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Biomedical subjects

J Westermann

Publications and source records attributed to J Westermann.

At least 73 records · Page 4Linked to original sources
PubMed1997

Initiation and perpetuation of rat adjuvant arthritis is inhibited by the anti-CD2 monoclonal antibody (mAb) OX34.

OBJECTIVE: The purpose of this study was to investigate the therapeutic potential of the anti-CD2 mAb OX34 first with regard to bone protection in established rat adjuvant arthritis (AA) and secondly with regard to prevention of AA induction. METHODS: Established AA was treated with dexamethasone (1 mg/kg body weight) for two days plus OX34 mAb or control mAb over three days (2 mg and then 1 mg) starting at different time points of the disease. For prevention studies animals were injected as above with mAb before induction of AA. Arthritis score (AS), hindpaw thickness, and body weight were blindly measured three times per week. Flow cytometry and hindpaw radiography were performed at the end of the study (day 29). RESULTS: Treatment of early AA with OX34 mAb combined with dexamethasone but not dexamethasone plus control mAb dramatically suppressed established AA as assessed by AS and hind paw thickness (> 65% and > 80% reduction, respectively; p < 0.05). Most importantly, early treatment in the course of AA almost completely prevented bone destruction in established AA. When given before AA induction OX34 alone prevented the initiation of arthritis compared with controls (AS reduction 83-95%, p < 0.05). In addition, OX34 plus dexamethasone treatment resulted in depletion of CD4+ T cells but not CD8+ T cells. IL2R+ and CD45RC- ('memory') T cells were significantly reduced. CONCLUSIONS: Anti-CD2 mAb treatment prevents AA induction confirming the role of CD4+ T cells in the induction phase of AA. In addition, early OX34 plus dexamethasone treatment resulted in pronounced clinical improvement and joint protection. OX34 treatment therefore inhibits the initiation and the perpetuation of rat AA.

Animals↗
PubMed1997

The lung as a source and a target organ for T- and B-lymphocytes.

In lung transplantation, a substantial number of donor leukocytes are transferred from the donor to the recipient by the graft. Using a rat model, it was analyzed in this study to what extent leukocytes leave the lung, to which phenotype they belong, and to which organs they migrate. The model used was the orthotopic transplantation of the left lung of LEW.7B(RT7b) rats into LEW(RT7a) recipients. Lung allografts are not rejected in this strain combination, which differs only in the RT7 system, a genetic polymorphism of CD45. Using the RT7b marker (monoclonal antibody His41), the distribution of donor leukocytes passively transferred with the graft was studied by immunohistology 2 wk after transplantation. At this time, 2.9 +/- 0.1% (n = 6) of the peripheral blood leukocytes in the recipients were derived from the donor lung. The donor cell population detected in the blood consisted of T cells (59 +/- 4%), B cells (5.1 +/- 0.2%) and a surprisingly high fraction of natural killer (NK) cells (36 +/- 3%). No monocytes or granulocytes were found. In lymph nodes, spleen and thymus donor-derived T- and B-cells could be shown in typical T- and B-areas, respectively. Donor-derived leukocytes were found in the liver and the skin. In the tissue and the bronchoalveolar lavage (BAL) of the host lung, predominantly T cells were found. Furthermore, in the donor tissue and BAL more than 70% of T- and B-cells were host type, demonstrating that the donor lung had been repopulated to a great extent by host lymphocytes. This supports the relevance of BAL as a diagnostic tool in lung diseases. Thus, the lung is an immunologically important site, releasing lymphocytes which migrate to other organs and also attracting many lymphocytes from the circulation.

Animals↗
PubMed1997

Long-term oral application of 5-bromo-2-deoxyuridine does not reliably label proliferating immune cells in the LEW rat.

To study the lifespan of immune cell populations in the LEW rat, 5-bromo-2-deoxyuridine (BrdU) was administered in the drinking water. After 12 weeks, the epithelium of gut and skin was completely BrdU+. In contrast, thymus, bone marrow, and germinal centers of Peyer's patches contained only a few BrdU+ cells, although most should have been labeled during this time. The lack of labeling was due neither to obvious toxic effects of BrdU on these organs nor to insufficient detection of incorporated BrdU. Analysis of the kinetic pattern of the appearance of BrdU+ cells in bone marrow, blood, spleen, and lymph nodes over 12 weeks revealed that the dosage of BrdU initially was high enough to label the proliferating cells in the bone marrow, but then became too low, although the BrdU uptake of the rats was similar over the entire time. This indicates that in the LEW rat the metabolism of orally applied BrdU changes over time, leading to a reduction in the amount of BrdU available for incorporation into the DNA below a level necessary for labeling all proliferating cells. This effect appears to be species- and strain-dependent, and should be considered when the BrdU technique is used.

Administration, Oral↗
PubMed1997

Successful retroviral mediated transduction of a reporter gene in human dendritic cells: feasibility of therapy with gene-modified antigen presenting cells.

In this study we have analyzed the feasibility of gene transfer in human dendritic cells (DCs). DCs were generated from T and B cell-depleted peripheral blood mononuclear cells cultured for 7 days in the presence of granulocyte/macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). The cells showed morphologic and immunophenotypical features typical of DCs, including expression of major histocompatibility complex (MHC) class I and II molecules, CD1a, CD80, CD86, CD13, CD33, CD40, and CD54. The cells showed high stimulatory activity in both allogeneic and autologous mixed lymphocyte reaction (MLR). The bacterial reporter gene lacZ coding for beta-galactosidase (beta-gal) was introduced in DCs by three sequential cycles of infection using a MFG retroviral vector system. After 7 days of culture 35-67% of the cells showed high expression of beta-gal activity, proving successful gene transfer. Stable integration of the lacZ gene was demonstrated by genomic DNA-polymerase chain reaction (PCR) up to 20 days after gene transfer. The percentage of transduction was similar when DCs were further purified by immunomagnetic separation according to CD1a-expression. We conclude that human DCs can be efficiently gene modified, further broadening the spectrum of possible DC-based clinical applications.

Antigen Presentation↗
PubMed1997

Evaluation of urinary metanephrine and normetanephrine enzyme immunoassay (ELISA) kits by comparison with isotope dilution mass spectrometry.

Determination of urinary 3-O-methylated catecholamines (metanephrines) is generally considered a principal test for the clinical chemical diagnosis of pheochromocytoma and is currently performed predominantly with chromatographic techniques such as gas-liquid chromatography and HPLC. Enzyme immunoassays based on microtiter plate technology have recently been developed for the quantitative determination of urinary metanephrine (M) and normetanephrine (NM). We compared the results for urinary M and NM determined by these ELISA methods with those obtained by a recently developed isotope dilution mass spectrometric method. From this comparative study we can conclude that the investigated ELISA methods are applicable in the quantification of urinary M and thus can be successfully used to establish the diagnosis of pheochromocytoma. These relatively simple methods can be executed in any clinical laboratory and in time may replace the present, more complicated, chromatographic techniques.

Adolescent↗
PubMed1996

Both activated and nonactivated leukocytes from the periphery continuously enter the thymic medulla of adult rats: phenotypes, sources and magnitude of traffic.

Although the thymus is primarily noted for the export of T cells to the periphery, a small influx of cells has also been observed. It is still a matter of debate whether entry into the thymus depends on prior activation. The phenotypes, sources and degree of immigration are largely unknown. We monitored by quantitative immunohistochemistry the entry of cells from the periphery into the rat thymus in three experimental models. We injected i.v. recirculating, small, nonactivated CD4+ T cell subsets, often referred to as naive (CD45RC+) and memory or antigen-experienced (CD45RC-) cells, purified from thoracic duct lymph of allotype-marked donors, allotype-marked leukocytes released from spleen or lung transplants, or leukocytes labeled in the periphery for 12 weeks during the S-phase of the cell cycle by oral application of 5-bromo-2-deoxyuridine (BrdUrd). Early after i.v. injection (0.5 h), significantly more antigen-experienced (CD45RC-) CD4+ T cells entered the thymus, and by 24 h four times as many cells from the CD45RC- subset as from the CD45RC+ subset had entered the thymus and localized to the medulla. None of the thymic entrants expressed the interleukin (IL)-2 receptor. Following spleen transplantation approximately 40% of donor cells entering the thymic medulla were T cells and approximately 55% were B cells. In contrast, from a lung transplant, approximately 85% of peripheral immigrants were T cells and approximately 10% were B cells. After both procedures, a small number of NK cells and monocytes/macrophages were found among the immigrants (< 5%). Rats were fed BrdUrd continuously for 12 weeks, a procedure which labeled approximately 30% of peripheral lymphocytes but not cortical thymocytes. BrdUrd-labeled cells were localized almost exclusively to the thymic medulla and represented approximately 10% of medullary cells. Of the thymic immigrants approximately 50% were T cells, approximately 30% were B cells (including approximately 15% IgD+ cells), approximately 15% were NK cells and the remainder (approximately 5%) were monocytes/macrophages. Only a quarter of BrdUrd-labeled cells expressed the IL-2 receptor. The thymus is continuously infiltrated by both activated and nonactivated leukocytes from the periphery, including T cells, B cells, NK cells and monocytes. These immigrants are supplied by lymphoid and nonlymphoid organs in a characteristic subset composition. Their entry is facilitated by prior antigen experience or activation. Thus, the participation of the thymic medulla in general leukocyte traffic suggests a mechanism by which the T cell repertoire could potentially be modulated by the peripheral tissues.

Animals↗
PubMed1996

Distribution of immunocompetent cells in various areas in the normal laryngeal mucosa of the rat.

The larynx can be divided into a supraglottic, a glottic and a subglottic area, each serving different functions. In many cases of laryngitis the site of infection is located in one area, leaving other areas unaffected. It seems reasonable to speculate that the underlying cause of the heterogeneous infection pattern in the larynx is the different processing of infectious agents. Therefore, the number and distribution of granulocytes, macrophages, dendritic cells, natural killer cells and T and B lymphocytes in the normal laryngeal mucosa of young rats were studied. The results show that, with the exception of granulocytes, all subpopulations were present in different numbers. Many macrophages and dendritic cells but only a few natural killer cells and T and B lymphocytes were located in the mucosa. Dendritic cells, natural killer cells and T and B lymphocytes were rarely present in the vocal fold area, whereas in the subglottic area they were present in high numbers. Thus, differences in the composition of immunocompetent cell populations between laryngeal areas were detectable.

Animals↗
PubMed1996

The marginal blood pool of the rat contains not only granulocytes, but also lymphocytes, NK-cells and monocytes: a second intravascular compartment, its cellular composition, adhesion molecule expression and interaction with the peripheral blood pool.

To leave the blood, leucocytes marginate to the vessel wall. Granulocytes thereby form the so-called marginal pool. It is unclear to what extent such a second intravascular compartment also exists for lymphocytes subsets, NK-cells and monocytes. Samples of the peripheral blood and the marginal pool of the LEW rat were analysed by flow cytometry. In the marginal pool the percentage of granulocytes and monocytes was significantly higher compared to that of the peripheral blood, and the proportion of 'naive' T and B lymphocytes was decreased. The expression of LFA-1 was higher on all leucocyte subsets of the marginal pool except the granulocytes, whereas no differences were seen for the expression of other adhesion molecules (alpha 4-integrins, ICAM-1, CD2, L-selectin, and CD44). In addition, splenectomy influenced the cellular composition of peripheral blood and marginal pool differently and, after injection of blood leucocytes, these cells were found in both compartments showing its characteristic cellular composition. Thus, not only granulocytes, but also B and T lymphocyte subsets, NK-cells and monocytes form a second distinct intravascular compartment. This marginal pool probably influences the cellular composition of leucocyte subsets available for entry into the tissues.

Animals↗
PubMed1996

Blood leucocyte subsets of the rat: expression of adhesion molecules and localization within high endothelial venules.

Although several distinct adhesion pathways are now well characterized, it is not clear whether analysis of adhesion molecule expression on leucocytes is sufficient to predict their interaction with endothelium in vivo. Therefore, in the present study this question was addressed by investigating the interaction between blood leucocyte subsets and high endothelial venules (HEV). The expression of different types of adhesion molecule (CD44, alpha 4-integrins, LFA-1, ICAM-1, CD2 and L-selectin) on lymphocytes, NK cells, monocytes and granulocytes of rat blood was determined by flow cytometry. In the same animals the numbers of blood leucocyte subsets present in the HEV of axillary lymph nodes and Peyer's patches were analysed using immunohistology. In the HEV of both axillary lymph nodes and of Peyer's patches lymphocytes (greater than 10,000 per mm2), as well as small numbers of NK cells and monocytes (less than 500 per mm2), were found. In contrast, granulocytes were not detected here. Lymphocytes, NK cells, monocytes and granulocytes each expressed CD44, alpha 4-integrins, LFA-1, ICAM-1, CD2 and L-selectin in a pattern characteristic to cell type, but this did not correlate with the different ability of the leucocyte subsets to interact with the two types of HEV. In conclusion, determining the expression of CD44, alpha 4-integrins, LFA-1, ICAM-1, CD2 and L-selectin on blood leucocytes alone is not sufficient to predict leucocyte/endothelium interaction in vivo.

Animals↗
PubMed1996

Age dependency of the composition of immunocompetent cells and the expression of adhesion molecules in rat laryngeal mucosa.

Clinical evidence shows that laryngeal infections in infants differ significantly from those in adults. Therefore, the composition of the mucosal immune system (granulocytes, macrophages, dendritic cells, natural killer cells, and T and B lymphocytes) and the epithelial expression of class II-MHC molecules and adhesion molecules ICAM-1, VCAM-1, and E-selectin were studied in the larynx of newborn, 5-week-old, and 3-year-old rats. With the exception of macrophages, the immunocompetent cells began to immigrate into the laryngeal mucosa after birth, indicating that the laryngeal mucosa in newborn rats is immature. In contrast, ICAM-1 was already expressed. The number of immunocompetent cells and the expression of epithelial class II-MHC and ICAM-1 increased with age. Immunocompetent cells and epithelial class II-MHC and ICAM-1 expression were mainly detected in the subglottic region, but were almost absent in the vocal fold region.

Aging↗
PubMed1996

The mucosa of the middle ear and Eustachian tube in the young rat: number of granulocytes, macrophages, dendritic cells, NK cells and T and B lymphocytes in healthy animals and during otitis media.

To gain a better understanding of immune reactions during otitis media, the middle ear and Eustachian tube mucosa were studied as a unit in young rats with respect to the composition of immunocompetent cells before and after middle ear infection via the tube. Using immunohistology, the distribution of NK cells, important for the defence against viral antigens, and of dendritic cells, known to be most capable of antigen uptake, processing and presentation, was determined. Furthermore, the composition of cells of the unspecific immune system (i.e. granulocytes and macrophages) and the specific immune system (i.e. T and B lymphocytes) was studied. Macrophages and dendritic cells were spread over the whole middle ear mucosa, whereas only few NK cells and T and B lymphocytes and almost no granulocytes were detected. In the Eustachian tube mucosa, immunocompetent cells, with the exception of dendritic cells and macrophages, were only rarely seen. After induction of otitis media by severing the soft palate, immunocompetent cells increased in both the middle ear and Eustachian tube mucosa, but surprisingly they were almost absent from the area of the tubal orifice to the middle ear. The results indicate that immune reactions take place similarly in the Eustachian tube and in the middle ear mucosa.

Animals↗
PubMed1995

Interaction of B and T lymphocyte subsets with high endothelial venules in the rat: binding in vitro does not reflect homing in vivo.

Lymphocytes continuously migrate through the body, and their efficient extravasation from the blood via high endothelial venules (HEV) is essential for initiating an appropriate immune response. Most investigations have focused on the lymphocyte/HEV interaction in vitro. However, to what extent such systems reflect the situation in vivo is not known. It is also unclear whether lymphocyte subsets immigrate into the HEV in proportion to their presence in the blood, and whether import capacity is limited by the HEV. When rat mesenteric lymph node lymphocytes were incubated in vitro on cryostat sections, the well-known preferential binding of B lymphocytes to HEV of Peyer's patches (PP) and T cells to HEV of axillary lymph nodes (axLN) was observed (axLN vs. PP: B lymphocytes 21.2 +/- 5.0% vs. 40.6 +/- 11.0%, T lymphocytes 84.6 +/- 6.3% vs. 56.5 +/- 12.9%). However, when labeled mesenteric lymph node lymphocytes were injected and their location within the HEV was analyzed 15 min later, no preferential interaction was seen. After injection of labeled thoracic duct lymphocytes, the percentage of labeled cells among B and T lymphocytes in the blood was significantly different (4.4 +/- 0.9% vs. 8.9 +/- 3.6%), whereas that in HEV of axLN (19.0 +/- 6.4% vs. 16.6 +/- 6.0%) and PP (30.6 +/- 6.1% vs. 33.9 +/- 4.4%) was comparable. Although the number of injected lymphocytes was similar in magnitude to the total blood lymphocyte pool, after injection there was no increase in lymphocyte numbers in the HEV. Thus, the adhesion assay in vitro does not completely reflect immigration into HEV in vivo. In addition, our data suggest that both the availability of lymphocyte subsets in small venules and the immigration rate into HEV are actively regulated in vivo.

Animals↗
PubMed1995

Lymphocyte traffic through lymph nodes and Peyer's patches of the rat: B- and T-cell-specific migration patterns within the tissue, and their dependence on splenic tissue.

The migration routes of lymphocyte subsets through organ compartments are of importance when trying to understand the local events taking place during immune responses. We have therefore studied the traffic of B, T, CD4(+), and CD8(+ )lymphocytes through lymph nodes and Peyer s patches. At various time points after injection into the rat, labeled lymphocytes were localized, and their phenotype characterized in cryostat sections using immunohistochemistry. Morphometry was also performed, and the recovery of 51Cr-labeled lymphocytes in these organs was determined. B and T lymphocytes entered the lymph nodes via the high endothelial venules in similar numbers. Most B lymphocytes migrated via the paracortex (T cell area) into the cortex (B cell area), and then back in substantial numbers into the paracortex. In contrast, T lymphocytes predominantly migrated into the paracortex and were rarely seen in the cortex. No obvious differences were seen between various lymph nodes and Peyer s patches and the routes of CD4(+) and CD8(+)lymphocytes. After injection of lymphocytes into animals with autotransplanted splenic tissue, the number of B lymphocytes that had migrated into the B cell area of lymph nodes and of Peyer s patches was significantly decreased, whereas CD4(+) lymphocytes migrated in larger numbers into the T cell area of both organs.

Animals↗
PubMed1995

The neuropeptide substance P does not influence the migration of B, T, CD8+ and CD4+ ('naive' and 'memory') lymphocytes from blood to lymph in the normal rat.

Thoracic duct lymphocytes (TDL) continuously patrol through the body, facilitating immune responses at most sites. The neuropeptide Substance P might regulate immune responses by influencing the migration of TDL. Therefore, it was investigated whether Substance P affects the migration of thoracic duct B, T, CD8+ and CD4+ ('naive' and 'memory') lymphocytes from blood to lymph in vivo. Labelled TDL were either incubated with Substance P and then injected into normal rats, or incubated without Substance P and then injected into rats continuously receiving Substance P intravenously. The numbers of labeled B, T, CD8+ and CD4+ ('naive' and 'memory') lymphocytes were determined in blood and thoracic duct lymph for 1 and 5 days, respectively. Neither the in vitro incubation with Substance P nor its in vivo application influenced the disappearance of any lymphocyte subset from the blood or its reappearance in the lymph. In addition, continuous intravenous application of the Substance P antagonist CP 96.345 did not alter the volume or the lymphocyte number of the efferent lymph. The present study indicates that the nervous system does not influence immune responses via Substance P by altering the migration pattern of B, T, CD8+ and CD4+ ('naive' and 'memory') lymphocytes.

Animals↗
PubMed1994

Migration of so-called naive and memory T lymphocytes from blood to lymph in the rat. The influence of IFN-gamma on the circulation pattern.

It has been suggested that naive T lymphocytes migrate directly from the blood into the lymph nodes, whereas memory T lymphocytes arrive via the afferent lymphatics. However, these routes were defined indirectly by determining only the frequencies of naive and memory T lymphocytes in the afferent and efferent lymph of sheep. In this study naive (CD45RC+) and memory (CD45RC-) CD4+ lymphocytes obtained by thoracic duct cannulation of the rat were injected i.v. and their reappearance in the thoracic duct lymph (efferent lymph) was monitored in absolute numbers over 5 days. In addition, it was investigated whether continuous application of IFN-gamma influences the migration of the two subsets differently. After i.v. injection both naive and memory T lymphocytes returned to the thoracic duct in considerable numbers and with similar kinetic patterns. Interestingly, within 5 days at least 25% of memory phenotype lymphocytes converted to naive phenotype lymphocytes. When naive and memory T lymphocytes were injected in animals receiving a continuous IFN-gamma infusion, only the reappearance of the naive T lymphocytes but not that of memory T lymphocytes in the thoracic duct lymph was reduced. Thus, by investigating the migration of labeled lymphocytes, data were obtained that contradict conclusions drawn by analyzing preferential accumulation of lymphocyte subsets only. Our results suggest that in unstimulated animals naive and memory thoracic duct lymphocytes migrate at a similar tempo and to a comparable extent from the blood via the lymph node into the efferent lymph. IFN-gamma only influences the traffic of naive lymphocytes, indicating that the migration of the two populations is regulated by different mechanisms.

Animals↗
PubMed1994

B and T lymphocyte subsets enter peripheral lymph nodes and Peyer's patches without preference in vivo: no correlation occurs between their localization in different types of high endothelial venules and the expression of CD44, VLA-4, LFA-1, ICAM-1, CD2 or L-selectin.

Many lymphocytes enter tissues such as peripheral lymph nodes, and Peyer's patches through high endothelial venules (HEV). It is known that HEV differ in the expression of adhesion molecules as lymphocyte subsets do. Through the interaction of these molecules B and T lymphocyte subsets are thought to be preferentially directed into lymphoid organs. However, it is unclear which role these mechanisms play in vivo, since there are no studies demonstrating that blood lymphocyte subsets preferentially interact with different types of HEV in vivo. Therefore, in the present study the frequency of B, T, CD4+ and CD8+ lymphocytes in the wall of the HEV of rat peripheral lymph nodes and Peyer's patches was analyzed by immunohistology. In addition, the expression of CD44, VLA-4, LFA-1, ICAM-1, CD2 and L-selectin on B and T lymphocyte subsets of the blood was determined by flow cytometry. Although B and T lymphocytes showed significantly different levels of expression for each adhesion molecule investigated, the relation of B and T lymphocytes within the HEV of peripheral lymph nodes and Peyer's patches was strikingly comparable (38.0 +/- 5.2% vs. 40.6 +/- 5.7% and 62.0 +/- 5.2% vs. 59.4 +/- 5.7%, respectively). The same was true for CD4+ and CD8+ cells. Thus, although HEV and the blood lymphocyte subsets differ markedly in their expression pattern of adhesion molecules, the existing levels are sufficient to mediate comparable entrance of B and T lymphocyte subsets into both types of HEV.

Animals↗
PubMed1994

Which steps in lymphocyte recirculation are regulated by interferon-gamma?

Lymphocyte traffic throughout the body is a basic mechanism of immune surveillance. Most studies of the regulation of the extravasation of lymphocytes have focused on the interaction between endothelial cells of the high endothelial venules (HEV) in lymphoid organs and lymphocytes via the interaction of various adhesion molecules. Cytokines play a major role in the regulation of immune reactions, and some have been shown to upregulate adhesion molecules important for lymphocyte migration. Using interferon-gamma (IFN gamma) as an example of such a cytokine, we summarize the available data on regulation by IFN gamma of the different phases of lymphocyte migration from the blood via HEV, through the lymphoid organ and finally exiting the organ. Much data obtained in in vitro assays have not yet been confirmed in vivo, and therefore a number of questions remain unanswered. Our hypothesis is that the interaction of lymphocytes with endothelial cells represents just one aspect of regulation, and that lymphocyte migration is probably regulated much more effectively within the lymphoid organ.

Animals↗