Figure 3

CD8⁺ T cells are essential for alum-induced tumor suppression.

(A) Balb/c mice were inoculated s.c. with H22 cells and treated with Al(OH)3 or PBS. Tumor-bearing mice were injected i.p. with 100 μg of anti-Ly6G, anti-mouse CD8 or rat IgG2a κ isotype control antibody in 200 μl PBS 1 day after each Al(OH)3 injection. The tumor volume was measured every 3 days. (B) Draining LNs were harvested from tumor-bearing mice in PBS- and Al(OH)3-treated groups 15 days after tumor inoculation. Single cell suspensions were prepared, labeled with cell proliferation dye eFluor 670 and stimulated with 10 μg/ml H22 cell lysis (protein) for 72 h and analyzed by FACS. Peripheral blood, spleen, draining LNs and tumor were harvested from tumor-bearing mice 3 days after the 1st, 3rd, 6th injection. The percentages of CD8⁺ (C) and CD4⁺ (D) T cells in total T cells or in total cells were analyzed by FACS. P values for D15 CD8⁺ and CD4⁺ cells in draining lymph nodes and CD8⁺ cells in tumor are 0.035, 0.045 and 0.047 respectively.