Center for Clinical and Translational Science

Rockefeller University cell biologist Dr. Ralph M. Steinman, who discovered the immune system’s sentinel dendritic cells and demonstrated that science can fruitfully harness the power of these cells and other components of the immune system to curb infections and other communicable diseases, is one of this year’s recipients of the Nobel Prize in Physiology or Medicine. Dr. Steinman was awarded one half of the prize and the other is shared by Bruce A. Beutler of the University of Texas Southwestern Medical Center in Dallas and the Scripps Research Institute in San Diego and Dr. Jules A. Hoffmann of Institut de Biologie Moléculaire et Cellulaire, Université Louis Pasteur de Strasbourg.

Dr. Steinman passed away on September 30. He was 68. He was diagnosed with pancreatic cancer four years ago and his life was extended using a combination of surgery, standard chemotherapy and experimental dendritic-cell based immunotherapy of his own design.  When an infectious agent enters the human body, the immune system responds to get rid of it. But how does the immune response get started? That was the question that intrigued Dr. Steinman when he joined the Rockefeller laboratory of Zanvil A. Cohn (1926-1993) in 1970. It led him to discover a new type of immune system cell—the dendritic cell.  Dr. Steinman soon established that dendritic cells are the sentinel cells of the immune system, initiating the immune response. Subsequent research has revealed their complex roles: dendritic cells are now known to orchestrate the interactions of more than a dozen types of immune system cells, and they also play a role in preventing the immune system from attacking the body's own tissues. Understanding the basic biology of dendritic cells is leading to ways to harness them therapeutically in treating cancer and autoimmune diseases, and in developing new vaccines.

Drs. Steinman and Cohn began by studying cultures of cells called macrophages, which were known to be important in the immune response. When these experiments proved disappointing, Dr. Steinman decided to take another tack. Other investigators had shown that an immune response could be stimulated in a mixture of T cells, B cells, and unknown "accessory" cells harvested from mouse spleen. When he looked closely at the accessory cells using phase-contrast light microscopy, he saw large cells with branch-like projections, which continually extended and retracted. He called them dendritic cells, after the Greek word for tree.

In the following years Steinman and colleagues characterized dendritic cells and proved their potency in initiating a T-cell response, a crucial step in the immune response. They also developed techniques to grow dendritic cells in culture rather than isolate them from mixtures of immune cells. Making cultured dendritic cells readily available for study opened the door to other researchers, and today hundreds of laboratories around the world devote their work to the basic biology and clinical applications of dendritic cells. Many groups are now using them as part of immune therapies for cancer. Dr. Steinman and his colleagues developed novel ways to target dendritic cells so as to enhance the response to vaccines to protect against HIV and other infectious diseases.

Dr. Steinman was born in Montreal, Canada on January 14, 1943. He received a B.S. degree, with honors, from McGill University in 1963, and an M.D., magna cum laude, from Harvard Medical School in 1968.  After completing an internship and residency at Massachusetts General Hospital, he joined The Rockefeller University in 1970 as a postdoctoral fellow in the Laboratory of Cellular Physiology and Immunology headed by Cohn and the late James G. Hirsch. He was appointed an assistant professor in 1972, associate professor in 1976, and professor in 1988. He was named Henry G. Kunkel Professor in 1995, and director of the Christopher Browne Center for Immunology and Immune Diseases in 1998.

A recipient of the Freidrich-Sasse, Emil von Behring, and Robert Koch Prizes, Dr. Steinman also has received the Rudolf Virchow and Coley Medals and the Gairdner Foundation International Award. He was awarded honorary degrees from the University of Innsburck and Free University of Brussels. He also received the 2004 New York City Mayor’s Award for Science and Technology, the 2007 Lasker Award for Basic Medical Research and the 2009 Albany Medical Center Prize in Medicine and Biomedical Research. He was a member of the U.S. National Academy of Sciences and its Institute of Medicine. A scientific symposium in honor of Steinman is being planned for the spring of 2012.