CD8⁺ T cells are required for OX86-mediated rejection. (A) Mice bearing CT26 tumors of 3–4 mm in diameter were depleted of CD8⁺ T cells immediately before receiving an intratumor injection of 100 μg of purified anti-OX40 mAb. As controls, mice received either anti-OX40 alone (B) or anti-CD8 (C) mAb. Lines represent the tumor growth kinetics in each single mouse within the different experimental groups. The number of tumor-free mice out the total number of treated mice is indicated. One representative of two independent experiments is shown.