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Biomedical subjects

I Oláh

Publications and source records attributed to I Oláh.

At least 19 recordsLinked to original sources
PubMed2005

Oesophageal tonsil of the chicken.

The oesophageal tonsil of the chicken is a novel member of the mucosal-associated lymphoid tissue (MALT), which is located around the entrance of the proventriculus. It consists of 6 to 8 single units, which are surrounded by a thin fibrous capsule. Each one is organised around the bottom of the longitudinal folds of the oesophagus, and serves as a 'tonsillar crypt'. Stratified squamous epithelium is infiltrated by lymphoid cells, i.e. T cells, plasma cells, macrophages, and dendritic cells, but not B cells, to form lymphoepithelium (LE). In the LE vimentin-, MHC II- and ATPase-positive cells possibly represent Langerhans' cells, but the appearance of 74.3 positive cells in the LE is unusual, because the 74.3 monoclonal antibody (mAb) recognises chicken follicular dendritic cells in the germinal centre and medulla of the bursal follicles. The subepithelial lymphoid tissue is organised into T- and B-dependent regions, which are the interfollicular areas and the germinal centres, respectively. Existence of high-endothelial venules in the interfollicular region suggests an extensive cellular connection between the oesophageal tonsil and the other lymphoid organs. In the resting oesophagus the lumen is closed, but during swallowing a bolus the crypt opens and the lymphoepithelium can be exposed to undigested food, antigens, infectious agents and vaccines. The location of the oesophageal tonsil, cranial to the stomach, may provide this organ with a unique role as compared to the other parts of the MALT; namely, it may contribute to the replication of infectious bursal disease virus (IBDV) and/or the pathogenesis of infectious bursal disease.

Animals↗
PubMed2004

Origin of the bursal secretory dendritic cell.

The origin of vimentin-positive secretory dendritic cells of the bursa of Fabricius was studied by chick-quail chimera, parabiosis and immunohistochemistry using species-specific monoclonal antibodies. Quail bursal primordia of different ages were transferred to coelomic cavity of 3-day-old chicken embryos and further incubated for 18 days. In transplanted quail bursas the secretory dendritic cells of chicken and quail origin were detected by double staining of vimentin plus 74.3 and vimentin plus QCPN monoclonal antibodies, respectively. In bursal primordia of 5- and 6-day-old quail embryos both dendritic cells and B cells were of host, i.e. chicken origin. Mixed dendritic cell population of quail and chick origin emerged in chimeric birds of 6.5 days of age. In quail embryos transplanted at 7 and 8 days of age both dendritic cells and B cells were mixed i.e. of chicken and quail origin. Bursal secretory dendritic cells and medullary epithelial cells create "dendro-epithelial tissue" to receive pre-B cells. Colonization of dendro-epithelial tissue by pre-B cells initiates at day 7, thus the colonization of bursal anlage by blood-borne cells is a two-step process; entering of dendritic cells at day 6.5 is followed by that of B cells at day 7 and afterwards. It is discussed that bursal secretory dendritic cells and their product are key elements of bursal function therefore the mammalian bursa equivalent organ might be represented by a cell, which is analogous with the bursal secretory dendritic cell.

Animals↗
PubMed2003

Esophageal tonsil: a novel gut-associated lymphoid organ.

The esophageal tonsil of the chicken is a novel, significant element of the gut-associated lymphoid tissue (GALT). Its stable location and histological organization fulfills the meaning of the term "tonsil." The six-to-eight-isolated tonsillar units are located at the border of the esophagus and the proventriculus. The number of tonsillar units is identical with that of the esophageal folds. Each tonsillar unit consists of a crypt lined by lymphoepithelium and surrounded by dense lymphoid tissue, which is organized into T- and B-dependent regions, like peripheral lymphoid organs. The excretory ducts of the mucosal glands of the esophagus are frequently involved in the formation of the lymphoepithelium. The esophageal tonsil is anatomically located cranial to the stomach, unlike the other parts of the GALT. Therefore, it is continuously exposed to undigested environmental antigens, allergens, food, and infectious agents. To develop effective oral vaccines, the existence of the esophageal tonsil has to be taken into account.

Animals↗
PubMed2002

Diverse expression of the K-1 antigen by cortico-medullary and reticular epithelial cells of the bursa of Fabricius in chicken and guinea fowl.

The immunocytochemical study of the K-1 monoclonal antibody indicates that the epithelial components of the bursa of Fabricius of the chicken and guinea fowl express the K-1 positive molecule. During embryogenesis, the K-1 antigen expression appears together with the bud-formation. As the number of B cells increases in the developing follicle, the K-1 expression gradually diminishes in the medullary reticular epithelial cells and completely ceases by hatching, which suggests that the molecule is developmentally regulated. After hatching, the expression of the molecule is restricted to the sealing off zone of the lymphoepithelial or medullary region of the follicle: i.e. to the cortico-medullary (CM) epithelial cells and the follicle associated epithelium (FAE) supporting cells in guinea fowl and to the latter ones in the chicken. The expression of the K-1 antigen by these epithelial components may support their structural identity. After hatching, the K-1 molecule is restricted to the CM epithelial cells and/or FAE supporting cells, which suggests that the function of the embryonic epithelial bud is taken over by the CM epithelial cells. The K-1 positive CM epithelial cells form arches, which encompass blast-like cells. The possible relationship of the CM epithelial cells and blast-like cells, which may represent the precursors of bursal secretory dendritic cells is discussed.

Animals↗
PubMed2001

Development of the follicle-associated epithelium and the secretory dendritic cell in the bursa of fabricius of the guinea fowl (Numida meleagris) studied by novel monoclonal antibodies.

Two stromal elements, follicle-associated epithelium and secretory dendritic cells of the bursa of Fabricius were studied by light microscopy and two novel MAbs, that were produced against splenic cell suspensions of guinea fowls. Both antigens recognized by these MAbs, designated GIIF3 and NIC2, are localized in the cytoplasm of the stromal cells, and their molecular weights are 50 and 30 kD, respectively. During embryogenesis the GIIF3 and NIC2 cells emerge in the mesenchyme of the folds before follicle formation. The GIIF3 and the NIC2-positive cells accumulate under the surface epithelium of the plicae and migrate into the epithelium, that precedes the bud-formation. From the bud, the GIIF3-positive cells migrate up to the luminal surface, and they transform to distinct, highly polarized follicle-associated epithelial cells. Single GIIF3-positive cells are also present in the interfollicular epithelium. The NIC2 MAb recognized mesenchymal cells harbor in the lymphoepithelial compartment of the folliculus, and they elaborate cytoplasmic granules. Around Day 20 of embryogenesis large amount of NIC2-positive substance appear extracellularly in the medulla and around it. This period well correlates with the starting up of the bursal functions; clonal expansion of B cells, and generation of immune repertoire. After hatching the NIC2 stainability diminishes, and it is restricted to the medullary bursal secretory dendritic cells. The NIC2-positive, possibly elderly bursal secretory dendritic cells, are capable for migration into the follicle-associated epithelium. In eight-day old birds some cells of the follicle-associated epithelium reveals temporary NIC2 positivity, that may prove the transport of the follicle-associated epithelial cells into luminal direction. By 12 weeks of age the presence of NIC2-positive substance in the intercellular space of the FAE, rather than in the cells of FAE may indicate the termination of the transport of secretory substance. In conclusion, two types of mesenchymal cells enter the surface epithelium of the bursal folds. The GIIF3-positive cells appear on the luminal surface of the follicles and occupy the place of the follicle-associated epithelial cells. The NIC2-positive cells become secretory in nature and differentiate to bursal secretory dendritic cells. The follicle formation possibly, requires the joint presence of both GIIF3 and NIC2 cells in the epithelium.

Animals↗
PubMed2001

Apoptotic and mitotic activity in squamous cell carcinoma cells after combined modality treatment with gamma-irradiation and dibromodulcitol.

A-431 squamous cell carcinoma cells were treated in vitro with either 4 Gy radiation of 15 (or 45) microg/ml dibromodulcitol (DBD), as well as with combined 4 Gy irradiation and DBD, with the latter as either a pretreatment or post-treatment. DBD alone or in combination with radiation had a greater effect on cell proliferation than the effect of radiation alone. The difference is due to a higher level of apoptosis induced by DBD, especially in conjunction with radiation. Such a combination may therefore be useful in the treatment of squamous cell carcinoma, which in general responds poorly to radiation therapy.

Antineoplastic Agents, Alkylating↗
PubMed2001

A novel monoclonal antibody identifies all avian embryonic myogenic cells and adult smooth muscle cells.

A novel monoclonal antibody, designated GIIF3, recognized prospective and differentiated smooth muscle cells in avian species studied - guinea fowl, chicken and quail. The GIIF3 antigen appeared in the myocardial, and the myotomal cells of the embryos at Hamburger-Hamilton stages 10 and 14, respectively. The expression of the GIIF3 molecule in the vascular smooth muscle cells emerged in the ventral wall of the dorsal aorta at Hamburger-Hamilton stage 16. The visceral smooth muscle cells started to produce the GIIF3 molecule from Hamburger-Hamilton stage 28 onwards. In both cardiac and skeletal muscles the GIIF3 expression gradually diminished, and it was lost by the end of the embryonic period, unlike in the differentiated vascular and visceral smooth muscle cells. In the latter cells the GIIF3 immunoreactive product showed a fine granular pattern that accumulated in the central region of the cytoplasm; it also occurred in the nucleus. A heavily stained discontinuous layer was associated with the cell membrane. The immunoblotting of the GIIF3 antibody recognized protein bands at 50 and 42 kDa in lysates of adult avian gizzard. A detailed comparative immunohistochemical study was made by smooth muscle markers, which confirmed the results of the immunoblotting, namely, that the GIIF3 monoclonal antibody recognized an avian myogenic cell specific molecule. During smooth muscle cell differentiation the GIIF3 molecule appeared as early as the alpha-smooth muscle actin, and in adult birds continued to be expressed; therefore the GIIF3 molecule could be regarded as a novel avian smooth muscle specific marker.

Age Factors↗
PubMed2001

Ontogeny of the dendritic, and follicle-associated epithelial cells in the bursa of Fabricius of guinea fowl (Numida meleagris).

A panel of monoclonal antibodies was produced to study the mesenchymal stromal elements of the bursa of Fabricius in guinea hen. The intracellular antigens recognized by GIIF3 and NIC2 monoclonal antibodies are of 50 and 30 kD, respectively. The cells identified by these antibodies emerge in the mesenchyme around day 12 of incubation, and immigrate into the surface epithelium of the bursal folds, which precedes the follicle formation. The GIIF3 cells move up to the luminal surface of the follicle and differentiate to follicle-associated epithelial cells. The NIC2 cells remain in the medulla, produce and secrete large amount NIC2 positive substance, when the bursal function starts up. The presence of double positive (GIIF3 and NIC2) cells in the medulla around hatching, seems to indicate, that the two cells might have a common origin. The NIC2 positive product of the bursal secretory dendritic cells contributes to the microenvironment, and possibly necessary for the B cell clonal expansion and establisment of the immune repertoire in the guinea hen.

Animals↗
PubMed1996

The lymphoid substance of the chicken's harderian gland is organized in two histologically distinct compartments.

Light and electron microscopical investigations revealed that the lymphoid structure of the chicken Harderian gland is organized in different histological frameworks. In the head the surface epithelium of the central canal can be classified as a lymphoepithelial tissue which covers the dense lymphoid substance. It consists of small and medium-sized lymphocytes, dendritic-like cells, and occasional macrophages. High endothelial venules are associated with intense lymphocyte migration and homing that gives circumstantial evidence for a T-dependent region, as found in a secondary lymphoid organ. The B-dependent germinal centers are also common structural units of the head region's lymphoid substance. The body of the gland is loaded with plasma cells of different maturation stages. They immigrate into the epithelium of the central canal and produce IgM and IgA. Only a few scattered IgG producing plasma cells can be found in the gland of Harder. This plasmocytic region accounts for the immunosurveillance on the conjunctiva and in the upper respiratory tract through antibody production against bacterial or parasitic infections. In both the head and body regions of the gland, anti-B-L (anti-Ia) antibody recognized scattered elongated cells which might represent dendritic cells. The immunological relationship between the two histologically different parts of the Harderian gland is unknown, but we speculate that the dense lymphoid tissue with high endothelial venule receives the blood-borne, immunologically mature, but uncommitted B cells. By the influence of local antigen stimulus, these B cells transform to plasma cells which gradually appear in the body of the gland. The lymphoid structures of the head and the body fulfill the function of secondary and tertiary lymphoid organs, respectively.

Animals↗
PubMed1996

Expression of intermediate filaments and N-cadherin adhesion molecule in the thymus of domesticated birds.

Stromal cells of the thymus from the domestical birds (chicken and guinea fowl) were studied by antibodies against their intermediate filaments (keratin, vimentin and desmin). The medulla revealed large irregular shaped keratin free areas, surface of which is dentate but sharply outlined. The keratin free areas are connected with the substance of the interlobular septae which indicates that the medullary microenvironment is rather similar to that of the peripheral lymphoid tissue. The vimentin intermediate filament is expressed by the entire medullary region. The immunologically competent medullary T cells are vimentin positive unlike the immature cortical T cells. The anti-desmin antibody revealed a three dimensional network in the medulla which includes desmin negative "channels". The myoid cells, locating close to the "channels", are possibly the well-differentiated forms of the desmin positive network. N-cadherin is expressed by the cortico-medullary epithelium and it is suggested that this adhesion molecule plays some role in the thymocyte selection. Both keratin and desmin intermediate filaments indicate that the medulla of the thymus has a complex stromal structure which further compartmentalizes the thymic medulla.

Animals↗
PubMed1995

Dendritic cells in the bursal follicles and germinal centers of the chicken's caecal tonsil express vimentin but not desmin.

BACKGROUND: Immunohistochemical studies with anti-vimentin and anti-desmin monoclonal antibodies were designed to determine the origin of bursal secretory dendritic cells (SDC) and follicular dendritic cells. METHODS: The binding sites of anti-vimentin, anti-desmin, and anti-chicken-IgG specific monoclonal antibodies were visualized with a biotinylated anti-mouse-IgG, ABC Elite kit, and 4-chloronaphthol. Cells were double stained (anti-vimentin and rabbit anti-chicken-IgG Fc) to determine if the vimentin positive cells possessed surface IgG. RESULTS: Vimentin positive cells were observed in the cortex and medulla of the bursa and germinal center and lymphoepithelial compartment of the caecal tonsil. The mesenchymal reticular cell, the basic supporting cell of the germinal center, was stained prominently by anti-vimentin and anti-desmin. Both antibodies stained the bursal cortex but only anti-vimentin bound the bursal secretory dendritic cell of the medulla. In addition to being vimentin positive and desmin negative, the bursal secretory dendritic cell possessed and the follicular dendritic cell appeared to possess IgG on their surfaces. In all the observations, B-cells were vimentin negative. CONCLUSION: These studies suggest that follicular dendritic cells and mesenchymal reticular cells in the caecal tonsil's germinal centers may be functionally different cell populations while the bursal secretory dendritic cell and follicular dendritic cell of the caecal tonsil may have a common origin.

Animals↗
PubMed1995

The surface phenotype of swine blood and tissue eosinophil granulocytes.

Cell surface antigens of swine eosinophil granulocytes were studied with flow cytometry and immunohistochemistry. The monoclonal antibody 335-2, specific for swine differentiation antigen swC1a, originally described to be present on swine T and myeloid cells, is able to distinguish swine eosinophils (swC1a negative) from neutrophils (swC1a positive). This monoclonal antibody (mAb) was used in two-colour fluorescence measurements in combination with anti-swine -CD2, -CD4, -CD8, -MHC class II, -LFA-1 or -swC3 mAbs. All of the blood eosinophils proved to be positive for LFA-1 and swC3, a common marker of swine monocytes, granulocytes and macrophages. However, they do not react with antibodies recognizing swine CD2, CD4, CD8 or MHC class II cell surface molecules. The reactivity pattern of tissue eosinophils with these mAbs was determined on cryostat sections of different tissues of swine. Tissue eosinophils were negative for swC1a, CD2, CD8, while all of them reacted with swC3. In contrast with blood eosinophils, 10-30% of tissue eosinophils were demonstrated to be negative for LFA-1. In some cases, a few tissue eosinophils were found to be stained weakly by antibodies to swine CD4 or MHC class II antigens.

Animals↗
PubMed1994

Schweigger-Seidel sheath or ellipsoid in the spleen of guinea hen.

Splenic Schweigger-Seidel sheath or ellipsoid was studied by anti-vimentin monoclonal antibodies, clones 3B4 and V9. The 3B4 mAb recognizes a cell type with cytoplasmic granules and long processes which make a network around the endothelial cells of the penicilliform capillaries. The V9 mAb identifies the reticular cells of the spleen which form the supporting system of the Schweigger-Seidel sheath. The sheath covers the entire length of the penicilliform capillary from the central artery, including the branching area. The appearance of the Schweigger-Seidel sheath in a section depends on the section plane; namely, at the branching area its shape is highly irregular, while close to the red pulp it looks like a sleeve. Therefore, the English term "ellipsoid" does not cover the morphological appearance of this unique splenic structure; the Schweigger-Seidel sheath is a correct term.

Animals↗
PubMed1994

A mouse monoclonal antibody reacting with swine leukocytes: a flow cytometrical and immunohistochemical study.

A mouse monoclonal antibody (Mab) was prepared by immunization of Balb/c mice with porcine peripheral blood mononuclear cells. Its reactivity was studied by flow cytometry and immunohistochemistry. By flow cytometry 75-90% of blood lymphocytes and 93-97% of blood granulocytes showed positivity, while all monocytes were labelled. The specificity of the Mab was investigated further by immunohistochemical methods using different tissues of swine. Both cortical and medullary thymocytes strongly expressed the target antigen of Mab 335-2. Intensive staining of T cell dependent areas in the lymph nodes, spleen and tonsils was also observed. Many positive cells occurred in the red pulp of the spleen. In the non-lymphoid tissues no organ-specific staining was observed, except for the connective tissue which contained scattered positive cells. Kupffer's cells and some glial cells reacted with this Mab. These results suggest that this novel Mab recognizes a major antigen present on immature and mature T cells; however, subpopulations of myeloid cells (neutrophils, monocytes, and some types of macrophages) share this antigen.

Animals↗
PubMed1992

Plasma cell proliferation in the chicken harderian gland.

Studies to examine the percentages of proliferating plasma cells (PPC) in the Harderian gland (HG) were carried out in chicks between 5 and 12 weeks of age. Two methods, 5-bromo-2'-deoxyuridine (BrdUrd) incorporation into DNA and flow cytometric analysis of propidium iodide (PI) stained cells, were employed in control and emetine dihydrochloride treated birds. Flow cytometric analysis of PI stained cells showed the percentages of plasma cells in S phase were highest between 6 and 8 weeks of age. After this period of time, the number of S phase plasma cells decreased and remained low through 12 weeks of age. The lowest percentages of plasma cells in G0 + G1 were found at 6 and 8 weeks of age, and all ages had equal percentages of plasma cells in G2 + M phase. After administration of the protein synthesis inhibitor emetine dihydrochloride a common pattern of plasma cell depletion and repopulation in the HG was observed. At 3 and 5 days post-treatment the plasma cell population in the gland decreased and by 7 days post-treatment repopulation of the gland with plasma cells had taken place. Anti-BrdUrd staining of frozen sections revealed that the number of PPC were decreased at 3 days after emetine treatment but were as high as, or higher than, controls at 5 and 7 days post-treatment. Flow cytometric analysis indicated that some birds were more severely affected by emetine. Namely, the percentages of plasma cells in S phase were lower at 3 and 5 days post-treatment. Even though most birds were severely affected by emetine treatment during the experiments, they possessed a cell population with the proliferative capacity to quickly repopulate the HG by 7 days post-emetine treatment.

Animals↗
PubMed1990

Effect of emetine on the plasma cell population of chicken's gland of Harder.

The emetine effectively abolished the plasma cell population in the chicken's gland of Harder by day 3 of treatment. The plasma cell content regenerated by day 5 following emetine injection, possibly from a metabolically inactive, resting B cell population which was resistant to the emetine treatment. By day 7 extracellular substance in a very large quantity appeared among the plasma cells and epithelial cells which might represent a hyperactive plasma cell secretion. The changes in the circulating antibodies measured by hemagglutination well-correlated with the plasma cell content in the gland of Harder. The gland of Harder (GH) is an accessory lacrimal gland. Its main function is to lubricate the nictitating membrane and keep the surface of the eyeball wet. The presence and regulatory function of cAMP dependent histone kinase was showed. Since it has been published that in chicken the interstitium of this gland contains a proper amount of plasma cells, this observation called the attention of many investigators to study the role of GH in the immune response. The B cell maturation in the chicken GH has been studied. The surface marker studies have proved that beside the B cells the gland contains functionally adequate number of T cell which exert stimulatory effect on B cells to promote their transformation to plasma cells. In addition to T and B cells small number of macrophages also occur. In the 9 H the number of plasma cells is age dependent. At hatch only a few plasma cells occur in the interstitium of the gland but by 3 weeks of age they become predominant. Different isotypes of immunoglobulins are secreted by these plasma cells.

Animals↗
PubMed1988

Structural changes in the mouse thymus and lymph node after emetine treatment.

The effect of emetine which is a potent immunosuppresant was studied on the thymus and lymph node. The subcapsular zone of the thymus was depleted and large number of adherent cells accumulated in this thymic region. The medulla enlarged but the cortico-medullary border remained distinct. In the paracortex (T dependent area) of the lymph node many non-lymphoid pyroninophil cells appeared which is followed by an increased cell proliferation 24 hours after emetine injection. 48-60 hours after administration many macrophage-like cells appeared in the medullary sinuses. This macrophage invasion precedes the adherent cell accumulation in the subcapsular zone of the thymus suggesting a possible non-lymphoid (adherent) cell migration from the lymph node's paracortex to the thymus.

Animals↗