Automatic image analysis for quantification of apoptosis in animal cell culture by annexin-V affinity assay

Apoptosis is a form of cell death in which the dying cell plays an active part in its demise. At the morphological level, it is characterised by cell shrinkage rather than the swelling seen in necrotic cell death. In cell culture, apoptosis limits the yield of economically and medically important products, and can result in synthesis of imperfect molecules. Therefore, this process must be identified, monitored and fully understood, so that a means to regulate it can be developed. We have developed a new automatic image analysis assay for detecting apoptosis in animal cell culture on the basis of the annexin-V affinity assay. The results of this assay were compared with data generated by flow cytometry and manual scoring. All three methods were found to correspond well but image analysis like flow cytometry offers operator-independent results, and can be used as a tool for rapid monitoring of viable cell number, apoptosis and necrosis in animal cell culture. Furthermore, reduction in cell size was measured and was found to precede the appearance of phosphatidylserine on the cell surface.