THE INFLUENCE OF CORTISONE ON EXPERIMENTAL VIRAL INFECTION Vl. INHIBITION BY HYDROCORTISONE OF INTERFERON SYNTHESIS IN THE CHICK EMBRYO*

The several and sometimes paradoxical effects of cortisone and its analogues on the course of a variety of infections may be duplicated in the relatively simple chick embryo-influenza virus model in which the interrelationships of a single obligate intracellular parasite and the cells of a single target organ (the allantoic entoderm) may be examined. Even in this simple system the influence of cortisone may be favorable (1, 2) or detrimental (3, 4) to the host depending on experimental conditions. The observation that the administration of cortisone to chick embryos (3) or in tissue culture (5) increases final yields of influenza B virus although it reduces early viral synthesis (2) is explicable as a result of inhibition of viral autointerference (4). A preliminary report has indicated that the interferon synthesis that accompanies influenza virus infection of the chick embryo is inhibited by cortisone and by a substituted C-19nor-steroid that is also active in inhibiting viral interference (6). This report had suggested also that cortisone inhibited the action of preformed interferon as well as its synthesis. The present paper presents further evidence for the effect of cortisone (hydrocortisone) on interferon formation in the chick embryo and on interference in vitro and reexamines the question of whether or not interferon action is also moderated.