FIG 9 .
NhhA potentiates the commensal persistence of N. meningitidis. CD46+/+ mice (n = 6 to 8) were pretreated with 50 nM heat-inactivated (control) or native NhhA for 3 days prior to intranasal bacterial challenge (108 CFU of FAM20 per mouse). Nasal lavage fluid and head tissue were collected 12 h after infection. (A) Bacterial burden in nasal lavage fluid. (B) Levels of IL-6 and IL-10 in the nasal fluid as determined by ELISA. Bars in panels A and B represent the mean ± standard deviation of data pooled from three experiments. *, P < 0.05 compared to control group using paired Student’s t test. (C) H&E-stained thin section of the nasal mucosa of both control and NhhA-pretreated mice. Original magnification of images, ×100. Representative images of three independent experiments are presented.