Treponema denticola is resistant to human β-defensins

Spirochetes, including Treponema denticola, are implicated in the pathogenesis of periodontal disease. Because T. denticola lacks lipopolysaccharides that serve as targets for human beta-defensin (hbetaD) binding, we postulated that T. denticola would resist killing by hbetaD. We showed that T. denticola is resistant to hbetaD-1 and -2. Protease inhibitors did not enhance killing of T. denticola by hbetaD-2, suggesting that degradation of hbetaD-2 by treponemal proteases is not a major factor in T. denticola resistance.