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O Förster

Publications and source records attributed to O Förster.

At least 19 recordsLinked to original sources
PubMed1990

Lectin binding of rat bone marrow cells during colony-stimulating factor type 1--induced differentiation: soybean agglutinin as a marker of mature rat macrophages.

Rat bone marrow cells (BMC) cultured in the presence of murine colony-stimulating factor type 1 (CSF-1) differentiate within 7 days into a cell population containing 96-100% macrophages (M phi). In this study, binding of 10 different fluorescein isothiocyanate (FITC)-conjugated lectins to cultured BMC at various stages of differentiation into M phi was investigated. Only soybean agglutinin (SBA) showed a binding pattern that was significantly correlated to M phi differentiation. Nearly all adherent (A) cells bound SBA. Binding of SBA to nonadherent (NA) cells increased from 20% on day 0 to 80% on day 8. NA cells were separated by means of a fluorescence-activated cell sorter into SBA-, SBA +/-, and SBA+ fractions. On day 0 and day 2, M phi, blast-like cells, eosinophils, and some neutrophils were found in the SBA+ population. From day 4 onwards, the SBA+ fraction contained almost exclusively M phi. Neutrophils and some blasts were found in the SBA- population on days 0 and 2. In the SBA +/- fraction, mainly blasts and lymphocytes were identified. With increasing time of culture, M phi or M phi precursors prevailed also in the SBA-/ +/- cell population. Cells forming colonies in soft agar in the presence of CSF-1 were highly enriched in the SBA +/- fraction. A large number of cells in S-G2/M phases but few colony-forming cells were found in the SBA+ population. Our data suggest that SBA is a useful additional tool to define late stages of M phi differentiation.

Animals↗
PubMed1989

Expression of a binding structure for sialic acid-containing glycoconjugates on rat bone marrow-derived macrophages and its modulation by IFN, TNF-alpha, and dexamethasone.

Rat macrophages express a binding structure for sialic acid-containing glycoconjugates (sialic acid-binding receptor, SAR) which can be detected by a rosette assay utilizing SRBC coated with bovine brain gangliosides (E-G). Freshly isolated rat bone marrow cells (BMC) contain about 5% SAR-positive cells. Rat BMC cultured for 1 wk with tissue culture media containing CSF-1 differentiate into a virtually pure population of bone marrow-derived macrophages (BMDM phi). All BMDM phi bound E-G coated with an optimal concentration of gangliosides (100 micrograms/ml). When BMC were cultured for 1 wk with murine recombinant granulocyte-macrophage CSF, irrespective of the dose of GM-CSF, approximately 90% of the cells were identified as rat macrophages, and practically all expressed SAR. Only about 50% of BMDM phi bound SRBC coated with a suboptimal concentration of gangliosides (20 micrograms/ml). However, this percentage increased markedly after 8 to 72 h incubation with 1 to 10,000 U/ml purified murine IFN-alpha or IFN-beta, whereas murine or rat rIFN-gamma at doses above 10 U/ml led to a decrease of E-G binding. Human and murine rTNF-alpha enhanced rosette formation in a dose-dependent manner. These effects could be blocked by the respective anti-cytokine antibodies. Treatment of BMDM phi with dexamethasone also augmented E-G rosetting. The enhancement of E-G binding was abolished by pretreatment of BMDM phi with cycloheximide and actinomycin D but not with mitomycin C, suggesting that de novo synthesis of protein and RNA, but not DNA, is required. Our results demonstrate that all rat BMDM phi constitutively bear SAR, and that murine IFN-alpha, IFN-beta, and TNF-alpha, as well as dexamethasone, may augment SAR expression.

Adjuvants, Immunologic↗
PubMed1989

Murine recombinant GM-CSF-driven rat bone marrow cell differentiation and factors suppressing cell proliferation.

Rat or mouse bone marrow cells (BMC) cultured for one week with a crude mouse L929 cell supernatant or with purified colony stimulating factor type 1 (CSF-1) differentiate into an essentially pure population of macrophages (M phi). Surprisingly, 90 to 95% of the cells obtained by culturing rat BMC for seven days with recombinant murine granulocyte-macrophage CSF (rmGM-CSF), regardless of concentrations, were classified as M phi. The majority of the remaining cells were granulocytes. This effect is in contrast to that on mouse BMC cultures, where the percentage of granulocytes increased with higher concentrations of rmGM-CSF. The proliferative capacity of rat BMC was demonstrated by colony formation in soft-agar, enumerating total cell number in liquid cultures or measuring 3H-thymidine uptake. A crude L929 cell supernatant and rmGM-CSF induced cell proliferation in a dose-dependent manner. Maximal DNA-synthesis was observed on the fifth day of incubation when BMC were cultured at a density of greater than or equal to 1 x 10(5) cells/well. In cultures initiated with lower cell density, prolonged DNA synthesis was observed. Thereafter, the rate of proliferation declined rapidly. Simultaneous incubation of BMC with GM-CSF and indomethacin led to increased levels of DNA synthesis, suggesting that prostaglandins may suppress cell proliferation. Furthermore, the CSF-induced BMC proliferation was dose dependently inhibited by dexamethasone and 1,25-dihydroxy-vitamin D3 as well as by interferon-gamma and tumor necrosis factor-alpha. The suppressive effect of both cytokines could be abrogated by the addition of the respective anticytokine antibodies.

Animals↗
PubMed1988

Expression of the VEP13 antigen (CD16) on native human alveolar macrophages and cultured blood monocytes.

Human alveolar macrophages (AM phi) from thirteen patients, who were suffering from various lung diseases were harvested by bronchoalveolar lavage. Peripheral blood monocytes from eight healthy donors were isolated by Ficoll-Hypaque gradient centrifugation and adherence to plastic surface. To detect the VEP13 antigen (CD16) on these cells, a rosette assay employing ox erythrocytes coated by the CrCl3 method with purified VEP13 monoclonal antibody (Eo-VEP13) was used. A mean of 31.3% of freshly isolated AM phi and 3.9% of blood monocytes formed Eo-VEP13 rosettes. Monocytes cultured for 3 or 6 days in the presence of a supernatant from mouse L929 cells, which had been shown previously to improve long-term viability of human monocytes in culture, showed 12.5% and 25.3% Eo-VEP13 rosettes, respectively. No significant increase in VEP13 antigen expression was noted by culturing monocytes without L929 cell supernatant. The factor in L929 supernatant that induces VEP13 antigen expression has not been identified. Tunicamycin at 10 micrograms/ml inhibited significantly VEP13 antigen expression on monocytes. In contrast, IgG rosette formation was not reduced by tunicamycin. Our data show that subpopulations of native human AM phi and peripheral blood monocytes cultured in presence of a supernatant of L929 fibroblasts containing mainly murine CSF may express the CD16 antigen, which is normally found on large granular lymphocytes (LGL). Suppression by tunicamycin indicates that Fc receptor glycosylation takes place during a later differentiation step of mononuclear phagocytes.

Antibodies, Monoclonal↗
PubMed1988

Augmentation of IgE receptor expression and IgE receptor-mediated phagocytosis of rat bone marrow-derived macrophages by murine interferons.

Receptors for IgE (Fc epsilon R) on rat bone marrow-derived macrophages (BMDM phi) were demonstrated by a rosette assay employing trinitrophenyl-coated ox erythrocytes (EoTNP) sensitized with mouse IgE anti-dinitrophenyl monoclonal antibody (EoTNP-IgE). Virtually all BMDM phi emerging from bone marrow cells cultured for 1 week in the presence of mouse L929 cell supernatant, with partially purified murine CSF-1 or recombinant murine GM-CSF, formed IgE rosettes. To study the effect of interferons (IFNs) on Fc epsilon R expression, 1-week-old rat BMDM phi were incubated with murine recombinant IFN-gamma, purified IFN-alpha or IFN-beta, and were tested for their capacity to bind and ingest EoTNP sensitized suboptimally with IgE. A marked increase in the percentage of cells forming IgE rosettes or phagocytosing EoTNP-IgE was noted after 8-72 hr incubation of BMDM phi with 0.1-1000 U/ml of IFNs. At similar concentrations IFN-gamma and IFN-beta triggered EoTNP-IgE binding or ingestion more efficiently than IFN-alpha. The enhancing effect was blocked by the respective anti-IFN antibodies, cycloheximide or actinomycin D but not by mitomycin C. The IgE rosette formation and IgE-mediated phagocytosis were dose-dependently inhibited by native rat IgE but not by heat-denaturated IgE myeloma protein IR162 or monomeric rabbit IgG. Our results demonstrate that rat BMDM phi express constitutively Fc epsilon R, and that murine IFNs augment Fc epsilon R-mediated binding and ingestion in a time- and dose-dependent manner. This effect probably reflects an increase in the number of Fc epsilon R per cell, as a result of de novo synthesis of Fc epsilon R.

Animals↗
PubMed1987

Differentiation of rat bone marrow cells into macrophages under the influence of mouse L929 cell supernatant.

Bone marrow cells (BMC) flushed from femora of Lewis rats were cultured in Dulbecco's modification of Eagle's medium supplemented with mouse L929 cell supernatant as a source of colony-stimulating factor (CSF). Differentiation of macrophage progenitor cells into macrophages (M phi) and expression of various markers were kinetically assessed. The proportion of M phi increases from approximately 4% in freshly isolated BMC to 100% after 7-8 days of cell culture. These cells, termed bone marrow cell-derived macrophages (BMDM phi), adhere to and spread on plastic surface; exhibit M phi morphology; stain intensely for nonspecific esterase; are able to phagocytose latex particles, IgG-sensitized erythrocytes, and C3-coated red cells; and express receptors for IgG and C3. A subpopulation of BMDM phi expresses MHC class II antigens as demonstrated by immunofluorescence using MRC OX6 and MRC OX17 monoclonal antibodies which recognize antigens coded in the I-A or I-E subregion of the MHC, respectively. Collectively, our results show that supernatant from mouse L929 cells supports and is continuously required for proliferation and differentiation of rat BMC into typical M phi, and suggest that mouse CSF cross-reacts with the putative receptor on rat M phi.

Animals↗
PubMed1986

Specificity of ganglioside binding to rat macrophages.

The binding specificity of rat alveolar macrophages (AM phi) for sheep erythrocytes (E) coated with gangliosides GM1, GM2, GM3, GD1a, GD1b or GT1b was analyzed in a rosette assay by studying the inhibitory effect of gangliosides, various carbohydrates, IgG, C3b-like C3, and fibronectin in this assay. The uptake of gangliosides by E was calculated from radioactivity measurements using 3H-labeled gangliosides. The different gangliosides were taken up by E at 37 degrees C to a similar extent. Uptake of 3H-labeled GM2 correlated linearly to its concn in the incubation medium. Erythrocytes pretreated with the same molar concn of GM2, GD1a, GD1b or GT1b were bound to AM phi to the same degree reaching a maximum of about 90% rosette forming cells. A mean of 17.8% AM phi-bound GM3-coated E. Treatment of E with asialo-GM2 (GA2) or GM1 did not induce significant rosette formation. A dose-dependent inhibition of rosette formation was observed when AM phi were preincubated at 0 degree C with GM2, GM3, GD1a, GD1b or GT1b, but not with GM1 or GA2 Of the tested carbohydrates, sialyl-lactose had a strong inhibitory effect, while lactose was completely ineffective. N-acetyl-neuraminic acid, N-glycolyl-neuraminic acid and N-acetyl-galactosamine were slightly inhibitory. A series of other carbohydrates including highly negatively charged compounds, as well as fibronectin, IgG or C3b-like C3 did not show significant inhibition. Our data indicate the expression of a receptor on rat AM phi recognizing carbohydrates containing sialic acid at or near the non-reducing terminus.

Animals↗
PubMed1985

Age-related changes in lymphocyte subset proportions, surface differentiation antigen density and plasma membrane fluidity: application of the eurage senieur protocol admission criteria.

Peripheral blood lymphocytes from 260 "apparently healthy" males and females, aged 20-97, have been investigated for age-related changes in a number of immunological parameters (percent and number of lymphocytes, OKT 4+ and OKT 8+ cells; OKT 4/8 ratio; intensity of fluorescence of OKT 4 and OKT 8 stained cells; membrane fluidity). Data were then reassessed after exclusion of people who did not conform to the SENIEUR PROTOCOL admission criteria of EURAGE (European Economic Community's Concerted Action Program on Aging) in order to investigate whether the differences observed were attributable to underlying disease. A slight decrease in the number and percentage of lymphocytes, OKT 4+ and especially OKT 8+ cells was found. Intensity of fluorescence of OKT 4 and OKT 8 stained cells from the elderly was reduced and may explain the lower percentages. Membrane fluidity was decreased in old persons (over the age of 75); the free cholesterol/phospholipid molar ratio in the serum increased up to the age of 75 and then declined, and it did not correlate with decreased membrane fluidity. Exclusion of the 20-60% of the study groups who were not eligible for admission according to the SENIEUR PROTOCOL criteria did not affect these results. The feasability and applicability of the PROTOCOL is discussed.

Adult↗
PubMed1979

Effect of proteinases on EA (IgG)-binding receptors of rat macrophages.

Pronase, trypsin and delta-chymotrypsin deplete rat alveolar peritoneal macrophages of EA (IgG)-binding activity. Trypsin and delta-chymotrypsin show an initially--under certain conditions and lasting--enhancement of receptor activity. Cycloheximide, an inhibitor of protein biosynthesis, accelerated the loss of Fc-receptors and inhibited their reappearance. There are differences between alveolar and peritoneal macrophages in the rate of loss as well as of regeneration of Fc-receptors.

Animals↗
PubMed1978

Separation and characterization of anti-benzylpenicilloyl (BPO) antibodies. II. Immunological properties of different IgG fractions.

Affinity chromatography and subsequent ion-exchange chromatography of pooled anti-benzylpenicilloyl (anti-BPO) hyperimmune sera separated 5 different anti-BPO IgG fractions as described in the preceding paper. These fractions were tested for activities in passive hemagglutination (PHA), passive immune hemolysis (PIH), antibody-dependent cellular cytotoxicity (ADCC) and influence on IgM-induced hemolysis. It was found that anti-BPO IgG fractions with low avidity (dissociation constant K = 4.4--6.7 X 10(-8) moles/l) were poorly active in PHA and ADCC and had no blocking activity in IgM hemolysis. Among the highly avid antibodies (K = 0.7--3.4 X 10(-8) mole/l) no correlations were found between avidity and activities in the immunological tests. The results presented demonstrate that ion-exchange chromatography allows the separation of blocking and lytic antibodies as shown by their influence on IgM-induced complement-dependent lysis of lightly hapten-coated sheep erythrocytes.

Analysis of Variance↗
PubMed1978

[Lung irrigation].

A segmental bronchus is washed with normal saline solution by bronchoscopy. The lavage fluid is collected by aspiration. Lavage is performed to obtain free cells (lymphocytes, alveolar macrophages) for cell culture and specimens for immunological investigations.

Alveolitis, Extrinsic Allergic↗
PubMed1976

[The effect of decomplementation on model experimental inflammatory responses (rat paw oedema) (author's transl)].

An investigation was carried out of the effect of decomplementation by either aggregated human gamma globulin (aggHGG) -- activating the classical complement cascade -- or cobra-venom factor (CVF) -- acting through the alternative pathway -- on rat paw oedema induced by various agents. The direct, passive Arthus reaction (DPA) and dextran-and carrageenin-induced oedema were inhibited by both decomplementing measures, whilst serotonin-and formalin-induced oedema remained unaffected. The paw swelling induced by synthetic bradykinin was significantly reduced only by aggHGG, not by CVF. These observations strongly support -- but do not yet prove -- the assumption that complement is involved in the development not only of the DPA but also of the responses to the polysaccharides, dextran and carrageenin in the rat. The partial inhibition of bradykinin-induced paw oedema by aggHGG and not by CVF might be explained by a densensitization or blocking of bradykinin receptors by a peptide derived from the early-reacting complement components (C 1, 4, 2). Investigations of the effect of aggHGG and CVF on blood pressure, haematocrit, partial thromboplastin time, plasmakininogen and kinase activity, leucocytes and thrombocytes indicate that non-complement-dependent factors are unlikely to be involved in the observed inhibition of experimental rat paw oedema.

Animals↗
PubMed1976

Demonstration of two distinct macrophage specific antigenic determinants in rats.

Exhaustive cross-absorptions of rabbit anti-rat alveolar macrophage sera with peritoneal macrophages and of anti-rat peritoneal macrophage sera with alveolar macrophages did not prove the existence of antigenic determinants specific for alveolar or peritoneal macrophages. Titer-differences of these sera on RAM and RPM seem to be caused by a different distribution of two or more macrophage specific determinants present in both cell populations. Macrophages from other rat tissues show reactivity with these two sera different as well from alveolar as from peritoneal macrophages.

Animals↗
PubMed1976

[BPO-Specific, complement-dependant cell-lysis of differently sensitized sheep red cells: evaluation of haptenic groups and their influence on IgM and IgG-induced lysis (author's transl)].

Sheep erythrocytes were coated with bencylpenicilloyl-(BPO)groups. Different incubation periods resulted in erythrocyte preparations with different hapten density. Complement dependent lysis induced by IgM or IgG antibodies was studied with the cell preparations. The calculation of hapten density on the erythrocyte surface was not possible by direct measurement of coupled radioactive BPO since more than 90% of radioactive material was found in the soluble supernatant after osmotic cell lysis and less than 10% was fixed to the cellular membrane. Measurement of membrane bound immunologically relevant BPO-groups was achieved, therefore, by comparison of the inhibitory capacity of the test cells with that of a standard cell preparation. The latter consisted of tannic acid treated erythrocytes coated with protein complexed radioactive BPO. Surface hapten density of the different target cell preparations varied between 1.9 x 10(5) and 4.8 10(5) BPO-groups per cell depending on the time of incubation. Complement dependent antibody mediated cell lysis was significantly reduced by reduction of haptenic sites per target cell, IgG induced lysis being much more affected than hemolysis induced by IgM antibodies. Statistical calculations led to the conclusion that 18,000 protein islets per cell bearing 4 or more BPO-groups are not sufficient for hemolysis induced by IgG antibodies. 48,000 protein islets with this hapten density are necessary for "optimal" sensitization. IgG antibodies must be apparently bound to the cell surface in bivalent form.

Cell Membrane↗
PubMed1975

Quantitative measurement of delayed hypersensitivity in the guinea pig paw.

To facilitate quantitative measurement of a delayed hypersensitivity reaction, a tuberculin reaction was produced in the paws of sensitized guinea pigs and the resulting edema estimated by one of the usual techniques. The edema formation was shown to be an expression of the delayed hypersensitivity reaction. Optimal conditions for this reaction were assessed. This model may be used for testing the influence of drugs on delayed hypersensitivity reactions.

Animals↗