3 Immunologists Share Nobel Prize in Medicine
medpagetoday.com
It's here at SI that I learned about toll-like receptors and dendritic cells
By John Gever, Senior Editor, MedPage Today
Published: October 03, 2011
The discoverers of dendritic cells and Toll-like receptor function -- both central to the immune system -- were awarded the 2011 Nobel Prize in Physiology or Medicine.
The newly named laureates are Bruce Beutler, MD, of the Scripps Research Institute in La Jolla, Calif., Jules A. Hoffmann, PhD, of the French national lab CNRS in Strasbourg, and Ralph Steinman, MD, of Rockefeller University in New York City.
However, the status of Steinman's share of the prize was unclear because Steinman died on Friday after a battle with pancreatic cancer, according to an announcement Monday from Rockefeller University.
Nobel Prize rules stipulate that awards cannot be made posthumously. The committee at Stockholm's Karolinska Institute that selects Nobel medicine laureates was apparently unaware of Steinman's death.
Beutler and Hoffmann led separate teams that uncovered the roles of Toll-like receptors in what is known as the innate immune system.
In studies published in the mid-1990s, Hoffmann and colleagues found that fruit flies with mutated Toll genes were highly vulnerable to bacterial and fungal infections, indicating that their gene products -- the Toll-like receptors -- were needed by insects to ward off microbial pathogens.
At about the same time, Beutler's group found that the same family of receptors were the factors that mediated responses to bacterial lipopolysaccharide, the well-known trigger for septic shock in mammals.
Steinman's research, meanwhile, focused on the immune system's other main element, adaptive immunity. Beginning in 1973, he published a series of papers identifying what was then a novel immune cell type, dubbed dendritic cells for their tree-like appearance.
These cells are the gatekeepers in the adaptive system, determining when to activate a T-cell attack -- in part by responding to signals from the innate system.
According to the Nobel committee's announcement, the three researchers were instrumental in advancing medical understanding of the immune system's basic architecture.
"We know ... how antibodies are constructed and how T cells recognize foreign substances. However, until the work of Beutler, Hoffmann, and Steinman, the mechanisms triggering the activation of innate immunity and mediating the communication between innate and adaptive immunity remained enigmatic," the committee said in a press release.
The prize will be awarded at a Dec. 10 ceremony in Stockholm.
The Nobel Prize in Chemistry, which also sometimes honors advances in basic medical science, is to be announced Wednesday.
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