One of the central questions in immunology is the understanding in molecular terms of antigen-antibody interactions and of the cellu- lar recognition of antigens. It is hoped that this understanding will extend eventually to the immunobiological basis of host defense to infectious agents and of tissue damage or deranged cell functions which stem from these reactions. A variety of natural and artificial substances have been used as models for these studies. Emphasis was placed upon substances of known and relatively uncomplicated chemical structures. These included polysaccharides, amino acid...

The structural features responsible for the immunogenicity of certain parts of native protein molecules have been of interest to immunochemists and protein chemists for over three decades. Following the early work of Landsteiner in 1942, which showed that peptide fragments from silk fibroin exhibited an inhibitory activity toward the reaction of the protein with its antibodies, fragments from many other protein systems have been isolated and studied. However, no concerted effort was (or could be) devoted to the elucidation of the complete antigenic structure of a protein. In order for these...