A suburban Chicago native, Fred Ramsdell, has earned one of science’s highest honors, sharing the 2025 Nobel Prize in Physiology or Medicine with Mary E. Brunkow and Dr. Shimon Sakaguchi for their pioneering discoveries on peripheral immune tolerance. Their groundbreaking work unveiled how the body prevents immune cells from attacking its own tissues—a finding that has revolutionized the field of immunology and paved the way for new treatments for autoimmune diseases and cancer.