Protection against Multiple Subtypes of Influenza Viruses by Virus-Like Particle Vaccines Based on a Hemagglutinin Conserved Epitope

Figure 6

Protection of mice against lethal heterologous influenza A virus challenge by intranasal administration of LAH-HBc with CTB^*. Sixty BALB/c mice were randomly divided into six groups (10 mice in each group). Three groups were immunized three times with 25 μg LAH-HBc plus CTB^* at 2-week intervals. The remaining three groups were unimmunized controls. Three weeks after the last immunization, mice were challenged, respectively, with a lethal dose (5 × LD₅₀) of A/California/07/2009 (H1N1), A/reassortant/NIBRG-14 (Vietnam/1194/2004 x PR/8/34) (H5N1), and A/Chicken/Jiangsu/7/2002 (H9N2). The survival rates (a) and bodyweight changes (b) of postinfection were determined. ^*Significant difference compared to the control group (), respectively.

(a)

(b)