Three scientists shared the 2011 Nobel Medicine Prize for their work on the immune system which the jury said opened up new prospects for curing cancer and other diseases.
The laureates are Bruce Beutler of the United States, Jules Hoffmann of Luxembourg and Ralph Steinman of Canada.
"This year's Nobel laureates have revolutionised our understanding of the immune system by discovering key principles for its activation," the jury said in a statement.
The three were lauded for their work on immunology -- the body's complex defence system in which signalling molecules unleash antibodies and killer cells in response to invading germs and viruses.
Understanding this is a key to new drugs and also to easing immune disorders, such as asthma, rheumatoid arthritis and Crohn's disease.
"Their work has opened up new avenues for the development of prevention and therapy against infections, cancer and inflammatory diseases," the jury said.
Beutler and Hoffmann, who shared one half of the 10 million Swedish kronor ($1.48 million, 1.08 million euros) prize, discovered receptor proteins that activate the first step in the body's immune response system.
Steinman, who won the other half, discovered the dendritic cells, allowing the immune system to identify and attack the harmful micro-organisms while staying clear of the body's own endogenous molecules.
They will receive their prize at a formal ceremony in Stockholm on December 10, the anniversary of prize founder Alfred Nobel's death in 1896.