Three scientists shared the 2011 Nobel Prize in Physiology or Medicine, announced the Nobel Committee at Swedish Karolinska Institute in Stockholm on Monday. Half of the 2011 Nobel Prize in Physiology or Medicine went to Bruce A. Beutler and Jules A. Hoffmann \"for their discoveries concerning the activation of innate immunity\" and the other half went to Ralph M. Steinman \"for his discovery of the dendritic cell and its role in adaptive immunity,\" said Goran Hansson from the Nobel Assembly.