The effect of CD8 T cells on tumor protection of the pCDNA3-CRT/LT vaccine. (A) Schematic diagram of the vaccination regimen for in vivo antibody depletion experiments. C57BL/6 mice (5 per group) were vaccinated by gene gun with pcDNA3-CRT/LT DNA vaccine on D0. Vaccinated mice were boosted two times at the same dose and regimen at one week intervals. Beginning 1 day after last vaccination, vaccinated mice were intraperitoneally injected with anti-CD8 monoclonal antibody other day. Antibody-depleted mice were then challenged with B16/LT tumor (1 × 105 cells/mouse) subcutaneously in the right flank on D22. Mice were monitored for evidence of tumor growth by inspection, palpation and tumor size was measured twice a week. (B) Survival analysis of B16/LT tumor-bearing mice treated with pcDNA3-CRT/LT DNA vaccine.