AAT Bioquest

What stain should I use to analyze apoptosis in flow cytometry?

Posted May 9, 2020


A good option for analyzing apoptosis is an Annexin V/PI assay. Annexin V can be conjugated to a variety of fluorophores such as FITC and works by binding to phosphatidylserine (PS) residues, which translocate from the inner to the outer leaflet of a plasma membrane during apoptosis. Cells undergoing apoptosis will thus stain positive for Annexin V. Meanwhile, PI (propidium iodide) binds to DNA and stains dead cells.

Using the Annexin V/PI assay can distinguish between early apoptotic cells, which stain Annexin V+/PI-, and late apoptotic cells, which stain Annexin V+/PI+. Live cells stain negative for both Annexin V and PI. However, it is important to note that necrotic cells can stain both Annexin V-/PI+ and Annexin V+/PI+.

Additional resources

Brauchle, E., Thude, S., Brucker, S. Y., & Schenke-Layland, K. (2014). Cell death stages in single apoptotic and necrotic cells monitored by Raman microspectroscopy. Scientific reports, 4, 4698.

Cell Meter™ FITC-Annexin V Binding Apoptosis Assay Kit *Optimized for Flow Cytometry*

Annexin V, FITC Labeled