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E C Hoefsmit

Publications and source records attributed to E C Hoefsmit.

At least 37 records · Page 2Linked to original sources
PubMed1993

Separation of alveolar macrophages and dendritic cells via autofluorescence: phenotypical and functional characterization.

In a previous study we demonstrated that an increase of monocytes and dendritic cells (MDC) was In the current study, the bright autofluorescence of alveolar macrophages (AMs) was used to separate them efficiently from the MDC. Sorting of freshly isolated BAL cells resulted in a high-autofluorescent fraction, consisting predominantly of AMs, and a low-autofluorescent fraction containing the MDC, lymphocytes, and granulocytes. Thus, a clear separation between suppressive (AM) and stimulating (MDC) activity was obtained as shown in antigen-specific T cell responses. Flow cytometric parameters, density fractionation, and a series of ED monoclonal antibodies raised against rat macrophage antigens showed that both AMs and MDC were diverse populations. After overnight culture, more than 80% of an MDC population with a density range of 1.065-1.079 changed to a lower density (< 1.056) and morphologically developed into DCs with many processes. Concomitantly, monoclonal antibody ED1 expression changed from a granular pattern to a discrete juxtanuclear spot localization.

Animals↗
PubMed1993

Immuno-effector characteristics of peritoneal cells during CAPD treatment: a longitudinal study.

Peritoneal cells (PC) from 75 patients were immuno-phenotypically and functionally characterized during the first year of CAPD treatment (PCcapd) and compared to PC obtained by laparoscopy of healthy women (control peritoneal cells). Patients were divided, according to their peritonitis incidence (PI), into a high PI (HPI) and a low PI group (LPI). The yield of PCcapd decreased significantly over the year. The differential cell count and immunophenotype of PCcapd remained unchanged in the LPI group, but the percentage of macrophages decreased over the year in the HPI group. Macrophages in the PCcapd, when compared to control peritoneal cells, had a less mature phenotype as measured by RFD7 expression but a higher Fc-receptor expression. The PCcapd showed a higher percentage of B cells, CD4 positive T cells and activated T cells bearing HLA-DR/DQ when compared to the control peritoneal cells. Over the year a decrease in chemotactic activity of the PCcapd towards 10(-8) M N-formylmethionyl-leucyl-phenylalanine and dialysis effluent was observed in LPI patients but not in HPI patients. After one year of treatment, a significantly higher percentage of phagocytosing macrophages in the PCcapd of HPI patients was found when compared to LPI patients. During the year there was an increase of immunophagocytosis of PCcapd independent of PI. In conclusion, the CAPD peritoneal cellular immune system showed signs of both immaturity and activation. The decrease in the yield and in the chemotactic activity of PCcapd suggests an adaptation to the chronic stimulus of the dialysis fluid.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

T cell priming in situ by intratracheally instilled antigen-pulsed dendritic cells.

In the present study, splenic dendritic cells (DC) and alveolar macrophages (AM) were pulsed with antigen in vitro and subsequently intratracheally instilled to test whether these cells have the capacity to sensitize T cells in the draining lymph nodes of the lung. The data demonstrate that antigen-pulsed DC, instilled in the bronchoalveolar lumen, induce antigen-specific T cell priming in vivo in the draining lymph nodes. T cell priming is only seen with viable but not with killed antigen-pulsed DC. Amounts as low as 5 x 10(3) to 10 x 10(3) cells can still induce some responsiveness. In addition, it was found that instillation of viable as well as killed pulsed Ia-negative AM also leads to T cell priming, although about 10 times higher numbers of cells had to be used in comparison with DC. The results suggest that DC instilled in the bronchoalveolar lumen present antigen directly to naive T cells, whereas for AM other mechanisms are involved.

Animals↗
PubMed1993

Migration of dendritic cells into the draining lymph nodes of the lung after intratracheal instillation.

The migration of dendritic cell (DC)-enriched populations and alveolar macrophage (AM) populations isolated from PVG RT7.2 rats was studied after local administration to recipient PVG RT7.1 rats. The monoclonal antibody His41, which is directed against the common leukocyte antigen of the RT7.2 rat, was used to detect migrated cells. Injection of the splenic DC and AM subcutaneously into the footpads resulted in migration of both cell types to the popliteal lymph nodes after 24 h. DC located predominantly in the T cell-dependent areas, whereas AM located more in the medulla and medullary cords and spread throughout the outer cortex area. After intratracheal instillation of splenic DC, these cells were found predominantly in T cell-dependent areas of the draining lymph nodes of the lung after 24 h. In contrast, AM did not migrate to the draining lymph nodes after intratracheal instillation. Combined with those from earlier studies, these data show that DC present in the alveolar lumen may pick up airborne antigen and migrate to the draining lymph nodes of the lung, where they can induce primary T cell responses.

Animals↗
PubMed1993

Ultrastructural study of macrophages of the rat thymus after cyclosporin treatment.

Young adult male Wistar rats were given 30 mg per kg of cyclosporin (CS) for 21 consecutive days. After CS treatment thymic medulla virtually disappears and the thymus is almost entirely composed of cortical tissue. Macrophages are scattered throughout the thymic cortex. These cells are very large, rounded, with inconspicuous prolongations and euchromatic nucleus with prominent nucleoli. These cells are loaded with lipid bodies and vacuolar cytoplasmic inclusions of different size and diverse content, but very rarely contain phagocytosed lymphocyte remnants. The cytoplasm between inclusions has very active aspect with abundance of polyribosomes, granular endoplasmic reticulum and vesicles. Mitoses of lymphocytes in the vicinity of macrophages are frequently seen. We discuss the morphological similarity between cortical macrophages of CS-treated thymus and macrophages of cortico-medullary zone (CMZ) of the normal rat thymus, as well as functional significance of described morphological characteristics of this type of thymic macrophages, which probably reflect the metabolism of arachidonic acid.

Animals↗
PubMed1992

Differential effect of cyclosporin application on epithelial cells of the rat thymus. Immunohistochemical study.

Young adult male Wistar rats were given 30 mg per kg of cyclosporin (CS) for 21 consecutive days. A panel of monoclonal antibodies was used to study the phenotype of thymic epithelial cells. After treatment with CS, subcapsular epithelial cells, although phenotypically similar to medullary epithelial cells, were changed in a similar manner to phenotypically distinct epithelial cells of the deep cortex. These cells became enlarged, stockier and their cytoplasmic prolongations were thicker and coarser compared with control cells and their number was not decreased. In contrast, the number of medullary epithelial cells was markedly reduced, whereby the cells with the most mature phenotype (CK8+10-19- and CK8+10+19-) were the most prominently depleted. No proliferation of thymic epithelial cells was detected as monitored by incorporation of 5-bromodeoxyuridine.

Animals↗
PubMed1992

Effect of Bacillus Calmette-Guérin inoculation on numbers of dendritic cells in bronchoalveolar lavages of rats.

Dendritic cells (DC) are present in all lymphoid tissues and are widely distributed in the airway epithelium and lung parenchyma. In this study DC were morphologically and cytochemically identified in normal rat bronchoalveolar lavage (BAL), although in very low percentages. Furthermore, the total population as well as different Percoll density fractions demonstrated poor antigen-presenting capacity and even suppressed antigen-specific stimulation by rat splenic DC. In contrast, when an inflammatory response was induced by intratracheal inoculation of Bacillus Calmette-Guérin (BCG), an increase of Ia-positive cells, containing high percentages of monocytes and DC (MDC) was found. In BAL, DC increased about 25 times within 48 h after BCG inoculation. These BCG-induced BAL cells as well as the different density fractions showed a high antigen-presenting capacity at low concentrations. However, at higher concentrations they were suppressive, except for the highest density fraction which lacked alveolar macrophages (AM). These results indicate that the increased numbers of Ia-positive MDC during an inflammatory reaction are very likely responsible for antigen presentation in vitro. In contrast, AM suppress the antigen-specific T cell proliferation in a concentration dependent manner.

Animals↗
PubMed1991

A combined method for both endogenous myeloperoxidase and acid phosphatase cytochemistry as well as immunoperoxidase surface labelling discriminating human peripheral blood-derived dendritic cells and monocytes.

On light microscopical (LM) level dendritic cells (DC) isolated from lymphoid organs can be discriminated from macrophages (M phi) by the presence of acid phosphatase (APh) activity in a spot near the nucleus and constitutional expression of class II antigens. The aim of our study was to investigate whether DC and monocytes (Mo) enriched from human peripheral blood could be discriminated on the electron microscopical (EM) level. Therefore we developed a triple method by which we compared the presence of myeloperoxidase (MPO) containing vesicles, the localization of APh containing vesicles and expression of MHC class II and RFD1 (a DC-associated class II-like antigen) plasma-membrane antigens. DC, functionally characterized as potent stimulators in a MLR, are MPO-negative, whereas Mo show MPO in cytoplasmic granules. Although both DC and Mo show little APh activity at LM level, both types of cells show APh activity at the EM level but at different locations. In DC APh containing vesicles are present in a distinct juxtanuclear area, in contrast to Mo, which show APh activity in lysosomes scattered throughout the whole cytoplasm. Moreover, on both LM and EM level, DC are strongly class II positive, whereas Mo show variable labelling intensity for class II, while RFD1 was only found on DC.

Acid Phosphatase↗
PubMed1991

Langerhans cells in nasal mucosa of patients with grass pollen allergy.

Langerhans cells (LC) are known to be present in squamous epithelia of the human body. They are dendritic cells (DC) and characterized by the presence of Birbeck granules (BG). In previous studies, DC positive for CD1a and HLA-DR were found in the cylindrical epithelium and the lamina propria of the nasal mucosa. In our study, more CD1a cells occurred in the allergic patients than in the non-allergic controls. In a combined light microscopy (LM) and electron microscopy (EM) study, biopsies of nasal mucosa in allergic patients were studied. We used monoclonal antibodies against CD1a and HLA-DR, to identify DC in LM cryostat sections. The presence of BG identified most of the intra-epithelial DC as LC on the EM level, whereas a minority of DC in the lamina propria also contained BG. The ultrastructure of LC and DC in the ciliated cylindrical epithelium and the lamina propria is compared.

Adult↗
PubMed1991

Localization of class II molecules in storage vesicles, endosomes and lysosomes in human dendritic cells.

Class II molecules are a prerequisite for antigen presentation. We studied whether class II molecules can be found in the endocytic and/or lysosomal route of dendritic cells (DC), which are very potent antigen-presenting cells. Therefore first immunolabelling for HLA-DR alpha chain was applied on ultrathin cryosections of cells of which plasma membrane HLA-DR/DQ molecules were labelled in suspension, followed by incubation with the endocytic marker BSA-gold. Second, immunolabelling for HLA-DR alpha chains was applied on ultrathin cryosections of cells on which enzyme cytochemistry for acid phosphatase (APh) was performed to see whether the class II positive vesicles belong to the lysosomal compartment. Third, this immunolabelling was applied on cryosections of cells pretreated with the protein synthesis inhibitor cycloheximide (CHX) to see whether the class II positive vesicles are derived from biosynthesis. We found limited uptake of BSA-gold into endosomes and lysosomes, some of which also contained endocytozed HLA-DR/DQ. APh and HLA-DR were observed in the same vesicles but also vesicles containing either HLA-DR or APh were found. However, many class II positive vesicles were found, which were apparently not accessible to exogenous molecules. Moreover, the amount of class II positive vesicles decreased after treatment of the cells with CHX, suggesting that these vesicles form part of the biosynthetic route. These results imply that there is a cluster of class II positive vesicles, probably a storage compartment, that has connections with the lysosomal system. The concentration of lysosomes and class II positive vesicles in the juxtanuclear area of DC is probably of crucial importance in the processing of antigens.

Alkaline Phosphatase↗
PubMed1991

Localization of pepsinogen (A and C) and cellular differentiation of pepsinogen-synthesizing cells in the human gastric mucosa.

The localization of pepsinogens (PG A and PG C) was studied intracellularly in human gastric biopsies embedded in Lowicryl K4M, using affinity-purified antibodies and protein A-gold. The homogeneous secretory granules of the chief cells contained both PG A and PG C, as was proved by serial sections. Identical reaction was also seen in the core of the biphasic mucous neck cell granules, whereas the mantle did not label. The rough endoplasmic reticulum (RER) and Golgi complex of the chief cells and mucous neck cells contained ample label. Transitional cells identified by the presence of granules of both chief cells and mucous neck cells were recognized. This type of mucous neck cell is thought to transform into a chief cell. However, an increase of RER that could explain an increase of the pepsinogen production was not observed. A mixture of these granules was also found in cells morphologically characterized as young parietal cells, suggesting a common precursor for these three cell types. These observations make the transformation from mucous neck to chief cells questionable. Antral gland cells contained only PG C, as was shown in serial section, too.

Cell Differentiation↗