Antigen-presenting cells that phagocytose apoptotic tumor-derived cells are potent tumor vaccines

We have reported recently that treatments combining injections of apoptotic bodies from tumor cells and interleukin 2 Led to tumor regression and indu ced specific protection. In the present study, we show that tumor-bearing r ats were cured with an 80% success rate by injection of antigen-presenting cells (APCs) that had phagocytosed apoptotic bodies derived from poorly imm unogenic tumor cells, whereas phagocytic cells exposed to nonapoptotic tumo r cell extracts were essentially without effect. In addition, curative vacc ination using APCs that had phagocytosed apoptotic bodies generated a tumor -specific cytotoxic T-cell response and long-term protection from parental tumor challenge. Thus, systems using the processing and presentation of ant igenic molecules by professional APCs after phagocytosis of apoptotic bodie s appear to offer new possibilities for anticancer treatment.