Stability of pseudorabies virus during freeze-drying and storage: effect of suspending media.

The effect of suspending media on the stability of pseudorabies virus upon freeze-drying and subsequent storage was studied. A variety of media was tested, including: sodium glutamate; sucrose; lactose; lactalbumin hydrolysate; peptone; a combination of sucrose, dextran, and glutamate; and various combinations of sucrose, glutamate, and potassium phosphates. Suspending media containing glutamate, either alone or in combination with sucrose and either dextran or phosphates, afforded the greatest degree of protection during the freeze-drying process and upon storage. Some possible functions of these additives in preventing injury to the virus during freezing and drying have been suggested.