The international workshop on "Specificity and Function of Clonally Developing T Cells" was held at SchloG Rei- sensburg (near UIm, West Germany) on March 17-20, 1985. The meeting brought together immunologists study- ing clonal T-cell development in man and mouse in various in vitro systems at the cellular as well as molecular level. It was an attempt to provide an overview of the current research interests of groups working on (a) the developmen- tal potential of in vitro expanding primary T-cell clones (investigated using limiting dilution analysis) and cloned T -cell lines established in long-term culture; (b) the signals required for the expression of particular patterns of (func- tional and antigen receptor) phenotypes by T cells which are either freshly explanted in vitro, or maintained in vitro as cloned long-term lines; and (c) the generation of an MHC-restricted T-cell repertoire. In the study of thymocytes emphasis has shifted towards the presumably immature adult/embryonic subset(s) which is (are) devoid of subset-specific differentiation markers (L3T4, Lyt-2). Neither the signal requirement(s) for clonal expansion in vitro of these cells, nor their precursor role for any functional T -cell lineage are as yet unambiguously established. The multiple modes of human T-cell activation (e.g., via Tp44, T11, T3/Ti molecular complexes) were em- phasized by a number of presentations and raised the ques- tion of whether these different modes of activation induce different functional activities in individual T-cell clones.

Table of Contents:
A: Development of T Lymphocytes in the Thymus.- Introductory Remarks.- Development of T Lymphocytes Within the Thymus and Within Thymic Nurse Cells. With 3 Figures.- Thymus Development.- Major Histocompatibility-Restricted Cytolytic T-Lymphocyte Precursors from the Thymus of In Vivo Primed Mice: Increased Frequency and Resistance to Anti-Lyt-2 Antibody Inhibition. With 1 Figure.- Thymic Stem Cells: Their Interaction with the Thymic Stroma and Tolerance Induction.- B: Murine T-Cell Receptor Genes.- Organization, Rearrangement, and Diversification of Mouse T-Cell Receptor Genes. With 1 Figure.- Expression of T-Cell Receptor by a Mouse Monoclonal Antigen-Specific Suppressor T-Cell Line.- Somatic Variation of Antigen-Recognition Specificity in H-2b-TNP-Specific Cytotoxic T-Cell Clones.- The Change of Specificity, Karyotype, and Antigen-Receptor Gene Expression is Correlated in Cytotoxic T-Cell Lines.- C: Phenotype and Functional Potential of T-Cell Clones.- Introductory Remarks.- A Study of the Functional Potential of Mouse T-Cell Clones.- Generation, Propagation, and Variation in Cloned, Antigen-Specific, Ia-Restricted Cytolytic T-Cell Lines.- Significance of T4 or T8 Phenotype of Human Cytotoxic T-Lymphocyte Clones. With 1 Figure.- Natural and Unnatural Killing by Cytolytic T Lymphocytes. With 2 Figures.- Acquisition of Suppressive and Natural Killer-Like Activities Associated with Loss of Alloreactivity in Human "Helper" T-Lymphocyte Clones. With 3 Figures.- Expression and Function of Class II I-Ak Antigens on an Antigen-Specific T-Suppressor Cell Clone. With 2 Figures.- D: Signal Requirements for T-Cell Activation.- Introductory Remarks.- Heterogeneity of the Signal Requirements During the Primary Activation of Resting Lyt-2+ Cytotoxic T-Lymphocyte (CTL) Precursors into Clonally Developing CTL. With 2 Figures.- Regulation of Lytic Function by Recombinant IL2 and Antigen. With 4 Figures.- The Target Structure for T11: A Cell Interaction Molecule Involved in T-Cell Activation? With 3 Figures.- Antigen- and Lectin- Sensitized Murine Cytolytic T Lymphocyte- Precursors Require Both Interleukin 2 and Endogenously Produced Immune (?) Interferon for Their Growth and Differentiation. With 3 Figures.- Activation Requirements for Resting T Lymphocytes.- E: Self-Nonself Discrimination in the T-Cell Compartment.- Introductory Remarks.- Functional Clonal Deletion and Suppression as Complementary Mechanisms in T Lymphocyte Tolerance.- Human T Cell Clones, Tolerance, and the Analysis of Autoimmunity. With 1 Figure.- Antiself Suppressive (Veto) Activity of Responder Cells in Mixed Lymphocyte Cultures. With 6 Figures.- Analysis of T Suppressor Cell Mediated Tumor Escape Mechanisms. With 2 Figures.- The T-Cell Receptor Recognizes Nominal and Self Antigen Independently. A Theoretical Alternative to the Modified Self Concept. With 3 Figures.- F: T-Cell-Mediated Autoreactivity.- Introductory Remarks.- T-Cell Reactivity to Polymorphic MHC Determinants. I. MHC-Guided T-Cell Reactivity.- T-Cell Reactivity to Polymorphic MHC Determinants. II. Self-Reactive and Self-Restricted T Cells. With 6 Figures.- T-Cell Reactivity to Polymorphic MHC Determinants. III. Alloreactive and Allorestricted T Cells. With 9 Figures.- Appearance of New Specificities in Lectin-Induced T-Cell Clones Obtained from Limiting Dilution T-Cell Cultures. With 2 Figures.- Syngeneic Cytotoxicity and Veto Activity in Thymic Lymphoid Colonies and Their Expanded Progeny. With 4 Figures.- Functional Analysis of a Self-I-A Reactive T-Cell Clone Which Preferentially Stimulates Activated B Cells.- Indexed in Current Contents.