Murine FL5 cells (FL5-NEO) and FL5 cells transfected with Bcl-xL expression plasmid (FL5-BCL-XL) were fixed with buffered paraformaldehyde and then permeabilized with saponin. The cells were incubated with BCL2L1 monoclonal antibody, clone 7B2.5 followed by phycoerythrin-conjugated goat anti-mouse IgG, and then were analyzed by flow cytometry.