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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.
Characterization of the inflammatory infiltrate and cytokine expression in the skin of horses with recurrent urticaria. Recurrent urticaria (RU) is a common skin disease of horses, but little is known about its pathogenesis. Objective: The aim of this study was to characterize the inflammatory cell infiltrate and cytokine expression pattern in the skin of horses with RU. Methods: Biopsies of lesional and nonlesional skin of horses with RU (n = 8) and of skin from healthy control horses (n = 8) were evaluated. Methods: The inflammatory cell infiltrate was analysed by routine histology. Immunohistochemistry was used to identify T cells (CD3), B ells (CD79), macrophages (MAC387) and mast cells (tryptase). E...
Lymphoma risk in livestock farmers: results of the Epilymph study. We explored the risk of lymphoma and its most prevalent subtypes associated with occupational contact with livestock, and whether risk was modified by age at first contact, in 2,348 incident lymphoma cases and 2,462 controls who participated in the EPILYMPH case-control study. A detailed occupational history was collected in cases and controls, including working in a livestock farm, species of livestock, its approximate number and circumstances of contact. For each disease outcome, and each type of livestock, odds ratios (OR) and their 95% confidence intervals (95% CI) were calculated using un...
Immunohistochemical and immunopathologic characterization of superficial stromal immune-mediated keratitis in horses. To describe the immunopathologic characteristics of superficial stromal immune-mediated keratitis (IMMK) immunopathologically by characterizing cellular infiltrate in affected corneas of horses. Methods: 10 client-owned horses with IMMK. Methods: Immunohistochemical staining was performed on keratectomy samples with equine antibodies against the T-cell marker CD3 and B-cell marker CD79a (10 eyes) and the T-helper cytotoxic marker CD4 and T-cell cytotoxic marker CD8 (6 eyes). Percentage of positively stained cells was scored on a scale from 0 (no cells stained) to 4 (> 75% of cells stained)....
Immunoglobulin genes and diversity: what we have learned from domestic animals. This review focuses on the diversity of immunoglobulin (Ig) genes and Ig isotypes that are expressed in domestic animals. Four livestock species-cattle, sheep, pigs, and horses-express a full range of Ig heavy chains (IgHs), including μ, δ, γ, ϵ, and α. Two poultry species (chickens and ducks) express three IgH isotypes, μ, υ, and α, but not δ. The κ and λ light chains are both utilized in the four livestock species, but only the λ chain is expressed in poultry. V(D)J recombination, somatic hypermutation (SHM), and gene conversion (GC) are three distinct mechanisms by which immunog...
Fell Pony syndrome: characterization of developmental hematopoiesis failure and associated gene expression profiles. Fell Pony syndrome (FPS) is a fatal immunodeficiency that occurs in foals of the Fell Pony breed. Affected foals present with severe anemia, B cell lymphopenia, and opportunistic infections. Our objective was to conduct a prospective study of potential FPS-affected Fell Pony foals to establish clinical, immunological, and molecular parameters at birth and in the first few weeks of life. Complete blood counts, peripheral blood lymphocyte phenotyping, and serum immunoglobulin concentrations were determined for 3 FPS-affected foals, 49 unaffected foals, and 6 adult horses. In addition, cytology o...
Expression of essential B cell development genes in horses with common variable immunodeficiency. Common variable immunodeficiency (CVID) is a heterogeneous disorder of B cell differentiation or function with inadequate antibody production. Our laboratory studies a natural form of CVID in horses characterized by late-onset B cell lymphopenia due to impaired B cell production in the bone marrow. This study was undertaken to assess the status of B cell differentiation in the bone marrow of CVID-affected horses by measuring the expression of genes essential for early B cell commitment and development. Standard RT-PCR revealed that most of the transcription factors and key signaling molecules ...
Monoclonal antibodies to equine CD23 identify the low-affinity receptor for IgE on subpopulations of IgM+ and IgG1+ B-cells in horses. CD23, also called FcεRII, is the low-affinity receptor for IgE and has first been described as a major receptor regulating IgE responses. In addition, CD23 also binds to CD21, integrins and MHC class II molecules and thus has a much wider functional role in immune regulation ranging from involvement in antigen-presentation to multiple cytokine-like functions of soluble CD23. The role of CD23 during immune responses of the horse is less well understood. Here, we expressed equine CD23 in mammalian cells using a novel IL-4 expression system. Expression resulted in high yield of recombinant IL-4/...
Virus-specific CD8⁺ T-cells detected in PBMC from horses vaccinated against African horse sickness virus. African horsesickness (AHS) is an infectious but noncontagious viral disease affecting all species of Equidae. The recall immune response of AHSV naïve horses immunised with an attenuated African horsesickness virus serotype 4 (AHSV4) was characterised using immune assays including ELISPOT, real-time PCR (qPCR) and flow cytometry. The recall immune response detected in PBMC isolated from three inoculated horses showed an upregulation of circulating B lymphocytes that correlated with elevated IL-4 mRNA expression indicative of humoral immunity, but reduced frequency of CD4⁺ cells. In additio...
A case of Borrelia-associated cutaneous pseudolymphoma in a horse. This case report describes a 10-year-old horse that developed multiple dermal papules over the right masseter area following removal of a tick from the same site 3 months earlier. Histological examination of a biopsy from a papule was suggestive of either a T-cell-rich B-cell lymphoma or cutaneous lymphoid hyperplasia, a form of pseudolymphoma sometimes associated with a tick bite. Positive serological testing and PCR of the biopsy sample for Borrelia in conjunction with immunohistochemical testing of the skin biopsy, the clinical history and response to treatment with doxycycline strongly sup...
Mapping B-cell epitopes in equine rhinitis B viruses and identification of a neutralising site in the VP1 C-terminus. Erbovirus is a genus of the family Picornaviridae and equine rhinitis B virus (ERBV) is the sole species. Erboviruses infect horses causing acute respiratory disease and sub-clinical and persistent infections. Despite the high seroprevalence and worldwide distribution of these viruses, the pathogenesis and antigenic structure of the three ERBV serotypes (ERBV1, 2 and 3) is poorly understood. To characterise linear epitopes on ERBV structural proteins, a set of fusion proteins were expressed in Escherichia coli. These proteins were tested in Western blot and ELISA and reactive proteins were als...
Pulmonary angiocentric lymphoma (lymphomatoid granulomatosis) in a donkey. A 36-year-old donkey developed dyspnoea, pyrexia, hypoalbuminaemia and oedema. Following continued clinical deterioration the donkey was humanely destroyed. Grossly, there were numerous nodules (5-10mm) scattered throughout the lung. Microscopically, the lung was infiltrated by an angiocentric and bronchocentric to diffuse mixed population of small mature and atypical lymphocytes, histiocytes, plasma cells and fewer eosinophils. The infiltrate was composed of numerous small mature and fewer atypical CD3(+) T lymphocytes. Low numbers of CD20(+) and CD79a(+) B cells, some atypical, accompanied t...
Presence of mononuclear cells in normal and affected laminae from the black walnut extract model of laminitis. There is increasing evidence of involvement of inflammatory cells in acute laminitis. Objective: To immunolocalise monocytes/macrophages and B and T lymphocytes in the laminar tissue of normal horses and those with black walnut extract (BWE)-induced laminitis. Methods: Immunohistochemistry was used in archived laminar tissue samples from 20 horses divided equally into 4 groups: control animals (CON), and those administered BWE at 1.5 h (1.5H DTP group), at the onset of leucopenia (3H DTP group) and at the onset of lameness (LAM group). Antibodies against CD3, CD20 and CD163 were used to recogn...
Cutaneous T-cell-rich B-cell lymphoma in a horse. Cutaneous malignant lymphomas are rare in horses and comprise predominantly T-cell-rich B-cell lymphomas. They are characterized by multiple tumour nodules affecting predominantly female horses with a survival rate of months to years. At the final stage, metastases to regional lymph nodes occur, whereas widespread organ involvement is rarely reported. In this case report, a cutaneous T-cell-rich B-cell lymphoma in a 7-year-old standardbred gelding with metastases is described. Clinically, multiple cutaneous and subcutaneous nodules, enlarged superficial lymph nodes, rapid weight loss, and vent...
Equine herpesvirus-1 infected peripheral blood mononuclear cell subpopulations during viremia. Infection with equine herpesvirus-1 (EHV-1) causes respiratory disease, late term abortions and equine herpesvirus myeloencephalitis (EHM) and remains an important problem in horses worldwide. Despite increasing outbreaks of EHM in recent years, our understanding of EHM pathogenesis is still limited except for the knowledge that a cell-associated viremia in peripheral blood mononuclear cells (PBMCs) is a critical link between primary respiratory EHV-1 infection and secondary complications such as late-term abortion or EHM. To address this question our objective was to identify which PBMC subpo...
Equine neonates have attenuated humoral and cell-mediated immune responses to a killed adjuvanted vaccine compared to adult horses. The objectives of this study were to compare relative vaccine-specific serum immunoglobulin concentrations, vaccine-specific lymphoproliferative responses, and cytokine profiles of proliferating lymphocytes between 3-day-old foals, 3-month-old foals, and adult horses after vaccination with a killed adjuvanted vaccine. Horses were vaccinated intramuscularly twice at 3-week intervals with a vaccine containing antigens from bovine viral respiratory pathogens to avoid interference from maternal antibody. Both groups of foals and adult horses responded to the vaccine with a significant increase in ...
Radiation therapy communication: nasal passage and paranasal sinus lymphoma in a pony. An aged pony with extensive paranasal sinus and nasal passage B-cell lymphoma was treated with palliative radiation therapy. Sixteen gray were administered in two fractions, 7 days apart. A lateral field was used for the first fraction and a dorsal field for the second. Because of tumor being present in the left frontal sinus, gross tumor was knowingly excluded from the treated volume in the lateral field. The tumor regressed within 2 months and the pony remained free of clinical disease for 2.5 years. Acute, temporary blindness developed shortly after the second radiation fraction, but a dire...
IgE in horses: occurrence in health and disease. Since the initial characterization of IgE by Ishizaka et al. (1966), IgE was described in several mammalian species. In horses, a single gene encoding the IgE heavy chain constant region (IGHE gene) exists per haploid genome and several allelic variants of the equine IGHE gene were found. IgE occurs in its soluble form in equine serum and physiological concentrations of total IgE are around 1000-fold higher in normal horse than in normal human serum. Maternal IgE is enriched in the colostrum and transferred to the neonatal foal after birth. Foals do not produce detectable concentrations of end...
Immunophenotypical characterization in Andalusian horse: variations with age and gender. Assessment of lymphocyte subsets is an effective method for characterizing disorders such as leukemia, lymphomas, autoimmune and infectious diseases. In order to clinically interpret these parameters, normal reference values should be set, estimating age- and gender-related variations. This research aimed to: (1) characterize lymphocyte subpopulations in Andalusian horse, and (2) evaluate age and gender-related variations of lymphocyte subsets. Jugular blood samples were obtained from 159 animals, 77 males and 82 females, belonging to four age groups-1: 1-2 years (N=39; 21 males and 18 females...
Expression of essential B cell genes and immunoglobulin isotypes suggests active development and gene recombination during equine gestation. Many features of the equine immune system develop during fetal life, yet the naïve or immature immune state of the neonate renders the foal uniquely susceptible to particular pathogens. RT-PCR and immunohistochemical experiments investigated the progressive expression of developmental B cell markers and immunoglobulins in lymphoid tissues from equine fetus, pre-suckle neonate, foal, and adult horses. Serum IgM, IgG isotype, and IgA concentrations were also quantified in pre-suckle foals and adult horses. The expression of essential B cell genes suggests active development and gene recombinati...
Linear B-cell epitope mapping using enzyme-linked immunosorbent assay for libraries of overlapping synthetic peptides. The aim of this chapter is to provide a strategy for mapping linear antibody epitopes of protein antigens in order to discover candidates for vaccines or diagnostic tests. A set of overlapping peptides was designed and synthesised based upon a known amino acid sequence of the target protein, virulence-associated protein A (VapA) of the bacterium Rhodococcus equi, an important pulmonary pathogen in foals.The peptides were biotinylated and used in an ELISA to screen immune sera from foals. These biotinylated peptides were coated directly onto micro titre plates that had been pre-coated with Neut...
Horses experimentally infected with Sarcocystis neurona develop altered immune responses in vitro. Equine protozoal myeloencephalitis (EPM) due to Sarcocystis neurona infection is 1 of the most common neurologic diseases in horses in the United States. The mechanisms by which most horses resist disease, as well as the possible mechanisms by which the immune system may be suppressed in horses that develop EPM, are not known. Therefore, the objectives of this study were to determine whether horses experimentally infected with S. neurona developed suppressed immune responses. Thirteen horses that were negative for S. neurona antibodies in serum and cerebrospinal fluid (CSF) were randomly assig...
Maternal transfer of IgE and subsequent development of IgE responses in the horse (Equus callabus). Immunoglobulin E (IgE) mediates the immune response to parasites, but can also cause allergies. In humans maternal IgE is not transferred to cord blood and high levels of cord blood IgE are associated with subsequent allergy. In horses, both maternal IgG and IgE are transferred via colostrum; the IgE levels in the mare's serum, the colostrum and the foal's serum are correlated but the consequences of IgE transfer to foals are not known. By about 6 weeks of age the levels of IgE in foal serum have dropped to a nadir, at 6 months of age the level of IgE has risen only very slightly and is no lon...
A proteomic approach for studying the pathogenesis of spontaneous equine recurrent uveitis (ERU). Equine recurrent uveitis (ERU) is a wide spread disease of the eye, which is the main cause for blindness in horses worldwide. Meanwhile, ERU is also accepted as the only reliable spontaneous model for human autoimmune uveitis. We identified and characterized novel autoantigens by analyzing the autoantibody-binding pattern from ERU cases to the retinal proteome. Cellular retinaldehyde-binding protein (CRALBP) and malate dehydrogenase (MDH) were detected as novel ERU autoantigens by this approach. B- and T-cell autoreactivity was detected to both autoantigens in ERU cases. The evaluation of the...
Lymphoproliferative disease with features of lymphoma in the central nervous system of a horse. Lymphoma (malignant lymphoma, lymphosarcoma) is uncommon in horses in the United Kingdom. This report describes an unusual form of lymphoproliferative disease with features of lymphoma restricted to the central nervous system (CNS) and with no evidence of a primary lesion elsewhere. Immunohistochemical examination defined an overwhelming predominance of T lymphocytes with admixed B lymphocytes and activated macrophages. This case exemplifies the challenges associated with definitive diagnosis of lymphoproliferative disease of the equine CNS.
Common variable immunodeficiency in horses is characterized by B cell depletion in primary and secondary lymphoid tissues. Common variable immunodeficiency (CVID) in horse patients is characterized by late-onset B cell lymphopenia or depletion, hypo- or agammaglobulinemia, impaired humoral response to tetanus toxoid vaccination, and recurrent fevers and bacterial infections. Conclusions: This study describes the clinical and immunologic findings of 14 affected horses (average age 10.7 +/- 4.4 years) of both genders (six females, eight males) and different breeds (eight Thoroughbreds, four Quarter Horses, one Warmblood, one Pony). Serial immunological testing in peripheral blood revealed persistent, severe B cell l...
Immunohistochemical characterization of mononuclear cells and MHC II expression in the brain of horses with experimental chronic Trypanosoma evansi infection. An histochemical and immunohistochemical study was carried out to evaluate the mechanisms of immune response of horses experimentally infected by Trypanosoma evansi. For this purpose the HE histochemical stain and the avidin biotin peroxidase method were used. To determine the presence and immunoreactivity of immune cells we used anti-major histocompatibility complex II antibodies. Cellular infiltration phenotype was characterized with the aid of anti-CD3 antibody for T lymphocytes and by anti-BLA 36 antibodies for B lymphocytes. Macrophages were marked with an antibody against myeloid/histyoc...
A West Nile virus (WNV) recombinant canarypox virus vaccine elicits WNV-specific neutralizing antibodies and cell-mediated immune responses in the horse. Successful vaccination against West Nile virus (WNV) requires induction of both neutralizing antibodies and cell-mediated immune responses. In this study, we have assessed the ability of a recombinant ALVAC-WNV vaccine (RECOMBITEK WNV) to elicit neutralizing antibodies and virus-specific cell-mediated immune responses in horses. In addition, we examined whether prior exposure to ALVAC-WNV vaccine would inhibit B and cell-mediated immune responses against the transgene product upon subsequent booster immunizations with the same vaccine. The results demonstrated that the recombinant ALVAC-WNV va...
The composition of the inflammatory infiltrate in three cases of polyneuritis equi. Polyneuritis equi (PNE) is a rare neurological disease in the horse. Because of the suspicion in PNE of a T-lymphocyte mediated immune response against the myelin, the objective of this study was to determine the composition of the inflammatory infiltrate in the involved nerves of 3 horses with PNE, studied retrospectively. T-lymphocytes were demonstrated in the lesions, which suggests a T-lymphocyte mediated immune response against myelin. In addition, the presence of B-lymphocytes indicated a local production of antibodies. More research, involving a prospective study, is needed to determine...
Blood lymphocyte subpopulations, neutrophil phagocytosis and proteinogram during late pregnancy and postpartum in mares. 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 ...
Suspected immune-mediated myositis in horses. Although immune-mediated myositis (IMM) is commonly reported in other species, this condition is poorly described in horses. Objective: IMM occurs in horses. Methods: Thirty-seven horses with suspected IMM were included in the study. Methods: The database of the Neuromuscular Diagnostic Laboratory was reviewed to identify 37 horses with muscle biopsies characterized by lymphocytic infiltrates. A retrospective standardized questionnaire regarding clinical signs and response to treatment was answered by horse owners. Results: Horses with suspected IMM were predominantly of Quarter Horse bloodlin...
