|Born||January 14, 1943
Montreal, Quebec, Canada
|Died||September 30, 2011 (aged 68) 
Manhattan, New York City, United States
|Residence||New York City, United States|
|Fields||Immunology and cell biology|
|Institutions||Rockefeller University, New York City|
|Alma mater||McGill University
|Academic advisors||Elizabeth Hay (Harvard)
James G. Hirsch and Zanvil A. Cohn (Rockefeller University)
|Known for||Discovery of dendritic cells and its role in adaptive immunity|
|Notable awards||2011 Nobel Prize in Physiology or Medicine (posthumous)|
Ralph Marvin Steinman (January 14, 1943 – September 30, 2011) was a Canadian immunologist and cell biologist at Rockefeller University. He studied a kind of cell in the immune system and called them dendritic cells. He made these discoveries while working in the laboratory of Zanvil A. Cohn.
On October 3, 2011, the Nobel Committee announced that Steinman had received one-half of the Nobel Prize in Physiology or Medicine, for "his discovery of the dendritic cell and its role in adaptive immunity". The other half went to Bruce Beutler and Jules Hoffmann, for "their discoveries concerning the activation of innate immunity". However, the committee did not know that Steinman had died three days earlier, on September 30, from pancreatic cancer. The committee considered what to do about Steinman's prize, since the rule is that the prize is not awarded posthumously.
The committee later decided that, as the decision to award the prize "was made in good faith", they would not change the award.
Steinman's daughter said that he had joked the previous week with his family about hanging on until the prize announcement. Steinman said: "I know I have got to hold out for that. They don't give it to you if you have passed away. I got to hold out for that".
Steinman had received numerous other awards and recognitions for his life-long work on dendritic cells, such as the Albert Lasker Award (2007), the Gairdner Foundation International Award (2003), and the Cancer Research Institute William B. Coley Award (1998). In addition, he was made a member of Institute of Medicine (U.S.A.; elected 2002) and the National Academy of Sciences (U.S.A.; elected 2001).
- "Rockefeller University scientist Ralph Steinman, honored today with Nobel Prize for discovery of dendritic cells, dies at 68". Rockefeller University. October 3, 2011. http://newswire.rockefeller.edu/?page=engine&id=1192.
- Steinman RM, Cohn ZA (1973). "Identification of a novel cell type in peripheral lymphoid organs of mice. I. Morphology, quantitation, tissue distribution". J. Exp. Med. 137 (5): 1142–62. doi:10.1084/jem.137.5.1142. PMC 2139237. PMID 4573839.
- Nobel Foundation (October 3, 2011). "Nobel Prize in Physiology or Medicine 2011". Press release. http://www.nobelprize.org/nobel_prizes/medicine/laureates/2011/press.html.
- "Nobel winner died days before award announced". CNN. October 3, 2011. http://www.cnn.com/2011/10/03/health/nobel-prize/index.html?hpt=he_c2. Retrieved 3 October 2011.
- "Montreal-born scientist dies before Nobel honour". CBC News. October 3, 2011. http://www.cbc.ca/news/technology/story/2011/10/03/nobel-prize-medicine.html. Retrieved October 3, 2011.
- "Ralph Steinman remains Nobel Laureate". The Nobel Foundation. October 3, 2011. http://www.nobelprize.org/press/nobelfoundation/press_releases/2011/steinman.html. Retrieved October 4, 2011.
- Nobel jury left red faced by death of laureate