Fig. 1.

The effect of vaccination or convalescence on colonization and leukocytosis. Naïve animals, aP-vaccinated animals, wP-vaccinated animals, and previously infected [convalescent conv.)] animals were directly challenged with B. pertussis (n = 3–4 per group). (A) Colonization was monitored by quantifying B. pertussis cfu per mL in biweekly nasopharyngeal washes with a limit of detection of 10 cfu per mL. For each animal the time to clearance is defined as the first day that no B. pertussis cfu were recovered from nasopharyngeal washes. (B) The mean time to clearance is shown for each group (n = 3 per group). Because no B. pertussis organisms were recovered from the conv. animals, the mean time to clearance was defined as the first day of sampling (day 2, indicated by the dashed line). *P < 0.05 vs. Naïve, †P < 0.05 vs. aP, ‡P < 0.05 vs. wP. (C) The mean circulating white blood cell counts before and after challenge are shown for each group of animals (n = 3–4 per group). **P < 0.01 vs. preinfection from same group.