Figure 1.

Successful treatment of preestablished B16-BL6 using anti–CTLA-4 and GM-CSF–producing BL6 vaccine. C57BL/6 female mice (five per group) were injected with 10⁴ B16-BL6 cells subcutaneously on the back, on the same day (A) or 4, 8, or 12 d (B–D) before treatment was started. Treatment consisted of three consecutive injections (in a 6-d time frame as indicated in Materials and Methods) of anti–CTLA-4 antibody 9H10 intraperitoneally (•), control hamster IgG (100, 50, 50 μg; ○), or 10⁶ irradiated BL6/g cells subcutaneously, in combination with 9H10 (▪) or hamster IgG (□). Tumor growth (mm²) was scored by measuring perpendicular diameters and was averaged for all mice within each group. In some treatment groups, only a fraction of the mice (indicated between brackets) developed a tumor.