FIGURE 6.

Analyses of cellular responses in tumor-bearing and tumor-free mice after ACT and DC vaccination. A and B, Lack of proliferative responses (A) and CTL activity (B) in splenocytes of NXS2-bearing mice. A, Splenocytes isolated from mice that developed progressively growing tumors after ACT of naive splenocytes and 47-LDA polypeptide-DC vaccine were loaded with CFSE and cultured with 47-LDA-expressing syngeneic DCs (ratio 20:1) for 72 h. Cells were stained with PE-conjugated anti-CD4 or anti-CD8 mAbs and analyzed by flow cytometry. The percentage of cells that underwent more than one round of cell division is indicated. Data are from one representative experiment of four performed. B, CTL activities of stimulated or control CD8⁺ splenocytes from tumor-bearing mice against NXS2 cells were analyzed in a standard ⁵¹Cr-release assay. All determinations were made in triplicate samples, and results are presented as the means ± SD of three independent experiments. C and D, Analyses of proliferative responses (C) and CTL activities against NXS2 (D) in tumor-free mice after receiving ACT from naive mice and the 47-LDA-Fcγ2a-DC vaccine. Experiments were conducted as described in A and B.