FIG. 3.

Dose range experiment for A/Albany/1/98 influenza virus and amantadine in the HFIM system. Virus-infected cells (10²) and uninfected MDCK cells (10⁸) were loaded into hollow-fiber units and continuously infused with various concentrations of amantadine for 6 days. Each hollow-fiber unit was sampled daily, and the amount of virus produced was measured by plaque assay. The boxed region indicates the portions of the time course from which viruses samples were plated on MDCK cells to form plaques. Ten of these plaques were picked and the M2 gene sequenced to determine the presence of coding regions that lead to amantadine resistance. Determinations were in duplicate. The mean values are shown, and the error bars represent standard deviations.