The present invention relates to polypeptides of SEQ ID NO: 1 (as well as biologically active derivatives thereof), that bind specifically to BACE1 and/or IL-4Rα. Compositions and methods incorporating the polypeptide of SEQ ID NO: 1 (or biologically active derivatives thereof) for treating and/or preventing neurological disorders, such as Alzheimer's disease, as well as disorders associated with an increase of the Th2 immune response, such as allergic inflammation, are also disclosed.