The prize was divided, with one half going jointly to Bruce A. Beutler and Jules A. Hoffmann "for their discoveries concerning the activation of innate immunity" and the other half to the late Ralph M. Steinman "for his discovery of the dendritic cell and its role in adaptive immunity".
The three scientists together have “revolutionized our understanding of the immune system”, according to a statement from The Nobel Assembly at Karolinska Institutet through research unlocking secrets about how people's bodies fight off diseases.
Beutler, an American currently at the Scripps Research Institute in California and Jules Hoffmann, a Luxembourg-born scientist who spent most of his career in France, discovered receptor proteins that can recognize such microorganisms and activate innate immunity, the first step in the body's immune response.
Meanwhile, Steinman a Canadian affiliated with Rockefeller University in New York, discovered the dendritic cells of the immune system and their unique capacity to activate and regulate adaptive immunity, the later stage of the immune response during which microorganisms are cleared from the body.
Steinman died last weekend of cancer, according to a report in the Canadian press, with the news only reaching the Nobel Committee after the award had been announced.
While much about the immune system has been learned over the course of the 20th century, prior to the work of the three scientists, the mechanisms triggering the activation of innate immunity and mediating the communication between innate and adaptive immunity remained a mystery.
Together, the discoveries "provided novel insights into the activation and regulation of our immune system", according to the Nobel Committee.
"They have made possible the development of new methods for preventing and treating disease, for instance with improved vaccines against infections and in attempts to stimulate the immune system to attack tumors."
In addition, the discoveries have increased understanding as to why the immune system can "attack our own tissues", information which offers clues for new treatments of inflammatory diseases.