This invention provides, among other things, proteins, polypeptides, and fragments thereof, derived from the bacteria Neisseria meningitidis B. Also provided are nucleic acids encoding for such proteins, polypeptides, and/or fragments, as well as nucleic acids complementary thereto (e.g., antisense nucleic acids). Additionally, this invention provides antibodies which bind to the proteins, polypeptides, and/or fragments. This invention further provides expression vectors useful for making the proteins, polypeptides, and/or fragments, as well as host cells transformed with such vectors. This invention also provides compositions of the proteins, polypeptides, fragments, and/or nucleic acids, for use as vaccines, diagnostic reagents, immunogenic compositions, and the like. Methods of making the compositions and methods of treatment with the compositions are also provided. This invention also provides methods of detecting the proteins, polypeptides, fragments, and/or nucleic acids.