A composition for use in a method for inducing in a mammalian subject anti-bacterial GNA1870 polypeptide antibodies against at least three strains of Neisseria meningitidis that are heterologous for PorA, the composition comprising: isolated antigenic vesicles prepared from a first Neisseria meningitidis bacterium, in where the Neisseria meningitidis bacterium is genetically modified to overexpress a GNA1870 polypeptide at a level that is more than three times greater than a level of the GNA1870 polypeptide expressed in a parental strain from which the first Neisseria meningitidis bacteria is derived, and a pharmaceutically vehicle acceptable, wherein when the vesicles are administered to said subject, they induce said bactericidal anti-GNA1870 polypeptide antibodies to at least three strains of Neisseria meningitidis that are heterologous to PorA.Una composicion para uso en un metodo para inducir en un sujeto mamifero anticuerpos anti polipeptido GNA1870 bactericidas contra al menos tres cepas de Neisseria meningitidis que son heterologas para PorA, comprendiendo la composicion: vesiculas antigenicas aisladas preparadas a partir de una primera bacteria Neisseria meningitidis, en donde la bacteria Neisseria meningitidis esta modificada geneticamente para sobreexpresar un polipeptido GNA1870 a un nivel que es mas de tres veces mayor que un nivel del polipeptido GNA1870 expresado en una cepa parental a partir de la que deriva la primera bacteria Neisseria meningitidis, y un vehiculo farmaceuticamente aceptable, en donde cuando las vesiculas se administran a dicho sujeto, inducen dichos anticuerpos anti polipeptido GNA1870 bactericidas para al menos tres cepas de Neisseria meningitidis que son heterologas para PorA.
