In this April 24, 2009 photo, Dr. Ralph Steinman of Rockefeller University speaks during a news conference in Albany, N.Y., Friday, April 24, 2009. [File photo]?

Three scientists shared the 2011 Nobel Prize in Physiology or Medicine, announced the Nobel jury -- the Nobel Assembly at Swedish Karolinska Institute in Stokcholm on Monday.

"The 2011 Nobel Prize in Physiology or Medicine shall be divided, with half jointly to Bruce A. Beutler and Jules A. Hoffmann for their discoveries concerning the activation of innate immunity and the other half to Ralph M. Steinman for his discovery of the dendritic cell and its role in adaptive immunity," said Goran Hansson, Secretary of the Nobel Committee.

"This year's Nobel Laureates have revolutionized our understanding of the immune system by discovering key principles for its activition," the committee explained in a statement.

The discoveries of the three Laureates have revealed how the innate and adaptive phases of the immune response are activated and thereby provided novel insights into disease mechanism.

"Their work has opened up new avenues for the development of prevention and therapy against infections, cancer and inflammatory diseases," the statement said.

The winner of the physics prize will be announced on Tuesday, to be followed by those for chemistry on Wednesday, literature on Thursday, peace on Friday and economics next Monday.

The annual Nobel Prizes are usually announced in October and are handed out on Dec. 10, the anniversary of the 1896 death of Alfred Nobel, a Swedish industrialist and the inventor of dynamite.

Nobel died childless and dedicated his vast fortune to create "prizes to those, who, during the preceding year, shall have conferred the greatest benefit on mankind."

The prizes have been awarded since 1901. Each prize consists of a medal, a personal diploma and a cash award of 10 million Swedish kronor (about 1.46 million U.S. dollars).