Figure 6. Serial passage of the MAMM mutant in the presence of oseltamivir.

A) Viral titers in culture supernatants. The wild type and MAMM mutant were serially passaged in MDCK cells in the presence of oseltamivir. The viral cultures were harvested at 72 hr post-infection and the supernatant from passages 1, 3, 5 and 7 were titrated by standard plaque assays. A representative data set from duplicated experiments was shown. B) Protein sequence of the NA stalk. The passage histories and NA sequences from the parental controls, passaged controls and MAMM escape mutants were as shown. The IC₅₀ of oseltamivir towards these viruses were presented.