Cell sorter

FACS Flow activated cell sorter factor B Serine protease in the C3 converting enzyme of the alternative pathway... 

Perfetto, S. P. Ambrozak, D. R. Koup, R. A. Roederer, M. Measuring containment of viable infectious cell sorting in high-velocity cell sorters. Cytometry (Pt. A) 2003, 52A, 122-130. 

Fluorescence-activated cell sorter, 26 971 Fluorescence band maxima, 20 512 Fluorescence detection, 17 635 Fluorescence detectors, liquid... 

A fluorescence-activated cell sorter (FACS) is a flow cytometry instrument used to separate and identify cells in a heterogeneous population. Cell mixtures to be sorted are first bound to fluorescent dyes such as fluorescein or phycoerythrin. The labeled cells are then pumped through the instrument and are excited by a laser beam. Cells that fluoresce are detected, and an electrostatic charge is applied. The charged cells are separated using voltage deflection. 

Electronic Standards for Transmission of Regulatory Information European Union antigen-binding fragment fluorescence-activated cell sorter fetal bovine serum constant fragment... 

Fluorescence-activated cell sorters (FACS) have been used to separate subpopulations of cells for subsequent treatment or analysis (see Chapter 30). However, this approach requires that the cells be in suspension. In the case of adherent cells, some cannot be easily suspended, or the treatments used to suspend them may interfere with subsequent analysis. In these situations, a laser microheam system capable of fluorescence imaging can serve two purposes. At low power, the laser can excite fluorescence to produce an image, and at a higher power, the laser can be used to kill the undesired cells. 

Sklar, L. A. and Finney, D. A. (1982) Analysis of ligand-receptor interactions with the fluorescence activated cell sorter. Cytometry 3,161-165. 

Dividing cells in culture exposed to vinblastine or vincristine are arrested from further growth during mitosis (12,13). In fact, the antimitotic effects of this class of compounds is ubiquitous. These effects are observed at relatively low concentrations (<1 iM), and are reversible when drug is removed from the media prior to lysis of the arrested cells. The concentration of drug required to elicit an antimitotic effect is usually comparable to that required to produce a cytotoxic effect in the same cell type (14,15). Originally, this type of analysis was exceedingly laborious, but the introduction of laser- and computer-based fluoresence activated cell sorters (FACS) has rendered this type of analysis routine. Nevertheless, a cytotoxic, non-cell cycle-specific bisindole alkaloid has yet to be discovered. 

Measured after 5 hr of exposure to drug using a fluorescence activated cell sorter. Key -I- -i-, >75% of cells in mitosis -F 50-75% <50%. 

Newer strategies for stem cell identification have been developed based on the knowledge of cell functions. A primitive and multipotential subpopulation of bone marrow mononuclear cells has been identified on the basis of the intracellular presence of aldehyde dehydrogenase (ALDH). Those cells can be marked on the basis of the presence of ALDH and are called aldehyde dehydrogenase-bright cells (ALDH cells), allowing for their separation from a bone marrow aspiration mononuclear subpopulation under fluorescence-activated cell sorter (FACS) analysis. 

The various organs of the immune system such as spleen, lymph nodes, thymus and bone marrow containing the cells involved in the various immune responses offer the possibility to harvest these cells and perform in vitro assays for evaluation of effects on the immune system. When part of an in vivo animal study this may indicate a direct toxic effect of pharmaceuticals, that is, immunosuppression (Table 18.2). So, it is feasible to obtain cell suspensions for further evaluation such as determination of cellular subsets of T and B leukocytes by fluorescent activated cell sorter analysis (FACS analysis), and determination of natural killer (NK) cell activity of the spleen cell population. An advantage of this approach is that it may lead to identification of a biomarker to be used in clinical studies. In addition, in vitro stimulation of spleen cells with mitogens activating specific subsets may indicate potential effects on the functionality of splenic cell populations. Concanavalin A (Con A) and phytohemagglutinin (PHA) activate Tcells, while lipopolysaccharide (LPS) activates primarily B cell populations. Blood is collected for total white blood cell (WBC) determination and blood cell differential count. In addition, serum can be obtained for determination of serum immunoglobulins. 

A number of devices have been made based on this microvalve system. One of the first devices built was a cell sorter on a chip. By manipulating nanoliters of fluid, different strains of fluorescently activated E. coli were introduced, sorted according to their fluorescent properties, recovered from the chip, and cultured. 

Fluorescence-activated cell sorter (FACS) To predict and select cells in the population that express target protein Sensitive and allows direct sorting and cloning of positive cells Required proteins expressed intracellnlarly or on the cell snrface. Not sensitive for expression system engineered to secrete the protein... 

Parks, D. R., Bryan, V M., Oi, V. I, and Herzenberg, L. A (1979) Antigen-specific identification and cloning of hybridomas with a fluorescent-activated cell sorter (FACS) Proc Natl Acad Sci USA 76, 1962-1966... 

Abts, H, Emmerich, M Miltenyi, S Radbruch, A, and Tesch, H (1989) CD20 positive human B lymphocytes separated with the magnetic cell sorter (MACS) can be induced to proliferation and antibody secretion in vitro. J Immunol Methods 125, 19-28. 

Semple, J W, Allen, D., Chang, W, Castaldi, P, and Freedman, J (1993) Rapid separation of CD4+ and CD19+ lymphocyte populations from human peripheral blood by a magnetic activated cell sorter (MACS). Cytometry 14,955-960. 

Fluorescence-activated cell sorter (FACS), e.g., Becton Dickinson FACScan (see Chapters 33 and 34). 

Sort cells with a Cytomation MoFlo cell sorter with the following parameters forward scatter, side scatter, 730 (LIN mode, amplification factor 6) FL1, 600 (LOG mode) FL2, 600 (LOG mode) trigger parameter, side scatter. The sample flow rate should be adjusted to an event rate of approximately 30 000 s-1. Adjust the sorting gate so that approximately 0.1% of the cells fall within the positive window. 

Kamentsky LA, Melamed MR (1967). Spectrophotometric cell sorter. Science 156 1364-1365. 

A third aspect of flow cytometry (known sometimes simply with the acronym for fluorescence-activated cell sorter, FACS, or even more familiarly as just flow) that distinguishes it from many other techniques is the way in which its wide and increasing usefulness has continued to surprise even those who consider themselves experts. What began as a clever technique for looking at a very limited range of problems is now being used in universities, in hospitals, within industry, at marine stations, on submersible buoys, and on board ships plans have existed for use on board space ships as well. The applications of flow cytometry have proliferated (and continue to proliferate) rapidly both in the direction of theoretical science, with... 

Fig. 1.2. Reprinted from Kamentsky LA and Melamed MR (1967). Spectro-photometric cell sorter. Science 156 1364-1365. 1967 by the American Association for the Advancement of Science.

This is not the only kind of cell sorter which is possible. Basically there are three different types. Firstly, there are those which utilise electrical forces only. The travelling wave device is an example of this. Since the electrical forces scale with particle volume, this kind will sort according to the passive electrical properties of the cells [51-53]. Secondly, there are those which use an electrical and another force in combination. Flow is the most promising candidate. As the... 

The first practical applications are likely to include field cages for cell positioning, inexpensive cell sorters and single cell cultivation depots. But once the basic elements for cell handling have been developed, very many kinds of device will become easy to produce. We can expect to see new systems for use in medical diagnosis and pharmaceutical testing within the next decade and a range of cell based biosensors. 

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