Figure 1.

Susceptibility of fresh PBT and ConA blasts to anti-Fas mAb (CH11), soluble human FasL (AL-1), and recombinant soluble mouse FasL (WX1). (a–c), Fresh PBL or ConA blasts were cultured in the presence of the indicated concentrations of CH11 (a), AL-1 (b), and WX1 (c) for 14 h. Cells were then stained with FITC-anti-Fas mAb, PE-conjugated mAb against either CD4 or CD8, and PI. Percent specific cell killing of CD4⁺ and CD8⁺ cells was determined as described in Materials and Methods. (d–g) Fresh PBL (d and e) and ConA blasts (f and g) cultured with (solid line) or without (dotted line) 4,000 units/ml of WX1 for 14 h were stained as described above, and 5 × 10⁴ total cells (including both viable and dead cells) were analyzed in a FACScan^®. Staining profiles for FITC-anti-Fas mAb of viable (PI⁻) CD4⁺ (d and f) or CD8⁺ cells (e and g) are shown.