Studies on isolation of virus from patients seemingly affected with influenza--isolation of influenza virus by MDCK cells stored in a frozen state

Abstract

To save labor and make it easy to take an immediate countermeasure at the time of isolation of influenza virus, studies were made on a method to inoculate a sample directly into cells which had been stored in a frozen state. The following results were obtained.1. When MDCK cells were stored at -80°C with DMSO as a low-temperature protecting agent, they showed a survival rate of more than 95% after storage for 6 months.2. MDCK cells stored in a frozen state presented a high susceptibility to the standard strain of influenza virus.3. When used for the isolation of virus from samples collected from patients, MDCK cells stored in a frozen state gave results not inferior to those obtained from monolayer culture cells.4. It was possible to take an immediate countermeasure when cells stored in a frozen state were used for the isolation of virus. Furthermore, the use of these cells could make it easy to isolate influenza virus even at a laboratory which was lacking in the equipment for cell culture and in experienced workers.