Tumour growth in anti-CD25 mAb-treated mice. (a) Mice were injected i.p. with 1 mg of either anti-CD25 mAb (solid lines) or 1 mg of an isotype control antibody (dashed lines) 1 and 3 days prior to s.c. inoculation with 2 x 10⁴ B16F10 cells. Each line represents an individual mouse. As indicated in parenthesis, tumour growth was not observed in 3 out of 7 anti-CD25 mAb-treated mice. (b) Tumour growth in groups of 4 mice following injection with anti-CD25 mAbs and anti-CD4-depleting antibodies. (c) Tumour growth in groups of 4 mice following injection with anti-CD25 mAbs and anti-CD8-depleting antibodies.