Quantitation of the immunogenic potential of protein antigens

A procedure to quantitate the immunogenic potential of protein antigens is presented. It is hypothesized that the intrinsic immunogenicity of an accessible region on the protein arises from the overall structural effect of the presence of the particular assemblage of amino acid residues in the given region. Structural parameters previously derived by Grantham [Science 185, 862-864 (1974)] to differentiate the various amino acids are assigned to each residue position. At each point chosen on the molecule, an av. value is computed due to all residues within 8.5 A of this point; it is proposed that this local average is proportional to the immunogenic potential of the region centered at this point. The method can be used to locate the immunodominant regions of a molecule and to compare the antigenicity of related molecules. Test calculations on hen egg-white lysozyme, sperm whale myoglobin and horse cytochrome c show that segments in these molecules, that have been shown in immunochemical studies to possess antigenic activity, are predicted by this method to be immunodominant.