Serum bactericidal activity elicited in mice by a native OMV vaccine prepared from a mutant with attenuated endotoxin activity and overexpressed fHbp. N. meningitidis strain designations are shown below the X axis (all expressed fHbp in the variant 1 group). Vaccine groups: recombinant (open bars), multicomponent vaccine containing 2 fusion proteins, GNA 2091-fHbp variant 1 and GNA 2132-GNA 1030, and NadA (See Figure 6); Detergent-OMV, WT (hatched bars), a clinical lot of detergent-treated OMV vaccine from Norway (strain H44/76); native OMV, mutant (gray bars), a native (not treated with detergent) OMV from a mutant strain of H44/76 with attenuated endotoxin (LpxL1KO) and overexpressed fHbp in the variant 1 group. Al(OH)3 (black bars), adjuvant alone (also used for the 3 vaccines). Copyright © 2008 by the Infectious Diseases Society of America. All rights reserved.