Fig. 2.

WT-1-specific CD8⁺ T-cell responses and protection against WT-1 tumor challenge upon i.m. immunization with WT-1-derived peptides mixed with two adjuvants, 7DW8-5 and MPLA. (A) Groups of HLA-A2 transgenic mice with B6 background (n = 5) received three doses of i.m. immunization with pooled HLA-A2-restricted WT-1-derived peptides, WH (SLGEQQYSV) and WT (CMTWNQMNL), with 7DW8-5 (10 µg) and/or MPLA (2 µg). (A) Two weeks after the last immunization, splenocytes were collected from immunized as well as naïve mice, and the level of CD8⁺ T-cell response specific for separated or pooled WT-1 peptides was determined by ELISpot assay. (B) Two weeks after the last immunization, immunized as well as naïve mice (n = 4–5) were subcutaneously challenged with WT-1⁺HLA-A2⁺C1498 tumor cells, and the size (diameters in millimeters) of the tumor growth was measured up to 50 days. (C) Cross-sectional comparison of tumor size (diameters in millimeters) among immunized mouse groups (WT-1 peptides with or without adjuvants) as well as a naive mouse group at day 15 post challenge with WT-1⁺HLA-A2⁺ C1498 tumor cells. (D) Survival rate of immunized mouse groups as well as a naïve mouse group after challenge with WT-1⁺HLA-A2⁺ C1498 tumor cells. (E) Results for the comparisons of survival curves registered for groups of mice consisting of a non-immunized, naïve mouse group, as well as groups immunized with WT-1 peptides with or without adjuvants. Statistical analyses of survival rates were performed using Gehan-Breslow Wilcoxon test. In Fig. 2, experiments were repeated twice. Statistical significance was displayed as ***, **, or *, if the p value is <0.001, <0.01, or <0.05, respectively.