A small number of defined antigens can provide broad protection against meningococcal infection, and the invention provides a composition which, after administration to a subject, is able to induce an antibody response in that subject, wherein the antibody response is bactericidal against two or three of hypervirulent lineages A4, ET 5 and lineage 3 of N.meningitidis serogroup B. Rather than consisting of a single antigen, the composition comprises a mixture of 10 or fewer purified antigens, and should not include complex or undefined mixtures of antigens such as outer membrane vesicles. Five protein antigens are used in particular: (1) a 'NadA' protein； (2) a '741' protein； (3) a '936' protein； (4) a '953' protein； and (5) a '287' protein. Oligomeric 'NadA' is particularly useful.
