CD86-silenced-DCs had unchanged expression of CD80 and significantly suppressed the proliferation of lymphocytes. CD86-silenced-DCs simultaneously reduced IL-2 and INF-γ and increased IL-10, TGF-β and IDO, while had minimal effect on IL-4. The CD86-silenced-DCs also improved cell viability and function of xeno-islets when compared to untransfection and transfection control groups