Steinman was awarded half the prize. The other half went to Dr. Bruce A. Beutler, 53, of the Scripps Research Institute in La Jolla, Calif., who is an American, and Dr. Jules A. Hoffmann, 70, of France.
They are being honored for discoveries of essential steps in the immune system’s response to infection. Steinman was diagnosed with pancreatic cancer four years ago and devised a treatment for himself based on his discovery.
Rockefeller University, which has close ties with the Karolinska Institute, did not know of Steinman’s death until yesterday morning, said Joseph Bonner, a spokesman for the university. The president of Rockefeller, Marc Tessier-Lavigne, immediately called the chairman of the Nobel committee to inform him.
Susuma Tonegawa of the Massachusetts Institute of Technology, who received the prize for his work in immunology in 1987, said the decision was a wise one. “All I can say is that the work deserved the prize, and it will be nicer if they make some adjustment.’’
In 1973, Steinman discovered a new class of cell, known as dendritic cells, which are key activators of the adaptive immune system. The dendrites engulf pathogens and display parts of them to the T cells of the immune system. The T cells then proliferate and destroy cells infected by the pathogen.
His work on dendritic cells faced considerable skepticism at first, because the number of cells in the bloodstream seemed far too few to activate the T and B cells of the immune system, Locksley said. But Steinman persisted, and researchers later came to realize that many more dendritic cells lay outside the bloodstream in the body’s tissues.
A practical consequence of Steinman’s work is that dendritic cells have begun to be used as adjuvants in vaccines and in the treatment of certain cancers, Locksley said.
As for the other prize recipients, Hoffmann in 1996 discovered the cell receptors in laboratory fruit flies that are activated by pathogenic bacteria or fungi.
