Fig. 3.

CD8 T lymphocytes are required for efficient therapeutic effect of triple-combination treatment. a FACS analysis of leukocyte population infiltrating tumor samples from triple-combination treatment in comparison with untreated tumors at 5 days after second therapeutic treatment. Mean of four tumors per group is shown; the experiment repeated twice. Antibodies for CD45, CD4, CD8 and CD11b have been used, and gating on CD45+ cells has been done to evaluate the percentage of the different leukocyte populations. b Upper panel percentage of tumor-free mice after intra-prostatic T1525p tumor cell injection and subsequent triple-combination treatment in immune-competent mice in comparison with CD4, CD8 or CD8 + CD4 T cell-depleted mice. T cell depletion has been performed prior to first therapeutic treatment and efficient depletion (>95 %) evaluated by FACS analysis with CD4- and CD8-specific antibodies; difference in percentage of mice with regressing tumor between TC and all the other treatment is statistically significant (p < 0.005), but for CD4-depleted mice. Mice with regressing tumor became completely tumor free in 15–20 days and remained as such for the whole observation period, at least 80–100 days. Lower panel mean tumor volume from the same samples; cumulative results of two independent experiments are shown, and the total number of mice is indicated in the figure. c growth of T1525p tumors injected in tumor-free mice after triple-combinatory therapy and in naïve mice as controls; mean tumor volume is shown; cumulative results of three independent experiments are shown, and the total number of mice is indicated in the figure