Abstract: Compounds that modulate natural &bgr; amyloid peptide aggregation are provided. The modulators of the invention comprise a peptide, preferably based on a &bgr; amyloid peptide, that is comprised entirely of D-amino acids. Preferably, the peptide comprises 3-5 D-amino acid residues and includes at least two D-amino acid residues independently selected from the group consisting of D-leucine, D-phenylalanine and D-valine. In a particularly preferred embodiment, the peptide is a retro-inverso isomer of a &bgr; amyloid peptide, preferably a retro-inverso isomer of A&bgr;17-21. In certain embodiments, the peptide is modified at the amino-terminus, the carboxy-terminus, or both. Preferred amino-terminal modifying groups include cyclic, heterocyclic, polycyclic and branched alkyl groups. Preferred carboxy-terminal modifying groups include an amide group, an alkyl amide group, an aryl amide group or a hydroxy group.

Abstract: Antigen E or Amb a I of ragweed pollen has been shown to be a family or families of proteins. cDNAs encoding Amb a I, the major human allergen of ragweed and Amb a II, peptides derived from Amb a I or Amb a II, antibodies against the peptides; and methods of treating individuals for sensitivity to ragweed are disclosed.