Intrinsic and extrinsic factors in protein antigenic structure.

Recent advances in the preparation of synthetic peptide vaccines and the use of synthetic peptides as probes of antigenic structure and function have led to renewed interest in the prediction of antigenic sites recognized by antibodies and T cells. This review focuses on antibodies. Features intrinsic to the antigen, such as hydrophilicity and mobility, may be useful in the selection of amino acid sequences of the native protein that will elicit antibodies cross-reacting with peptides, or sequences which, as peptides, will be more likely to elicit antibodies cross-reactive with the native protein. Structural mobility may also contribute to protein-protein interactions in general. However, the entire accessible surface of a protein is likely to be detectable by a large enough panel of antibodies. Which of these antibodies are made in any individual depends on factors extrinsic to the antigen molecule, host factors such as self-tolerance, immune response genes, idiotype networks, and the immunoglobulin structural gene repertoire.