Long-term stability of baculoviruses stored under various conditions.

The long-term stability of baculoviruses under various storage conditions was investigated. The results showed that the titers of baculovirus working stocks were significantly reduced after the viruses had been stored in polypropylene tubes for several months or a year at 4 degrees C. The virus was not lost by sticking to the plastic tubes, because the same results were obtained when the virus was stored in glass tubes. The major factor contributing to the loss of viral infectivity was exposure to light. Virus stocks stored at temperatures ranging from -85 degrees to 37 degrees C were quite stable, as long as they were protected from light. Finally, viral infectivity was not significantly reduced by multiple freeze-thaw cycles. These results demonstrated that baculovirus working stocks may be stored frozen or refrigerated with little long-term loss of infectivity, as long as they are protected from light.