Abstract

Regulatory immune cells are well-recognized in regulating immune responses and thus maintain the immune tolerance. By contrast, several studies, including our findings, reported impaired functions of several regulatory immune cell subsets in the autoimmune pathogenesis, including primary Sjögren’s syndrome (pSS). Our findings suggested that regulatory B (Breg) cells and myeloid-derived suppressor cells (MDSCs) critically restrained effector T cells in the development of experimental SS (ESS) in mice. Mechanistic studies first revealed the decrease of transcriptional regulation of effector molecule IL-10 in Breg cells. Acteoside, a caffeoyl phenylethanoid glycoside from a medicinal herb Radix Rehmanniae could dose dependently promoted IL-10-producing capacity in human and murine Breg cells, thus ameliorating ESS pathology in mice. Moreover, we found that polymorphonuclear MDSCs (PMN-MDSCs) highly expressed hydrocarbon receptor (AhR), while activation of AhR significantly enhanced the regulatory function of PMN-MDSCs, and thus suppressed effector T cells in ESS mice. Together, our findings demonstrated novel therapeutic strategies by targeting the regulatory immune cells for the treatment of autoimmunity.