Found in most tissues of the body, dendritic cells are among the most efficient antigen-presenting cells in the body. The immune system recognizes antigens after going through a complex process of education, learning to distinguish self from non-self. Current treatments for cancer, such as chemotherapy or radiation, target rapidly dividing tumor cells, but lead to serious side-effects because they attack healthy cells as well as tumors. Scientists are looking for more specific ways to attack tumor cells without damaging healthy cells. One such technique is immunotherapy, which attempts to activate the immune system to recognize tumors as foreign and reject them, based on tumor-specific antigens that are presented on a molecule called MHC, a highly diverse set of proteins responsible for allowing dendritic cells to communicate with T cells.
MHC molecules are different in each person, giving each individual a unique immune system.
Even the most common MHC molecule is found in only 50 percent of Caucasians. Birthe Sauter, M.D., and Assistant Professor Nina Bhardwaj, M.D., Ph.D., provides an avenue for using the cell's natural machinery to bypass this requirement, allowing the individual's own dendritic cell to determine the correct part of the tumor antigen that fits their MHC molecules. In a model system, the researchers collected human tissue and infected it with influenza. The dying cells were cultured with dendritic cells, making the dendritic cells capable of activating killer T cells that specifically target influenza antigen. In this way, an individual's own immune system is revved up to attack the tumor based on the expression of tumor-specific antigens.