Fig 7.

 Sodium dodecyl sulfate–resistant Fas aggregates formed in response to CH11 agonistic antibody treatment are no longer observed in the presence of heparin or dextran sulfate. Jurkat T cells were either kept untreated (NT) or treated for various time periods (30, 60, or 120 minutes) with 100 ng/mL of CH11 antibody, 100 μg/mL of heparin (H) or dextran sulfate (DS), or both. Control experiments were also performed in which cells were treated for 10, 30, or 60 minutes with 100 μg/mL of either heparin (H) or dextran sulfate (DS). Protein samples were prepared as described in the Materials and Methods and analyzed by electrophoresis in a 12% polyacrylamide gel. An immunoblot analysis was performed, which was probed with a monoclonal antibody specific to the Fas death domain. An autoradiograph of the enhanced chemiluminescence detection is presented. The white arrows indicate the different forms of Fas that are detected. (B) The same analysis was done with Jurkat T cells either kept untreated (NT) or treated for 60 minutes with 100 ng/mL of anti-Fas CH11 antibody in the absence or presence of 20 μM of z-VAD-fmk or IETD-fmk. (C) Similar type of experiment as above, but in this case Jurkat T cells were either kept untreated (NT) or treated for different time periods (10–180 minutes) with 100 ng/mL of recombinant Fas ligand. A control of cells treated for 180 minutes with 100 ng/mL of CH11 antibody is presented. Autoradiography of the immunoblots is presented