Effects of tolerogenic dendritic cells generated by siRNA-mediated RelB silencing on immune defense and surveillance functions of T cells.

Dendritic cells (DCs) can initiate immune responses or induce immune tolerance, according to their level of maturation. In this study, we inhibited RelB expression in immature (im)DCs using small interfering RNA (siRNA) to maintain their immature status. RelB-silenced DCs induced donor-specific hyporesponsiveness in T cells. In contrast, T cells primed by RelB-silenced DCs maintained normal proliferation and cytokine secretion when stimulated by influenza virus antigen. Proliferation was similar between T cells stimulated with syngeneic tumor antigen or donor-specific antigen stimulation, but was significantly lower compared with T cells stimulated with influenza virus antigen. Moreover, an altered pattern of micro181a and micro155 transcriptional levels in T cells was involved in the differential regulation. This study demonstrates that RelB-silenced DCs could induce donor-specific hyporesponsiveness and slightly impair immune surveillance of T cells, while retaining their immune defense functions.