Figure 4: High titers of antibodies against NP, but not against H5 HA or NA, are elicited with both vaccination regimens and reflect observed difference in heterosubtypic protection. Characterization of humoral immune response induced by 3x Inflexal 2009 (3xSV09), 3x H1 HA DNA followed by a boost of Inflexal 2009 (H1- DNA/SV09) or 4x PBS (PBS) in pre-challenge serum of mice challenged with H5N1 A/Hong Kong/156/97 (Immunogenicity of animals in challenge is reported; n=8 for PBS and 3x SV09; n=7 for H1-DNA/SV09). Binding Ab titer measured in ELISA against A) rHA of H5N1 A/Hong Kong/156/97 and rHA of H1N1 A/Brisbane/ 59/07 B) rNA of H5N1 A/Hong Kong/156/97 and rNA of H1N1 A/ Brisbane/59/07 C) rNP of A/Puerto Rico/8/34 (due to lacking serum n=5 for PBS; n=5 for 3x SV09; n=6 for H1-DNA/SV09). Group medians are shown.