FIG. 4.

Effect of oral administration of L. casei strain Shirota on viral titer in nasal washings. Aged mice were fed either the control diet (○) or the L. casei strain Shirota diet (•) for 4 months. One day thereafter, the aged mice were intranasally infected with PR8, and 3 days later the viral titers in the nasal washings from the infected mice were measured. Each bar represents the mean value for 11 or 12 mice. *, statistically significant difference from the control value by Student’s t test at a P value of <0.05.