Fig. 1.
Gingipains are essential for the development of lethal P. gingivalis infection. a, b Kaplan-Meier plots showing mortality after a bacterial challenge (log-rank test). Young (8-week-old; a) and old (40-week-old; b) mice were intratracheally inoculated with 3 × 109P. gingivalis W83 (WT), gingipain mutants (ΔKgp, ΔRgp, or KRAB), or an inhibitor-treated bacterial suspension (W83-KYT). Histological evaluation of lung tissue from 8-week-old (c) and 40-week-old (d) mice infected with P. gingivalis. Mice were sham-infected by intratracheal instillation of PBS or intratracheally inoculated with 3 × 109 CFU of P. gingivalis W83 or KRAB. Lungs were surgically removed at 24 h postinfection and formalin-fixed sections were prepared and stained with hematoxylin and eosin. Representative images are shown. Magnification ×200. A section from an untreated animal (control) is also shown. The outline of the experimental setup is presented in online supplementary figure S1.