FIGURE 4.

Boosting of anti-influenza IgG by vaccination does not enhance NK cell responses. Increased levels of serum IgG against TIV (A–C) or H1N1 (D–F) were detected after vaccination with ID (A and D) and i.m. (B and E) but not after IN (C and F) vaccination. Data are shown as median values with IQRs. Expression of IFN-γ (G), CD107a (H), and CD25 (I) was measured in NK cells from all 52 study donors at baseline (0) or 4 wk postvaccination (4) after culture with inactivated H1N1 virus in the presence of autologous plasma taken either at baseline (0) or 4 wk after vaccination (4). Trend analysis was performed using one-way ANOVA with correction for multiple comparisons. Paired comparisons were made using Wilcoxon signed-rank test. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.