FIG 3.

Vaccine efficacy with regard to pneumococcal colonization in focal infection models. Groups of six C57BL/6 mice were intranasally immunized with the indicated antigens and challenged 2 weeks after the third immunization with 19F/CMCC31693 (1 × 10⁸ CFU) (A and B) or 6B/CMCC31207 (1 × 10⁸ CFU) (C and D). Levels of nasopharynx and lung colonization in individual mice were determined at day 4 after challenge. Each dot represents one mouse. The horizontal lines indicate the median CFU per nasopharynx or lung. The detection line is 10 CFU. *, P < 0.05, and ***, P < 0.001, compared with the DnaJ group.