Outer membrane vesicles from group B Neisseria meningitidis Δgna33 mutant: Proteomic and immunological comparison with detergent‐derived outer membrane vesicles

Abstract We compared the proteome of detergent‐derived group B Neisseria meningitidis (MenB) outer membrane vesicles (DOMVs) with the proteome of outer membrane vesicles (m‐OMVs) spontaneously released into culture supernatant by MenB Δ gna33 , a mutant in which the gene coding for a lytic transglycosylase homologous to the E. coli MltA was deleted. In total, 138 proteins were identified in DOMVs by 1‐ and 2‐DE coupled with MS; 64% of these proteins belonged to the inner membrane and cytoplasmic compartments. By contrast, most of the 60 proteins of m‐OMVs were classified by PSORT as outer membrane proteins. When tested for their capacity to elicit bactericidal antibodies, m‐OMVs elicited a broad protective activity against a large panel of MenB strains. Therefore, the identification of mutations capable of conferring an OMV‐releasing phenotype in bacteria may represent an attractive approach to study bacterial membrane composition and organization, and to design new efficacious vaccine formulations.