After initiating apoptosis, most cell types translocate the membrane phospholipid phosphatidylserine (PS) from the inner face of the plasma membrane to the cell surface. Once on the cell surface, PS can easily be detected by staining with a fluorescent conjugate (PE) of Annexin V, a member of the annexin family of intracellular proteins that binds to phosphatidylserine (PS) in a calcium-dependent manner. This kit applies PE Annexin V staining in conjunction with a vital dye such as 7-Amino-Actinomycin (7-AAD) to identify early apoptotic cells (7-AAD negative, PE Annexin V positive). Viable cells with intact membranes exclude 7-AAD, wheras the membranes of dead and damaged cells are permeable to 7-AAD. For example, cells that are considered viable are PE Annexin V and 7-AAD negative; cells that are in early apoptosis are PE Annexin V positive and 7-AAD negative; and cells that are in late apoptosis or already dead are are both PE Annexin V and 7-AAD positive. This assay does not distinguish between cells that have undergone apoptotic death versus those that have died as a result of a necrotic pathway because in either case, the dead cells will stain with both PE Annexin V and 7-AAD. However, when apoptosis is measured over time, cells can be often tracked from PE Annexin V and 7-AAD negative (viable, or no measurable apoptosis), to PE Annexin V positive and 7-AAD negative (early apoptosis, membrane integrity is present) and finally to PE Annexin V and 7-AAD positive (end stage apoptosis and death). The movement of cells through these three stages indicates apoptosis.
10X Annexin V Binding Buffer (20 ml)
PE Annexin V (0.5 ml)
7-AAD (2 ml)
Flow Cytometry, Fluorescence Microscopy
20 tests ; 50 tests ; 100 tests
Store between 2°C-8°C. Do not freeze.
Celltechgen provides high-quality reagents and materials for research use only. For proper handling of potentially hazardous chemicals, please request the Safety Data Sheet (SDS) provided for the product.