title: Neisseria lactamica antigens complexed with a novel cationic adjuvant.
abstract: Colonization of the nasopharynx by non-pathogenic Neisseria species, including N. lactamica, has been suggested to lead to the acquisition of natural immunity against Neisseria meningitidis in young children. The aim of this study was to identify a model complex of antigens and adjuvant for immunological preparation against N. meningitidis B, based on cross reactivity with N. lactamica outer membrane vesicles (OMV) antigens and the (DDA-BF) adjuvant. Complexes of 25 µg of OMV in 0.1 mM of DDA-BF were colloidally stable, exhibiting a mean diameter and charge optimal for antigen presentation. Immunogenicity tests for these complexes were performed in mice. A single dose of OMV/DDA-BF was sufficient to induce a (DTH) response, while the same result was achieved only after two doses of OMV/alum. In addition, to achieve total IgG levels that are similar to a single immunization with OMV/DDA-BF, it was necessary to give the mice a second dose of OMV/alum. Moreover, the antibodies induced from a single immunization with OMV/DDA-BF had an intermediate avidity, but antibodies with a similar avidity were only induced by OMV/alum after two immunizations. The use of this novel cationic adjuvant for the first time with a N. lactamica OMV preparation revealed good potential for future vaccine design.
authors.affiliation: Embrapa Southern Region Animal Husbandry; Bagé, RS Brazil; Institute of Biomedical Sciences; Department of Microbiology; University of São Paulo; São Paulo, SP Brazil.
authors.forename: Emanuelle B
authors.initials: EB
authors.lastname: Gaspar
authors.forename: Andreza S
authors.initials: AS
authors.lastname: Rosetti
authors.forename: Nilton
authors.initials: N
authors.lastname: Lincopan
authors.forename: Elizabeth
authors.initials: E
authors.lastname: De Gaspari
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage* / Q000378:metabolism; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000276:immunology* / Q000378:metabolism*; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology* / Q000302:isolation & purification; D002412:Cations / Q000008:administration & dosage* / Q000378:metabolism; D005260:Female; D007074:Immunoglobulin G / Q000097:blood; D008589:Meningococcal Infections / Q000517:prevention & control; D051379:Mice; D042806:Neisseria lactamica / Q000276:immunology*; D022142:Secretory Vesicles / Q000276:immunology / Q000378:metabolism
chemical_list: D000276:Adjuvants, Immunologic; D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001428:Bacterial Vaccines; D002412:Cations; D007074:Immunoglobulin G
keywords: Neisseria lactamica; Neisseria meningitides; bilayer fragments; dioctadecyldimethylammonium bromide; immune response; outer membrane vesicles