Antiviral effect of cyclic amines on a 1969 isolate of A2 influenza

Cyclooctylamine and amantadine inhibit the growth of 1969 isolates of A(2) influenza virus to a significant degree. There was slightly more inhibition of the virus by the cyclooctylamine (COA) than the amantadine; however, the dose of COA used was greater than the dose of amantadine. There was no significant difference between flasks treated 3 or 4 hr and those treated 2 hr. However, there was a curious relationship of more plaques in the flasks exposed to the two drugs for the longer intervals. Other experiments done with slight modifications in technique support the antiviral effect demonstrated in this experiment when the cell system is pretreated prior to virus infection. In two experiments, pretreating the cells for 2 hr with COA at 100 mug/ml but removing the drug solution and washing the cells prior to virus inoculation revealed no differences in plaque counts between controls and treated cells. This would indicate that the antiviral effect required the presence of the drug during the early stages of penetration of the cells by the virus particles.