Functional DISC formation in KG1a and Jurkat cells lines.

(A) Expression of FADD and of procaspase-8 and -3 in KG1a and Jurkat cell lines. FADD, procaspase-8, and procaspase-3 expression in KG1a and Jurkat cells was detected by Western blot as described in “Materials and methods.” (B) DISC formation. KG1a or Jurkat cells were treated, respectively, for 1 hour or 15 minutes by Fas-L–FLAG and anti-FLAG monoclonal antibody before immunoprecipitation. FADD and procaspase-8 were detected by Western blot, as described in “Materials and methods.” (C-F) Fas-induced caspase-8 and -3 activation in KG1a and Jurkat cell lines. Jurkat cells (C, E) were treated for 1 hour with 0.5 μg/mL CH11 or IgM isotypic control. KG1a cells (D, F) were treated by 2 μg/mL CH11 or IgM isotypic control for 24 or 48 hours. Cellular extracts were analyzed by Western blot for caspase-8 (C, D) or caspase-3 (E, F) activation, as described in “Materials and methods.”