Flow cytometry has been used by researchers and clinicians for over 30 years to distinguish specific cell types in heterogeneous cell populations based on external and internal expression of cellular markers. Cytometry is the measurement of physical and chemical properties of biological cells, whereas flow cytometry is the measurements of these cell properties while cells flow through an instrument in a fluid suspension. As the cells move in this stream they pass through a beam of laser light. The cells, or particles, scatter light as they move through the beam and this scattered light is picked up by two detectors. The Forward Scatter (FSC) detector is in line with the light beam and detects light scattered in the forward direction. The Side Scatter (SCC) detectors are perpendicular to the light beam and pick up light scattered in those directions. In addition to these detectors, a flow cytometer has one or more fluorescent detectors. If a cell population has been “tagged” with a fluorescent chemical (e.g.,fluorescent antibody) the laser beam excites the fluorescent chemical into emitting light at a longer wavelength than the light source. With these combinations of fluorescent and scattered light, thousands of cells per second can be interrogated for size, shape and internal complexity. In addition, any function or cellular components detected by a fluorescent signal can be analyzed.
The capability for analysis of both cell surface and intracellular components has made flow cytometry a well established and essential tool in medical diagnostics, as well as pharmaceutical and clinical research. The fields of immunology, transplantation, hematology, genetics, cancer and HIV have particularly benefited due to flow cytometry’s capabilities to detect many parameters from a single cell in a rapid, accurate, non-invasive manner. Current applications of flow cytometry include:
Assists in the prognosis and monitoring of disease states
Drug therapy monitoring
Monitoring immunological response in transplant patients
Determining the adequacy of immunosuppressive therapies through T-cell analysis
Detection of subtle changes in cellular components
Determining mechanisms of infectious diseases
The rapid expansion in flow cytometry applications will allow flow cytometry to play an even larger role in medicine and systems biology.
The Flow Cytometry Lab at Viracor-IBT performs clinical, pharmaceutical and research testing. The lab has a custom-configured BD Biosciences LSR II Flow Cytometer™ that is capable of detecting up to 12 parameters (2 scatter and 10 fluorescent) per cell, two Beckman Coulter FC 500™ cytometers with the capacity to conduct 2 scatter, 5-color analysis with a single or dual laser configuration and a Guava PCA™ for easy 2-color detection.
Beckman Coulter, Flow Cytometry as a Diagnostic Tool, www.expresspharmaonline.com 2008, June
Melamed M, Lindo T, Mendelsohn M, Flow Cytometry and Sorting, 2nd edition 1991
Shapiro H, Practical Flow Cytometry, 4th edition, John Wiley & Sons, 2003
Stein R, Flow Cytometry’s Expanding Niche, Genetic Engineering & Biotechnology News, 2009, Nov; (Vol. 29, No.20)
Stetler-Stevenson M, Flow Cytometric Immunophenotyping: Emerging as an Important Diagnostic Tool in the Evaluation of Cytopenic Patients, Leuk Res. 2009 August; 33(8): 1020-1021