Fig. 5. FACScan analysis of Fas and FasL expression in the melanoma cell line 530 under normoxia and hypoxia. 530 melanoma cells were stained with a primary mouse antihuman FasR moAb or mouse antihuman FasL moAb. Incubation with isotype mouse IgG served as a control. After that, cells were washed, and a phycoerythrin-conjugated secondary Ab was added for 30 min at 4°C. Analysis was performed by flow cytometry (FACScan; Becton Dickinson). Ten thousand cells were counted. Isotype control (background staining) is shown as dotted lines.