The Fifth Ir Gene Workshop was held at the Chase-Park Plaza Hotel, St. Louis, MO, August 28-31, 1982; 240 scientists participated in the Workshop. The man­ uscripts compiled in this book describe the state of the art concerning Ir genes. Although the notion of Ir Genes: Past, Present, and Future has not been ad­ dressed specifically by each author, the reader is certain to get this flavor from the contributions. In this Preface, we have tried to summarize some of the salient ob­ servations and discussions from the Workshop. The mUltiple genes of the I region have been defined traditionally by serolog­ ical analysis of intra-H-2 recombinant mice and the pattern of immune responses to certain antigens developed by these recombinant mice. The application of sev­ eral new techniques, such as gene cloning and DNA sequencing, production of T and B cell hybridomas, and development of cloned T cell lines has changed this tradition and introduced a new phase into the analysis of the I region, Ia antigens, and Ir genes.

Genetic Organization of I-Region Genes.- Ia Genes, Gene Products, and Determinants.- Murine T Cell-Specific IA Antigens: Helper T Lymphocytes Express a Unique I-A-Encoded Molecule.- Definition of New Ia+ T Cell Subsets.- Antibody and T Cell Recognition of Select Ia Determinants Using the I-A Mutant B6.C-H-2bm12.- Induction of Autoreactive T Cells by Stimulation Across the I-J Subregion.- Enhancement of Murine T Cell I-J Expression by Limited Proteolysis.- Isolation and Analysis of Subpopulations of I-Ab Molecules with Monoclonal Antibodies.- Partial Characterization of 8 Anti-I-J and 3 Anti-Ia Monoclonal Reagents.- Interspecies Cross Reactivity of Monoclonal Anti-I-E Antibodies Specific for Polymorphic Ia Determinants.- Structural Characterization of I-Ab Subsets Using Monoclonal Antibodies.- Factor-Mediated Regulation of the Expression of the H-2 Linked Low Molecular Weight Proteins (LMP).- Quantitation of Ia Antigens on Normal and Leukemic Human Lymphocytes.- Use of Monoclonal Antibodies for Studies of Anti-Ia Receptor Idiotypes.- A Recombinatorial Event Separating the Immune Response Genes for LDH-B and MOPC-173: Implications for a New Model of I Region Gene Organization.- Expression of Ia Antigens and Ir Gene Function During Differentiation of Bone Marrow Derived Macrophage.- The IR-THY-1 Genes: Possible Mechanism of Their Effect.- Complementing Ir-Genes Located in the I-A Subregion and Between the S and D Regions are Required for the Response to TNP-Ficoll.- Chemistry of I-Region Gene Products and DNA Cloning of I-Region Gene Products.- Ia Oligosaccharide Structure and Its Relation to Differential Recognition of Ia.- Structures of the Oligosaccharides of I-Ak Antigen and Localization of Antigenic Sites to A?k and A?k Chains.- Biosynthesis and Genetics of Ia Antigens and Their Associated Invariant Chain.- Biochemical Characterization of the Murine Invariant Polypeptide and a 23,000 Dalton Iad Encoded Polypeptide.- Identification of an Invariant Chain ? of Murine Class II Antigens and Its Relationship to the Invariant Chain ?(Ii).- Molecular Heterogeneity of Ia Antigens: Novel Components and Complexes.- Partial Chemical Characterization of T Lymphocyte I-Region Associated Antigens.- Three Distinct Human Ia Molecules Isolated from a DR5 Homozygous Lymphoblastoid Cell Line.- The Human "Invariant" Chain: Structural Characterization.- Two-Dimensional Gel Analyses of HLA-DR and HLA-DS Molecules.- Partial Structural Characterization of Human SB Antigens.- Two Alpha Chains and Three Beta Chains of Human Ia Antigens.- Isolation and Characterization of I Region Genes from the Major Histocompatibility Complex.- Structure and Expression of the Murine Ia ? Chains.- Extensive Restriction Site Polymorphism Surrounding a Single Copy I-A? Gene.- Analysis of the Human Ia Antigens by Gene Cloning.- The Cloning and Structure of the Heavy Chain Gene of HLA-D(R).- Ir Gene Function: Cellular Site(s) and Mechanism(s) of Action.- Determinant Selection Vs. Clonal Deletion Models of Immune Response Gene Function.- Absence of Ir-Gene Control in T-Cell Responses Restricted by Allogeneic MHC Molecules.- Both Low and High Responder Myoglobin-Specific T Cells, Tolerant to F1, Help High but Not Low Responder B Cells.- Ir Gene Control as a Consequence of Holes in the Antigen Specific Repertoire of T Lymphocytes.- Ia Restriction Elements and Epitopes of Insulin Appear to be Recognized by Mouse T Cells as Functional Units.- Molecular Aspects of the Processing and Presentation of Avidin by Macrophages to T Lymphocytes.- The Effect of Antigen and Ia Molecule Interaction on Immune Response Gene Control.- T Cells with Differing Specificity Exist for a Single Determinant on Lysozyme.- Hierarchical Relationships Among Epitopes: Only Certain Potentially Utilizable Epitopes on Protein Antigens are Actually Presented in a Particular Haplotype.- Antigen-Specific Suppressor T Cells as One Mode of Expression of Immune Response Genes.- Assessment of the Role of T Lymphocytes and Antigen Presenting Cells in the GAT Nonresponsiveness of SJL and DBA/1 Mice.- Mechanism of H-2-Controlled Interaction Between LDHB-Specific Helper and Suppressor T Cells.- Dissociation of Cellular and Humoral Immune Responsiveness to GAT.- T Cell Function in Allotype Linked and H-2 Linked Immune Response to Insulin in Mice.- H-2 Linked Ir Gene Control of H-2 Unrestricted Cytotoxic T Lymphocytes.- Immune Response Gene Effects in Cytotoxic T Cell Responses as a Consequence of Self Tolerance.- Involvement of Syngeneic Ia in T Cell Responses to Class I Alloantigens.- Control of Cytotoxic T-Lymphocyte Responses by Class-I and Class-II H-2 Molecules, Studied with H-2 Mutants.- Characterization of "Veto" Cells that Cause Nonresponsiveness to Minor Histocompatibility Antigens.- Interactive Control of Cytotoxic T Cell Responses to H-Y by H-2 and Non H-2 Ir Genes.- Graft-Versus-Host-Associated Immune Suppression Involves In Vivo Recognition of Allogeneic I-A Determinants.- Genetic Regulation of the Cytolytic T Lymphocyte Response to Influenza Viruses.- The Role of Ia Antigens in Restricted Cell Interactions.- Ir Genes, Adaptive Differentiation and Self-Recognition.- The Contributions of the Developmental and Priming Environments to the Expression of the T Cell Receptor Repertoire.- Ia Antigens as Restriction Molecules in Ir-Gene Controlled T-Cell Proliferation.- Functional Evidence for Two Antigen Presentation Sites for a Single I-A Molecule.- The Effect of Nominal Antigen and Ia Molecule Concentrations on the Magnitude of the Proliferative Response of T Cell Clones.- Differential Requirements of Ia+ Accessory Cells for T Cell Activation.- I-Region-Controlled Sugar Inhibition of T-B Collaboration.- I-A Antigens in Cell Collaboration: Studies Using the B6.C-H-2bm12 Mutant.- Cloned T Cell Lines Do Not Discriminate Between Self Ia Molecules on B Cells and Antigen Presenting Cells.- Do T Cells Recognize the Same IA Epitopes of Antigen Presenting Cells and on B Cells?.- Ir Gene Regulation of the T Cell Dependent Activation of Distinct B Cell Subpopulations.- Functions of Helper T Cell Hybridomas in B Cell Antibody Responses.- Genetic Restriction of Polyclonal Stimulation of B Cell Proliferation by Antigen-Specific T Cell Clones.- H-2 Class I and Class II Alloantigens as Triggering Stimuli of Suppressor T Cells.- Susceptibility of Allo-Ia Specific T Lymphocytes to Unresponsiveness in Neonatal Tolerance.- Induction of I-J Restriction on Suppressor Cells.- Activation of Suppressor Cells is Genetically Restricted by the I-J Subregion.- Immunogenetic Aspects of Cellular and Humoral Autoimmunity to Acetylcholine Receptor.- Lessons on Ir Genes Derived from T Cell Clones and T Cell Hybridomas.- Multiple Restriction Sites Per Ia Molecule Recognized by T Cell Clones.- Multiple Genes Control Human Immune Responses.- Analysis of the T Cell Recognition System Using (T,G)-A--L Specific Helper T Cell Li…