B-CLL killing by anti-third-party CTLs is not inhibited by CD95/CD95L blockade. (A) B-CLL cells (2.5 × 106) obtained from patients in stage IV were cultured alone (i) or with 5 × 105 allogeneic anti-third-party CTLs in the absence (ii) or presence of contact inhibition by means of incubation in transwell plates (iii), preincubation with LFA-1-blocking antibodies (iv) or following preincubation of B-CLL cells with anti-CD95-blocking Ab (v). Three days later, different wells were sampled and stained with the corresponding fluorescent Abs. Subsequently, cells were tested for apoptosis by annexin staining, as described in “Materials and methods.” A representative experiment is shown. (B) B-CLL cells (2.5 × 106) obtained from patients in stage IV were cultured alone (i) or with 5 × 105 allogeneic anti-third-party CTLs in the absence (ii) or presence (iii) of anti-CD95-blocking Ab. Three days later, different wells were sampled and stained with the corresponding fluorescent Abs. A representative experiment is shown. Numbers in graphs represent percent of cells in the upper-right quadrant (double positive cells).
