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T Sminia

Publications and source records attributed to T Sminia.

At least 73 records · Page 4Linked to original sources
PubMed1986

The macrophage population of the gastro-intestinal tract of the rat.

The macrophage population of the gastro-intestinal tract of the rat was studied by using a set of three monoclonal antibodies (ED1, ED2 and ED3) directed against rat macrophages, an anti-Ia monoclonal antibody and by performing an acid phosphatase reaction. The lamina propria of the whole gastro-intestinal tract comprised quite high numbers of macrophages. This macrophage population was heterogeneous. The Ia-positivity and the acid phosphatase activity of the macrophages were higher in the intestines than in the stomach and esophagus. ED1-positive macrophages were also quite numerous in the intestines; their number was relatively low in the esophagus and stomach. ED2-positive macrophages were found equally dispersed along the gastro-intestinal tract; ED3-positive cells were hardly found. The functional implications of the present findings are discussed.

Animals↗
PubMed1986

Anti-TNP-forming cells in bronchus-associated lymphoid tissue (BALT) and paratracheal lymph node (PTLN) of the rat after intratracheal priming and boosting with TNP-KLH.

The aim of the present study was to elucidate the role of the paratracheal lymph node (PTLN) and bronchus-associated lymphoid tissue (BALT) in the generation of antigen-specific antibody-forming cells after intratracheal administration of trinitrophenyl-conjugated keyhole limpet haemocyanin (TNP-KLH). Priming as well as boosting resulted in the occurrence of specific antibody-forming cells in the PTLN, in BALT and in the lung. No anti-TNP-forming cells were observed in Peyer's patch, mesenteric lymph node and popliteal lymph node. From the data on the kinetics of anti-TNP-forming cells, it is concluded that intratracheal administration of antigen leads to a locally confined plasmacellular reaction. This suggests that the migrating and/or homing capacities of memory cells generated in the lung environment (PTLN, BALT) differ from those generated in the gut.

Animals↗
PubMed1986

Rat thymus macrophages: an immunohistochemical study on fetal, neonatal and adult thymus.

The pre- and postnatal development of the macrophage population of rat thymus is investigated applying enzyme-histochemical and immunohistochemical techniques, both on tissue sections and cell suspensions. A set of three monoclonal antibodies (ED1, ED2 and ED3), each of which recognizes cells of the monocyte-macrophage lineage in the rat, enabled us to distinguish between macrophages in the various compartments of the thymus. The medulla is characterized by ED1-positive dendritic cells, the corticomedullary region comprises numerous monocyte-like ED1-positive macrophages and the cortex contains a particular subpopulation of branched ED2-positive macrophages. Both the medullary dendritic cells and the cortical branched cells show Ia-membrane staining. ED3-positive cells are only occasionally present. During fetal life ED1-positive monocyte-like macrophages and dendritic cells are present. Just after birth ED2-positive cortical macrophages start to develop. Their number increases strongly during the first week after birth. The role of the various subpopulations of thymic macrophages is discussed.

Animals↗
PubMed1985

The postnatal development of cell populations in the rat popliteal lymph node. An immunohistochemical study.

The postnatal development of the various cell populations in the rat popliteal lymph node was investigated applying enzyme-histochemical and immunohistochemical techniques. From birth, T-lymphocytes and interdigitating cells were demonstrable. During the development of the young lymph node, T-lymphocytes of the helper phenotype outnumbered the T-cells with a suppressor phenotype; they account for approximately 70% and 30% of all T-lymphocytes, respectively. At the very first day of postnatal life, post-capillary venules were already present. B-lymphocytes occurred later than T-cells during ontogeny; they were found on the second day after birth, most of them being IgM- or IgG-bearing lymphocytes. The first primary follicles occurred at day 18 and contained principally membrane-stained IgM cells and, to a lesser extent, membrane-stained IgG cells. The appearance of follicular dendritic cells correlated with the formation of primary follicles. With respect to the macrophages, it appeared that the ED1- and ED3-positive subpopulations were present with a similar distributional pattern as seen in adults, but in considerably lower numbers. The expression of ED2, however, showed a sudden increase in the third week of life. Findings of the present study are discussed in relation to those obtained in other investigations dealing with the ontogenetic development of lymphoid organs.

Aging↗
PubMed1985

Characterization of an oxygen-tolerant cell line derived from Chinese hamster ovary. Antioxygenic enzyme levels and ultrastructural morphometry of peroxisomes and mitochondria.

To study the cellular defense mechanism against oxygen toxicity, an oxygen-tolerant cell line from Chinese hamster ovary (CHO) was obtained by multistep adaptation to increased O2 levels. The hyperoxia-adapted (HA) cells were able to proliferate under an atmosphere of 99% O2/1% CO2, an O2 tension lethal to the parental (control) cells. When grown under normoxic conditions (20% O2/1% CO2/79% N2) the cells remained tolerant for at least 8 weeks, suggesting a genetic basis for the oxygen tolerance. Compared to the parental cells, the HA cells were irregularly shaped, had larger mitochondria, contained more lipid droplets and showed a reduced growth rate. Ultrastructural morphometry revealed a 1.8-fold (p less than 0.001) increase of the mitochondrial volume fraction in the HA cells, resulting from an increase in both number and average volume of the mitochondria. The volume fraction of peroxisomes was increased over two-fold in the HA cells, as appeared from a approximately 1.9-fold (p less than 0.001) increase in number and a 1.2-fold (p less than 0.025) increase in size. There was no evidence for ultrastructural damage in the HA cells. Specific activities of antioxygenic enzymes were considerably higher in the HA cells compared to controls: CuZn-superoxide dismutase, X 2.5; Mn-superoxide dismutase, X 2.1; catalase, X 4.0; glutathione peroxidase, X 1.9. Oxygen tolerance in CHO cells is therefore associated with increased levels of antioxygenic enzymes, confirming the proposed important role of these enzymes in the defense against oxygen toxicity.

Adaptation, Physiological↗
PubMed1985

Non-lymphoid cells of bronchus-associated lymphoid tissue of the rat in situ and in suspension. With special reference to interdigitating and follicular dendritic cells.

Immunohistochemical, enzyme-histochemical and electron-microscopical methods were used to study non-lymphoid cells of control and stimulated rat bronchus associated lymphoid tissue (BALT) in situ and in suspensions. Particular attention was paid to the so-called antigen-handling cells, i.e., the interdigitating cells (IDC), which are situated in the T-cell areas, the follicular dendritic cells (FDC), which appear to be restricted to germinal centers, and macrophages, present both in T-cell and B-cell areas. The interdigitating cells were distinguished by being Ia-positive and by the presence of acid phosphatase and non-specific esterase activity in an area near the nucleus. Follicular dendritic cells could be observed in situ by using a monoclonal antibody and by the in vitro trapping of HRP-anti-HRP complexes. Several types of macrophages were found. At the electron-microscopical level no well-developed IDC and FDC could be detected in control BALT. However, in BALT of lipopolysaccharide-stimulated and mycoplasma-infected rats, well-developed IDC and FDC were found. It can be concluded that IDC's and FDC's can be found in BALT.

Animals↗
PubMed1985

Search for shared antigens in the schistosome-snail combination Trichobilharzia ocellata-Lymnaea stagnalis.

Mother and daughter sporocysts of Tricholbilharzia ocellata, developing in the snail host Lymnaea stagnalis, were searched for substances with antigenic similarities to the snail's haemolymph. Antisera to cell-free snail haemolymph and fractions thereof were used in three different immunocytochemical staining methods, applied on sections of parasitized snails. Snail tissue was consistently stained; cercariae were stained, indicating that the applied methods were successful. Most sections through mother and daughter sporocysts were completely unstained. It is concluded that neither mother nor daughter sporocysts are masked by the antigens studied or substances mimicking these. The relevance of the present observations is discussed.

Animals↗
PubMed1985

Specific antibody-forming cells in bronchus-associated lymphoid tissue (BALT) and lung of the rat after intratracheal challenge with horseradish peroxidase.

After intratracheal or subcutaneous priming with horseradish peroxidase (HRP), no anti-HRP-forming cells were present in the bronchus-associated lymphoid tissue (BALT) or the lung of the rat. After intratracheal priming and intratracheal boosting with HRP no specific antibody-forming cells were observed either in the BALT or the lung. A few blast cells containing anti-HRP antibody were found in paratracheal lymph nodes, which is possibly the source of anti-HRP-forming cells. After subcutaneous priming in the hind footpad and intratracheal boosting specific antibody-forming cells were present in both the BALT and in the lung. In the BALT these cells were found peripherally, and in the lung perivascularly and peribronchiolarly. The simultaneous appearance of these anti-HRP-forming cells at both sites, their localization and their morphology strongly indicate that they are recruited from the circulation and not formed in situ; the probable source is the popliteal lymph node.

Animals↗
PubMed1985

Characterization of pulmonary macrophages and bronchus-associated lymphoid tissue (BALT) macrophages in the rat. An enzyme-cytochemical and immunocytochemical study.

Three subpopulations of macrophages present in the lung, viz. pulmonary alveolar macrophages (PAM), pulmonary tissue macrophages (PTM), and macrophages in the bronchus-associated lymphoid tissue (BALT), were compared using enzyme-cytochemical and immunocytochemical methods. BALT macrophages can be distinguished from PAM and PTM on the basis of their enzyme reaction products. With three monoclonal antibodies, ED1, ED2, and ED3, that recognize different antigen determinants of rat macrophages, the three subpopulations could be clearly distinguished. PAM are ED1-positive and PTM are ED2-positive. The macrophage subpopulation scattered throughout BALT is ED1-positive; macrophages situated at the peripheral site of BALT, near artery and bronchus, are ED2-positive. No ED3-positive macrophages were observed either in the lung or in BALT. These results are discussed with respect to the possible relationship between the subpopulations of pulmonary macrophages.

5'-Nucleotidase↗
PubMed1985

Histological changes in rat bronchus-associated lymphoid tissue after administration of five different antigens.

Histological changes in bronchus-associated lymphoid tissue (BALT) following single intratracheal administration of five different antigens were studied in the rat. After administration of T-dependent antigens (i.e., horseradish peroxidase, bovine serum albumin, and Bacillus Calmette Guérin) only minor changes in BALT in the rat occurred. Intratracheal administration of a T-independent antigen (lipopolysaccharide) and a partly T-independent antigen (paratyphoid vaccine) resulted after 1 week in an increase in cytoplasmic IgM-containing (cIgM) blast cells and plasma cells; these appeared to enter via the high endothelial venules (HEV). After 6 weeks, germinal centers were seen.

Animals↗
PubMed1985

Effects of a single oral dose of dinitrochlorobenzene on T lymphocyte distribution and migration in the gut.

In the present study the effects of a large oral dose of the contact allergen dinitrochlorobenzene (DNCB) on the distribution of T-cell subsets in the small intestines and the emigration pattern of lymphocytes from Peyer's patches were investigated. Apart from the inflammatory effects, DNCB administration resulted in an influx on the T-helper cells in the villi. Precise quantification of T lymphocytes showed a decrease in Peyer's patches and an increase in mesenteric lymph node cell suspensions. However, no differences could be found in the emigration rate of T-cell subsets from Peyer's patches into mesenteric lymph nodes, suggesting that the increase of T cells in mesenteric lymph nodes results from T-helper cells directly immigrating from the villi.

Allergens↗
PubMed1985

Veiled cells in the gastrointestinal tract.

Lately it has become known that for the initiation of an immune response an antigen presenting cell is needed. In the skin the antigen presenting cell system has been studied and is extensively supposed to consist of Langerhans' cells in the epidermis and dermis, veiled cells in the skin lymph, and interdigitating cells in the skin lymph nodes. These cells are considered to belong to the mononuclear phagocyte system which is in principle composed of cells stemming from the promonocyte/monocyte. To detect whether an antigen presenting cell system is present in the gut, we studied cell suspensions of gut tissues. Monoclonal cells with long actively moving cytoplasmic veils were found in cell suspensions from small intestinal villi of guinea pig and pig, but not of rat. These veiled cells appeared to be strongly Ia positive, as are the cells from the skin antigen presenting system. They share several ultrastructural and enzyme cytochemical characteristics with these skin cells. Gut veiled cells localize within the lympho-epithelium of Peyer's patches of the rat, just underneath this lympho-epithelium and in the T-dependent interfollicular area, according to Ia stainings on frozen tissue sections and to ultrastructural observations. From stainings with anti-IgA, -IgE, -IgG, -IgM and anti-T lymphocyte sera it is concluded that these cells do not belong to the lymphocyte series. It is suggested that these gut veiled cells belong to the monocyte/macrophage family and form an antigen presenting cell system in mucosa-associated lymphoid tissue, similar to the antigen presenting cell system in the skin.

Animals↗
PubMed1985

A comparative study on the internal defence system of juvenile and adult Lymnaea stagnalis.

The immunological immaturity of juvenile specimens of some snail species, e.g. Lymnaea stagnalis, may contribute to their greater susceptibility to infection by schistosome parasites. In a comparison between juvenile and adult specimens of the pond snail L. stagnalis, we have shown that the blood cells (amoebocytes) of juvenile snails are less efficient at phagocytosing: fewer amoebocytes are competent and the average number of particles engulfed per cell is lower. This functional immaturity seems to correlate with morphological immaturity of the amoebocytes. Opsonic and haemagglutinating activities are low in juvenile snail plasma, but much higher in adult plasma. Finally, however, the initial rate at which injected bacteria are eliminated from the circulation seems only slightly slower in juvenile snails than it is in adults.

Aging↗
PubMed1984

Selective emigration of suppressor T cells from Peyer's patches.

The emigration of Peyer's patch lymphocytes to mesenteric lymph nodes was studied by injecting fluorescein isothiocyanate (FITC) directly into Peyer's patches. Using double immunofluorescence it was demonstrated that at 2 and 4 hr after FITC injection 70% of the labeled cells that migrated to mesenteric lymph nodes were T lymphocytes, although rat Peyer's patches contain only 15-20% T lymphocytes. At later time points after FITC injection this percentage of T cells derived from Peyer's patches gradually declined, most likely caused by selective interaction and/or retention inside the mesenteric lymph node. Determination of helper and suppressor T-cell subsets within this emigrating population showed an increased number of T suppressor cells migrating into mesenteric lymph nodes. The putative role of suppressor T cells in inducing systemic tolerance after oral antigen administration was discussed.

Animals↗