OPG demonstrated antibacterial properties against Gram-positive bacteria. OPG reduced the growth of Gram-positive bacteria E. faecalis
(A) and S. pyogenes
(B) only (no effect on Gram-negative bacteria [C, D]). Blocking OPG within the conditioned media of OMLP-PCs significantly restored the growth of Gram-positive E. faecalis
(E) and S. pyogenes
(F) bacteria. Data are expressed as the percentage of growth ± SEM, with bacteria-only cultures set to 100%. ∗, p ≤ .05; ∗∗, p ≤ .01; ∗∗∗, p ≤ .001. Abbreviations: EFs, enriched fibroblasts; IFN-γ, interferon-γ; OMLP-PCs, oral mucosal lamina propria-progenitor cells; OPG, osteoprotegerin.