What is the significance of the work of L. Pasteur and I. I. Mechnikov for biological science?

The works of Louis Pasteur (1822–1895) and Ilya Ilyich Mechnikov (1845–1916) determined the appearance of immunology. In 1876, Pasteur devoted himself completely to immunology, having finally established the specificity of the causative agents of anthrax, cholera, rabies, chicken cholera and other diseases, developed ideas about artificial immunity, and proposed a method of protective vaccinations, in particular against anthrax, rabies. The first vaccine against rabies was given by Pasteur on July 6, 1885. In 1888, Pasteur created and headed the Research Institute of Microbiology (Pasteur Institute), in which many famous scientists worked.
Having discovered the phenomenon of phagocytosis in 1882, Mechnikov developed on its basis a comparative pathology of inflammation, and later on a phagocytic theory of immunity, for which he received the Nobel Prize in 1908 together with P. Erlich. Numerous works of Mechnikov on bacteriology are devoted to the epidemiology of cholera, typhoid fever, tuberculosis and other infectious diseases. Mechnikov created the first Russian school of microbiologists, immunologists and pathologists; actively participated in the creation of research institutions developing various forms of combating infectious diseases.