FACS analysis of Fas antigen expression on the surface of Jurkat cells.

Jurkat cells were treated for 8 hours with PMA/ionomycin in the presence or absence of 100 μg/mL of poly-l-lysine or collagen I. The cells were harvested and stained as described in “Methods.” The upper left panel represents negative and positive staining of unstimulated Jurkat cells with an isotype-matched control antibody and anti-Fas antibody, respectively. The 3 other panels show antiFas staining in stimulated Jurkat cells that had been treated with PMA/ ionomycin, poly-l-lysine and collagen I as indicated. X axis, relative fluorescence intensity; Y axis, cell number.