Inhibition of Multiplication of Influenza Virus by Tannic Acid.

Abstract

Recently several reports describing the inhibition of multiplication of certain viruses have appeared. In some instances the substances which inhibit virus multiplication also inhibit virus hemagglutination. Furthermore, some of these substances are themselves capable of agglutinating erythrocytes. The interrelationships among these phenomena, if indeed any exist, are not clear. During the course of studies on hemagglutination it was found that tannic acid in concns. as low as 45-[gamma]/ml. agglutinates chicken erythrocytes. Further investigations revealed that tannic acid, in dilutions higher than those which produce hemagglutination, actually inhibits the agglutination of chicken erythrocytes by influenza A virus. Concns. ranging from 5 to 20-[gamma]/ml. inhibit virus hemagglutination. Moreover, tannic acid inhibits the multiplication of influenza A virus in vivo and inactivates the virus in vitro. When injd. into the chorio-allantoic sacs of embryonated eggs, 1 mg. per egg markedly inhibits the multiplication of virus. The inhibitory effects of tannic acid. appear to be due, at least partly, to a direct action upon the virus.