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S Miltenyi

Publications and source records attributed to S Miltenyi.

9 recordsLinked to original sources
PubMed1997

Large-scale isolation of CD34+ cells using the Amgen cell selection device results in high levels of purity and recovery.

The Amgen Cell Selection Device (ACSD) is a fully automated system based on the research scale magnetic-activated cell separation (MACS) system (Miltenyi Biotech GmbH, Bergisch Gladbach, Germany) for the selection of CD34+ cells. Leukapheresis products (LP) (n = 30) from normal donors mobilized with recombinant human granulocyte colony-stimulating factor (rhG-CSF) were selected with the ACSD to evaluate the performance of this system. The starting LP contained a median of 0.51% CD34+ cells (range 0.21%-1.54%) and a median WBC count of 3.0 x 10(10) (range 1-4.7 x 10(10) cells). After selection on the ACSD a mean purity of 91.5% +/- 0.6% CD34+ cells was obtained, with a median purity of 95.5% CD34+ cells. A median of 98 x 10(6) total CD34+ cells were recovered postselection, with a range of 31-323 x 10(6) cells collected from the LP. This represented a mean recovery of 81.7% +/- 6% of CD34+ cells and a median of 78% compared with starting CD34+ cell numbers in the LP. FACS analysis of the selected products demonstrated a 4-5 log depletion of T cell subsets, including CD3, CD4, CD8, and CD56 subsets. These data demonstrate the high performance obtained with the ACSD resulting in a final product of greater than 90% purity of CD34+ cells. CD34+ cells selected with the ACSD represent an ideal product for clinical applications, such as tumor cell purging, T cell depletion for allogeneic transplant, ex vivo expansion, and gene therapy.

Antigens, CD↗
PubMed1996

Specific expression of surface interferon-gamma on interferon-gamma producing T cells from mouse and man.

Interferon (IFN)-gamma is a potent immunoregulatory protein secreted by CD4+ and CD8+ T cells and by natural killer cells. Here, we show that IFN-gamma is specifically displayed at a low concentration on the cell surface of those activated T cells from mouse and man which express IFN-gamma. It is transiently expressed on the cell surface with kinetics similar to those of intracellular IFN-gamma expression. Detectable surface IFN-gamma is not expressed by activated T helper (Th) cells producing other cytokines but which do not express IFN-gamma. Thus, surface IFN-gamma is the first available marker for live T lymphocytes expressing IFN-gamma, e.g. Th1 cells.

Animals↗
PubMed1995

Analysis and sorting of live cells according to secreted molecules, relocated to a cell-surface affinity matrix.

We have developed a technology for analysis and sorting of live cells according to secreted molecules. An artificial affinity matrix, specific for the secreted product of interest, is created on the cell surface, and the cells are allowed to secrete for a defined time period. The secreted molecules bind to the affinity matrix on the secreting cell and are subsequently labeled with specific fluorescent or magnetic staining reagents for cytometric analysis and cell sorting. Crossfeeding of the secreted products to other cells is prevented by decreasing the permeability of the incubation medium. This approach will have a wide range of applications in biotechnology and biomedical research. Here, we describe analysis and sorting of hybridoma cells, according to secreted antibodies, and of activated T lymphocytes, according to secreted cytokines.

Animals↗
PubMed1994

Enrichment of fetal cells from maternal blood by high gradient magnetic cell sorting (double MACS) for PCR-based genetic analysis.

For simple and effective isolation of fetal cells from peripheral maternal blood, we combined depletion of maternal cells and enrichment of fetal cells by high-gradient magnetic cell separation (MACS). First CD45+ and CD14+ cells were depleted from maternal peripheral blood mononuclear cells by MACS. From the depleted fraction, CD71+ erythroid cells were enriched up to 80 per cent by MACS. This double-MACS' procedure yielded an average depletion rate of 780-fold and an average enrichment rate of 500-fold, with approximate recovery rates of 40-55 per cent. For paternity testing, cells from unseparated blood and the various fractions were analysed for polymorphism of the HLA-DQ-A1 locus and D1S80 locus by the polymerase chain reaction (PCR). In CD45-/CD71+ sorted cells from maternal blood, but not in unfractionated cells from maternal blood or CD45-/CD14- cells, paternal alleles could be detected. In the CD45-/CD71+ fraction, the relative frequency of paternal alleles compared with maternal alleles ranged from 1 in 20 to 1 in 200 (determined by titration and depending on the quality of separation and biological variation). In 7 out of 11 cases, between weeks 12 and 25 of gestation, we could identify paternal alleles by PCR, either HLA-DQ-A1 or D1S80. This double-MACS procedure is simple, fast, efficient, and reliable for non-invasive prenatal diagnosis.

Antigens, CD↗
PubMed1992

Specific MR imaging of human lymphocytes by monoclonal antibody-guided dextran-magnetite particles.

Human lymphocytes were labeled with biotinylated anti-lymphocyte-directed monoclonal antibodies, to which streptavidin and subsequently biotinylated dextran-magnetite particles were coupled. This labeling resulted in a strong and selective negative contrast enhancement of lymphocyte suspensions at 2.0 T, caused predominantly by the specific increase of R2 with a small but significant specific increase of R1. The R1 was found to decrease with increasing field strength. The immunolabeling procedure described here may be used for the selective signal depletion of target cells in MR imaging.

Antibodies, Monoclonal↗
PubMed1990

High gradient magnetic cell separation with MACS.

A flexible, fast and simple magnetic cell sorting system for separation of large numbers of cells according to specific cell surface markers was developed and tested. Cells stained sequentially with biotinylated antibodies, fluorochrome-conjugated avidin, and superparamagnetic biotinylated-microparticles (about 100 nm diameter) are separated on high gradient magnetic (HGM) columns. Unlabelled cells pass through the column, while labelled cells are retained. The retained cells can be easily eluted. More than 10(9) cells can be processed in about 15 min. Enrichment rates of more than 100-fold and depletion rates of several 1,000-fold can be achieved. The simultaneous tagging of cells with fluorochromes and very small, invisible magnetic beads makes this system an ideal complement to flow cytometry. Light scatter and fluorescent parameters of the cells are not changed by the bound particles. Magnetically separated cells can be analysed by fluorescence microscopy or flow cytometry or sorted by fluorescence-activated cell sorting without further treatment. Magnetic tagging and separation does not affect cell viability and proliferation.

Animals↗
PubMed1989

CD20 positive human B lymphocytes separated with the magnetic cell sorter (MACS) can be induced to proliferation and antibody secretion in vitro.

A method is described for the efficient purification of human B lymphocytes from peripheral blood by magnetic separation. Biotinylated, superparamagnetic particles were coupled to target cells by fluorescein isothiocyanate conjugated avidin and biotinylated monoclonal antibodies directed against cell surface antigens. This combination permitted flow cytometric control of the magnetic separation. Ficoll-Paque-separated peripheral blood mononuclear cells were first eliminated from monocytes by leucine-methyl ester treatment. B cells were enriched to 97% after magnetic depletion of CD3-positive T cells and magnetic enrichment of CD20-positive B cells. The separated B cells could be induced to proliferation and antibody production by various in vitro stimuli.

Antibody-Producing Cells↗