В течение второй половины XIX века врачами и biologists of that time actively investigated the role of pathogenic microorganisms in the development of infectious diseases, as well as the ability to form artificial immunity to them. These studies led to a study of the facts about the natural protection of the body from infections. Pasteur offered the scientific community the idea of a so-called "exhausted force". According to this theory, viral immunity is a condition in which the human body is not a beneficial nutrient medium for infectious agents. However, this idea could not explain a whole series of practical observations.
Mechnikov: cellular theory of immunity
This theory appeared in 1883.The creator of the cellular theory of immunity relied on the teaching of Charles Darwin and based on the study of digestion processes in animals that are located at different stages of evolutionary development. The author of the newly discovered theory discovered a certain similarity in intracellular digestion of substances in cells of endoderm, amoebas, tissue macrophages and monocytes. Actually, the cellular theory of immunity was created by the famous Russian biologist Ilya Mechnikov. His work in this area lasted long enough. The beginning of it was laid in the Italian city of Messina, in which the microbiologist observed the behavior of marine fleas and starfish larvae.
The pathologist has found that wandering cellsobservable creatures alien bodies surround and then absorb them. In addition, they dissolve and then destroy those tissues that are not needed by the body more. He put a lot of effort to develop his concept. The creator of the cellular theory of immunity introduced, in fact, the concept of "phagocytes", derived from the Greek words "phages" - to eat and "kitos" - a cell. That is, the new term literally meant the process of eating cells. The scientist came to the idea of such phagocytes a little earlier when he studied intracellular digestion in various connective tissue cells in invertebrates: sponges, amoebas, and others.
Representatives of the higher fauna mostwhite blood cells, that is, leukocytes, can be called typical phagocytes. Later, the creator of the cellular theory of immunity proposed to divide these cells into macrophages and microphages. The correctness of this separation was confirmed by the achievements of the scientist P. Ehrlich, who differentiated various types of white blood cells through staining. In his classic works on the pathology of inflammation, the creator of the cellular theory of immunity was able to prove the role of phagocytic cells in the process of eliminating pathogens. Already in 1901, his fundamental work on immunity to infectious diseases came to the world. Apart from Ilya Mechnikov himself, a significant contribution to the development and spread of the theory of phagocytic immunity was made by I.G. Savchenko, F.YA. Chistovich, L.A. Tarasevich, A.M. Birch, V.I. Isaev and a number of other researchers.
