Metchnikoff

Elie Metchnikoff, also spelled Mechnikov or Mechnikoff (1845–1916), was a Russian-born biologist whose work laid the foundations of modern immunology. In 1882 he described phagocytosis, the process by which certain white blood cells engulf and digest invading microbes, having observed this in starfish and other organisms. This work introduced the concept of cellular immunity and positioned phagocytes, especially macrophages, as central to host defense, complementary to the humoral approaches later developed by others. For his discoveries concerning the immune system, he shared the 1908 Nobel Prize in Physiology or Medicine with Paul Ehrlich.

Mechnikoff spent much of his career in Europe, including periods in Italy and Paris, where he joined the Institut Pasteur and conducted influential immunology research. In addition to his work on phagocytosis, he pursued theories on aging and nutrition. He argued that aging results from toxins produced by intestinal bacteria and that altering gut flora could promote longevity. He advocated fermented dairy products, notably yogurt, as a source of beneficial bacteria and helped popularize the probiotic concept through his writings, including The Prolongation of Life.

Mechnikoff’s legacy extends beyond phagocytosis to the broader field of innate and cellular immunity, influencing subsequent research on immune defenses and the relationship between gut microbiota, diet, and health. Alternate transliterations of his name include Mechnikov.