Ilya Ilich Metchnikoff (1845–1915) and Paul Ehrlich (1854–1915): the Centennial of the 1908 Nobel Prize in Physiology or Medicine

Ilya Metchnikoff and Paul Ehrlich shared the 1908 Nobel Prize in Physiology or Medicine – Metchnikoff for discovering the major types and functions of phagocytes and Ehrlich for discovering the types of blood leukocytes, helping to uncover how to generate and use antibodies to protect against bacterial toxins, and formulating the receptor concept of antibodies binding to antigens. In 1908 phagocytic and humoral defences were thought to be unrelated but it was realized much later that they influence one other. Thus, it is fitting that the 1908 Nobel Laureates in Physiology or Medicine remain closely connected in the minds of modern immunologists. Metchnikoff and Ehrlich shared qualities of natural curiosity and tenacity coupled with remarkable inductive-mechanistic thinking and a zest for experimentation. However, their approaches to and methods of research were decidedly different – Metchnikoff's by evolutionary biology and an approach to experimentation via microscopy and Ehrlich's by an imaginative side-chain theory and organic chemistry.