Elie Metchnikoff's and Paul Ehrlich's impact on infection biology

The 100th anniversary of the Nobel Prize for Medicine to Paul Ehrlich and Elie Metchnikoff gives us a good opportunity to reflect on their research about infectious diseases. Elie Metchnikoff was not only the first to describe phagocytosis of invading pathogens by specialized blood cells - macrophages and neutrophils - he also was interested in the impact of normal flora on well-being and in pre- and probiotic diet and their influence on the normal flora. Paul Ehrlich not only developed the concept of the side-chain theory of antibody formation but also discovered the first chemotherapeutic agent against microbial pathogens through a combination of chemical modification of a lead substance and experimental animal screening on a broad-scale. Hence, they are not only the founders of immunology but also were the first to envisage infection biology as the result of an interplay between host and pathogen. (C) 2008 Elsevier Masson SAS. All rights reserved.