Immunization of mice with WT1 vaccine A, but not vaccine B, induces proliferative T-cell responses.

Three weeks after the third immunization, spleen cells of mice that had been inoculated with vaccine A or vaccine B were cultured with medium alone (medium) or spleen cells and medium (B6/no antigen), B6 spleen cells pulsed with the peptides p6-22, p117-139, p244-262 (vaccine A) or p287-301, p299-313, p421-435 (vaccine B) at 25 μg/mL, and were assayed after 96 hours for proliferation by (³H) thymidine incorporation. Bars represent the mean stimulation index (SI), which is calculated as the mean of the experimental wells divided by the mean of the control (B6 spleen cells with no antigen) and standard deviations.