Fig. 2.

A, antitumor immunity generated by the combination of cyclophosphamide plus cryoablation can be passively transferred by lymphocytes in a dose-dependent manner. Surviving animals from the first two experiments were sacrificed at day 150. Spleen and draining lymph nodes were harvested, and a single-cell suspension was prepared. Naive animals were injected with 2 × 10⁵ CT26 cells intravenously along with 0, 10⁵, 10⁶, or 10⁷ spleen and lymph node cells (n = 5 per group). B, CD8⁺ T cells are effectors of antitumor response. Splenic suspensions from surviving animals of previous experiments were depleted of CD4⁺ or CD8⁺ T cells or both by incubating with respective antibodies. Naive animals were injected with 2 × 10⁵ CT26 cells intravenously along with 10⁷ cells obtained from whole spleen, CD4⁺ T cell depleted, CD8⁺ T cell depleted, or double-depleted splenic suspension (n = 10 in each arm).