Various aspects of the actions of human interferon (IFN)-gamma will be examined with the aid of biological and biochemical techniques. Both highly purified natural and recombinant, E. coli-derived IFN-gamma will be employed in these studies. Studies will include evaluations of the relative efficiency of IFN-gamma in inhibiting various viral functions in different cell systems and in some immunoregulatory activities. We shall also continue to explore regulatory interactions between IFN-gamma and some other lymphokines and monokines. Monoclonal antibodies specific for IFN-gamma will be prepared and characterized with respect to their ability to bind to and neutralize natural and recombinant IFN-gamma. (HF)