Fig. 4.

Efficacy of vaccine after sublethal heterologous influenza infection. HLA-A2.1 transgenic C57BL/6 mice were immunized twice with either peptide-loaded virosomes with CpG (red), peptide mixed with incomplete Freund’s adjuvant and CpG (green), WIV (brown) or PBS (blue). As a positive control, mice were challenged with a sublethal dose of HKx31 virus. Subsequently, mice were infected with heterologous HKx31 (H3N2) influenza virus and their weight was monitored for 14 days. Data represents mean ± SEM (n = 6); *p < 0.0001 for PBS and P + IFA + CpG groups versus HKx31.