Rimantadine hydrochloride blocks the second step of influenza virus uncoating

Two steps of influenza virus A/WSN uncoating in MDCK cells are described. The products of the first step are cores which accumulate in the nuclear-associated cytoplasm. The products of the second step are ribonucleoproteins which penetrate the nuclei. Rimantadine blocks the second step without interfering with the first one.