1 Cell-Surface Antigens in Acute Leukemia.- 1. Introduction.- 2. Methods of Identification of Leukemia-Associated Membrane Antigens.- 3. Acute Lymphoblastic Leukemia-Associated Membrane Antigens.- 3.1. T-Cell Antigens.- 3.2. Ia Antigen.- 3.3. Common Acute Lymphoblastic Leukemia Antigen (CALLA).- 3.4. B-Cell Antigens.- 3.5. 26,000-Dalton Surface Antigen.- 4. Acute Myeloblastic Leukemia-Associated Membrane Antigens.- 4.1. Identification of Myeloid Antigens with Polyclonal Antisera.- 4.2. Monoclonal Antibodies Specific for Myeloid Surface Antigens.- References.- 2 Suppressor Cells in Tumor-Host Interactions.- 1. Introduction.- 2. Immunoregulation and Suppressor T Cells.- 3. The Tumor-Bearing Host.- 3.1. Humoral and Cellular Immunodeficiency.- 3.2. Macrophage Functions and Natural Cytotoxicity.- 3.3. Other Changes.- 4. Suppressor Mechanisms in Tumor-Bearing Hosts.- 4.1. Suppressor Factors Produced by Tumors and Suppressor Serum Factors.- 4.2. Suppressor T Cells.- 5. Suppressor Cells in Human Cancer.- 6. Conclusions.- References.- 3 The Interleukins: Regulation of Lymphocyte Differentiation, Proliferation, and Functional Activation.- 1. Introduction.- 2. The Interleukins.- 3. Interleukin 1.- 3.1. Initial Characterization.- 3.2. Superinduction and Purification of IL 1.- 3.3. Biological Effects of IL 1 on Lymphocytes.- 3.4. Biological Effects of IL 1 on Nonlymphoid Cells.- 4. Interleukin 2.- 4.1. Initial Observations.- 4.2. Cell Source of IL 2.- 4.3. T-Cell Lines Producing IL 2.- 4.4. Role of IL 1 in the Induction of IL 2 Synthesis.- 4.5. Possible Cell Cycle Dependence of IL 2 Production.- 4.6. Binding of IL 2 to Target T Cells.- 4.7. Biochemical Studies on IL 2.- 4.8. Preparation of Monoclonal Antibodies against IL 2.- 5. Interplay of Interleukins and Other Lymphokines.- 5.1. Lymphokine-Induced IL 1 Production.- 5.2. Generation of Cytotoxic Effector Cells.- 5.3. Antibody Synthesis.- 6. Therapeutic Potential of the Interleukins.- References.- 4 The Interaction of Human T-Cell Growth Factor with Normal and Neoplastic T Cells.- 1. Introduction.- 2. Purification and Biochemical Characterization of Human TCGF.- 2.1. TCGF Assays.- 2.2. Purification of Human TCGF.- 2.3. Biochemical Characteristics of Human TCGF.- 3. Culture Conditions for Generation of Human TCGF.- 3.1. General Considerations.- 3.2. The Cellular Origin of TCGF.- 3.3. Mitogens Effective in Production.- 3.4. Tissues Used for TCGF Production.- 3.5. Different Culture Conditions.- 3.6. Interfering Substances in Crude Conditioned Media: Removal of PHA.- 3.7. TCGF Activity: Lack of Correlation between [3H]-TdR Incorporation and Long-Term T-Cell Growth.- 4. Relationship between TCGF and Other Lymphokines.- 4.1. Nomenclature.- 4.2. Lymphocyte-Activating Factor.- 4.3. B-Lymphocyte-Stimulating Factors.- 4.4. Production of Hematopoietic Growth Factors.- 4.5. The Role of TCGF in Immune Reactivity.- 5. Development and Maintenance of Functional T-Cell Clones.- 5.1. T-Cell Activation: TCGF Receptors.- 5.2. Variable Growth of Human T Lymphocytes in TCGF: A “Crisis” Period.- 5.3. The Clonal Derivation of T-Cell Lines.- 5.4. Cytotoxic T Cells.- 5.5. Helper T-Cell Lines.- 5.6. Suppressor T-Cell Lines.- 5.7. The Effects of TCGF on Natural Killer Cells.- 5.8. In Vivo Function of Cloned T Cells and TCGF.- 6. Interaction of TCGF with Neoplastic T Cells.- 6.1. Role of TCGF in Growth of Neoplastic T Cells.- 6.2. Mature T-Cell Leukemia Cell Lines Produce and Respond to TCGF.- 6.3. Production of Hematopoietic Factors by Malignant Mature T Cells.- 6.4. Possible Role of TCGF in the Transformation of Mature T Cells.- 7. Isolation of a New Class Type-C Retrovirus from Human T Cells.- 7.1. Isolation and Characterization of Human T-Cell Leukemia—Lymphoma Virus.- 7.2. Susceptibility of T Cells to HTLV Infection.- 8. Concluding Remarks: The Functional Implications of TCGF.- References.- 5 Interferons: Biological Response Modification and Pharmacology.- 1. Introduction.- 2. The Interferon System.- 3. Factors Influencing Cellular Activity.- 3.1. Interactions with the Cell Surface.- 3.2. Genetic Control of Interferon Action.- 3.3. Cell-Surface Alterations Resulting from Interferons.- 4 Immunomodulation.- 4.1. T Cells.- 4.2. NK Cells.- 4.3. K Cells.- 4.4. Macrophages.- 4.5. B Cells.- 4.6. Cell-Surface Characteristics of Immunologic Significance.- 4.7. Clinical Effects upon Immune Functions.- 5. Enzymatic Alterations.- 5.1. Interferon-Inducible Genes.- 5.2. Oligoadenylate Synthetase.- 5.3. Occurrence and Actions of 2-5A.- 5.4. 2-5A Synthetase Assays.- 5.5. Distribution and Induction of 2-5A Synthetase.- 5.6. 2?-Phosphodiesterase.- 5.7. Protein Kinase.- 5.8. Biological Applications of the Interferon-Induced Enzyme Assays.- 5.9. Regulatory Mechanisms in Actions of Interferons.- 6. Clinical Pharmacology.- 6.1. Interferon ?.- 6.2. Interferon ?.- 6.3. Distribution of Interferons.- 6.4. Metabolism.- 6.5. Interferons and the Cytochrome P-450 System.- 7. Conclusion.- References.- 6 Role of Thymosin and Other Thymic Hormones in T-Cell Differentiation.- 1. Introduction.- 2. Biochemical Characteristics of Thymosin.- 3. Biological Effects of Thymosin and Other Thymic Factors in Experimental Animal Models.- 3.1. Induction of T-Cell Markers.- 3.2. Induction of T-Cell Function.- 3.3. Experimental Models of Clinical Relevance.- 4. Biological Effects of Thymosin and Other Thymic Factors in Man.- 4.1. Induction of T-Cell Markers.- 4.2. Induction of T-Cell Functions.- 5. Concluding Remarks.- References.- 7 Host Factors Influencing the Growth and Spread of Tumors.- 1. Introduction.- 2. Regional Differences in Tumor Growth.- 2.1. Spontaneous Tumors.- 2.2. Carcinogen-Induced Tumors.- 2.3. Transplanted Tumors.- 2.4. Mechanisms Underlying Regional Differences in Tumor Growth.- 3. Regional Differences in Normal Tissue Growth and Function.- 3.1. Regional Differences in Immune Responsiveness.- 3.2. Regional Differences in Proliferative Activity.- 3.3. Regional Differences in Growth of Transplanted Normal Tissues.- 3.4. Topographical Aspects of Wound Healing.- 4. Host Factors Involved in Vascularization of Tumors.- 5. Inductive Tissue Interactions.- 6. Host Factors in Tumor Cell Seeding and Development.- 7. Other Host Factors Influencing Tumor Growth.- 8. General Comments.- References.- 8 The Biological Diversity of Malignant Neoplasms.- 1. Introduction.- 2. Biological Diversity of Metastatic Neoplasms.- 3. The Development and Progression of Metastasis.- 4. Implications of Phenotypic Diversity for Experimental Studies: Propagation of Heterogeneous Tumors Used to Evaluate Therapeutic Agents.- 5. Phenotypic Diversity of Neoplasms and the Challenge for Therapy.- 5.1. Variations in Drug Sensitivity.- 5.2. Variations in Immune Response.- 6. Circumvention of the Problem of Cellular Diversity.- 6.1. Use of Macrophages in Therapy of Heterogeneous Metastases.- 6.2. Stimulation of Tumoricidal Properties of Macrophages.- 7. Concluding Remarks.- References.