Fig. 2.

Epitope mapping of the anti-FasL autoantibodies in SLE patients. Recombinant human FasL fragments 1, 2, 3, 4 and 5 were produced and purified using Ni-NTA resin. The proteins were blotted onto polyvinylidene difluoride membranes, stained with Ponceau-S (a), and reacted with immunization-induced rabbit anti-FasL antibody (d) or anti-FasL autoantibodies from SLE patients (b,c). Data shown are representative of seven independent experiments. Note that the immunization-induced antihuman FasL whole extracellular domain (fragment 5) antibody from three rabbits showed the same reaction pattern to the FasL deletion-mutant proteins (d). Among 21 SLE patients studied in this experiment, anti-FasL autoantibodies were present in the seven patients. The seven SLE patients showed the same reaction pattern (b,c).