Figure 3
Surek induces killing of B78-D14 cells in vitro in cultures containing T cells and DCs. All groups contained 1 × 105 B78-D14 or B16-EpCAM cells per well at the beginning of the experiment on d 0. (A) FACS analysis of cocultures on d 4. Dead cells were excluded by PI staining. Viable tumor cells were detected by gating for PI-negative, CD8−, CD4−, CD11c−, CD11b− and GD2+ cells. Numbers of living tumor cells per well were enumerated by using counting beads. (B) Microscopic pictures of cocultures. Almost no living (adherent) B78-D14 tumor cells are detectable in cocultures containing DCs, T cells and Surek on d 6 in contrast to the control groups containing DCs and T cells without Surek or T cells alone with Surek. Magnification 20×. (C) Tumor cell killing assessed in XTT assays. Only intact Surek antibody in combination with DCs induced tumor cell elimination. Corresponding bsF(ab′)2 fragments were ineffective even in the presence of DCs.