FIG. 4.

Adoptively transferred anti-LPaV serum confers protection against challenge with RB50 in mice. Mice were intraperitoneally injected with LPaV-specific serum or sterile PBS 3 to 4 h prior to intranasal challenge with 5 × 10⁵ CFU of RB50 in 25 μl. Seven days postchallenge, mice were sacrificed, and bacterial colonization in the nasal septum, trachea, and lungs was determined. The dashed line indicates the limit of detection. Each symbol indicates the results for a single mouse. The horizontal lines indicate the means for the groups. An unpaired two-tailed Student t test was used to determine statistical significance. The asterisks indicate P values (one asterisk, P ≤ 0.05; two asterisks, P ≤ 0.005).