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Outer membrane vesicles (OMVs) of Neisseria meningitidis contain important antigens to trigger an immune response against meningococci and have been studied as vaccines compounds. The immune response to a vaccine may be affected by its constitution and route of administration. Therefore, Swiss mice were immunized by different routes with OMVs of N. meningitidis B with dimethyl dioctadecyl ammonium bromide in bilayer fragments (DDA-BF) or aluminum hydroxide (AH) as adjuvants. The adjuvants and different routes were compared regarding the immune responses by ELISA, western blot, delayed type hypersensitivity (DTH) and histopathologic analysis. The antigenic preparation generated humoral and cellular immune responses. In quantitative analyzes, in general, AH was superior to DDA-BF. However, analysis such as IgG avidity index, bactericidal activity and immunoblot, revealed no important differences regarding the adjuvant or route of immunization. Regarding the parameters tested, it was not possible to define a superiority between the adjuvants and routes of immunization proposed by this study. [ABSTRACT FROM AUTHOR]

Abstract: The aim of the present study was to investigate the immune response to native outer membrane vesicles (NOMVs) of Neisseria lactamica with and without Bordetella pertussis (BP) as adjuvant in intranasal (i.n./i.m) immunization. N. lactamica NOMVs delivered intranasally (i.n) to BALB/c mice in a final volume of 5μl that was gradually introduced with a micropipette, Animals received 1, 2, 3, or 4 doses of antigens at 3, 7, 9 and 12 days after birth. On the 35th day, the animals were immunized intramuscularly (i.m.) with (NOMV) of N. lactamica. The prime-booster strategy using NOMV of N. lactamica with BP as adjuvant in the primer (i.n.) and booster (i.m.) is an effective immunization protocol for inducing humoral immune responses producing IgG antibodies of intermediate to high avidity. [Copyright &y& Elsevier]