A Lectin-EGF antibody promotes regulatory T cells and attenuates nephrotoxic nephritis via DC-SIGN on dendritic cells

BACKGROUND: Interactions between dendritic cells (DCs) and T cells play a critical role in the development of glomerulonephritis, which is a common cause of chronic kidney disease. DC-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN), an immune-regulating molecule of the C-type lectin family, is mainly expressed on DCs and mediates DC adhesion and migration, inflammation, activation of primary T cells. DC-SIGN triggers immune responses and is involved in the immune escape of pathogens and tumours. In addition, ligation of DC-SIGN on DCs actively primes DCs to induce Tregs. Under certain conditions, DC-SIGN signalling may result in inhibition of DC maturation, by promoting regulatory T cell (Treg) function and affecting Th1/Th2 bias. METHODS: A rat model of nephrotoxic nephritis was used to investigate the therapeutic effects of an anti-lectin-epidermal growth factor (EGF) antibody on glomerulonephritis. DCs were induced by human peripheral blood mononuclear cells in vitro. The expression of DC surface antigens were detected using flow cytometry; the levels of cytokines were detected by ELISA and qPCR, respectively; the capability of DCs to stimulate T cell proliferation was examined by mixed lymphocyte reaction; PsL-EGFmAb targeting to DC-SIGN on DCs was identified by immunoprecipitation. RESULTS: Anti-Lectin-EGF antibody significantly reduced global crescent formation, tubulointerstitial injury and improved renal function impairment through inhibiting DC maturation and modulating Foxp3 expression and the Th1/Th2 cytokine balance in kidney. Binding of anti-Lectin-EGF antibody to DC-SIGN on human DCs inhibited DC maturation, increased IL-10 production from DCs and enhanced CD4(+)CD25(+) Treg functions. CONCLUSIONS: Our results suggest that treatment with anti-Lectin-EGF antibody modulates DCs to suppressive DCs and enhances Treg functions, contributing to the attenuation of renal injury in a rat model of nephrotoxic nephritis.