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Biomedical subjects

I Olah

Publications and source records attributed to I Olah.

At least 19 recordsLinked to original sources
PubMed1996

Expression of an anti-H58A monoclonal antibody recognized molecule in rabbit tonsillar epithelium.

The H58A monoclonal antibody (mAb) recognizes a highly conserved determinant on MHC class I molecules in various species. This mAb was used in immunohistochemical studies to determine the presence of this molecule in rabbit tonsils. The molecule is strongly expressed in all layers but the germinal one, of the stratified epithelium (SSE) of the oral cavity and tonsillar crypt. The expression of this molecule is completely abolished in the lymphoepithelial regions of the crypt epithelium. In cortison-induced immunosuppressed animals, the lymphoepithelium is depleted and gradually transforms to SSE. Consequently, the expression of the H58A mAb recognized molecule reappears. Further studies are needed to determine if this molecule plays any kind of functional role in the formation of lymphoepithelial tissue.

Animals↗
PubMed1995

Characterization of a novel monoclonal antibody, EIV-E12, raised against enriched splenic ellipsoid-associated cells.

A monoclonal antibody, EIV-E12, was produced against ellipsoid-associated cells. In postnatal chicks, the antigen defined by EIV-E12 associated with about 90% of bursal cells and accumulated in B cell-rich areas of lymphoid organs. The antigen was expressed by many splenic cells on day 9 of embryogenesis and about 1 day later in the bursal anlage, where the cells positive for the antigen localized in close proximity to the plical epithelium. In the bursa, these early EIV-E12 cells appeared before Bu-1-positive cells and may represent a dendritic cell precursor. B cells within the developing bud acquired the EIV-E12 antigen. Immunoprecipitation studies revealed a molecular weight of 233 (nonreduced) and 205 (reduced) for the EIV-E12 antigen. These values were markedly different from the molecular weight of the antigen identified by Bu-1 but similar to that of a CB10 antigen. The CB10 and EIV-E12 MAbs exhibited some differences in cellular staining. Taken together these data suggest that EIV-E12 MAb recognizes a unique cellular population during embryogenesis.

Animals↗
PubMed1993

Bursal secretory dendritic-like cell: a microenvironment issue.

In 1978, Olah and Glick identified in the medulla of the bursa of Fabricius a dendritic cell, the bursal secretory dendritic-like cell (BSDC). The morphology of BSDC, the functional relationship of BSDC to bursal follicle development and the spleen, and the identification in the embryo of the BSDC precursor was reported. The precursor BSDC appeared in the bursa before B cells. A monoclonal antibody to vimentin, an intermediate filament, will identify BSDC and not B cells in posthatch chickens. The vimentin-positive cells, but not B cells, in hatched chicks express complete IgG chain. Taken together, the present data may contribute to the events occurring during the bursal-dependent stages of B cell development. Immunoglobulin gene rearrangement, within the bursa or at extra-bursal sites, and clonal expansion at extra-bursal sites are antigen-independent and dependent, respectively. The bursal-dependent stage includes the expansion of the Ig rearranged cells and gene conversion, which contributes to antibody diversity. The IgG and granular products produced by BSDC may act as ligand and signals for B cell expansion and gene conversion.

Animals↗
PubMed1993

Plasma cells of the chicken Harderian gland.

The chicken Harderian gland (HG) is densely populated in its subepithelial spaces with plasma cells (PC). These immune cells produce and secrete Ig of the IgA, IgG, and IgM classes. Such Ig secretion into the tears affords the upper respiratory tract with protective antibodies. The immunological role of the HG is quite interesting; yet this gland is a site of unusual PC proliferation. Studies of the gland utilizing bromodeoxyuridine (BrdUrd) incorporation into DNA and propidium iodide (PI) staining of PC DNA have verified previous suggestions in the literature that PC of the chicken HG proliferate. Both isolated PC suspensions and frozen sections of the HG from chicks aged 6 to 9 wk reveal that BrdUrd is incorporated into PC DNA. Furthermore, flow cytometric analysis of PI-stained PC indicates a relatively high percentage of PC in S phase of the cell cycle. Continued studies are examining possible mechanisms controlling proliferation and differentiation of PC in the HG. It is believed that the stromal elements of the HG produce and secrete a factor(s) that influences PC proliferation and differentiation. Isolation and characterization of this influencing factor(s) will allow for the possible systemic application of the factor(s) for enhancement of immune responses.

Animals↗
PubMed1992

Anti-vimentin monoclonal antibody recognizes a cell with dendritic appearance in the chicken's bursa of Fabricius.

The bursa of Fabricius was studied by immunohistochemical method using anti-vimentin monoclonal antibody (clone 3B4). This monoclonal antibody identified a vimentin positive cell in the medulla of the bursal follicle. During the first 2 weeks of life the vimentin positive cells located along the corticomedullary border and later became prominent in the medulla with the exception of a narrow zone adjacent to the corticomedullary border. After hatching the accumulation of vimentin-type intermediate filaments on one side of the nucleus endowed the vimentin positive cells with a polarized appearance. This "cap-like" vimentin positive area of the cytoplasm determined the position of the major cell process. Within the medulla the Ia positive secretory dendritic cells contained secretory granules in one of the cell processes. The distribution, shape, and polarized appearance of the vimentin positive cells were identical with that of the secretory dendritic cells. Therefore, the anti-vimentin monoclonal antibody proved to be useful for identification of the bursal secretory dendritic cells. During rapid bursal growth the number of secretory dendritic cells increased, possibly, by proliferation of vimentin negative secretory dendritic cell precursors located along the corticomedullary border.

Animals↗
PubMed1992

Differentiation of bursal secretory-dendritic cells studied with anti-vimentin monoclonal antibody.

Embryonic and posthatched differentiation of bursal secretory dendritic cells, which express vimentin intermediate filaments, were studied with anti-vimentin (clone 3B4) and anti-cytokeratin (clone Lu5) monoclonal antibodies. Anti-cytokeratin staining revealed that medullary reticular epithelial cells formed a continuous network at every age, whereas the vimentin positive cells were single and showed dendritic appearance. On the basis of location, number, shape, polarized appearance, and Ia staining, the vimentin-positive cells and secretory dendritic cells appeared to be the same cell. Secretory dendritic cell precursors entered the bursal epithelium between 11 and 13 days of embryogenesis. The first vimentin positive cell appeared in the bud of 14-day embryos. Bud formation preceded the appearance of vimentin-positive cells. These observations suggested that the secretory dendritic cell precursor did not express vimentin when it entered the epithelium. Between 15 days of embryogenesis and 2 weeks of posthatch development, the changes in vimentin staining pattern revealed a cytological differentiation of the vimentin-positive cell. During rapid bursal growth, the number of secretory dendritic cells (vimentin-positive cells) increased about 18 times possibly by proliferation of vimentin-negative precursors in the epithelial arches of the corticomedullary border.

Animals↗
PubMed1992

Follicle-associated epithelium and medullary epithelial tissue of the bursa of fabricius are two different compartments.

The bursae of Fabricius from the chicken and turkey were studied by light and electron microscopy and immunohistochemical methods. The study focused on the relationship of follicle-associated epithelium to the medulla. The follicle-associated epithelium was supported by 3 to 5 layers of stratified epithelial cells which were a continuation of the corticomedullary epithelial cells. The follicle-associated epithelium consisted of M cells and scattered secretory dendritic cells. The network of the reticular epithelial cells of the medulla was filled with secretory dendritic cells, B cells, and a few T cells and macrophages. The cellular content of the follicle-associated epithelium and the medulla suggested that they were different cellular compartments. Communication between the follicle associated epithelium and medullary epithelial compartment occurred through the supporting cells of the follicle-associated epithelium. When the supporting layers of the follicle-associated epithelium infolded into the medulla, they formed lamellated epithelial bodies similar to the thymic Hassall bodies. The lamellated bodies enclosed secretory dendritic cells but not lymphocytes. The infolding of supporting cells varied from follicle to follicle. The asynchronization of infolding contributed to heterogeneity of follicle composition. Follicle heterogeneity was demonstrated by differences in reactivity with a battery of monoclonal antibodies.

Animals↗
PubMed1992

Plasma cells expressing immunoglobulins M and A but not immunoglobulin G develop an intimate relationship with central canal epithelium in the harderian gland of the chicken.

In the Harderian gland of the chicken, the epithelial and plasma cell relationships were studied by light and electron microscopy and immunohistochemical methods. In the wall of the central canal a dark epithelial cell was identified that had long branching cell processes. An anticytokeratin monoclonal antibody demonstrated that the dark cells provided an extremely large contact area for the plasma cells. Although IgM-, IgG-, and IgA-producing plasma cells were present in the Harderian gland, only IgM- and IgA-positive cells were capable of a distinct relationship with dark epithelial cells. The surface of the primary branches contained scattered IgA deposits whereas the epithelial cells of the secondary branches possessed IgA along the lateral cell membrane but not on the surface. Anti-IgA and anti-cytokeratin antibodies produced a similar staining pattern in the acini and secondary branches. Taken together, these observations suggest that IgA secretion is a function of secondary branches and that intracellular transport is influenced by the cytoskeletal system.

Animals↗
PubMed1992

Dynamic changes in the intermediate filaments of the epithelial cells during development of the chicken's bursa of Fabricius.

The development of bursal follicles and the differentiation of the follicle-associated epithelium and interfollicular epithelium were studied immunohistochemically using monoclonal anti-vimentin and anti-cytokeratin antibodies. In 10-day-old embryos the entodermal and cloacal epithelia coexpressed vimentin- and cytokeratin-intermediate filaments. Both undifferentiated and differentiated bursal surface epithelium simultaneously expressed vimentin- and cytokeratin-intermediate filaments during the entire period of embryogenesis. Vimentin expression in reticuloepithelial cells was related to bursal cell differentiation but was not linked to immune function. Sequential loss of vimentin from interfollicular epithelium, follicle-associated epithelium, and reticuloepithelial cells may reflect sequential acquisition of maturity in these three compartments. The presence of cytokeratin-intermediate filaments suggested that follicle-associated epithelium was not of mesenchymal origin. Testosterone treatment did not influence the vimentin and cytokeratin filament expression in the epithelial cell.

Animals↗
PubMed1992

Non-lymphoid cells produce IgA-like substance in the corticomedullary zone of the chicken thymus. IgA-like substance in non-lymphoid cells.

Anti-IgA monoclonal antibody identified two different types of cells at the corticomedullary border of the chicken thymus. While cell Type I might be a plasma cell, Type II was an epithelial cell with intracytoplasmic and intracystic reaction products. The alpha chain reaction product of the epithelial cell was not recognized by anti lambda light chain antibody suggesting that the product was not a complete immunoglobulin A. It is proposed that the product of some corticomedullary epithelial cells may contribute to the induction of T alpha cells.

Animals↗
PubMed1991

An Ig-A-like substance in the chicken's pineal.

Immunohistochemistry revealed an Ig-A-like substance on the luminal surface of the pineal follicles and in the parafollicular layer. This substance was observed around 1 week of age and disappeared by 8 weeks at the time when the transformation of the follicular pattern leads to an adult-type pineal tissue.

Animals↗
PubMed1991

Endogenous peroxidase- and vimentin-positive cells accumulate at the corticomedullary border of the chicken thymus.

The granulopoietic activity of the thymus and bursa of Fabricius was analyzed using an anti-vimentin monoclonal antibody and endogenous peroxidase reaction to detect possible hemopoietic precursors and functionally mature cells, respectively. Endogenous peroxidase-positive cells (EPC) and vimentin-positive cells (V9) were located at the corticomedullary zone of the thymus. The cells were grouped, suggesting their clonal expansion. The first EPC appeared in the thymus on Day 15 of embryonic age, 2 and 3 days later than in the bursa of Fabricius and spleen, respectively. They were intermingled with thymocytes. Although the bursal EPC disappeared by Day 7 after hatching, the number of thymic EPC continued to increase. The thymic EPC and V9 cells persisted for more than 12 wk of age. The V9 cells were present either as single cells or grouped cells in the 15-day-old embryos. The V9 cells represented a distinct cell population of the corticomedullary border that may cooperate with the EPC.

Animals↗
PubMed1990

Effect of the progestogen, allylestriol, on the bursal development of the chicken.

Fertile eggs were dipped on the fifth day of incubation into varying concentrations of allylestriol (AE), a synthetic progesterone, and testosterone propionate (TP). Concentrations of AE higher than 0.1% inhibited hatchability. The AE inhibited the differentiation of the bursal mesenchyme and follicular development and subsequently resulted in bursectomy. The AE caused bursectomy in 40-50 times lower concentrations than did TP. An unusual lymphocyte accumulation occurred around the postcapillary venules in the bursal mesenchyme of AE-treated birds. This observation suggested that inhibition of mesenchyme differentiation may lead to a modification in bursal function. The AE modification of bursal development was compared to those produced by TP. We demonstrated that AE caused immunosuppression of the B-cell system.

Animals↗
PubMed1990

Effect of human adenovirus on the ellipsoid-associated cells of the chicken's spleen.

Ellipsoid-associated cell (EAC) responded in two ways to the intravenously injected human adenovirus. The EAC may produce a chemotactic factor(s) which recruited heterophils to the periellipsoid white pulp. This early event was shown to occur immediately after the virus injection. Within 6 h of injection, the EAC disappeared from the ellipsoid and their vacated sites appeared edemic which suggested that the EAC may be the target cell of the adenovirus in the chicken spleen.

Adenoviridae Infections↗
PubMed1988

Origin of aortic cell clusters in the chicken embryo.

In 3-day-old embryos the aortic cell clusters formed two parallel ridges in the ventrolateral part of the aorta. The border of the somato- and splanchnopleures close to the aorta showed a very intensive cell proliferation and a cell emigration up to the aorta. This cell flow and the bilateral appearance of the intraaortic ridges suggested that the aortic cell clusters originated from the coelomic epithelium. This intraembryonic hemopoietic stem cell formation from the splanchnopleure was comparable to that of the blood island formation in the yolk sac from extraembryonic splanchnopleure. The appearance of the white blood cells and definitive erythrocytes with adult-type hemoglobin was preceded by the aortic cell clusters. We concluded that the stem cells of the adult-type blood developed from the aortic cell clusters whereas the blood islands of the yolk sac may contribute only the primitive red blood cells.

Animals↗
PubMed1987

Bursal secretory cells: an electron microscope study.

In addition to lymphocytes, macrophages, and epithelial cells, the bursa medulla possesses a cell we have named the secretory cell. The secretory cell, which makes up approximately 0.5% of the bursal cell population, exhibits an eccentric nucleus with a chromatin pattern similar to that of a small lymphocyte and an elongated cytoplasm with one or more cell processes. The electron-dense cytoplasmic granules of the immature secretory cell are localized around the cytocentrum, while in the mature secretory cell these granules are situated beneath the cell membrane of one process. The granular location endows a polarized appearance to the secretory cell. The surface of the membrane is covered with a finely spotted flocculated substance, which may originate from a granular discharge. The round, ovoid, or irregular-shaped granules reveal a homogeneous or distinctive internal pattern. The cortico-medullary border may be the germinal layer of the bursal medulla. The bursal secretory cell is a modified dendritic cell with possible endocrine functions that may be important in B-cell induction.

Animals↗