The Influence of Mineral Trioxide Aggregate on Adaptive Immune Responses to Endodontic Pathogens in Mice

This study assessed the influence of mineral trioxide aggregate (MTA) on adaptive immune responses. BALB/c mice were immunized with heat-killed Fusobacterium nucleatum (Fn) in MTA or other control adjuvants, and serum IgG responses to Fn were measured. Either Fn- or Peptostreptococcus anaerobius (Pa)-reactive memory T cells (Tm) were preincubated in vitro with/without MTA and restimulated with Fn or Pa. Tm proliferation and cytokine production were assessed. Compared with control groups, immunoglobulin G-antibody responses were upregulated in mice immunized with Fn in MTA in a similar manner to animals immunized with Fn in Freund's adjuvant or aluminum hydroxide adjuvant. Although MTA did not affect the upregulated expression of interleukin 10, tumor necrosis factor α, or RANKL by Tm, it suppressed the proliferation of Pa- or Fn-Tm and inhibited their production of Th1- or Th2-signature cytokines. MTA upregulated the adaptive humoral immune responses but had little or no effect on pro- or anti-inflammatory cytokine production by Tm.