Regulatory T cells (T_Rs) can suppress the function of other effector T cells in the setting of autoimmunity, transplantation, and resistance to tumors. The mechanism for the induction of T_Rs has not been defined. We previously reported that an injection of immature dendritic cells (DCs) pulsed with influenza matrix peptide (MP) led 7 days later to antigen-specific silencing of effector T-cell function in the blood of 2 healthy human subjects. Here, we found that interferon-γ–producing effectors return by 6 months. Importantly, in mixing experiments, CD8⁺ T cells from the sample obtained 7 days after injection could suppress MP-specific effectors obtained before injection and those in recovery samples. This suppression or regulation was specific for the immunizing peptide (MP) and cell-dose dependent, and it required contact between the 2 samples. These data show the capacity of immature DCs to induce antigen-specific regulatory CD8⁺ T cells in humans.