Flow cytometry technique is predominantly used to measure fluorescence intensity produced by fluorescent-labeled antrbodies or ligands (e.g., cytokines, hormones) that bind specific cell-assocrated molecules. Flow cytometry is quantitative, fast (analysis of >l0,000 cells/min), reliable, and reproducible. Cells can be analyzed individually and simultaneously for several different characteristics or parameters (e.g., size, expression of molecules, viability, cell activation). Flow cytometry offers the opportunity of electronic cell sorting. Flow cytometry is used for: 1. Analyzing the expressron of intracellular and surface molecules on a per cell basis, charactertizing and defining different cell types in heterogeneous populations; 2. Analyzing the purity of isolated subpopulatrons; 3. Analyzing cell size and volume; 4. Determining cell vlabrhty, 5. Detecting apoptosrs; 6. Analyzing DNA cell cycle; and 7. Measuring Ca(2+)flux.