FIG. 6.

Effect of macrophage PRR deficiencies on P. gingivalis internalization. Peritoneal macrophages from wild-type mice or mice deficient in CD14, TLR2, TLR4, or CR3 were incubated with FITC-labeled P. gingivalis (Pg) 381 or P. gingivalis JH1004 (nonfimbriated mutant) at a multiplicity of infection of 10:1 for the indicated times at 37°C. Internalization was assessed by flow cytometry after washing the macrophages and quenching extracellular fluorescence and was expressed as percent FITC-positive macrophages (A and B). The mean fluorescence intensity (MFI) at the 60-min time point is also shown (C and D) as a relative measure of the number of internalized bacteria. Results are shown as means ± SDs (n = 3; for clarity, only the upper or lower SD is shown in A and B). Asterisks indicate statistically significant (P < 0.05) differences between PRR deficiencies and wild-type (WT) controls (A, B, and D) or between wild-type and mutant P. gingivalis (C).