Dr. Leonard focuses on regulatory T cells-immune cells that normally prevent autoimmunity, but are co-opted by cancers in order to evade anti-tumor immune attack. He will use a combination of biochemistry, structural biology, and mouse models in order to understand how regulatory T cells recognize “self,” and how this process is exploited in prostate cancer. His results will inform efforts to develop therapies that disrupt the ability of cancer cells to recruit and activate regulatory T cells, thereby releasing the "brakes" and allowing the immune system to fight tumors more effectively.