FIG. 4.
Anti-TbpB and anti-Fha44 serum antibody responses after i.n. administration of B. pertussis BPIC1, BPIC3, or BPIC4. Groups of three 4-week-old female OF1 mice were infected i.n. with 5 × 106 CFU of B. pertussis BPIC1 (hatched bars), BPIC3 (black bars), or BPIC4 (white bars). Infections with similar amounts of B. pertussis BPRA or BPSM served as negative controls. At the indicated time points, the mice were bled by retro-orbital plexus puncture, and anti-TbpB and anti-Fha44 serum IgG titers were estimated by ELISA. Results are expressed as means ± standard deviations.