Abstract: The present invention is drawn to a penicillin-binding protein expressed by Neisseria meningitidis, or a fragment, or a variant, or a variant fragment thereof, or nucleic acids encoding them, or antibodies or antibody fragments directed against them, as medicaments or in pharmaceutical compositions. The invention is also directed to the use of penicillin-binding proteins expressed by Neisseria meningitidis, or nucleic acids encoding them, or antibodies directed against them for the prophylactic and/or therapeutic immunotherapy of mammals, preferably human beings, against infection by Neisseria meningitidis and/or by a bacterial strain expressing a variant of a Neisseria meningitidis penicillin-binding protein.