Figure 3.

Rejection of the 4-1BBL⁺ NRS1 tumour requires CD8⁺ T cells. (a) Athymic nu/nu mice in groups of five were injected s.c. with 5 × 10⁵ cells/mouse of either NRS1 or 4-1BBL⁺ NRS1 (clone 5.13) and tumour growth was measured as described in the Materials and methods. (b) C3H mice in groups of five were injected i.p. a total of five times with 500 µg of either immunoglobulin control, anti-CD4 (GK1.5), or anti-CD8 (53.6.72) mAb before and after tumour inoculation as described in the Materials and methods. Each group of mice was injected s.c. with 5 × 10⁵ cells of 4-1BBL⁺ NRS1 cells at day 0 and tumour size was measured. The results are expressed as tumour volume of each mouse. Similar results were obtained in two independent experiments.