Established leukemia disrupts leukemia/α-GalCer vaccine–mediated CD4⁺ T-cell function. Mice were challenged with C1498 intravenously 7 days before vaccination, and responses were analyzed 1 week later. (A) Splenocytes were cultured for 24 hours with (○) or without (●) DCs loaded with C1498 lysate. Supernatant IFN-γ was quantified. (B-F) The splenic CD4⁺ and CD8⁺ T-cell populations were analyzed by flow cytometry. (B) Representative flow cytometry plots showing identification of CD4⁺ and CD8⁺ T cells from mouse spleens. IFN-γ⁺ cells were determined by comparison with an isotype control antibody (lower left). MFI of CD44 expressed on (C) CD8⁺ and (E) CD4⁺ T cells. The proportion of (D) CD8⁺ and (F) CD4⁺ cells that produced IFN-γ. Graph in (A) represents 3 experiments. Statistical analysis compared experiments performed in the presence of DCs only. (B-F) Graphs represent 2 experiments, each with 5 mice per group. *P < .05, **P < .01, ***P < .001 (1-way ANOVA with a Bonferroni posttest for [A,C-F]). FSC-H, foward scatter height.