Dr. Tsuji’s research in the past few years has led to the identification and characterization of a unique CD4+ T cell subset, which is named “tumor-recognizing CD4+ helper T cell (TR-CD4 cell)," that directly recognizes cancer cells. Through direct recognition of cancer cells, TR-CD4 cells significantly inhibit tumor cell growth and potently enhance anti-tumor functions of cytotoxic CD8+ T cells. He also elucidated novel antigen presentation mechanisms that are involved in the presentation of intracellular tumor antigen proteins to CD4+ T cells. He recently established a method to generate large numbers of TR-CD4 cells by gene-engineering with T cell receptor (TCR) gene for the development of novel tumor adoptive T cell therapy using TR-CD4 cells.