Evaluation of apoptosis by annexin V staining shown by fluorescence microscopy at day 8 pi. (Left panel) phase contrast light microscopy; (right panel) immunofluorescence microscopy of the same field. Note the presence of one syncytium (left panel) that is negative after annexin V staining (right panel). On the other hand, a single cell in the bottom right part of the photograph shows intense green membrane staining. Original magnification × 400.