In recent years, substantial progress has been made in the understanding of the chemistry, biology and clinical potential of human interferons. Studies utilizing recombinant DNA as a source for specific interferons will lead to a better understanding of the critical aspects of the fine structure controlling a biologic activity. Progress has also been made in understanding the regulation of interferon production, and the cellular basis for its mechanisms of antiviral action, as well as its actions on cell growth and the immune response. Finally, through appropriate pharmacokinetic animal model testing, a firmer basis for carrying out clinical trials has been laid. With the increased availability of human interferons stemming from progress in cloning the human interferon genes and other biological sources, as well as the availability of highly purified preparations, new clinical trial results are expected as well. For example, by the time of this meeting several centers will have the first clinical trial data to present on the use of several varieties of recombinant DNA-produced interferon. The purpose of the present meeting is to bring together scientists working on clinical and animal studies with those whose work on the basic scientific aspects of interferons has provided a rationale for these studies. The emphasis of the meeting will be on the pharmacology of interferons and their clinical use; however, the developments in basic sciences that led to the current renewal of interest in human and animal studies will not be ignored. In addition there will be some discussion about how pure an interferon must be for human use. Because of the accelerating rate of work in this area of research, it is expected that important concepts will be developed with respect to structure, mechanisms of production and action, and animal models in order to direct future clinical trials. Therefore, this meeting is critically timed so as to promote effective exchange between both basic and applied scientists in order to evaluate the present status of the field and to set forth innovative approaches in solving the fundamental and clinical problems on which the meeting will forcus. All of these findings should permit better understanding of interferon's role in health and disease. With respect to the latter it should provide a forum to discuss what virus diseases and forms of cancer might be treated by interferons and how such treatments should be carried out.