Degradation of human alpha- and beta-defensins by culture supernatants of Porphyromonas gingivalis strain 381

Abstract

Porphyromonas gingivalis produces proteases capable of degrading cytokines, host heme proteins and some antimicrobial peptides. In this study, we show that P. gingivalis culture supernatants fully or partially degrade human neutrophil peptide alpha-defensins and human beta-defensins after 30 min. This observation suggests that proteases from P. gingivalis degrade defensins and this activity could abrogate defensin-related innate immune functions.

Fig. 1

MALDI-TOF mass spectrometry showing the masses of human α-defensin HNP-1 and human β-defensins HBD1, HBD2 and HBD3. Predicted masses were 3,448.1 Da for HNP-1, 3,934.6 Da for HBD1, 4,164.0 Da for HBD2 and 5,161.2 Da for HBD3. Distinct peaks were seen at 3,446.973 m/z, 3,934.616 m/z, 4,340.865 m/z and 5,167.895 m/z.

Fig. 2

Overlays of spectrograms after MALDI-TOF mass spectrometry (range 0–7,500 m/z). Shown is the spectrogram of the defensin mixture and the spectrogram of the culture supernatant of P. gingivalis incubated with the defensin mixture. Note that the defensins were degraded and nearly absent in the latter mixture.