Thyrocyte-derived exosome-targeted dendritic cells stimulate strong CD4+ T lymphocyte responses.

Exosomes have been intensively studied in autoimmune diseases, and circulating exosomes and microvesicles have also been explored in autoimmune thyroiditis (AITD). However, the role of thyroid cell-derived exosomes in immune responses is unclear. We showed that IFN-γ-treated Nthy-ori 3-1 cell-derived exosomes (IFN-γ-Exo) harbored TPO, HSP60 and MHC-II and activated dendritic cells (DCs) in vitro. Compared with Exo-targeted DCs (DCExo), IFN-γ-Exo-targeted DCs (DCIFN-γ-Exo) promoted the expression and release of proinflammatory cytokines, such as IFN-γ, IL-17A and IL-22, from CD4+ T lymphocytes and inhibited the expression and release of anti-inflammatory cytokines, such as IL-4, IL-10 and TGF-β1; however, IFN-γ-Exo did not have this effect compared with Nthy-ori 3-1 cell-derived exosomes (Exo). DCIFN-γ-Exo stimulates the expression and release of cytokines from CD4+ T lymphocytes more efficiently than IFN-γ-Exo. Thus, DCIFN-γ-Exo may effectively induce CD4+ T lymphocyte-mediated immune responses and play a role in the occurrence and development of AITD.