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 polymers, nu cleic acids and haptens. On the other hand. until recently there has been very little information on protein antigens. The complexity of these molecules posed an immense chemical obstacle to precise immuno chemical analysis. Indeed, it is this difficulty with proteins that spurred the synthesis and immunological studies of amino acid poly mers. The control and normal regulation of the immune system at the cellular-molecular interface and the great majority of antigens asso ciated with immune disorders are attributed to protein molecules. In the last few years great advances have been made in the analysis and synthesis of the antigenic sites of some proteins. The entire antigenic structures of myoglobin and lysozyme and the partial anti genic structures of several other proteins have been determined. Moreover, in the past seven years several biological responses resulting from the reactions of proteins and their peptides with cells of the immune system were described.

Zusammenfassung
The control and normal regulation of the immune system at the cellular-molecular interface and the great majority of antigens asso ciated with immune disorders are attributed to protein molecules.

Inhalt
Antigenic Structure of Proteins.- Identifying Antigenic Determinants on Cytochrome c for B and T Cells.- First Consequences of the Determination of the Entire Antigenic Structure of Sperm-Whale Myoglobin.- The Precise and Entire Antigenic Structure of Lysozyme: Implications of Surface-Simulation Synthesis and the Molecular Features of Protein Antigenic Sites.- Immunochemistry of Bovine Serum Albumin.- Analysis of a Complex Antigenic Site on Horse Cytochrome c (Discussion).- A Model Implicating Altered Macrophage Function in H-2 Linked Nonresponsiveness to Hen Lysozyme (Discussion).- Immunobiology of Proteins and Peptides.- T-Lymphocyte Activation by Immunogenic Determinants.- Immunochemical Studies on the Tobacco Mosaic Virus Protein.- Immunobiologic Properties of the Major Antigenic Determinants of the Ferredoxin Molecule.- In Vitro Responses of Myoglobin-Primed Lymph Node Cells to Myoglobin and Myoglobin Synthetic Antigenic Peptides.- Genetic Control of the Antibody Response to Sperm-Whale Myoglobin in Mice.- Genetic Control of the Immune Response to Staphylococcal Nuclease in Mice.- Peptides and Autoimmune Disease.- Mechanisms of Tolerance to HGG Induced in Neonatal and Adult Mice.- Recognition of Lysozyme by Lymphocyte Subsets.- Immunobiology of Protein Conjugates.- Complexity of Cell Interactions: Analysis Using Antigens Under Ir Gene Control.- Activation of B Cell Subsets by T-Dependent and T-Independent Antigens.- Regulation of Anti-Hapten Antibody Secretion by Carrier-Specific Suppressor T Cells.- Genetic Control of the T-Lymphocyte Proliferative Response to Cytochrome c.- Independent Precursors for Thymus Dependent and Thymus Independent IgG Memory B Cells (Discussion).- Immune Responses to Synthetic Polymers and to Proteins.- T-Cell Regulation of Restricted B-Cell Responses.- L-Glutamic Acid60-L-Alanine30-L-Tyrosine10 (GAT): A Probe for Regulatory Mechanisms in Antibody Responses.- The Nature and Functions of Specific Immune Response Genes and Their Products.- Genetic Control of the Immune Response to Insulin: Its Dependence Upon a Macrophage Mediated Selection of Distinct Antigenic Sites.- Immune Responses of Inbred Guinea Pigs and Mice to Helical Sequential Polymers of Amino Acids (Discussion).- Lymphocyte Membrane Structure.- Lymphocyte Differentiation as Analyzed by the Expression of Defined Cell Surface Markers.- Contributors.