title: Meningococcal Outer Membrane Vesicle Composition-Dependent Activation of the Innate Immune Response.
abstract: Meningococcal outer membrane vesicles (OMVs) have been extensively investigated and successfully implemented as vaccines. They contain pathogen-associated molecular patterns, including lipopolysaccharide (LPS), capable of triggering innate immunity. However, Neisseria meningitidis contains an extremely potent hexa-acylated LPS, leading to adverse effects when its OMVs are applied as vaccines. To create safe OMV vaccines, detergent treatment is generally used to reduce the LPS content. While effective, this method also leads to loss of protective antigens such as lipoproteins. Alternatively, genetic modification of LPS can reduce its toxicity. In the present study, we have compared the effects of standard OMV isolation methods using detergent or EDTA with those of genetic modifications of LPS to yield a penta-acylated lipid A (lpxL1 and pagL) on the in vitro induction of innate immune responses. The use of detergent decreased both Toll-like receptor 4 (TLR4) and TLR2 activation by OMVs, while the LPS modifications reduced only TLR4 activation. Mutational removal of PorB or lipoprotein factor H binding protein (fHbp), two proteins known to trigger TLR2 signaling, had no effect, indicating that multiple TLR2 ligands are removed by detergent treatment. Detergent-treated OMVs and lpxL1 OMVs showed similar reductions of cytokine profiles in the human monocytic cell line MM6 and human dendritic cells (DCs). OMVs with the alternative penta-acylated LPS structure obtained after PagL-mediated deacylation showed reduced induction of proinflammatory cytokines interleukin-6 (IL-6) and IL-1β but not of IP-10, a typical TRIF-dependent chemokine. Taken together, these data show that lipid A modification can be used to obtain OMVs with reduced activation of innate immunity, similar to what is found after detergent treatment.
authors.affiliation: Institute for Translational Vaccinology, Bilthoven, the Netherlands Department of Infectious Diseases and Immunology, Utrecht University, Utrecht, the Netherlands Afshin.zariri@intravacc.nl.
authors.forename: Afshin
authors.initials: A
authors.lastname: Zariri
authors.affiliation: Immunology of Infectious Diseases and Vaccines, National Institute of Public Health and the Environment, Bilthoven, the Netherlands.
authors.forename: Joep
authors.initials: J
authors.lastname: Beskers
authors.affiliation: Institute for Translational Vaccinology, Bilthoven, the Netherlands.
authors.forename: Bas
authors.initials: B
authors.lastname: van de Waterbeemd
authors.affiliation: Immunology of Infectious Diseases and Vaccines, National Institute of Public Health and the Environment, Bilthoven, the Netherlands.
authors.forename: Hendrik Jan
authors.initials: HJ
authors.lastname: Hamstra
authors.affiliation: Institute for Translational Vaccinology, Bilthoven, the Netherlands.
authors.forename: Tim H E
authors.initials: TH
authors.lastname: Bindels
authors.affiliation: Institute for Translational Vaccinology, Bilthoven, the Netherlands.
authors.forename: Elly
authors.initials: E
authors.lastname: van Riet
authors.affiliation: Department of Infectious Diseases and Immunology, Utrecht University, Utrecht, the Netherlands.
authors.forename: Jos P M
authors.initials: JP
authors.lastname: van Putten
authors.affiliation: Institute for Translational Vaccinology, Bilthoven, the Netherlands.
authors.forename: Peter
authors.initials: P
authors.lastname: van der Ley
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry*; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000378:metabolism; D003902:Detergents / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D006801:Humans; D007113:Immunity, Innate / Q000187:drug effects / Q000502:physiology*; D008050:Lipid A / Q000737:chemistry*; D008589:Meningococcal Infections / Q000276:immunology*; D009000:Monocytes / Q000378:metabolism; D009345:Neisseria meningitidis / Q000276:immunology*; D051193:Toll-Like Receptors / Q000378:metabolism
chemical_list: D001425:Bacterial Outer Membrane Proteins; D016207:Cytokines; D003902:Detergents; D008050:Lipid A; D051193:Toll-Like Receptors; D004492:Edetic Acid