NK Activity and Cytotoxic NK Cell Proportion. (A) NK activity was measured as described in materials and methods using PBMC (effector) obtained at day 0 (baseline), during (4W) and after the vaccination (8W). Stars indicate the statistical significance comparing day 0 vs. after the vaccination by p < 0.05. (B) Alteration of NK cell (0W: White bar) and after the vaccination (8W: Black bar) was measured by flow cytometry. Numbers indicate the CD16-FITC+ and CD56-PEdim cytotoxic NK cell proportion.