The present invention refers to a pharmaceutical composition which, in addition to allowing or producing an effective and specific immune response against Aβ40 (the antibodies produced are specific for Aβ40 without significantly binding to Aβ42), increases said response compared with the response produced by other conjugates also comprising CysAβ(33-40) peptide and KLH, and in which said elements have been bound or conjugated by means of another crosslinking agent that also allow the binding of a peptide to the transport protein.
