Detection of Snail in A549 Human Cell Line by Flow Cytometry. A549 human lung carcinoma cell line was stained with Goat Anti-Human Snail Alexa Fluor® 488-conjugated Antigen Affinity-purified Polyclonal Antibody (Catalog # IC3639G, filled histogram) or isotype control antibody (Catalog # IC108G, open histogram). To facilitate intracellular staining, cells were fixed and permeabilized with FlowX FoxP3 Fixation & Permeabilization Buffer Kit (Catalog # FC012). View our protocol for Staining Intracellular Molecules.