Compositions and methods for preventing and/or reducing amyloid deposition in a subject comprising treatment of a subject with a composition comprising a TLR4 agonist free of endotoxin are provided. Also provided is a TLR4 agonist free of endotoxin for preventing and/or reducing Alzheimers disease. Pharmaceutical compositions consisting of, or consisting essentially of, an aminoalkyl glucosaminide phosphate, 3D-MPL, AS01 B or an AGP in combination with an oil in water emulsion are also provided.