The history of Toll-like receptors — redefining innate immunity

The past 15 years have seen a breakthrough in the field of innate immunity. In this Timeline article, the authors discuss the early events that led to the identification of Toll-like receptors as the prototype pattern-recognition receptors that link innate and adaptive immune responses. The discovery of Toll-like receptors (TLRs) was an important event for immunology research and was recognized as such with the awarding of the 2011 Nobel Prize in Physiology or Medicine to Jules Hoffmann and Bruce Beutler, who, together with Ralph Steinman, the third winner of the 2011 Nobel Prize and the person who discovered the dendritic cell, were pioneers in the field of innate immunity. TLRs have a central role in immunity — in this Timeline article, we describe the landmark findings that gave rise to this important field of research.