Fluorescent confocal image of HeLa cells stained with Alkaline Phosphatase (ALPI) (Center) antibody. HeLa cells were fixed with 4% PFA (20 min), permeabilized with Triton X-100 (0.2%, 30 min). Cells were then incubated with AP1480c Alkaline Phosphatase (ALPI) (Center) primary antibody (1:100, 2 h at room temperature). For secondary antibody, Alexa Fluor� 488 conjugated donkey anti-rabbit antibody (green) was used (1:1000, 1h). Nuclei were counterstained with Hoechst 33342 (blue) (10 ?g/ml, 5 min). Alkaline Phosphatase (ALPI) immunoreactivity is localized to the cytoplasm of HeLa cells.