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J Westermann

Publications and source records attributed to J Westermann.

At least 91 records · Page 5Linked to original sources
PubMed1994

B- and T-lymphocyte subset numbers in the migrating lymphocyte pool of the rat: the influence of interferon-gamma on its mobilization monitored through blood and lymph.

The subset composition of the migrating lymphocyte pool is largely unknown. In order to determine the number of B, T, CD8+, CD4+ and CD4+ 'naive' (CD45RC+) and 'memory' (CD45RC-) lymphocytes in this pool, the thoracic duct lymph of the rat was drained for 7 days. The effect of lymphocyte depletion on the number of blood lymphocytes was also monitored. In addition, the influence of continuously applied interferon-gamma (IFN-gamma) on the mobilization of the migrating lymphocyte pool was investigated. Within 1 week 2 x 10(9) thoracic duct lymphocytes (TDL) were collected, which represents about 50% of the total lymphocyte pool of an adult rat. Among the migrating lymphocytes an early and a late mobilized population could be differentiated. In the former the CD4+ 'naive' (CD45RC+) T lymphocytes constituted the largest population, whereas in the latter it was the B lymphocytes. Continuous infusion of IFN-gamma did not affect the number of lymphocytes in the blood. In contrast, in the thoracic duct IFN-gamma reduced the appearance of all lymphocyte subsets. However, the pattern of reduction over time differed markedly depending on the population (early or late mobilized) and the phenotype (B- or T-lymphocyte subsets). Thus, the migrating lymphocyte pool of the rat is very heterogeneous regarding its populations and shows complex changes in the mobilization pattern after IFN-gamma stimulation. Future studies should focus on how the size and the composition of the migrating lymphocyte pool is regulated.

Animals↗
PubMed1993

IFN-gamma influences the migration of thoracic duct B and T lymphocyte subsets in vivo. Random increase in disappearance from the blood and differential decrease in reappearance in the lymph.

Thoracic duct lymphocytes (TDL) continuously patrol through the body, facilitating immune responses at most sites. IFN-gamma might regulate immune responses by influencing the migration of TDL. Therefore, it was investigated in vivo whether IFN-gamma affects the migration of thoracic duct B, T, CD4+, and CD8+ lymphocytes from blood to lymph. Labeled TDL were injected i.v. into rats continuously receiving IFN-gamma via a central venous catheter. The numbers of B, T, CD4+, and CD8+ lymphocytes were determined in blood and thoracic duct lymph for 120 h. IFN-gamma increased the disappearance of TDL from the blood to a similar extent in all subsets. In contrast, the reappearance of B and T lymphocyte subsets in the lymph was decreased: B lymphocytes were affected significantly more than T lymphocytes, whereas CD4+ and CD8+ lymphocytes were affected to a similar extent. Our study suggests that differential retention within the tissue rather than preferential immigration into the tissue creates a microenvironment with a distinct composition of lymphocyte subsets.

Animals↗
PubMed1992

An enzyme-linked immunosorbent assay for the quantification of solubilized CD14 in biological fluids.

A simple and robust two site-binding ELISA for the quantification of solubilized CD14 in human and animal body fluids is described. The principle of the assay depends on the specific binding of sCD14 to two monoclonal antibodies (MEM-18, RoMo-1) recognizing different epitopes of this glycoprotein. The detection limit for sCD14 was 1 ng/ml. The method was used to quantify sCD14 in different biological fluids, giving an intra-assay coefficient of variation and an interassay coefficient of variation of about 9%. The assay was used to measure sCD14 in human serum and plasma and other body fluids in health and disease, and in cell culture supernatants. With the exception of monkeys there was no reactivity with 29 other species screened. In healthy volunteers the sCD14 serum level had a mean value of 3.98 +/- 0.3 micrograms/ml (mean SEM, n = 102).

Antibodies, Monoclonal↗
PubMed1992

Random entry of circulating lymphocyte subsets into peripheral lymph nodes and Peyer's patches: no evidence in vivo of a tissue-specific migration of B and T lymphocytes at the level of high endothelial venules.

Lymphocytes continuously migrate through the body and thus immune competent cells are constantly delivered to most tissues. They interact with high endothelial venules (HEV) via specific homing receptors and vascular addressins, and these molecules seem to be the reason for a preferential homing of B lymphocytes into Peyer's patches and of T lymphocytes into peripheral lymph nodes. When lymphocytes derived from lymph node cell suspensions were applied in the in vitro lymphocyte/endothelium binding assay, the well-known preference of mouse lymph node B lymphocytes for Peyer's patch HEV compared to peripheral lymph node HEV was confirmed in the rat (2.8 times). When in the same in vitro assay thoracic duct lymphocytes (TDL) were used this preference was far less obvious (1.4 times). However, by injecting rat TDL intravenously and by tracing them directly in HEV, B, T, CD4+ and CD8+ lymphocytes are seen to enter Peyer's patches and peripheral lymph nodes in vivo without preference. Thus, in contrast to lymphocytes from lymph node cell suspensions, no evidence was found of a tissue-specific migration of thoracic duct B, T, CD4+ and CD8+ lymphocytes at the HEV level. This finding demonstrates the importance of considering both experimental conditions and the cell source used when investigating lymphocyte traffic.

Animals↗
PubMed1992

Distribution of lymphocyte subsets and natural killer cells in the human body.

The frequency and distribution of B and T lymphocyte subsets have been determined in many body tissues and fluids by preparing cell suspensions and tissue sections from lymphoid and nonlymphoid organs. In humans these studies often concentrate on the blood or on one particular cell source for obvious reasons. However, such data can only be interpreted correctly if the whole immune system is taken into consideration [64]. To facilitate this, reports on the frequencies and the absolute numbers of B and T lymphocyte subsets within various human tissues and fluids have been collected from a wide variety of journals and are briefly summarized here. Since the size of lymphoid organs varies with age (e.g. thymus, tonsils), only the data of adult individuals were included, unless otherwise stated. Natural killer (NK) cells are morphologically quite similar to lymphocytes [59], but very different functionally. For example, they are not able to recirculate from the blood via the lymph nodes and the thoracic duct back to the blood as lymphocytes do [19]. Thus, human NK cells have been compared with lymphocytes with respect to number and distribution.

Body Fluids↗
PubMed1992

Splenic autotransplantation provides protection against fatal sepsis in young but not in old rats.

Splenectomy increases the risk of contracting infections with high mortality. Thus, splenic tissue should be repaired orthotopically whenever possible. If all attempts fail, splenic autotransplantation might be a suitable method for splenic salvage. The protective function of such transplants in adults has been questioned, leading to a decreased frequency of splenic autotransplantations. However, the regeneration of splenic tissue is better in the young organism than in the old, suggesting that the protection provided by regenerated splenic tissue might be more reliable in children than in adults. In addition, children are at a higher risk in the case of overwhelming postsplenectomy sepsis. The protection warranted by regenerated splenic tissue after autotransplantation at different ages was examined using a highly standardized animal model. Sham operation, splenectomy, and splenic autotransplantation were performed on adult, weanling, and newborn rats, and Streptococcus pneumoniae was applied intranasally 9 months after the operation. After pneumococcal challenge about 80% of the splenectomized animals in the different age groups died of infection, whereas only 20% of the sham operated rats died. Regenerated splenic tissue resulting from splenic autotransplantation performed on adult or weanling rats demonstrated no protective function. However, in newborn rats with transplanted splenic tissue, both survival rate and survival time were increased significantly. Determination of lymphocyte subsets in the blood did not allow the protective role of splenic transplants to be predicted. This study indicates that disappointing results of splenic autotransplantation in adult patients should not lead to false pessimism about the role of this operation in children.

Age Factors↗
PubMed1991

The role of the spleen in lymphocyte migration.

In all species studied so far it was found that more lymphocytes migrate to the spleen than to all the lymph nodes together. Specific molecules on lymphocytes and endothelial cells regulate their entry into lymph nodes, but none of the known molecules play a role in homing to the spleen. The splenic compartments, comprising the red pulp, marginal zone, periarterial lymphatic sheath (PALS) and follicles, all show different kinetics for migrating lymphocytes. By combining 51Cr lymphocyte labeling with morphometry and two color immunohistochemistry, the migratory route of lymphocyte subsets can be followed through the spleen and absolute numbers of lymphocytes calculated in each compartment. T lymphocytes home preferentially to the PALS and B lymphocytes home not only to follicles but also in large numbers to the marginal zone and red pulp. CD4+ and CD8+ lymphocytes migrate similarly at early time points, but at 24 hours CD4+ lymphocytes are preferentially found in the PALS with CD8+ lymphocytes in the red pulp and marginal zone. The functional significance of the different routes of lymphocytes through the spleen has yet to be defined in relationship to specific immune functions and regulatory factors on splenic lymphocyte homing.

Animals↗
PubMed1990

The in vitro lymphocyte/endothelium binding assay. An improved method employing light microscopy.

The in vitro lymphocyte binding assay (HEV assay) has proved to be a useful approach for examining the first step of lymphocyte migration, i.e., homing to organs containing high endothelial venules (HEVs). Since fluorescence-labelled standard lymphocytes are usually included in each assay to account for day-to-day variations, HEV preparations have to be evaluated by fluorescence microscopy. Thus no counterstaining can be performed and HEVs without adherent lymphocytes cannot easily be recognized. Because the preparations are not suitable for storage they must be evaluated within a short time. In this study an improved technique is described which permits HEV preparations made with fluorescence-labelled standard lymphocytes to be evaluated by light microscopy in counterstained sections. The phenotypes of the sample lymphocytes can be determined by staining for surface antigens on the same slides and the preparations obtained are permanent.

Animals↗
PubMed1990

Absolute numbers of lymphocytes subsets migrating through the compartments of the normal and transplanted rat spleen.

Lymphocyte migration is one of the basic principles of the immune system. Up to now lymphocyte migration experiments have been performed either in a quantitative way, determining whole organ recoveries of radiolabeled lymphocytes without histologic localization, or based on autoradiography which does not provide absolute numbers of immigrant lymphocytes. In this study the traffic of lymphocyte subsets through the splenic compartments: red pulp (RP), marginal zone (MZ), periarteriolar lymphatic sheath (PALS) and follicle was evaluated in absolute numbers. In normal spleens and splenic transplants fluorescein isothiocyanate (FITC)-labeled immigrant lymphocytes were localized and characterized immunohistochemically in cryostat sections by light microscopy. In addition morphometry of the splenic compartments was performed and the recovery of 51Cr-labeled lymphocytes in the spleen was determined. The combination of these methods allowed total numbers of immigrant subset cells to be calculated in individual splenic compartments. At 15 min about 17% of the injected B lymphocytes were found in the MZ. This is the largest fraction of an injected lymphocyte subset found in a single splenic compartment. At 24 h immigrant B cells were not only found in the follicle, but they had reached comparable numbers in the three compartments: follicle, RP and MZ. Most immigrant T lymphocytes were found in the PALS, which from 6 h after injection onwards contained more T cell immigrants than any single organ of the body. CD4+ and CD8+ lymphocytes showed a similar distribution throughout the splenic compartments at early time points. At 24 h CD4+ lymphocytes homed preferentially to the PALS, whereas CD8+ cells seemed to prefer the RP and MZ. Both CD4+ and CD8+ cells also migrated into the follicles. In regenerated splenic tissue after autotransplantation lymphocyte immigration was reduced in all compartments and to the MZ in particular. An impaired lymphocyte migration to the MZ in splenic transplants may be one reason for the lack of protection provided against bacterial infections. Thus examining lymphocyte migration in absolute numbers provides additional information which cannot be gained by determining labeling indices or percentages of lymphocyte subsets alone.

Animals↗
PubMed1990

Lymphocyte subsets in the blood: a diagnostic window on the lymphoid system?

The assessment of peripheral blood lymphocyte numbers and ratios has been performed in almost every conceivable disease state, but do these values give any useful information about immune status? Jürgen Westermann and Reinhard Pabst try to answer this question and to put peripheral blood population assessments into the whole-body context.

Blood Cells↗
PubMed1990

Modulation of Forssman glycosphingolipid expression by murine macrophages: coinduction with class II MHC antigen by the lymphokines IL4 and IL6.

In contrast to murine spleen M phi, resident peritoneal M phi from health mice express very little Forssman glycolipid antigen (Fo). The following experiments suggest that Fo expression by peritoneal M phi may be associated with inflammation. Balb/c and CBA/J mice were given inflammatory stimuli by i.p. injection of live BCG, thioglycollate (TG), Corynebacterium parvum (CP), proteose peptone (PP), or LPS. Control animals received pyrogen-free saline. Expression of Fo and Ia antigen by peritoneal M phi was determined by immunofluorescence after 4 d. Application of TG or CP led to an up to 30-fold increase in Fo+, Ia+ double positive M phi over that in control animals. LPS caused mainly an increase in the percentage of double-positive M phi, whereas no effects were seen in BCG or PP treated animals. To clarify the possible involvement of cytokines in this process and to identify these, the effects of LPS and various cytokines on in vitro induction of Fo and Ia expression were studied in further experiments. LPS, IL6, and IL4 caused induction of up to 15% Fo+ and Ia+ M phi after a 4 d culture period. M phi colony stimulating factor (M-CSF) from lung-conditioned medium was also moderately active. IL1, TNF, and IL2 had no influence, whereas IFN-gamma only induced Ia. For a successful in vitro induction of Fo and Ia, a prior priming of the mice with PP appeared mandatory. This suggests that only M phi of a certain developmental stage can acquire Fo under the influence of the appropriate cytokines. The data may provide the first evidence for cytokine-mediated modulation of a glycolipid antigen of known chemical structure.

Animals↗
PubMed1990

Lymphocyte subsets in the blood. The influence of splenectomy, splenic autotransplantation, ageing, and the site of blood sampling on the number of B, T, CD4+, and CD8+ lymphocytes in the rat.

Removal of the largest single lymphoid organ, the spleen, leads to an increase in severe infections. To prevent this, transplantation of splenic fragments can be performed, which may, however, cause an increase in CD8+ lymphocytes in the blood of these patients. This is controversial since in the clinical situation it is often difficult to account for the different age of the patients, the time point after the operation and many other factors known to influence the number of lymphocyte subsets. Using a well-defined animal model, B, T, CD4+, and CD8+ lymphocytes were determined preoperatively in adult rats. Then, either sham splenectomy, splenectomy, or splenic autotransplantation was performed and the animals were followed up for 15 months after the operation. The surgical procedure itself, the site of blood sampling and ageing all influenced the number of lymphocyte subsets profoundly. Furthermore, giving the data as relative or absolute numbers leads to different results. Splenectomy caused lymphocytosis, due to a significant increase in B and CD8+ lymphocytes, as did splenic autotransplantation, which indicates that the number of lymphocyte subsets in the blood should not be used to argue in favour of or against splenic autotransplantation. This study demonstrates that the number of lymphocyte subsets in the blood is influenced by many factors and therefore should be determined in a highly standardized fashion.

Aging↗