FIG. 7.

Anti-Bordetella antibody titers in sera collected from RB50- and RB63-infected animals were measured by ELISA using RB50 (A) or RB63 (B) whole cells as the antigen. Specifically, total serum antibody, IgM, and IgG titers were determined. Sera collected from Lewis rats sacrificed at 10 and 30 days postinoculation were tested. Hatched bars represent RB50-infected animals; solid bars represent RB63-infected animals; ∗ indicates that antibody titers for RB63-infected animals were significantly lower than those for RB50-infected animals, with a P value of ≤0.02. Error bars represent 1 standard error from the mean. The lower limit of detection of antibody titer is 10 U. Mock (PBS)-infected animals had antibody titers below the level of detection.