Further studies to investigate the pathogenesis of fever are planned in the following area: 1. The role of purified endogenour pyrogen (EP) in prostaglandin release. 2. The effect of fever on the inflammatory response in lizards. 3. Production and properties of antibody to human leukocyte EP. 4. Characterization of EP production in mouse tumor cell lines. 5. Mechanism Ep production in vitro by antigen-antibody complexes. 6. Role of T and B cells from sensitized guinea pigs in activating normal peritoneal exudate cells to produce EP in vitro. 7. Mechanism of tolerance to fever in rabbits and guinea pigs desensitized to protein antigens. 8. Further studies of pyrogenic factors in purified flu virus (with Edwin Kilborne). BIBLIOGRAPHIC REFERENCES: Chao, P., Francis, L. and Atkins, E.: The release of an endogenous pyrogen from guinea pig leukocytes in vitro. J. Exp. Med. 145: 1288, 1977. Bernheim, H., Bodel, P., Askenase, P. and Atkins, E.: Mechanisms for life saving effect of fever in infected lizards. Clin. Res. 25:273A, 1977.