Biomedical subjects

O Förster

Publications and source records attributed to O Förster.

At least 19 recordsLinked to original sources

PubMed2001

A long-term validation of the modernised DC-ARC-OES solid-sample method.

The validation procedure based on ISO 17025 standard has been used to study and illustrate both the longterm stability of the calibration process of the DC-ARC solid sample spectrometric method and the main validation criteria of the method. In the calculation of the validation characteristics depending on the linearity(calibration), also the fulfilment of predetermining criteria such as normality and homoscedasticity was checked. In order to decide whether there are any trends in the time-variation of the analytical signal or not, also the Neumann test of trend was applied and evaluated. Finally, a comparison with similar validation data of the ETV-ICP-OES method was carried out.

Journal Article↗

PubMed2000

Expression and function of sialoadhesin in rat alveolar macrophages.

Alveolar macrophages (Amφ) represent an immunologically distinct sub-population within the reticuloendothelial system. Phagocytosis and possibly antigen presentation by Amφ are essential components of specific and innate primary immune defence processes against inhaled material. The mφ-restricted sheep erythrocyte receptor sialoadhesin (Sn) is a member of the immunglobulin superfamily and binds specifically to sialic acid-containing structures such as selectins and was originally identified as the sheep erythrocyte receptor (SER) responsible for sialic acid-dependent binding of native sheep erythrocytes (SE) to resident murine bone marrow macrophages in rosetting assays. Sn expression has been demonstrated on murine and rat mφ in lymphatic organs and is recognised by the monoclonal antibody (mAb) ED3 in the rat. In addition, sialic acid-dependent receptor (SAR) activities that mediate rosette formation of alveolar, peritoneal, splenic and bone marrow-resident rat mφ with SE pretreated with gangliosides and SER-like activities between native SE and trypsinised Amφ, have been described. The binding activities of both SAR and Sn show similar characteristics suggesting that these molecules are closely structurally related or identical. To clarify the relationship between Sn, SAR and SER-like activities, the binding of mAb ED3 to isolated rat Amφ was investigated by flow cytometry and rosetting assays. It is demonstrated that rat Amφ express Sn and evidence is provided that SAR and SER-like activities are mediated by Sn.

Animals↗

PubMed1999

Self-renewal, maturation, and differentiation of the rat myelomonocytic hematopoietic stem cell.

Hematopoiesis is viewed as a differentiating system emanating from a pluripotent hematopoietic stem cell capable of both self-renewal and differentiation. By identifying and characterizing a novel and highly specific in vitro mitogenic response to the N-acetyl glucosamyl/sialic acid specific, stem cell-binding lectin wheat germ agglutinin (WGA), we demonstrate the existance of a rare (0.1%), plastic adherent precursor in rat bone marrow capable of proliferation (two to seven divisions) in response to WGA. Stimulated cells possess a lineage (lin)low/- immunophenotype and immature blastoid morphology (WGA blasts). A subsequent proliferative response to stem cell factor (SCF), the ligand for the proto-oncogene receptor tyrosine kinase c-kit, is characterized by an initial maturation in immunophenotype and subsequent self-renewal of cells (SCF blasts) without differentiation for at least 50 generations. Although granulocyte colony-stimulating factor (G-CSF), interleukin (IL) -6, IL-7, and IL-11 synergize with SCF to increase blast colony formation, cytokines such as granulocyte-macrophage CSF or IL-3 are without significant effect. At all time points in culture, however, cells rapidly differentiate to mature neutrophils with dexamethasone or to mainly monocytes/macrophages in the presence of 1alpha,25-dihydroxyvitamin D3, characterized by cell morphology and cytochemistry. Removal of SCF during blast maturation, self-renewal, or induction of differentiation phases results in apoptotic cell death. Data indicate a pivotal role for SCF/c-kit interaction during antigenic maturation, self-renewal, and apoptotic protection of these lineage-restricted progenitors during non-CSF-mediated induction of differentiation. This approach provides a source of many normal, proliferating myelomonocytic precursor cells, and introduces possible clinical applications of ex vivo expanded myeloid stem cells.

Animals↗

PubMed1997

Galectin-3 inhibits granulocyte-macrophage colony-stimulating factor (GM-CSF)-driven rat bone marrow cell proliferation and GM-CSF-induced gene transcription.

The expression of galectin-3 (formerly known as IgE-binding protein or Mac-2) in rat bone marrow (BM) was investigated by FACS, immunocytochemical and immunoblot analysis. The functional significance of rat recombinant galectin-3 on mouse recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF)-driven proliferation of macrophage progenitors and gene transcription was further examined. Immunocytochemical analysis of in situ BM sections demonstrated galectin-3 in myelopoietic cells and surrounding stroma, whereas erythropoietic and lymphopoietic environments essentially lacked galectin-3 expression. FACS analysis demonstrated that incubation of freshly isolated BMC with lactose, a competing ligand for galectin-3 binding to glycoconjugates, decreased binding of antigalectin antibodies to cells primarily expressing the myeloid antigen recognized by mAb His-54. Similarly, lectin-mediated binding of exogenous galectin-3 to myeloid lineage cells was also demonstrated. Immunoblot analysis of BM eluates demonstrated galectin-3 both in the extracellular matrix and in a lactose elutable form, bound to the surface of BMC. [3H]Thymidine incorporation studies on BMC cultured in the presence of galectin-3 demonstrated suppression of GM-CSF-induced proliferation by galectin-3. In addition, differential display analysis of immediate early gene expression in BMC cultured in the presence of galectin-3 revealed a 76.2% inhibition of GM-CSF-induced gene transcription by galectin-3 assessed by the number of PCR-fragments generated. Our data suggest a role for galectin-3 in the organization of myelopoietic compartments in rat BM and regulation of the action of growth factors on myelopoietic precursor cells.

Animals↗

PubMed1996

Soybean agglutinin binds a 160-kDa rat macrophage membrane glycoprotein and enhances cell differentiation and activation.

Mature macrophages (M phi) differ from other rat leukocytes by their ability to bind soybean agglutinin (SBA). In this study we identify the SBA-binding structure on rat bone marrow-derived M phi (BMDM phi). Precipitation of iodinated membrane proteins from rat bone marrow cells (BMC) and BMDM phi with SBA revealed a major glycoprotein of Mr 160 kDa on BMDM phi but not on BMC. In addition minor bands migrating at 70 and 26 kDa were seen. Stimulation of BMDM phi with 100 nM SBA induced a decrease in surface density of Thy1.1 (MRC OX7) and His54 and an increase in the expression of MRC OX6 (RT1.B/I-A), MRC OX17 (RT1.D/I-E), MRC OX41 (gp 110/120), MRC OX42 (CD11b/c), Macl (CD11b/CR3) and Mac2 (galectin-3/IgE binding protein) antigen. Expression of other M phi differentiation antigens recognized by mAb MRC OX43 (M phi, endothelial cells) and ED9 (M phi/CD14 like) were not significantly altered. BMDM phi derived from cultures with M phi colony-stimulating factor (M-CSF) and SBA showed increased oxidative burst and phagocytic activity compared to cells cultured with M-CSF alone. Our data suggest that binding of a 160-kDa membrane glycoprotein on M phi by N-acetylgalactosamine-specific lectins stimulates M phi differentiation and activation.

Animals↗

PubMed1996

Immunophenotyping of human bone marrow-derived macrophages.

In vitro cultured cells derived from human bone marrow stimulated with macrophage-colony stimulating factor (M-CSF) or granulocyte-macrophage-colony stimulating factor (GM-CSF) were investigated for their immunophenotypic surface characteristics by flow cytometry. Approximately 80-90% of the cells showed morphological and histochemical features of macrophages and bore CD11a, CD11b, CD11c, CD14, CD29, CD32, CD33, CD44, CD45, CD54, CD64, CD71, HLA-DR antigen. The expression of CD4, CD25 and CD45RO were detected only in low density. Bone marrow-derived macrophages were negative for CD8, CD45RA, CD16 and CD23. Functionally, macrophages were able to phagocytose opsonized Escherichia coli, but no oxidative bursts were induced either by fmlp or by opsonized bacteria. Cell surface phenotyping revealed a CD pattern very similar to monocyte-derived phagocytes, and was partially distinct from resident stromal macrophages.

Adult↗

PubMed1995

Tumor necrosis factor-alpha induction of major histocompatibility complex class II antigen expression is inhibited by interferon-gamma in a monocytic cell line.

Regulation of major histocompatibility complex (MHC) class II antigen expression by cytokines has been suggested to play a major role in the initiation and propagation of immune and autoimmune processes. The analysis of class II gene regulation benefits greatly from the existence of mutants with defects in regulatory factors. We report the establishment of a subclone of the human monocytic cell line U937, termed C119/9, with unusual cytokine regulation of MHC class II expression. In contrast to the parental U937 cell line, only tumor necrosis factor (TNF)-alpha, and not interferon (IFN)-gamma induces the expression of MHC class II antigens on C119/9 cells, and paradoxically, this induction was inhibited almost completely by IFN-gamma. The HLA-DR induction is controlled at the transcriptional level by the first 150 bp of the class II promoter which contains all the class II consensus elements. Both HLA-DR and -DQ mRNA are induced by TNF-alpha treatment, and both are diminished upon co-treatment with TNF-alpha and IFN-gamma. This antagonism between TNF-alpha and IFN-gamma seem to be restricted to MHC class II genes. This subline of U937 cells may be useful in further studies of MHC class II regulation.

Blotting, Northern↗

PubMed1995

Expression of MHC class II antigens on rat bone marrow cells and macrophages, and their modulation during culture with murine GM-CSF or M-CSF.

Flow cytometric analysis employing MRC OX 6 and MRC OX17 monoclonal antibodies recognizing determinants on RT1.B or RT1.D molecules, equivalent to murine I-A and I-E, respectively, was used to detect rat MHC class II antigen (Ag) expression. Approximately 5% of freshly isolated rat bone marrow cells (BMC) expressed RT1.B and over 30% displayed RT1.D molecules. The RT1.D+ cells were W3/13+, OX 7+, OX 19- and OX 22-. After one week culture of BMC with murine recombinant granulocyte/macrophage colony-stimulating factor (GM-CSF), regardless of concentrations, 90 to 95% of the cells were scored as bone marrow-derived macrophages (BMDM phi), and over 30% expressed both RT1.B and RT1.D Ag. GM-CSF increases the percentage of BMDM phi bearing MHC class II Ag in a concentration-dependent manner. This effect seems to be specific because antibodies to interferon-gamma, tumor necrosis factor-alpha or interleukin-4 did not reduce the number of cells expressing RT1.B and RT1.D Ag. Furthermore, GM-CSF was able to trigger expression of class II molecules on rat peritoneal macrophages (M phi) and BMDM phi resulted from cultures of BMC with mouse M phi-CSF (M-CSF), and the RT1.B and RT1.D inducing effect of GM-CSF was opposed by M-CSF, and by anti-GM-CSF antibodies. The induction of MHC class II Ag synthesis by GM-CSF on rat BMDM phi was confirmed at the mRNA level by Northern blot analysis employing cDNA probes encoding the RT1.B alpha.

Animals↗

PubMed1994

Ligation of N-acetylgalactosamine-containing structures on rat bone marrow cells enhances myeloid differentiation and murine granulocyte-macrophage colony-stimulating factor-induced proliferation.

Previously we have reported the differentiation-dependent expression of a soybean agglutinin (SBA)-binding structure on rat bone marrow cells (BMCs) during their differentiation into macrophages (m phi s). In the present study we tried to analyze the functional role of the SBA-binding structure in BMC proliferation and differentiation. Addition of SBA to BMC cultures driven into m phi differentiation by recombinant murine granulocyte-macrophage colony-stimulating factor (rmGM-CSF), resulted in a two- to threefold increased proliferation rate compared with rmGM-CSF alone. However, the number of colonies in methyl cellulose was not increased by SBA. The effect of SBA was dose dependent (from 4 to 83 pM SBA), with a maximum effect at 83 pM. Experiments to detect a possible synergistic effect of additional cytokines produced by BMC after SBA treatment were inconclusive. The enhancing effect of SBA was also seen when high-density cells, which did not proliferate in response to rmGM-CSF (mainly granulocytes), were removed. Therefore, SBA may increase the CSF reactivity of responsive m phi progenitor cells directly by binding to N-acetylgalactosamine residues on their surface.

Acetylgalactosamine↗

PubMed1994

Phenotype and function of peripheral and prostatic lymphocytes in patients with benign prostatic hyperplasia.

In a previous report, we demonstrated intense lymphocytic infiltration of all benign prostatic hypertrophy (BPH) tissues analyzed in conjunction with HLA-DR expression on normally MHC-class-II-negative prostate epithelial cells. The composition of these infiltrates (70 to 80% CD3+ T-cells, but no granulocytes) resembles the situation seen in immune responses against altered self or self rather than against foreign antigens (infection). In the present study, phenotypic and functional immunoassays were used in order to investigate whether T-cells in BPH are indeed activated, and whether this activation is systemic or restricted locally to the prostate. Analysis of T-cell activation marker expression and proliferation requirements provided substantial evidence that these infiltrating lymphocytes, in contrast to their peripheral counterparts, are chronically activated. Since local accumulation of activated lymphocytes can cause tissue destruction, high concentrations of cytokines, and consequently tissue rebuilding, this process might contribute to the pathogenesis of BPH.

Adult↗

PubMed1993

T-T cell interactions in patients with endocrine autoimmunity. Definition of antiergotypic T lymphocytes.

T-T cell interactions are known to be of importance in the generation of immune responses and have been postulated to play a role in autoimmunity. Antiergotypic T lymphocytes are cells, which react with other activated T cells, which they may consecutively neutralize. Antiergotypic T cells have been described to play a role in animal models of autoimmunity and have been found in patients with rheumatoid arthritis. It was the aim of the present study to analyse, whether antiergotypic T cells were also present in the blood of patients with endocrine autoimmunity and to characterize them in vitro. We found that peripheral blood mononuclear cells from patients with Graves' disease, Hashimoto's thyroiditis and Diabetes mellitus show a pronounced proliferative response, when stimulated with autologous T cell lines. This response is dependent on the state of activation of the stimulator cell population, but is independent of its phenotype and is not MHC restricted. In contrast to normal control cells PBMC from patients with endocrine autoimmune disorders respond better to autologous T lymphocytes, than to allogeneic T cells and to autologous E- monocytic cells. T cells responsive to activated autologous T cell lines can also be expanded from PBMC. They may be CD4+ or CD8+ and recognize autologous T cells in the presence of autologous PBMC as feeder cells. These results suggest the presence of a T-T cell network in patients with endocrine autoimmune disease, which may have an important regulatory role in the disease process.

Adult↗

PubMed1993

Lectin binding to chronic inflammatory gingival tissue: possible adhesion mechanisms based on lectin-carbohydrate interactions.

In this study, we analyzed the expression of different leukocyte surface antigens, of the adhesion molecules ELAM-1 and GMP-140 and binding of various lectins and neoglycoproteins in inflamed gingival tissue. Cell suspensions from collagenase-digested gingiva were analyzed by flow cytometry in a FACScan. The expression of ELAM-1, GMP-140, carbohydrate structures and lectins in gingival specimens was also studied by immunohistochemistry. Gingival tissue of patients with active periodontal disease contained between 5% and 50% CD45+ mononuclear cells, consisting mainly of CD19+ cells (B lymphocytes). CD62, resembling GMP-140, and ELAM-1 were strongly expressed on endothelial cells of these patients. Control subjects usually contained almost no CD45+ cells in their gingiva and no CD62+ or ELAM-1-positive endothelial cells could be found in 5 of 6 control persons. Analysis of the glycosylation pattern revealed staining of infiltrating cells by peanut agglutinin (PNA; specificity for galactose), whereas soy bean agglutinin (SBA; specificity for N-acetyl-galactosamine) bound to epithelial cells. An endogenous lactosyl-specific lectin could be detected on endothelial cells by binding of lactosyl-BSA. Ulex europeus I agglutinin (UEA-1, specific for fucose) showed selective staining of endothelial and epithelial cells. Expression of a fucose-binding lectin, demonstrated by binding of fucosylated BSA, could be found on infiltrating cells. The adhesion molecules ELAM-1 and GMP-140 seem to be involved in cell adhesion during chronic inflammation of the gingiva. Interaction of other carbohydrate residues with endogenous lectins might resemble additional adhesion mechanisms in inflamed gingiva.

Antigens, CD↗

PubMed1993

Suramin affects human peripheral blood mononuclear cells in vitro: inhibition of T cell growth and modulation of cytokine secretion.

Suramin, a polyanionic compound, which has been in clinical use for the treatment of African trypanosomiasis for several decades, has recently been introduced in clinical oncology. Its effects on the immune system seemed therefore of interest. In the present study we tried to elucidate in vitro how suramin affected different functions of human peripheral blood mononuclear cells (PBMC). Suramin suppressed the proliferation of PBMC in response to various stimuli, including OKT3, phytohemagglutinin (PHA), phorbolmyristate-acetate (PMA) and ionomycin, purified protein derivate of Mycobacterium tuberculosis (PPD) and antibodies against CD2. It also inhibited the binding of monoclonal antibodies to T cell surface antigens. This effect was not dependent on the isotype of the antibody, but seemed to be highly epitope-specific. Among a panel of antibodies against one antigen, only a few were affected by the compound. Whereas the binding of Leu3a and OKT3 was for instance fully suppressed by suramin, OKT4 and Leu4 binding was only slightly affected. Suramin also decreased the expression of T cell surface molecules such as CD2, CD25 and CD4 in preactivated PBMC and had pronounced effects on cytokine production. Interestingly the compound had adverse regulatory effects on different cytokines. Whereas the secretion of interferon-gamma was completely suppressed by suramin, interleukin-2 (IL-2) and IL-4 production was stimulated. These results demonstrate that suramin affects T cell function in multiple different ways. This will have to be considered, when suramin is used in the treatment of cancer patients.

Adult↗

PubMed1993

Tumour necrosis factor-alpha augments the expression of Fc IgE receptor (Fc epsilon RII/CD23) on human monocytic cell lines and down-regulates interleukin-4-driven Fc epsilon RII expression on monocytes.

We investigated the expression of the low affinity Fc IgE receptor (Fc epsilon RII/CD23) on the human monocytic cell lines U937, THP-1, Mono-Mac-6, and cultured human peripheral blood monocytes under stimulation with human tumour necrosis factor-alpha (TNF-alpha) and other cytokines. Fc epsilon RII was demonstrated by flow cytometry analysis employing the anti-Fc epsilon RII monoclonal antibody 3-5. TNF-alpha alone had a weak but significant stimulating effect on the Fc epsilon RII expression on the cell lines U937 and THP-1, and very modestly on Mono-Mac-6 cells. TNF-alpha strongly synergized with interferon-gamma (IFN-gamma) and interleukin-4 (IL-4). IFN-alpha per se was ineffectual, but was able to increase the TNF-alpha effect. Furthermore, the action of TNF-alpha was slightly augmented by human IL-6. Similar effects were noted with TNF-beta alone or in combination with other cytokines. Interestingly, on human monocytes TNF-alpha weakly reduced the basal level of Fc epsilon RII, and markedly diminished the IL-4-induced Fc epsilon RII expression. Our results indicate that several cytokines may interact in a cytokine network to modulate Fc epsilon RII expression on monocytic cell lines. On human blood monocytes, TNF-alpha, like IFN-gamma or IL-6, counteracts the IL-4-induced Fc epsilon RII expression. These data suggest different regulatory pathways of Fc epsilon RII expression on blood monocytes and myelomonocytic cell lines.

Cell Line↗

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↗