In recent years our horizons regarding the role of nucleic acids in biological systems have been expanded vastly by the finding that these molecules not only carry and transmit specific infOImation but also can act as less specific triggers of antiviral factors and of immunological responses. The latter properties are of particular interest in terms of possible utilization in human and veterinary medicine and consequently led, in the last few years, to the development of a new research area that combines both fundamental and applied problems in a uniquely attractive way. Furthermore, the importance and the complexity of the problems has attracted investigators from many fields, including molecular biologists, virologists, immunologists, chemists, biophysicists, oncologists, pharmacologists, and clinicians. A discussion of new developments in this area of biological effects of polynucleotides, with particular emphasis on interferon induction and modification of immune responses, therefore, seemed a logical topic for one of the annual symposia that Miles Laboratories, Inc. , has sponsored in recent years. The manage ment of Miles accepted the suggestion with enthusiasm and thus once again earned the gratitude of the scientific community for sponsoring a catalytic meeting that was principally concerned with basic research problems and only tangentially with immediate applications. Springer-Verlag agreed to publish the proceedings of the meeting which was held at the Americana Hotel in New York City, June 4-5, 1970 and attracted an unusually large audience.

I Template Effects and Their Modification

Qualitative and Quantitative Aspects of Polynucleotide Modification
Template and Messenger Activities of Mutagen-Treated Polynucleotides
Discussion
II Interferon Stimulation
Double-Stranded RNA's in Relation to Interferon Induction and Adjuvant Activity
Factors Affecting the Interferon Response of Mice to Polynucleotides
Studies on the Anti-Tumor Action of Poly I: Poly C
Molecular Requirements for Synthetic RNA to Act in Interferon Stimulation
The Specificity of Interferon Induction
Structural Requirements of Ribopolymers for Induction of Human Interferon: Evidence for Interferon Subunits
Immunogenic Polynucleotides
Discussion
III Stimulation of Antibody Formation and Cell-Mediated Immunity
Spectrum and Mode of Action of Poly A: U in the Stimulation of Immune Responses
Stimulation of the Immune System by Homopolyribonucleotides
Effect of Polynucleotides (Poly I · C and Poly A · U) on Protein, RNA, and Polysomal Synthesis in Rabbit and Human Lung, and Rat and Human Peritoneal Macrophages
Conversion with Polynucleotides of a Genetically Controlled Low Immune Response to a High Response in Mice Immunized with a Synthetic Polypeptide Antigen
Influence of Synthetic Polynucleotides on the Bactericidal Power of Mouse Macrophages against Listeria monocytogenes
Remission Induction with Poly IC in Patients with Acute Lymphoblastic Leukemia (Preliminary Results)
Immunity and Tolerance to Synthetic Polynucleotides in New Zealand Mice
Discussion
IV Pharmacological Aspects of Polynucleotide Effects
The Double-Bitted Axe: A Study of Toxicity of Interferon Releasers
Polyinosinic-Polycytidylic Acid Toxicity
Discussion
V Polynucleotide-Associated Events in Immunocompetent Cells
Cell toCell Cooperation in the Immune Response: A Role for Macrophage RNA-Antigen Complexes?
Antigen Capture by a Unique Ribonucleoprotein of Macrophage Cells
Observations on the Regulatory Effects of the Transfer RNA Minor Base, N6-?2-(Isopentenyl)Adenosine, on Human Lymphocytes
Discussion.