Figure 4. Peptide A2-5 immunization induces HLA-A2 specific cytotoxic T lymphocyteresponses in HLA-A2 transgenic mice.

A. Effector cells (splenocytes) from immunized HLA-A2 transgenic mice were stimulated with peptide A2-5 (10 μg/ml) and IL-2 (10U/ml) and subjected to a standard ⁵¹Cr-release assay with H2981 cells as targets. Antibodies against HLA-A2, CD8 and mIgG isotype control were incubated with effector cells at 37°C for 1 hour. CTL assays were done with 3 mice per group and observed with effector/target (E/T) ratios of 100. ***P < 0.001. B. The treatment schedule is shown in the top. H2981 cells (1 × 10⁸) were subcutaneously inoculated into SCID mice. Then, the purified CD8+ T cells (1 × 10⁷) from peptide A2-5 immunized HLA2 Tg mice were adoptively transferred through the i.v. route into individual SCID mouse bearing H2981 tumors on day 7. Tumor size was monitored until day 57. Each group contains 6 mice. Error bars, SEM; **, P < 0.01.