Further Observations of the Effect of Acridines on the Growth of Viruses

Abstract

Infections of the allantoic sac of chick embryos with the viruses of meningo-pneumonitis or feline pneumonitis were markedly inhibited or completely eradicated by a nitroacridine but the closely related chloroacridine produced negligible effects. Allantoic infections with mumps virus were slightly inhibited both by the chloro- and nitro-acridines while only the nitro-compound showed any effect against influenza B (Lee strain) in the allantoic sac. Both compounds retarded to about equal degree the growth of the viruses of mumps, influenza A and influenza B in tissue culture. The effect of the two acridines on virus inactivation in vitro and on growth of fibroblasts, respiration, and glycolysis in tissue cultures was examined and the findings related to the observed inhibition of virus growth. The results do not justify the conclusion that the inhibition of virus growth at concentrations of drug between 0.01 and 0.02 mg/ml was brought about either by killing of cells or by extracellular inactivation of virus. Inhibition of intracellular virus by acridines may occur both with agents of the psittacosis-LGV group and with those of influenza and mumps, but the alternative possibility of their action through modification of the host cell metabolism cannot be ruled out.