15] Epitope mapping of allergens for rapid localization of continuous allergenic determinants

Abstract

The term “allergenic epitope” or “allergenic determinant” is used to denote a peptide sequence from a protein allergen that binds specific IgE. Such peptide allergenic determinants may be prepared by enzymatic or chemical degradation of the parent protein or by solid-phase peptide synthetic methods. Allergenic determinants may be of two types: continuous or conformational. A continuous determinant refers to a linear amino acid sequence in the protein chain. A conformational allergenic determinant is formed from residues that are in close proximity because of the three-dimensional structure of the protein. The allergenic determinants are localized to four distinct sequences. The first allergenic determinants are residues 13–32 in the AB loop, which function as a divalent allergenic determinant. The second and third are residues 33–44 and 65–74, which join the AB to CD and CD to EF loops, respectively. These allergenic determinants also bind IgE in vitro and have sequence homology in the regions 35–41 and 67–73. The fourth allergenic determinants are residues 41–64 in the CD loop.