This year, the Nobel Assembly at high school Karolinska in Stockholm has decided to award the 2011 Nobel Prize in Physiology and Medicine award to two researchers in the field of immunology. The award will be divided into two halves: one of them to Drs. Bruce A. Bruce A. Beutler and Jules A. Hoffmann for their discoveries related to the activation of innate immunity, and the other half to Dr. Ralph M. Steinman for his finding of dendritic cells and their role in adaptive immunity.

With this award the Nobel assembly intends to recognize the findings of these three researchers who have revolutionized our knowledge on the principles governing the activation of the immune system. Since the finding of the existence of the immune system, as responsible for defending the organism from attack by infectious agents such as bacteria or viruses, scientists have searched for the elements that determine the activation of these defense mechanisms. Bruce Beutler and Jules Hoffmann have been recognized for the finding of receptors that act as sensors of the infection by these microorganisms and activate the innate immune system, the first line of defense of the organism. On the other hand, Ralph Steinman discovered the existence of dendritic cells and their unique ability to activate and regulate the adaptive immune response, responsible for eliminating microorganisms that have managed to escape the control of the innate immune system.
The human body is constantly under attack by microorganisms (bacteria, viruses, fungi and parasites) that pose a continuous threat to our survival. The immune system, with its two lines of defense, innate and adaptive, is responsible for recognizing this invasion and reacting to eliminate it. The innate response can destroy the microorganisms and trigger an inflammatory process that contributes to blocking the spread of the infection. If the microorganisms overcome this first barrier, the adaptive immunity made up of T and B lymphocytes is capable of producing antibodies and killer cells that can destroy the infected cells.

The discoveries of these three Nobel laureates have revealed mechanisms by which the innate and adaptive immune system is activated and have led to the discovery of new elements for understanding how many diseases develop. Some of their findings have already enabled the development of drugs for diseases such as rheumatoid arthritis, Crohn's disease or psoriasis. His work has opened new avenues for the development of preventive strategies and therapies against infections, cancer and inflammatory diseases.

The awarding of this award has been overshadowed by the death last Friday of one of the laureates, Dr. Ralf Steinman.