Ilya Ilyich Metchnikoff (Elie Metchnikoff) (1845-1916)


Elie Metchnikoff first suggested the possibility of colonizing the gut with beneficial flora in the early 20th century.


Ilya Ilyich Metchnikoff the great Russian biologist, changed his name to Elie Metchnikoff, after his permanent move from Russia to Paris, France. Metchnikoff was a biologist and zoologist, best known for his pioneering research into the immune system. In particular, he is credited with the discovery of phagocytes (macrophages) in 1882, and his discovery turned out to be the major defense mechanism in innate immunity. He and Paul Ehrlich were awarded the 1908 Nobel Prize in Physiology or Medicine “in recognition of their work on immunity.“ He is also credited by some sources with coining the term gerontology in 1903, for the emerging study of aging and longevity. He established the concept of cell-mediated immunity, while Ehrlich that of humoral immunity. Their works are regarded as the foundation of the science of immunology. In immunology he is given an epithet the “father of natural immunity“.


Metchnikoff was born in the village Panasovka (or Ivanovka) near Kharkov (now Kharkiv in Ukraine), Russian Empire. He was the youngest of five children of Ilya Ivanovich Metchnikoff, an officer of the Imperial Guard. His mother, Emilia Lvovna (Nevakhovich), the daughter of the Jewish writer Leo Nevakhovich, largely influenced him on his education, especially in science. His elder brother Lev became a prominent geographer and sociologist. He entered Kharkov Lycee in 1856 and developed his interest in biology. Convinced by his mother to study natural sciences instead of medicine, in 1862 he tried to study biology at the University of Wurzburg. But the German academic session would not start by the end of the year. So he enrolled at Kharkiv University for natural sciences, completing his four-year degree in two years. In 1864 he went to Germany to study marine fauna on the small North Sea island of Heligoland. He was advised by the botanist Ferdinand Cohn to work with Rudolf Leuckart at the University of Giessen. It was in Leuckart’s laboratory that he made his first scientific discovery of alternation of generations (sexual and asexual) in nematodes. In 1865, while at Giessen, he discovered intracellular digestion in flatworm, and this study influenced his later works. He was greatly influenced by Charles Darwin’s theory of evolution. He first read Fritz Muller’s Fur Darwin (For Darwin) in Giessen. From this he became a supporter of natural selection and Ernst Haeckel’s biogenetic law. His scientific works and theories were inspired by Darwinism. Moving to Naples the next year he worked on a doctoral thesis on the embryonic development of the cuttle-fish Sepiola and the crustacean Nelalia. A cholera epidemic in the autumn of 1865 made him move to the University of Gottingen, where we worked briefly with W. M. Keferstein and Jakob Henle. In 1867 he returned to Russia to get his doctorate with Alexander Kovalevsky from the University of St. Petersburg. Together they won the Karl Ernst von Baer prize for their theses on the development of germ layers in invertebrate embryos. Metchnikoff was appointed docent at the newly established Imperial Novorossiya University (now Odessa University in Ukraine). Only twenty-two years of age, he was younger than his students.


After becoming involved in a conflict with a senior colleague over attending scientific meetings, in 1868 he transferred to the University of St. Petersburg, where he experienced a worse professional environment. In 1870 he returned to Odessa to take up the appointment of Titular Professor of Zoology and Comparative Anatomy. In 1882 he resigned from Odessa University due to political turmoil after the assassination of Alexander II. He went to Messina to set up his private laboratory, but then, returned to Odessa as director of an institute set up to carry out Louis Pasteur’s vaccine against rabies. Due to more difficulties, he left Russia for the last time in 1888 and went to Paris to seek Pasteur’s advice. Pasteur gave him an appointment at the Pasteur Institute, where he remained for the rest of his life.


Mechnikov became interested in the study of microbes, and especially the immune system. At Messina, in Ukraine, he discovered phagocytosis after experimenting on the larvae of starfish. In 1882 he first demonstrated the process when he pinned small thorns into starfish larvae, and he found unusual cells surrounding the thorns. The thorns were from a tangerine tree made into Christmas tree. He realized that in animals which have blood, the white blood cells gather at the site of inflammation, and he hypothesized that this could be the process by which bacteria were attacked and killed by the white blood cells. He discussed his hypothesis with Carl Friedrich Wilhelm Claus, Professor of Zoology at the University of Vienna, who suggested the term “phagocyte“ for cells which can surround and kill pathogens. Metchnikoff delivered his findings at Odessa University in 1883. His theory, that certain white blood cells could engulf and destroy harmful bodies such as bacteria, met with skepticism from leading specialists including Louis Pasteur, Behring and others. At the time most bacteriologists believed that white blood cells ingested pathogens and then spread them further through the body. His major supporter was Rudolf Virchow who published his research in his Arechiv fur pathologische Anatomie und Physiologie und fur klinische Medizin (now called the Virchows Archiv). His discovery of these phagocytes ultimately won him the Nobel Prize in 1908. In Paris he worked with ?mile Roux on calomel, an ointment to prevent people from contracting syphilis.


Metchnikoff also developed a theory that aging is caused by toxic bacteria in the gut and that lactic acid could prolong life. Based on this theory, he drank sour milk every day. He wrote The Prolongation of Life: Optimistic Studies, in which he espoused the potential life-lengthening properties of lactic acid bacteria (Lactobacillus delbrueckii subsp. bulgaricus). He attributed the longevity of Bulgarian peasants due to their yogurt consumption. This later inspired Japanese scientist Minoru Shirota to begin investigating a causal relationship between bacteria and good intestinal health, which eventually led to the worldwide marketing of Yakult, kefir and other fermented milk drinks, or probiotics. The original modern hypothesis of the positive role played by certain bacteria was first introduced by Metchnikoff, who in 1907 suggested that it would be possible to modify the gut flora and to replace harmful microbes with useful microbes. Metchnikoff, was at that time a professor at the Pasteur Institute in Paris. He proposed the hypothesis that putrefactive (proteolytic) microbes produced toxic substances in the large bowel. Proteolytic bacteria such as clostridia, which are part of the normal gut flora, do produce toxic substances, including phenols, indols and ammonia from the digestion of proteins. According to Metchnikoff these compounds were responsible for “intestinal auto-intoxication“ would “seed“ the intestine with harmless lactic-acid bacteria and decrease the intestinal pH and that this would suppress the growth of proteolytic bacteria. In 1907 he suggested that “the dependence of the intestinal microbes on food, makes it possible to adopt measures to modify the flora in our bodies and to replace the harmful microbes by useful microbes“. Metchnikoff himself introduced in his diet sour milk fermented with the bacteria he called “Bulgarian Bacillus“ and found his health benefited. Friends in Paris soon followed his example and physicians began prescribing the sour milk diet for their patients.


When his wife died, Metchnikoff tried to commit suicide, but his attempt failed. Metchnikoff died in 1916 in Paris from heart failure. And another beautiful person left the world better than when he entered.



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