FIG. 8.
Spleen weights of Y. pestis-infected animals. Twenty Swiss Webster mice were inoculated with ∼100 bacteria i.v. and euthanized at day 1, 2, 3, or 7. Spleens were removed and weighed. Increased spleen weight is an indication of increased immune infiltration in mice infected with the KIM5 Δail mutant. Decreased spleen weight is an indication of cell death within the spleen in a KIM5 infection. Statistical comparisons are between spleen weights on day 1 versus those on day 3 for KIM5 or for the KIM5 Δail mutant. *, P < 5 × 10−5 by the Student t test.