Together with Bruce Beutler, Hoffmann received one-half of the 2011 Nobel Prize in Physiology or Medicine for "their discoveries concerning the activation of innate immunity". Hoffmann discovered the function of the fruit fly "Toll" gene in innate immunity. Its mammalian homologues, the toll-like receptors, were discovered by Beutler. Toll-like receptors identify constituents of other organisms like fungi and bacteria, and trigger an immune response. This explains how septic shock can be triggered by bacterial remains.