In 2011, three NIAID grantees were awarded the Nobel Prize in Physiology or Medicine for their work on key components of the immune system, which defends the body against invading bacteria and other microorganisms. A better understanding of this system is providing new ways to prevent and treat infections, inflammatory diseases, and cancer.
While studying the immune system of fruit flies, Jules Hoffman of the Centre National de la Recherche Scientifique in Paris came across the groundbreaking discovery that the fruit fly protein Toll, previously established to be important in embryonic development, played a critical role in protecting the flies from infection by disease-causing bacteria and fungi. Meanwhile, Bruce Beutler of the Scripps Research Institute in California found that a protein similar to Toll in mice responded strongly to bacterial surface molecules, called lipopolysaccharides, which are associated with deadly septic shock. Together, the initial studies of Hoffmann and Beutler established the importance of Toll-like receptors in initiating the innate immune response to invading microbes. Since then several Toll-like receptors have been characterized and shown to be critical in the response to microbial infection.
In 1973 Ralph Steinman of the Rockefeller University in New York discovered a new type of immune system cell that he named the dendritic cells due to their tree-like shape. He tested whether these previously uncharacterized cells play a role in adaptive immunity—the second stage of the immune response, which eliminates microorganisms from the body. Steinman discovered that dendritic cells were capable of activating T cells, a critical component of the adaptive immune response, and thus serve as “sentinel cells” that initiate the immune response. Subsequent work by Steinman and others revealed that dendritic cells have a complex role in regulating the immune response and also in preventing the immune system from attacking the body’s own cells and tissues.
These researchers’ contributions provided important insights into how the human immune system reacts to microbial threats, and how an overactive immune system can lead to inflammatory diseases such as rheumatoid arthritis and lupus. Armed with these insights, researchers have been able to manipulate the immune system to improve our defense against these threats to public health, for example by developing vaccines against infectious diseases as well as new treatments for inflammatory diseases.
Last Updated January 11, 2013
Last Reviewed January 11, 2013