The influence of substances changing the intracellular concentration of cyclic adenosine 3'5'-monophosphate on interferon synthesis in chick embryo cell culture.

The influence of cyclic 3'5'-adenosine monophosphate (cAMP), adrenalin and theophylline on interferon synthesis induced by influenza B virus (Lee strain) in chick embryo cell cultures was studied. In 5-day-old cell culture, theophylline was shown to enhance the inhibiting effect of exogenous cAMP and adrenalin on interferon synthesis and in 1-day-old culture, on the contrary, to enhance interferon production whereas adrenaline under these conditions had no effect on interferon synthesis at all. In 5-day-old cultures the activity of adrenalin and theophylline was manifested when they were added to the maintenance medium not later than 4 hours postinfection, and was not associated with the influence on interferon inducer adsorption on to cells or on virus multiplication in sensitive systems. Treatment of cells with these substances had no effect on interferon release from the cells. In the concentration used, adrenalin and theophylline exerted no cytotoxic effect. Theophylline inhibited incorporation of 3H-uridine and 14C-leucine into the acid insoluble fraction of the infected cells in 1-day-old cultures, while in 5-day-old cultures this was observed only when adrenalin and theophylline were used together. It is suggested that endogenous cAMP is essential for control of interferon synthesis and that different cAMP levels in cells of different ages may be one of the causes of the varying potency for interferon synthesis in young and old cell cultures.