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I Oláh

Publications and source records attributed to I Oláh.

At least 19 recordsLinked to original sources
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↗
PubMed1988

Formation of lymphoepithelial tissue in the sheep's palatine tonsil.

Formation of lymphoepithelial tissue was studied in 1-, 10- and 21-day-old sheep. From each of the animals one of the tonsils was fixed in 4% glutaraldehyde for light- and electron microscopy while the other was frozen in liquid nitrogen for immunohistochemistry. These examinations revealed sequential histological events during the formation of reticular epithelium. (i) Appearance of a distinct epithelial cell indicates the initiation of the reticulation. The electron density of these epithelial cells is much lower than that of the common keratinocytes but the presence of cytoplasmic tonofibrils and desmosomes provides evidence that they are of epithelial origin. They may represent the precursors of M cells. Their appearance may be followed by expression of Ia+ molecules on the surrounding keratinocytes showed by isolated Ia+ areas in the epithelium. (ii) In the mesenchyme underneath the Ia+ epithelial areas, Ia+ dendritic-like cells emerge which immigrate through the basement membrane into the epithelium establishing a provisional dendro-epithelial tissue. In this stage of the reticular epithelium's formation large Ia+ areas are shown by immunostaining, which include the epithelium and mesenchyme. The origin of the Ia+ dendritic-like cells is uncertain but their distribution and dense accumulation underneath the epithelium suggest that they are transformed tonsillar mesenchymal cells. Similar cell transformation of mesenchymal cells takes place in the bursa of Fabricius prior to development of lymphoepithelial tissue. (iii) The M cell precursors together with the Ia+ dendritic-like cells adapt the epithelium to be suitable for receiving a large number of lymphoid cells. Immigration of the lymphoid cells into the epithelium transforms the dendro-epithelial tissue to a real lymphoepithelial one.

Animals↗
PubMed1987

The immunosuppressive effect of acute doses of emetine on murine thymic cells.

Emetine--a general inhibitor of protein synthesis--was investigated for its ability to depress specific immune response in animal models. A single dose (33 mg/kg) of emetine administered subcutaneously to mice markedly decreased thymus weight and thymic cell numbers. DNA, RNA and protein synthesis of thymic cells were reduced by 90, 50 and 65%, respectively. RNA synthesis was the first process to recover followed by the reconstitution of DNA and protein synthesizing capacity. Histological evidence revealed an effect on the cortical region of thymus upon emetine administration. Results suggest that emetine exerts an immunosuppressive effect on T-cell maturation in the thymus. These findings may enhance a therapeutic interest in the drug.

Animals↗
PubMed1987

In vitro effect of emetine and chloroquine on the macromolecular biosynthesis of murine thymus cells.

The in vitro effect of antiparasitic agents, emetine and chloroquine on the DNA, RNA and protein synthesis was studied in isolated murine thymocytes. Cytotoxic effect was observed at 10(-4) and 10(-3) M emetine concentrations causing 50% and 70% cell death, respectively. The toxic effect of emetine could be prevented when emetine was removed within 10 min of treatment. Inhibitory concentrations for DNA, RNA and protein biosynthesis were 10(-5), 5 x 10(-5) and 10(-8) M, respectively. The number of living cells decreased by 30 and 50% at 10(-4) and 10(-3) M chloroquine concentrations, respectively. Gradually decreasing rate of DNA synthesis was measured at increasing concentration of chloroquine between 10(-8) and 10(-3) while RNA and protein synthesis were effected at 5 x 10(-5) M concentration. These results indicate that protein biosynthesis is primarily affected by in vitro emetine and chloroquine treatment of murine thymocytes.

Animals↗
PubMed1986

Bursal development in normal and testosterone-treated chick embryos.

The development of the bursa of Fabricius was studied in normal and testosterone-treated embryos. The bursal anlage appears on the 5th day of incubation as an outgrowth of the dorso-caudal wall of the cloaca. By Day 7, the bursal lumen is present and separated from the anal invagination by a thin epithelial membrane. Shortly after this developmental state, the epithelial membrane disappears and the bursal lumen freely communicates with the amniotic cavity. The remnant of the bursal anlage forms the ventral wall of the anal invagination that is actually the bursal duct. Disappearance of the remnant of the bursal anlage, which takes place after the 16th day of incubation, allows the bursa to join the cloaca. Bursal folds appear on the 10th day of incubation. Mesenchymal cells then differentiate into dark and light cells. The dark cells, between 11 and 14 days of incubation, mobilize in the mesenchymal network and assemble in small groups under the epithelial rudiment of the folds. They, then, enter the epithelium where they induce bud formation. During the assemblage of dark cells beneath the epithelium and their emigration into the epithelium, they acquire cytoplasmic granules that resemble avian secretory cells. The light cells do not associate with the epithelium. They may be the precursors of cortical reticular cells. The differentiation of dark cells is inhibited in the presence of testosterone. Therefore, the failure of bud formation and subsequent follicular formation in the bursa of testosterone-treated embryos may be attributed to the elimination of an induction signal supplied by the differentiated dark cells of the mesenchyme.

Animals↗
PubMed1984

Meckel's diverticulum. I. Extramedullary myelopoiesis in the yolk sac of hatched chickens (Gallus domesticus).

We have described an extramedullary myelopoietic tissue located in the wall of the yolk sac. This myelopoietic site is absent at hatch and it produces only granulocytic and monocytic cells during the regression of the yolk sac from 2 to 7 weeks of age. The granulocytic and monocytic cells are located in two distinct zones. The monocytic cells migrate close to the lumen of the yolk sac where they may fuse and form giant cells. There are no mature granulocytes present. Cell migration has not been observed. Therefore, the fate and function of the young granulocytic cells are unknown. In this extramedullary myelopoietic tissue, the absence of erythrocyte and thrombocyte formation may indirectly suggest that these cells develop together in sinuses that are lacking in the wall of the yolk sac.

Animals↗
PubMed1984

Meckel's diverticulum. II. A novel lymphoepithelial organ in the chicken.

We have studied the lymphoid development and structure of Meckel's diverticulum (MD). The lymphoid accumulation began about 2 weeks of age. Between 2 and 5 weeks of age the longitudinal folds were filled with lymphoid tissue. The intensive germinal center formation occurred between 5 and 7 weeks of age. Germinal center formation was associated with the presence of secretory cells. The absence of the secretory cells in the germinal centers was followed by germinal center inactivity which was indicated by the lack of lymphoblasts and the high number of tingible body macrophages. The lymphoid tissue of MD seemed to be fully developed by 10 weeks of age and remained lymphoid at least until 21 months of age. Meckel's diverticulum produced large numbers of plasma cells which were comparable to those of the gland of Harder. We may regard MD as the third pouch of the intestine and suggest that it may be a novel lymphoepithelial organ in the chicken.

Aging↗
PubMed1984

Effect of soluble antigen on the ellipsoid-associated cells of the chicken's spleen.

The ellipsoid-associated cells (EAC) localize on the surface of the ellipsoid. They bind the IV injected horseradish peroxidase (HRP) and bovine serum albumin (BSA), migrate to the red pulp and then enter the systemic circulation. After protein injection, the number of white blood cells increased above the normal level. The highest number of white blood cells occurred between 4 and 6 hr after HRP injection. In this period, the cell enhancement resulted in HRP-positive mononuclear cells which might come from the spleen. This cell population may vary in size and number in the blood and may be identical with the dendritic cell of the chicken. The other type of blood mononuclear cell is histologically identical with the classical monocyte endogenous peroxidase positive type and their number is lower than that of the former. This type of monocytic (MN) cell could be of bone marrow origin.

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