OBJECTIVES Outer membrane vesicle (OMV) vaccines are used against outbreaks of capsular group B Neisseria meningitidis (MenB) caused by strains expressing particular PorA outer membrane proteins (OMPs). Ferric enterobactin receptor (FetA) is another variable OMP that induces type-specific bactericidal antibodies, and the combination of judiciously chosen PorA and FetA variants in vaccine formul...

Fundamental aspects of outer membrane vesicle (OMV) biogenesis and the engineering producer strains have been major research foci for many in recent years. The focus this study was OMV production a variety Escherichia coli including wild type (WT) (K12 BW25113), mutants (from Keio collection) proprietary [BL21 BL21 (DE3)] strains. present investigated proteome prospective mechanism that underpi...

The outer membrane vesicle (OMV) derived from Porphyromonas gingivalis plays an essential role in causing inflammation which, in turn, plays an important part in the pathogenesis of cardiovascular diseases such as atherosclerosis and thromboembolism. However, the contribution of oral bacteria to vascular calcification is yet to be determined. Here, we evaluated the effect of OMV on vascular smo...

Gram-negative bacteria maintain the barrier properties of the outer membrane (OM) in a wide array of physiological conditions despite their inability to degrade lipopolysaccharide (LPS) and protein material present in the outer leaflet of the OM. Through characterization of the native dynamics of outer membrane LPS change we recently described a mechanism in which these diderm organisms overcom...

BACKGROUND Outer membrane protein D (PD) is a highly conserved and stable protein in the outer membrane of both encapsulated (typeable) and non-capsulated (non-typeable) strains of Haemophilus influenzae. As an immunogen, PD is a potential candidate vaccine against non-typeable H. influenzae (NTHi) strains. OBJECTIVES The aim of this study was to determine the cytokine pattern and the opsonic...

Outer membrane vesicles (OMVs) are ubiquitously secreted from the outer membrane (OM) of Gram-negative bacteria. These heterogeneous structures are composed of OM filled with periplasmic content from the site of budding. By analyzing mutants that have vesicle production phenotypes, we can gain insight into the mechanism of OMV budding in wild-type cells, which has thus far remained elusive. In ...

We have studied the ability of the Norwegian group B meningococcal outer membrane vesicle (OMV) vaccine, when administered intranasally without adjuvant, to induce T-cell responses in humans. A group of 12 vaccinees was immunized with four doses of OMVs (250 micrograms of protein/dose) at weekly intervals, and a single booster dose was given 5 months later. In vitro T-cell proliferation in resp...

Xenorhabdus nematophilus secretes a large number of proteins into the culture supernatant as soluble proteins and also as large molecular complexes associated with the outer membrane. Transmission electron micrographs of X. nematophilus cells showed that there was blebbing of the outer membrane from the surface of the bacterium. The naturally secreted outer membrane vesicles (OMVs) were purifie...

Neisseria meningitidis and Bordetella pertussis are Gram-negative bacterial pathogens that can cause serious diseases in humans. N. meningitidis outer membrane vesicle (OMV) vaccines and whole cell pertussis vaccines have been successfully used in humans to control infections with these pathogens. The mechanisms behind their effectiveness are poorly defined. Here we investigated the role of Tol...

The prediction of efficacy of Neisseria meningitidis serogroup B (MenB) vaccines is currently hindered due to the lack of an appropriate correlate of protection. For outer membrane vesicle (OMV) vaccines, immunogenicity has primarily been determined by the serum bactericidal antibody (SBA) assay and OMV enzyme-linked immunosorbent assay (ELISA). However, the opsonophagocytic assay (OPA), surfac...