Figure 6. MFG-E8 reduces the periodontal bacterial burden without exerting direct antimicrobial activity.

Periodontal microbiota counts were determined in WT or Mfge8^−/− mice subjected to ligature-induced periodontitis (A) or to naturally-occurring periodontitis until the age of 13 months (B), as well as in WT mice in which ligature-induced periodontitis was performed with or without local treatment with 2.5 μg MFG-E8 (C). In A and C, bacteria were extracted from recovered ligatures and serial dilutions of bacterial suspensions were plated onto blood agar plates for anaerobic growth and CFU enumeration. In B, oral swabs held against the gumlines were taken and bacteria were cultured anaerobically for CFU enumeration as above. Each symbol represents an individual mouse and small horizontal lines indicate the mean. *P < 0.01. (D) Possible antimicrobial activity of MFG-E8 against mouse periodontal bacteria was determined by the disk inhibition zone method, using PBS and imipenem as negative and positive control, respectively. The experiment shown is representative of a total of 15 bacterial isolates and MFG-E8 consistently failed to inhibit bacterial growth. Numbers shown refer to μg of compound used.