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Biomedical subjects

R Pabst

Publications and source records attributed to R Pabst.

At least 163 records · Page 9Linked to original sources
PubMed1992

Homing of blood, splenic, and lung emigrant lymphoblasts: comparison with the behaviour of lymphocytes from these sources.

The distinctive homing patterns of [125I]deoxyuridine-labelled lymphoblasts and 51Cr-labelled lymphocytes from the three sites--splenic and pulmonary venous emigrants, and peripheral blood--were demonstrated by study of their entry into a large number of tissues. These included the major organs such as the lung, liver, bone marrow, spleen, skin, and muscle, and several lymph nodes (LNs), Peyer's patches (PPs), tonsils and thymus, portions throughout the gastrointestinal tract and immunologically-stimulated sites. Major differences in homing of blood blasts (up to 4-fold) were found in particular tissue types, such as the different LNs, three PP types, and the three tonsils, and their distribution was quite different from lymphocytes. While splenic blasts behaved like blood blasts, lung blasts showed even more distinctive homing, e.g. to tissues with particular blast uptake, including spleen, stomach, bladder, portal and stimulated LNs, and liver and lung. While blast recovery data showed that all types homed well to bone marrow (about 25%) and the gastrointestinal wall (about 15%), the roughly 50% found in blood, muscle, skin, lung, and liver showed some homing preferences: blood blasts tended to stay more in blood, splenic blasts to home to muscle, and lung blasts to liver and lung. These studies have demonstrated that physiologically-derived lymphoblasts are not predominantly mucosal-homing but distribute through several non-lymphoid organs and that, even considering only those in the blood compartments, they show differences in homing preference.

Animals↗
PubMed1992

Cellular changes in the bronchoalveolar lavage (BAL) of pigs, following immunization by the enteral or respiratory route.

Normal young pigs were immunized by the oral or aerogenic route with the viable or inactivated lung-pathogenic bacterium Actinobacillus (Haemophilus) pleuropneumoniae. Three weeks later the cellular composition as well as the lymphocyte subset composition of the bronchoalveolar space were examined by BAL. Lymphocytes in the lavage increased significantly, including CD4+ and CD8+ T cells. After oral immunization a dramatic increase of plasma cells and lymphoid blasts was found. Among immunoglobulin-positive lymphocytes IgG+ cells showed the most pronounced increase. For most lymphocyte subsets there was no difference between viable and inactivated bacteria. Oral immunization with a lung-pathogenic bacterium results in increased numbers of lymphocytes in the bronchoalveolar space and might play a critical role in protection against lower respiratory tract infections.

Actinobacillus pleuropneumoniae↗
PubMed1992

Effects of microbial stimulation on the number, size and activity of bronchus-associated lymphoid tissue (BALT) structures in the pig.

The development of bronchus-associated lymphoid tissue (BALT) was investigated in the pig, which is a species in which BALT is not found constantly. Different routes of contact with a specifically lung-pathogen bacterium Actinobacillus (Haemophilus) pleuropneumoniae were tested. Pigs, selected by bacteriological screening methods and the number of granulocytes in the bronchoalveolar lavage (BAL), were infected by aerosol. They were compared to previously enterally immunized pigs using active and inactivated bacteria. The development of BALT after the infection was compared to that in pigs with a single enteral, or no, contact with the bacterium. BALT was less frequent in these groups than in the infected pigs. Previously immunized pigs developed the highest number and the largest BALT with the most prominent morphological signs of activation. Immunization with living or inactivated bacteria did not cause histological differences. BALT was preferentially located around bronchioli and small bronchi. Additional BALT predominantly occurred in the walls of larger bronchi. Definite compartments of T and B lymphocytes were not found in immunohistological studies of BALT. It was concluded that the development of BALT can be induced by different modes of microbial stimulation.

Actinobacillus Infections↗
PubMed1991

Ileal Peyer's patch emigrants are predominantly B cells and travel to all lymphoid tissues in sheep.

The ileal Peyer's patch (PP) was selectively labeled with fluorescein isothiocyanate by extracorporeal perfusion in 7-12 week-old lambs and the lymphocyte lineage and fate of the emigrants was determined by fluorescence microscopy and flow cytometry. PP emigrants were found in all tissues examined, accounting for 10%-15% of ileal mesenteric lymph node (MLN). 1%-2% of jejunal MLN, jejunal PP, prescapular lymph node (PLN) and 3%-4% of spleen cells. All ileal PP emigrants enter the ileal MLN on their way to the circulation. Removal of the MLN prior to perfusion enabled emigrants to go directly to the circulation and extravasate in distant tissues faster than in intact animals. The ileal MLN might provide an additional level of regulation for ileal PP emigrants. The perfused ileal PP contained about 25 times more B cells than T cells. The emigrant cells found in different tissues included both T and B cells but came to reflect, although to a lesser degree, the B cell composition of the tissue from which they were derived. One day after perfusion the composition of PP emigrants was similar to that of the tissue within which they were found; the spleen was the exception with a bias towards B cells. By day 3 the ratio of B to T cells in the PP emigrants was 1 for jejunal MLN and PLN. 1.5 for ileal MLN and jejunal PP, and 4-5 for the spleen and blood. It was concluded that the PP-derived T cells were recirculating T cells that were in the ileal PP at the time of perfusion. These cells emigrated rapidly and equilibrated such that they accounted for about 1.5% of the T cell pool in various tissues. Most PP-derived B cells were probably produced in the PP. The greatest contribution (24.4%) that ileal PP emigrants made to the B cell pool of a tissue was with the ileal MLN through which they are obliged to pass. The contribution was lower but still very significant in blood (8.9%), spleen (6.8%), PLN (3.9%), jejunal MLN (3.5%) and jejunal PP (1.8%). There was no evidence that ileal PP emigrants made a greater relative contribution to either T or B cell populations in MLN or jejunal PP than to non-gut-associated sites. The B cells were distributed throughout the immune system, which is in accordance with the proposal that the ileal PP is a site of primary B cell genesis in sheep.

Animals↗
PubMed1991

The postnatal development of gut lamina propria lymphocytes: number, proliferation, and T and B cell subsets in conventional and germ-free pigs.

The lamina propria (LP) contains many lymphocytes that are effector cells as well as memory cells of the gut immune system. This compartment was studied in normal and germ-free pigs in the early postnatal period up to 91 d of age. The number of LP lymphocytes nearly doubled between the 1st and 29th d. LP lymphocytes proliferated more in the crypt region than in the villi with a mitotic rate/h comparable to that in nonfollicular compartments of Peyer's patches and lymph nodes. The determination of the subpopulations of LP lymphocytes showed a 10-fold increase in CD2+ cells between d 1 and 40. About 80% of the LP T cells in 1- and 5-d-old pigs had the unusual CD2+CD4-CD8- phenotype. Ig-positive cells appeared later in the postnatal period than the T cells. On d 1, only a few IgM+ cells were observed. In 40-d-old animals, the number of IgA+ cells exceeded that of IgM+. Ten times more Ig+ cells were detected in the crypt region than in the villi. The germ-free pigs at an age of 49 d had a T cell subset pattern comparable to that of 5-d-old normal animals.

Animals↗
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↗
PubMed1991

[Occupationally-induced diseases, a contribution to epidemiologic methodology with results from mining].

For mining exposures the work-relatedness of morbidity measures and functional organ-related disorders was analysed on the base of data concerning medical screening, occupational exposure and disablement. Morbidity corresponds with intensity of occupational exposure. Using risiko measures results for disorders were interpreted in relation to a hypothesis, which allows to distinguish in our opinion diseases without work-relatedness from work-related and occupational diseases. The availability of a "normal exposed" control group and the choice of a well-defined exposed group, for which the definition of selected diseases as work-related is applicable alone, are decisive for the results. For mining exposures functional disorders of muscular and skeletal system require particular consideration.

Cross-Sectional Studies↗
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

The epithelium overlying rabbit bronchus-associated lymphoid tissue does not express the secretory component of immunoglobulin A.

The epithelium associated with lymphoid aggregates in the bronchial tract (BALT) was studied in rabbits by immunohistochemistry using monoclonal antibodies against the secretory component (SC) of IgA. The normal bronchus epithelium was intensely labelled. In contrast, epithelium overlying the central parts of the follicles was negative. This specialized epithelium cannot participate in the SC-mediated transport of IgA, which might be a basis for the adherence and transport of microorganisms into the lymphoid tissue, thus initiating immune responses of the BALT.

Animals↗
PubMed1990

Cell composition and lymphocyte subsets in the bronchoalveolar lavage of normal pigs of different ages in comparison with germfree and pneumonic pigs.

For studies of lymphocyte kinetics in the different compartments of the lung, basic data on the cellular composition and lymphocyte subsets of porcine bronchoalveolar lavage (BAL) are essential. Therefore BAL was performed in pigs, and cytologic findings were studied using cytologic staining, enzyme cytochemistry, and immunologic labeling techniques. Four groups of normal pigs at different ages and of different breeds, 1 group with bacterial pneumonia, and 1 group of germfree animals were used. The total cell recovery was 10 x 10(6) in germfree pigs, in normal pigs it was 1.2-4 times higher, and in pneumonic pigs 23 times higher. The main cell type was macrophages, approximately 80% in normal and germfree and 50% in pneumonic pigs. The BAL contained 20% lymphocytes. Granulocytes were absent in normal BAL, but formed 30% of pneumonic BAL. Here the total number of macrophages was 3-9 times higher than normal, the total number of lymphocytes was 11-23 times higher. The proportion of surface immunoglobulin positive (sIg+) cells was 4.5% in the young and 8.5% in the older pigs, and of T cells it was 6% in the young and 14.9% in the older pigs. The BAL of germfree pigs contained few sIg+ cells and half of the normal number of T cells. In pneumonic animals the BAL contained twice the number of sIg+ and a normal percentage of T cells. The percentage of T-helper lymphocytes was approximately 2% without marked differences between the groups, whereas the percentage of T-suppressor lymphocytes varied significantly from 0.8% in germfree to 4% in young normal and 8% in the older pigs. In this respect the pneumonic pigs did not differ from the normal groups. The study shows that the pig is a suitable animal model for further investigation of the cellular immune system of the lung.

Age Factors↗
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

Size of jejunal Peyer's patches and migration of lymphocyte subsets in pigs after resection or transposition of the continuous ileal Peyer's patch.

In pigs there are two types of Peyer's patches in the small intestine: discrete patches in the jejunum (jejPP) and a continuous patch in the terminal ileum (ilPP). The ilPP was resectioned or transposed into the upper jejunum. After the operation the size of the remaining jejPP showed no compensatory growth in either group within 10 months. However, the number of CD8+ lymphocytes in the blood, spleen, mesenteric lymph nodes, tonsils, and Peyer's patches and the number of CD4+ cells in the spleen and tonsils was reduced in comparison to those of age-matched control pigs. Autologous blood lymphocytes were labelled with fluorescein isothiocyanate and retransfused. In control animals the mid-portion of the ilPP showed a lower entry of lymphocytes and the migration pattern of lymphocyte subsets was different in the animals with resectioned or transposed ilPP as compared to controls. Thus, the removal of the ilPP (about 60% of all small intestinal PP) did not result in the remaining patches adapting their size, but it did influence other lymphoid organs.

Animals↗