PubMed Health⌕ Search

Biomedical subjects

T Sminia

Publications and source records attributed to T Sminia.

At least 37 records · Page 2Linked to original sources
PubMed1991

The immune response in the rat to Streptococcus pneumoniae type 3 and type 4 capsular polysaccharide. Detection by double immunocytochemical staining of antibody-containing cells in situ and ELISA.

Two different methods have been used to study immune responses in the rat to Streptococcus pneumoniae type 3 and type 4 capsular polysaccharides (PPS). First, for simultaneous detection of the specificity and isotype of anti-PPS antibody-containing cells (ACC) in cryostat sections of lymphoid tissue, a double immunocytochemical method was developed. This method is a combination of a three-step immunoperoxidase method to demonstrate specific anti-PPS ACC as bright red cells and a two-step immunophosphatase method to detect the isotype of ACC as blue cells. Double positive cells appear violet. Using this staining procedure, the detection of antigen was also possible. Second, to study the anti-PPS response in serum, an ELISA procedure was modified. In this ELISA, polyvinylchloride microtiter plates are coated directly with type-specific pneumococcal polysaccharide. After intraperitoneal (i.p.) immunization of rats with PPS-3 or PPS-4, both antigen (PPS) and specific ACC could be detected. Specific ACC were found in the spleen and mesenteric lymph nodes. In the spleen, the specific ACC were found in the red pulp, marginal zone, outer PALS, and follicles. Most of these ACC were IgM-positive and to a lesser extent IgG-positive and IgA-positive. However, specific ACC in mesenteric lymph nodes were predominantly of the IgA isotype, with only few IgM or IgG positive cells. The anti-PPS response in serum, as measured by the ELISA, consisted mainly of IgM antibodies with small amounts of IgG and IgA. Both methods were found to be valuable in studies of immune responses against bacterial polysaccharides.

Animals↗
PubMed1991

Ontogeny of macrophage subpopulations and Ia-positive dendritic cells in pulmonary tissue of the rat.

The development of macrophage subpopulations dendritic cells in the rat lung was studied from day 15 of gestation until day 21 after birth by means of immunohistochemical techniques combined with acid phosphatase staining. To characterize these cell populations, monoclonal antibodies raised against rat macrophage subpopulations were used (ED1, ED2, ED7, and ED8) in addition to anti-Ia antibodies. Ia-positive cells with a dendritic morphology were found on day 16 of gestation. During ontogeny, the number of these cells gradually increased. They were always found in mesenchymal lung tissue between the epithelial tubules of future alveoli, and in perivascular or peribronchial areas. ED1-positive macrophages were found on day 17 of gestation, with a distribution different from that of Ia-positive dendritic cells. The distribution of ED1-positive cells changed during ontogeny: before birth, ED1-positive cells were present in mesenchymal areas of lung tissue, whereas after the first week of postnatal life ED1 recognized all free alveolar macrophages. No Ia-expression was found on free alveolar macrophages. This developmental pattern resembles the ontogeny of Ia-positive dendritic cells and ED1-positive macrophages in gut-associated tissue. The comparable development of these cell populations in gut and lung tissue indicates a common ontogeny in the mucosal immune system.

Animals↗
PubMed1991

Effects of Trichobilharzia ocellata on hemocytes of Lymnaea stagnalis.

We analyzed the effects of infection with Trichobilharzia ocellata on hemocytes of its snail host, Lymnaea stagnalis, and correlated them with successive stages of parasite development. Circulating hemocytes were studied at 0, 2, 4, 6, and 8 weeks post exposure (p.e.) with respect to cell number, distribution of subpopulations (as characterized by morphology, determinants recognized by either of two lectins and a monoclonal antibody) and to proliferative, phagocytic and endogenous peroxidase activity. Infection results in a net elevated level of activity of circulating hemocytes at 2 weeks p.e., when mother sporocysts are present in the head-foot-mantle region, as well as at 4 weeks p.e., when daughter sporocysts are migrating to and growing in the digestive gland region. A lower level of activity was observed at 6 weeks p.e., when cercariae are differentiating within daughter sporocysts. A net activation was again found at 8 weeks p.e., when cercariae are escaping. So, infection with T. ocellata results in a net general activation of the internal defense system of L. stagnalis, during several stages of development of the parasite.

Animals↗
PubMed1991

Generation of oxygen radicals in hemocytes of the snail Lymnaea stagnalis in relation to the rate of phagocytosis.

The kinetics of oxygen radical production by phagocytosing hemocytes of the pond snail Lymnaea stagnalis were investigated. After contact had been established between zymosan and hemocytes in monolayers at 0 degrees C, phagocytosis was initiated by a shift to room temperature. Until the internalization phase of phagocytosis was completed, oxidative activity was detected mainly extracellularly (superoxide dismutase inhibitable cytochrome C reduction and peroxidase-catalyzed phenol red oxidation were used for the detection of superoxide and hydrogen peroxide, respectively). Thereafter, extracellular oxygen radical production by phagocytosing hemocytes decreased. Luminol-dependent chemiluminescence activity grew and, after the internalization phase of phagocytosis, remained at a high level, suggesting continued oxygen radical activity intracellularly. These results indicate that contact between zymosan and the hemocyte's plasma membrane stimulates a membrane-bound system to generate and release oxygen radicals. After internalization, this system appears to continue oxygen radical production inside the phagosome. So far, oxygen radical production in snail hemocytes shows many similarities to the mechanism in mammalian leucocytes.

Animals↗
PubMed1991

The in situ immune response of the rat after intraperitoneal depletion of macrophages by liposome-encapsulated dichloromethylene diphosphonate.

This study concerns the contribution of peritoneal macrophages in vivo to local and systemic immune responses in the rat. Peritoneal macrophages as well as macrophages in the draining parathymic lymph nodes were selectively eliminated by intraperitoneal inoculation of dichloromethylene-diphosphonate-containing liposomes. This depletion resulted in an enhanced immune reaction to intraperitoneally administered trinitrophenyl keyhole limpet haemocyanin in the parathymic lymph nodes, as demonstrated by the higher numbers of specific anti-TNP antibody-forming cells in macrophage-depleted animals than in control animals from day 5 after immunization. The immune reaction peaked at day 7 and remained high until day 10. Specific antibody-forming cells were found occasionally in the mesenteric lymph nodes and spleen, but not in the mucosa of the gut or in the bronchus-associated lymphoid tissue. An elevated immune reaction found in parathymic lymph nodes associated with the depletion of local macrophages by liposome treatment indicates a regulatory role of peritoneal macrophages in local humoral immune response.

Animals↗
PubMed1991

Macrophage subsets in the rat gut: an immunohistochemical and enzyme-histochemical study.

Macrophages' subsets including dendritic cells were characterized in situ and in cell suspensions of Peyer's patches, intestinal villi, and mesenteric lymph nodes using monoclonal antibodies, lectins, and enzyme-histochemistry. By combined labelling procedures, it was found that Peyer's patches comprise dendritic cells in addition to 2 types of macrophages; dendritic cells were not observed among the various macrophage-like cells in the lamina propria of the villi. The lectins Dolichos biflorus and Griffonia simplicifolia I agglutinin appeared to be useful for discriminating between several subtypes of macrophages.

Animals↗
PubMed1991

Mucosal and systemic antibody formation in the rat after intranasal administration of three different antigens.

In order to study the role of nasal-associated lymphoid tissue (NALT) in the local nasal immune response, rats were immunized intra-nasally with either of the following trinitrophenylated (TNP) antigens; the thymus-dependent keyhole limpet haemocyanin (KLH), or the thymus-independent lipopolysaccharide (LPS), or with the particulate (thymus-dependent) sheep red blood cells (SRBC). Primary responses hardly occurred, while only TNP-KLH elicited a considerable secondary response. The major responding organ was the posterior cervical lymph node. Specific antibody-forming cells (AFC) occurred in the medulla and were mainly of the IgA or IgG isotype. Hardly any specific AFC were found in NALT or the surrounding mucosa. Intranasal immunization evoked no antibody response in the lung. Ample anti-TNP antibodies could be detected in the sera of animals, primed and boosted with TNP-KLH or TNP-LPS. No specific serum antibodies occurred after immunization with TNP-SRBC. The results are discussed in view of the immunological defence in the upper respiratory tract.

Administration, Intranasal↗
PubMed1991

Interferon-gamma induced IA antigen expression on cultured neuroglial cells and brain macrophages from rat spinal cord and cerebrum.

The inducibility of major histocompatibility complex class II (Ia) antigens on glial cells of the brain suggests that neuroglia have immunoregulatory functions within the central nervous system (CNS), i.e., recognition and presentation of antigens. The aim of the present study was to investigate rat recombinant-interferon-gamma (r-IFN-gamma) induced Ia antigen expression in rat cerebral cultures containing type-1 astrocytes and macrophages, and in rat spinal cord cultures enriched in type-2 astrocytes or oligodendrocytes. We compared induction of Ia antigen expression in glial cell cultures derived from Lewis rats, which are very susceptible to experimental allergic encephalomyelitis (EAE), with those from Wistar rats, which are but modestly EAE susceptible. After 5 days in culture we found in Wistar rat type-1 astrocyte-enriched cultures that Ia antigens were expressed by 19% of the astrocytes, whereas we found that in Lewis rat type-1 astrocyte cultures a considerably higher number of astrocytes expressed Ia antigens (53%). However, no significant difference were found in Ia antigen expression between type-2 astrocytes derived from Wistar rat spinal cord (49%) and Lewis rat type-2 astrocytes (56%). In contrast, in oligodendrocyte-enriched cell cultures derived from either Lewis or Wistar rats no Ia antigen expression was found. Interestingly, we found in type-1 astrocyte-enriched cerebral cultures a large number (approx. 46% of the cells) of brain macrophages (amoeboid microglia), all expressing Ia antigens after treatment with r-IFN-gamma.

Animals↗
PubMed1990

Lymphoid and non-lymphoid cells in nasal-associated lymphoid tissue (NALT) in the rat. An immuno- and enzyme-histochemical study.

Lymphocyte and macrophage subpopulations and the stroma of mucosa-associated lymphoid tissue in the nasal cavity of the rat were examined by application of immunohistochemical and enzyme histochemical methods to cryostat sections. Nasal-associated lymphoid tissue was composed of a loose reticular network with lymphocytes and macrophages, covered by epithelium. The epithelium was infiltrated with B cells. T helper (W3/13-positive) and T suppressor/cytotoxic or large granular cells (OX8-positive), ED1-positive macrophages and Ia-positive cells. The B cell areas were populated by B cells, immunopositive for surface IgM or IgG. B cells with surface IgA or IgE were rare. Germinal centres were found infrequently. T helper cells were scattered throughout the B cell area. A few ED1-positive macrophages and ED5-positive follicular dendritic cells were observed. Strong Ia staining (mostly of B cells) was found in this area. The T cell areas contained T helper and T suppressor/cytotoxic cells in about equal amounts, and numerous ED1-positive macrophages. ED1 staining was also found in the subepithelial area. Numerous ED1-, ED2- and ED3-positive macrophages were found in the border between the lymphoid mass and the surrounding connective tissue. A few non-lymphoid cells showed weak acid phosphatase or non-specific esterase activity. The morphological observations suggest that nasal-associated lymphoid tissue plays an important role in the first contact with inhaled antigens.

Animals↗
PubMed1990

The localization of macrophage subsets and dendritic cells in the gastrointestinal tract of the mouse with special reference to the presence of high endothelial venules. An immuno- and enzyme-histochemical study.

This study concerns the distribution of macrophages and dendritic cells (DC) in the gastrointestinal tract of the mouse. Heterogeneity of macrophage population was found by using the MOMA-1, MOMA-2, ERTR-9, Mac-1 and F4/80 monoclonal antibodies. MOMA-1, ERTR-9, Mac-1 and F4/80+ cells were detected mostly at the villous cores in the lamina propria of the villi, whereas MOMA-2+ cells were primarily found around the crypts at the base of the villi. These MOMA-2+ cells revealed a granular appearance throughout the cytoplasm and displayed a strong acid phosphatase (AcPh) activity. Few MOMA-2+ cells were seen at the top of the villi in the epithelium. Although MOMA-1 and ERTR-9+ cells have similar morphology and the same distribution patterns in the lamina propria, they are likely different populations, because in Peyer's patches (PP), MOMA-1+ cells were present, whereas ERTR-9+ cells could not be detected. Both populations displayed AcPh activity. Strongly stained Mac-1+ cells were abundantly seen in the lamina propria of the small intestine. F4/80+ cells were rare. NLDC-145+ cells with AcPh activity and weak Ia staining were also found. In the PP-associated villi and in the T-dependent area of PP, dendritic NLDC-145+ cells, which were strongly Ia positive, were detected. MIDC-8+ cells were found only in the T-dependent area. Few NLDC-145+ cells (dendritic cells) were found in the upper part of the oesophagus. These cells were also stained with the MIDC-8 antibody.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

The effects of Peyer's patches inactivation in the rat on the development of antibody-forming cells to intestinal antigen.

The effects of Peyer's patch (PP) inactivation on local and systemic immune response in rats was investigated. A cauterization method has been developed to inactivate PP. Animals were primed intraperitoneally or intragastrically with trinitrophenyl-keyhole limpet haemocyanin (TNP-KLH) one day before cauterization, and were challenged intraintestinally two weeks later. The secondary immune response in the spleen, mesenteric lymph node (MLN) and intestinal villi was studied by immunohistochemistry. Histological observations on PP after inactivation showed that most T cells in the interfollicular area had disappeared, as had B cells in the follicle. T cells repopulated PP much slower than B cells. Complete recovery of PP occurred no earlier than 2 weeks after inactivation. The immunization experiments revealed higher numbers of anti-TNP antibody-forming cells (anti-TNP AFC) of IgM, IgG and IgA isotypes in the spleen of the PP-inactivated animals than in the controls. Very few anti-TNP AFC were found locally in the lamina propria of the intestinal villi or in the MLN in both groups. It is suggested that PP play a role in the regulation of systemic immune responses against intestinally-administered thymus-dependent antigen. Moreover, inactivation of PP could alter the antigen uptake by gut epithelium and the local antigen processing. As a result, an increased amount of antigen could reach the spleen eliciting a higher immune response.

Animals↗
PubMed1989

An immunohistochemical study on the postnatal development of rat nasal-associated lymphoid tissue (NALT).

This study concerns the development of nasal-associated lymphoid tissue in the rat, using immuno- and enzyme-histochemical staining techniques on cryostat sections. Nasal-associated lymphoid tissue is present at birth as a small accumulation of mainly T lymphocytes and nonlymphoid cells; B cells are rare. Distinct areas of T and B cells appear at 10 days after birth; by that time high endothelial venules are also observed. Intra-epithelial lymphocytes are present, most of them being T-helper cells. ED1+ macrophages are seen throughout the tissue. The proportion of ED1+ cells does not change during ontogeny. ED2+ cells (tissue macrophages) are present predominantly at the border between the lymphoid tissue and the surrounding connective tissue, in all age-groups. ED3+ mononuclear cells are scattered throughout the nasal-associated lymphoid tissue of young animals. Later on, the ED3+ cells migrate into the border-area between lymphoid and connective tissue. Ia+ non-lymphoid cells in the nasal lymphoid tissue increase in number during ontogeny. Only a few of them show acid phosphatase activity, indicating that the proportion of classical scavenger macrophages is low. Some of them may be antigen presenting (dendritic) cells. Ia+ dendritic cells also occur between the epithelial cells. Moreover, some epithelial cells express the Ia marker.

Aging↗
PubMed1989

Observer agreement in the assessment of clinical signs in experimental allergic encephalomyelitis.

Rats suffering from experimental allergic encephalomyelitis (EAE) were examined by a number of investigators whose assessments were compared. Considerable consensus of opinion was reached, especially when a standard, easily interpretable, scoring classification was used. More discrepancies occurred when a more expanded scale, differentiating between more clinical grades, was used. It is demonstrated that part of these discrepancies can be overcome by having the examinations done by the same investigator. Possible consequences of these findings for the assessment of clinical signs in EAE are discussed.

Analysis of Variance↗
PubMed1989

Isolation and characterization of brain macrophages from the central nervous system of newborn and adult rats and of rats with experimental allergic encephalomyelitis.

A method has been developed to isolate brain macrophages (M phi) from normal neonatal and adult rats brain cell suspensions, as well as from brain cell suspensions of rat with experimental allergic encephalomyelitis (EAE), by making use of the ability of M phi to adhere to plastic surfaces. The isolated adherent cells were immuno- and enzyme-cytochemically identified. Phagocytic activity and the presence of Fc-IgG receptors were also examined. Approximately 30%-40% of the isolated adherent cells from neonatal rat brain are phagocytic and can be stained with macrophage-specific monoclonal antibodies, suggesting that these cells belong to the monocyte/macrophage lineage. From normal adult rat brain, only a small number of brain M phi could be isolated. A highly purified population of brain M phi was obtained from EAE rat brain. The isolated brain M phi are phagocytic, possess Fc-IgG receptors and rat M phi-associated antigens. Besides these features, the isolated brain M phi also express MHC class II antigens (Ia-antigens), which suggests that M phi may be involved in the regulation of immunological disorders of the CNS. The method reported here for rapidly isolating a large number of blood-monocyte-derived brain M phi from neonatal and adult brain allows an investigation of the precise role of M phi in inflammatory diseases of the central nervous system.

Animals↗
PubMed1989

Intra-epithelial lymphocytes and non-lymphoid cells in the human nasal mucosa.

Immunohistochemical staining of biopsy specimens was used to investigate the occurrence of lymphocyte subsets and non-lymphoid cells within the epithelial layer of the human nasal mucosa. The CD19 (B cell) marker was not expressed on the intra-epithelial lymphocytes, whereas the pan T cell marker CD2 was varyingly detected. The HLA-Dr antigen was abundantly present on epithelial cells, lymphocytes, and non-lymphoid cells. The latter are probably dendritic or Langerhans' cells. The findings stated above were the same in patient and control samples. In biopsy sections of 9 ear, nose, and throat patients, many CD8-positive (T suppressor/cytotoxic) cells and very few weakly stained CD4-expressing (T helper/inducer) cells were present. Quantification on single-cell preparations showed an average of 67% of the lymphocytes to be CD2 positive, 73% to be CD8 positive, while only 12% of the lymphocytes expressed the CD4 antigen. In control sections CD8 was similarly present as in patient sections, and, in addition, some clearly stained CD4-positive cells were seen.

Adolescent↗
PubMed1989

Structure and function of bronchus-associated lymphoid tissue (BALT).

This article deals with the ontogeny, morphology, and function of bronchus-associated lymphoid tissue (BALT). The surface epithelium of the respiratory tract, including the lymphoepithelium of BALT, is described, with emphasis on infiltrated nonepithelial cells (lymphocytes, macrophages). Special attention is given to antigen handling by the lymphoepithelium and the interaction with BALT and lung macrophages. The structure and function of the diverse types of BALT nonlymphoid cells are discussed. The local immune responses (cellular and humoral reactions), the relationships between local and systemic immune reactions, and the role of BALT in the common mucosal immune system are reviewed. The BALT is compared with Peyer's patches in terms of antigen processing, local immune responses, cell populations, and migration of lymphoid and nonlymphoid cells.

Animals↗