Detection of apoptosis in a heterogenous cell population using flow cytometry

Apoptosis induced in human leukemic cells (promyelocytic human leukemic cel ls HL-60, multidrug-resistant subline HL-60/VCR) and human ovarian carcinom a cells (A2780 and multidrug-resistant subline A2780/ADR) in vitro was dete cted by flow cytometric analysis or DNA electrophoresis. The cytofluorometr ic techniques utilized, i. e. detection of phosphatidylserine exposed at th e outer surface of the plasma membrane, identification of cells with "sub-G (O)" DNA content or increased light side scatter (cell internal structure) correlated with the electrophoretic determination of DNA fragmentation ("DN A ladder"). Detection of the 34 kDa mitochondrial protein recognized by the monoclonal antibody Apo2.7 yielded elevated percentages of apoptotic cells , suggesting that this technique detecting both early and late apoptosis in digitonin-fixed cells might not be restricted to the specific detection of programmed cell death.