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.
Evidence of a second polymorphic ELA class I (ELA-B) locus and gene order for three loci of the equine major histocompatibility complex. Two antisera, B-442 and R-2046, were produced by immunizing offspring with purified peripheral blood lymphocytes from a parent matched for the ELA-A specificity carried on the unshared haplotype. Absorption analysis demonstrated that these antisera contained at least two families of cytotoxic antibodies, one directed against antigens present on T and B cells, and a second directed preferentially against antigens present on surface Ig positive cells. Immunoprecipitation studies using these antisera demonstrated that both antisera contain antibodies specific for glycoproteins with molecular weig...
Multiple overlapping epitopes in the three antigenic regions of horse cytochrome c1. To gain a better understanding of the diversity of epitopes on a protein, the specificities of 103 monoclonal antibodies to a model antigen, horse cytochrome c(cyt c), were analyzed. The antibodies were generated in in vitro monoclonal, secondary antibody responses against horse cyt c coupled to hemocyanin in splenic fragment cultures. For this assay, horse cyt c-primed murine B lymphocytes were transferred to irradiated, hemocyanin-primed recipients. A panel of seven mammalian cyts c differing at one to six residues out of 104 and cyanogen bromide-cleaved fragments of horse cyt c containing r...
Alimentary lymphomas in the horse. A series of 9 cases of primary diffuse alimentary lymphoma of the equine small intestine is described. Clinically, the principal effects were attributable to malabsorption and disordered alimentary function and several cases had severe anaemia; in four this was of the haemolytic type. Hypoalbuminaemia and elevated gamma globulin levels were often present. The neoplasms were confined mainly to the small intestine and mesenteric lymph nodes, sometimes with some involvement of other lymph nodes as well. The large bowel was affected in one horse, but none of the cases showed detectable invasion of...
A new surface marker on equine peripheral blood lymphocytes. II. Characterization and separation of purified blood lymphocytes with receptors for Helix pomatia A hemagglutinin (HP). In a preceding report we have shown that the lectin Helix pomatia A hemagglutinin (HP) binds to two subpopulations of neuraminidase-treated equine peripheral blood lymphocytes (PBL), constituting about 20% and 75% of PBL, respectively. The aim of the present study was to further characterize these HP+ cells in regard to other surface markers such as receptors for guinea pig erythrocytes (GPR+ cells), membrane-bound immunoglobulins (sIg+ cells), receptors for activated complement (C3R+ cells) and receptors for IgG (Fc alpha R+ cells). This was done by double marker analysis and by lymphocyte fr...
In vitro induction of lymphocyte responsiveness by a Strongylus vulgaris-derived mitogen. Proliferation in vitro of peripheral blood lymphocytes both from horses infected with Strongylus vulgaris and from helminth-free ponies was observed in the presence of extracts of the fourth and fifth stage larvae and adults of S. vulgaris. In addition, S. vulgaris extracts induced transformation in cultures of peripheral blood lymphocytes from sheep and dogs and in mouse spleen cell cultures. Nylon wool non-adherent, T cell enriched fractions of lymphocytes from both mice and horses were stimulated by the S. vulgaris larval mitogen while no proliferation was observed in cultures containing ny...
Analysis of serum and lymphocyte surface IgM of healthy and immunodeficient horses with monoclonal antibodies. Nine monoclonal antibodies which reacted with equine immunoglobulin (Ig)M and not other equine Ig and serum proteins were prepared. Cells producing antibodies (C 1.9) which precipitated with IgM and bound to staphylococcal protein A were triple-cloned (C 1.9/3.2) and the antibodies further characterized. Monoclonal antibody C 1.9/3.2 reacted with an IgM determinant present on serum IgM from horses of several breeds. Studies with 125I-labeled IgM revealed the presence of this determinant on all IgM molecules. The monoclonal antibody enabled quantitation of IgM in presuckling foal and adult hors...
Cell-mediated immune response to Babesia equi-transformed lymphoblastoid cells in vitro. The capacity of equine peripheral blood lymphocytes (PBL) to proliferate in the presence of Babesia equi-transformed lymphoblastoid stimulator cells was tested in an autologous as well as in an allogenic one way mixed lymphocyte reaction (MLR). It was found that both autologous and allogeneic responder lymphocytes incorporated high amounts of 3H-thymidine. The incorporation of 3H-thymidine was lower in MLR using as stimulator cells lymphocytes from which the cell line had previously been established, than when using parasitized culture cells as stimulator. Proliferation of PBL was achieved onl...
The genetic control of antibody formation. Studies of the molecular biology of lymphoid cells have markedly increased our understanding of how millions of different antibodies can be synthesized by a single animal. To date, the most detailed understanding has been achieved for the mouse, primarily because of the relatively greater experimental availability of this species. These studies, as well as those involving other species, have shown that the complete genes for antibody polypeptide chains are assembled from disparate genetic elements which are originally widely separated in the genome. The assembly process itself, together with t...
Lymphocytes from ponies experimentally infected with equine herpesvirus 1: subpopulation dynamics and their response to mitogens. Six pony foals, free of detectable serum neutralization (SN) antibody against equine herpesvirus type 1 by the standard virus-neutralization (VN) test, were inoculated with equine herpesvirus type 1. The ponies showed typical clinical signs of respiratory tract disease and developed a transient leukopenia, involving lymphocytes as well as neutrophils. The leukopenia reached its lowest point on postinoculation days (PID) 3 to 5 and then returned to base-line values by PID 8 to 10. On quantitation of lymphocyte subpopulations, T and B lymphocytes were decreased during the onset of leukopenia and...
Immune recognition of Echinococcus granulosus. 1. Parasite-activated, primary transformation by normal murine lymph node cells. Culture of murine lymph node cells together with living protoscolices of Echinococcus granulosus is described. The presence of the parasite induced potent blastic transformation in lymphocytes of unimmunized mice as indicated by tritiated thymidine incorporation. The response was markedly reduced by killing the parasite immediately prior to culture. No blastogenic activity was detectable in supernatants from living parasites cultured alone. Protoscolices from artificially infected syngeneic mice were effective stimuli, as were protoscolices from naturally infected horse and sheep. Stimulation ...
Isolation and identification of equine lymphocytes and monocytes. Various cell populations of equine mononuclear leukocytes were identified and isolated. Mononuclear leukocytes were concentrated by isopyknic centrifugation, using a solution of Ficoll and Hypaque. Three additional techniques were explored to separate monocytes from lymphocytes, and 3 methods were used to separate lymphocyte types. Cytochemical techniques for the detection of nonspecific esterase readily distinguished equine monocytes from lymphocytes. Peripheral blood lymphocytes were separated into at least 2 populations. One population had surface traits identical to thymocytes [ie, they re...
Separation and identification of equine leukocyte populations and subpopulations. Various methods of separation and identification of major equine leukocyte populations and subpopulations were used. The purity of T and B lymphocytes separated in Sephadex anti-equine F(ab')2 columns was 87% to 99% and 83% of 97%, respectively. The purity of T lymphocytes separated in nylon-wool columns was 89% to 98%. Preparations of B lymphocytes separated in glass-bead columns were 68% to 79% pure. The presence (or absence) of surface immunoglobulin by immunofluorescence was the most consistent and reliable method for the identification of B or T lymphocytes, respectively. However, the ery...
Major histocompatibility locus in the Arabian horse. 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...
Immunologic aspects of combined immunodeficiency disease in Arabian foals. Tests for T- and B-cell quantitation and immune function were developed, and their application in the diagnosis of primary severe combined immunodeficiency disease (CID) in Arabian foals was investigated. Foals with CID had severe lymphopenia and had small or zero numbers of B cells, as shown by immunofluorescence of surface immunoglobulin (Ig), erythrocyte-antibody-complement rosetting, and staphylococcal protein A rosetting. Serum IgM was undetectable in four CID foals 25 to 71 days old. Demonstrable antibody responses were not elicited in CID foals by phage phi X-174, a potent antigen in no...
Ontogeny of lymphocyte function in the equine fetus. The capacity of cells from thymus, liver, spleen, mesenteric lymph nodes, peripheral blood, and bone marrow to respond to in vitro phytolectin and allogeneic lymphocyte-stimulation was determined in 16 pony fetuses 61 to 200 days old (gestational age). Phytolectin-responsive cells were detected in the thymus at the 80th gestational day, peripheral blood at 120 days, lymph node at 160 days, and spleen at 200 days. Mixed lymphocyte culture-responsive cells were detected in thymus at 100 days and in the spleen at 200 days (gestational age). Immunoglobulins (Ig) M and IgG were quantitated by radio...
A primary immune response to dextran B512 is followed by a period of antigen-specific immunosuppression caused by autoanti-idiotypic antibodies. 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 ...
Site of initiation of the plasma cell reaction in the rabbit lymph node. Ultrastructural evidence for two distinct antibody forming cell precursors. Two times sublethal total body-X-irradiation with weekly local thymus irradiation established a T-cell deprived experimental model in rabbits. Humoral immunity reactions in draining lymph nodes have been analyzed histologically and at the submicroscopical level after challenge with Salmonella Java vaccine, horse spleen ferritin, horse-gamma-globulin, a chemical sensitizer oxazolone (2 phenyl-4-ethoxymethylene-5-oxazolone) and after skin allografting respectively. The time sequence studies in these animals with an 'isolated B-cell system' are compared with similar experiments in normal non-irra...
Primary, severe, combined immunodeficiency disease of Arabian foals. 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...
Mixed lymphocyte culture responses in combined immunodeficiency of horses. Combined immunodeficiency in horses is a genetic disorder in which there is a defect in the production of committed B and T lymphocytes. In this study, peripheral blood mononuclear leukocytes from foals with combined immunodeficiency were examined for their capacity to stimulate and respond in one-way mixed lymphocyte cultures. Irradiated cells from combined immunodeficient foals were uniformly capable of stimulating cells from unrelated horses. However, none were able to respond to allogeneic stimulation. Examination of cells from known carrier horses revealed no difference in capacity to sti...
Erythrocyte rosette formation of equine peripheral blood lymphocytes. Erythrocyte rosette (ER) formation of equine peripheral blood lymphocytes (PBL) was characterized. Guinea pig and, to a lesser extent, human erythrocytes formed ER; cat, cow, dog, hamster, mouse, rat, and sheep erythrocytes showed negligible rosetting properties. Conditions of the assay were varied to determine which procedure allowed the largest percentage of rosette formation. The PBL from 20 normal horses were then assayed, averaging 38 +/- 2% ER. To characterize the erythrocyte receptor as being on T or B cells, equine thymocytes from 6 foals were assayed; the thymocytes formed an average ...
Combined immunodeficiency in foals in Arabian breeding: evaluation of mode of inheritance and estimation of prevalence of affected foals and carrier mares and stallions. Combined immunodeficiency (CID), a defect in both B- and T-lymphocytes, was found to occur in 2.3% of 257 foals of Arabian breeding. All affected foals died by 5 months of age. The belief that CID is transmitted as an autosomal recessive genetic defect was supported by results from matings of dams and sires that had previously produced affected foals. Based on a prevalence of 2.3%, the proportion of carriers of the CID trait among the adult population surveyed was estimated to be 25.7%. Recent descriptions of other immunologic defects in foals emphasized the need for careful differential diagn...
Combined immunodeficiency with failure of colostral immunoglobulins transfer in foals. Foals with combined immunodeficiency (CID), a fatal genetic defect in the production of both B and T lymphocytes, are born without immunoglobulins and are unable to synthesise them. CID foals receiving immunoglobulins via the dam's colostrum may live up to four months of age. Those CID foals with failure of passive transfer (FPT) die at a much earlier age. The occurrence of CID is of value in studying passive transfer of immunoglobulins, as no confusion exists as to when passive transfer ends and active synthesis of immunoglobulins begins. A high correlation has been found between early foal d...
The ultrastructure of the cell types in the endocrine pancreas of the horse. The islets of Langerhans of the equine pancreas were examined with the electron microscope after immersion or perfusion fixation. Five cell types could be distinguished after fixation by either technique: 1. A-cells, situated at the center of the islets, 2. B-cells, containing mostly "pale granules" and constituting the principal cell type of the periphery of the islets, 3. D-cells, also located mainly at the periphery of the islets, 4. G-cells, found at the edge of the islets and in the exocrine pancreas, and 5. S-cells, (small granule cells), which are relatively few in number and occur only...