Scientists win Nobel medicine prize for work on secrets of immune system

Three scientists who unlocked secrets of the body's immune system, opening doors to new vaccines and cancer treatments, have won the 2011 Nobel Prize for medicine. American Bruce Beutler and French biologist Jules Hoffmann, who studied the first stages of immune responses to attack, shared the $1.5 million (R12.1 million) award with Canadian-born Ralph Steinman, whose discovery of dendritic cells was the key to understanding the later stages.

Beutler is based at the Scripps Research Institute in La Jolla, California. Hoffmann conducted much of his work in Strasbourg. Their work has been pivotal to development of vaccines against infectious diseases and new ways of fighting cancer.

The research has helped lay the foundations for a new wave of "therapeutic vaccines" that stimulate the immune system to attack tumours. Better understanding of the complexities of the immune system has also given clues for treating inflammatory diseases, such as rheumatoid arthritis, where the components of the self-defence system attack the body's tissues.

The award citation noted that the world's scientists had long been searching for the "gatekeepers" of the immune response by which man and other animals defend themselves against attack by bacteria and other microorganisms. Beutler and Hoffmann discovered receptor proteins that recognise attacking microorganisms and activate "innate immunity", the first step in the body's immune response.

Ralph Steinman 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. The award panel at Sweden's Karolinska Institute said this year's Nobel laureates revolutionised our understanding of the immune system by discovering key principles for its activation.

By Patrick Lannin and Anna Ringström: Reuters, 4 October 2011