects of G. lucidum have never been reported. The purpose of this investigation was to understand the influence of G. lucidum feeding on blood biochemistry and immunocompetence in horses. Complete blood count (CBC) and blood biochemistry were surv...
Immunoglobulin and peripheral B-lymphocyte concentrations in Fell pony foal syndrome. Fell pony foals are affected by a congenital fatal disease that leads to profound anaemia and immunodeficiency. Previous studies comparing healthy and affected foals have shown normal T-cell populations, but a severe B-lymphopenia. Objective: To measure the levels of individual immunoglobulin subisotypes in normal and affected Fell ponies and correlate these levels with the number of peripheral B-lymphocytes. Methods: Serum levels of individual immunoglobulin subisotypes were measured by ELISA and correlated with the number of peripheral B-lymphocytes (measured by flow cytometry). Results: Aff...
Identification of another B-cell epitope in the type-specific region of equine herpesvirus 4 glycoprotein G. Recently, a novel 12-mer B-cell epitope, MKNNPIYSEGSL, in the type-specific region of equine herpesvirus 1 (EHV-1) glycoprotein G (gG) was identified and used as an antigen for enzyme-linked immunosorbent assay (Maeda et al., J. Clin. Microbiol. 42:1095-1098, 2004). Although our prototype strain, TH20p, possesses two repeat sequences containing the B-cell epitope, the EHV-4 NS80567 strain has two repeat sequences that are not identical. One repeat sequence stretch contained the B-cell epitope, while the other contained the 11-mer, MKNNPVYSESL (underlining indicates a different amino acid). In ...
Quantification of immune cell populations in the lamina propria of equine jejunal biopsy specimens. The histological diagnosis of inflammatory bowel disease (IBD) in horses and other species is subjective, and pathological assessments vary considerably as a result. One important criterion is increased infiltration of the lamina propria by eosinophils, plasma cells, lymphocytes or macrophages, but this is difficult to assess without a knowledge of the normal immune cell populations and potential for individual variation. Retrospective jejunal specimens were analysed from 14 horses aged 13-15 years which had not shown clinical or post-mortem signs of gastrointestinal disease. Populations of pl...
The uveitogenic potential of retinal S-antigen in horses. 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...
Immunogenecity of synthetic peptides representing linear B-cell epitopes of VapA of Rhodococcus equi. 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...
Natural killer cell receptors in the horse: evidence for the existence of multiple transcribed LY49 genes. 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...
Cross-species reactivity of seven monoclonal antibodies with equine lymphocytes by flow cytometry. 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, ...
Peripheral blood neutrophil function and lymphocyte subpopulations in cycling mares. 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...
Aid to the antemortem diagnosis of Fell pony foal syndrome by the analysis of B lymphocytes. Fell pony foals are affected by a congenital fatal immunodeficiency that commonly leads to anaemia and lymphopenia. Previous work has shown that the foals' circulating subpopulations of CD4 and CD8 T lymphocytes are unaffected. In this study it was shown that the mean population of B lymphocytes in 10 affected foals was less than 10 per cent of that in normal foals.
Mapping epitopes in equine rhinitis A virus VP1 recognized by antibodies elicited in response to infection of the natural host. Equine rhinitis A virus (ERAV) is an important respiratory pathogen of horses and is of additional interest because of its close relationship and common classification with foot-and-mouth disease virus (FMDV). As is the case with FMDV, the VP1 capsid protein of ERAV has been shown to be a target of neutralizing antibodies. In FMDV VP1, such antibodies commonly recognize linear epitopes present in the betaG-betaH loop region. To map linear B cell epitopes in ERAV VP1, overlapping fragments spanning its length were expressed in Escherichia coli as glutathione S-transferase (GST) fusion proteins....
Extranodal lymphoblastic lymphoma of suspected B-cell lineage in the gingiva of a racehorse, accompanied by mandibular osteolysis. A mass developed in the mandibular gingiva of a thoroughbred racehorse. When the horse could no longer eat unassisted, it was killed and immediately autopsied. Macroscopically, the mandible exhibited extensive osteolysis, with only a small amount of bone remaining around the tooth roots. The cut surface of the mass around the mandible consisted of neoplastic medullary tissue, in which osteogenesis was observed. The medullary tissue was composed of pleomorphic medium-sized to large cells, interlaced by collagen bundles. These cells had large, pale, round or ovoid, sometimes cleaved nuclei, with...
Cellular architecture of the synovium in the tendon sheath of horses: an immunohistochemical and scanning electron microscopic study. The intimal lining cells of the synovium in joints have been studied morphologically and histochemically and shown to consist of macrophagic cells (type A) and fibroblast-like cells (type B). It is believed that the structure of the synovium in the tendon sheath is similar to that in the joint, but there have been only a few morphological studies of the tendon sheath. The present study revealed the cellular architecture of synovium in the tendon sheath of horses by histochemistry and scanning electron microscopy (SEM). Like the joint, the inner surface of the tendon sheath was covered with a c...
Serum and mucosal antibodies of infected foals recognized two distinct epitopes of VapA of Rhodococcus equi. Virulence-associated protein A (VapA) of Rhodococcus equi has been proposed for use both as a vaccine and as a target for antibodies in immunotherapy and diagnostic tests. Epitope mapping of VapA allowed the identification of two B cell epitopes associated with R. equi pneumonia. The peptide NLQKDEPGRASDT was confirmed as an immunodominant N-terminal B cell epitope recognized by all sera from infected foals while VSFQYNAVGPYLNINFFDSS (C-terminal B cell epitope) was exclusively recognized by IgA from the tracheal aspirates. Moreover, specific antibodies produced against the VapA-specific peptid...
Common variable immunodeficiency in a horse. A 12-year-old Quarter Horse mare that was nonresponsive to medical treatment was evaluated for chronic respiratory disease and hepatobiliary disease. Serum immunoglobulin concentrations were measured by use of radial immunodiffusion that revealed trace to nondetectable concentrations of IgG, IgG(T), IgM, and IgA. Use of serum protein electrophoresis confirmed agammaglobulinemia by the absence of the expected peak in the gamma region. In addition, vaccination with tetanus toxoid did not result in specific immunoglobulin production. Flow cytometric analysis of blood lymphocyte subpopulations rev...
Immunohistochemical characterization of estrogen and progesterone receptors in lymphoma of horses. 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...
Echinococcus granulosus: regulation of leukocyte growth by living protoscoleces from horses, sheep, and cattle. 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...
Recombinant equine interferons: expression cloning and biological activity. 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...
[Malignant lymphoma in the horse: an atypical clinical manifestation]. In this case report we describe an atypical clinical manifestation of malignant lymphoma in a horse. The most obvious clinical symptoms were hyperaemic mucosae and skin lesions. The skin and mucosal lesions appeared to be caused by a leukemic form of malignant lymphoma. The lymphocytosis consisted mainly of different populations of T-lymphocytes. Histopathology and immunohistochemistry identified the malignant lymphoma as a T-cell rich B-cell lymphoma.
Idiopathic systemic granulomatous disease and macrophage expression of PTHrP in a miniature pony. Idiopathic systemic granulomatous disease, which has been reported in horses, cattle and human beings, is characterized by perivascular granulomatous and lymphoplasmacytic inflammation in many organ systems. Diagnosis is based on the exclusion of possible viral, fungal or bacterial causes. The disease was identified in a miniature pony with widespread lymphoplasmacytic and granulomatous inflammation, special staining techniques having revealed no evidence of any aetiological agent. Skin lesions, which were severe, consisted of hyperkeratosis and serocellular crust formation, with inflammatory ...
Age-related quantitative alterations in lymphocyte subsets and immunoglobulin isotypes in healthy horses. To characterize age-associated changes in lymphocyte population subsets and immunoglobulin isotypes. Methods: 30 healthy young light-breed horses (5 to 12 years old) and 30 healthy aged light-breed horses (> 20 years old). Methods: Lymphocyte subset populations were identified, using monoclonal antibodies to cell surface markers CD5, CD4, CD8, and IgG. Subset populations were quantitated by use of flow cytometric analysis of antibody-stained cells. Serum immunoglobulin concentration was determined using single radial immunodiffusion. Results: Absolute cell counts of total lymphocytes, T cells,...