Figure 6.

Resuspended VP from hTRAIL-PA317 expresses specific cytotoxicity. The hTRAIL-PA317 cell line was generated as described in Materials and Methods. Both hTRAIL VP (A) and cKrox control VP (B) were cultured with Jurkat target cells for 5 h, followed by the addition of dyes. Dye uptake was evaluated 1 h later. Red fluorescent ethidium homodimer dye is taken up by apoptotic cells, and green calcein acetoxymethyl ester is taken up by living cells. (C) A dose–response curve of cytotoxicity of the hTRAIL VP against ⁵¹Cr-labeled Jurkat targets. (D) Cytotoxicity of hFasL VP but not hTRAIL VP is inhibited by Fas-Ig. (E) The cytotoxicity of hTRAIL VP but not hFasL VP is sensitive to a soluble form of the hTRAIL DR5 receptor (sDR5).