Manganese Breaks the Immune Tolerance of HBs-Ag

Abstract Background Manganese (Mn2+) has been shown to promote type I interferon (IFN) production and activate the cyclic GMP-AMP synthase (cGAS)/Stimulator of Interferon Genes (STING) signaling pathway, suggesting that Mn2+ could be used as an adjuvant for vaccination. Methods In present study, the effects of Mn2+ on vaccination against hepatitis B virus (HBV) were evaluated. We treated mouse hepatocytes and kuppfer cells with Mn2+ with or without adeno-associated virus (AAV)–HBV infection. Expression of IFN-α and IFN-β and activation of TBK1 and IRF3 were monitored. Wild-type and STING-/- mice were treated with Mn2+ and then infected with AAV-HBV. Serum levels of HBV surface antigen (HBsAg), alanine aminotransferase (ALT) activity, IFN-α, and IFN-β were detected. Lymphocyte infiltration in the liver was evaluated. HBsAg-Tg mice were vaccinated with Mn2+ and HBsAg. The serum levels of HBsAg antibody, alanine transaminase activity, and IFN-β were monitored after vaccination. Results Mn2+ promoted IFN-α and IFN-β production in mouse hepatocytes and kuppfer cells. Mn2+ failed to promote IFN-α and IFN-β production in kuppfer cells deficient in STING. Mn2+ promoted activation/phosphorylation of TBK1 and IRF3 during AAV-HBV infection. Mn2+ decreased serum levels of HBsAG, increased serum levels of alanine aminotransferase (ALT), IFN-α and IFN-β, and enhanced lymphocyte infiltration and the percentage of IFN-γ-producing CD8+ T cells in the liver of AAV-HBV-infected mice. In contrast, Mn2+ treatment did not affect serum levels of HBsAG, ALT, IFN-α, or IFN-β in STING-deficient mice. Conclusions Mn2+ promoted HBsAG antibody, ALT, and IFN-β production after HBsAG immunization. Mn2+ promoted type I IFN production in AAV-HBV infection and HBsAG immunization and could be used as an adjuvant for vaccination.