Induction of Circulating Interferon by Synthetic Anionic Polymers of Known Composition

Abstract

RECENTLY, it has been demonstrated that interferon production can be stimulated by a variety of microorganisms other than virus (richettsia¹, trachoma inclusion conjunctivitis agents², pleuropneumonia-like organism (J. Younger and W. Stinebring, personal communication), bacteria³, protozoa^4,5) and various derivatives of living materials including endotoxin^6,7, phytohaemagglutinin⁸, and fungal extracts^9,10. Only one is of denned structure—the antibiotic, cyclohexamide¹¹. Unfortunately, the amount of this antibiotic required for interferon production results in irreversible inhibition of protein synthesis leading to death of the animal. Recently, Regelson described antiviral activity appearing in sera of mice injected with synthetic anionic copolymers of defined composition and suggested such activity might be interferon¹². This communication confirms his findings, characterizes this antiviral activity, identifies it as interferon, and explores certain of the structural requirements for copolymers to act as interferon inducers. The significance of these compounds is increased by the previous report of their activity as inhibitors of virus induced leukaemia in mice and their present trials in the therapy of human neoplasms¹².