I would like to thank all my co-workers who have collaborated with me, from 1963 until now, in biological and clinical research in the field of cancer active immunotherapy, of its immuno­ prevention and immunorestoration. They will often be quoted in this book. I am particularly grateful to those who have helped me to write it by reviewing some chapters: D. BELPOMME, J. F. DOR~, IRENE FLORENTIN, A. GOUTNER, I. J. Hm, R. HUCHET and MARIE-CHRISTINE SIMMLER. I also thank NICOLE VRIZ, MARIE-CLAUDE SCHNEIDER, FENELLARIsELEY and M. JUVET for their willing and efficient co-operation in the preperation of the manuscript. I am finally grateful to all authors of books or articles who authorized me to reproduce their figures or tables. Paris, April 1976 G. MAT~ Contents Chapter 1. Introduction and Definitions 1 Chapter 2. Biological Basis: Tumour Associated Antigens, the Immune Machinery and Its Behaviour Concerning Cancer Cells 5 2. 1. Tumour-Associated Antigens 5 2. 2. The Immune Machinery 19 2. 2. 1. Humoral Mediated Immunity and Cell Mediated Immunity 19 2. 2. 2. T- and B-Lymphocyte and Monocyte Differen­ tiation 22 2. 2. 3. T-Lymphocyte Functions 25 2. 2. 4. B-Lymphocyte Functions 30 2. 2. 5. Macrophage Functions 31 2. 2. 6. K-Cell Function 32 2. 3. The Immune Machinery and Cancer Cells 33 2. 3. 1. Mechanisms Involved in Tumour Cell Rejec­ tion 33 2. 3. 1. 1. In vivo Evidence for Tumour Immunity 33 2. 3. 1. 2.