Question

Which of the following processes was first discovered by Metchnikoff?
A. Phagocytosis
B. Immunization
C. Attenuation
D. All of the above

Answer 1

Hint: Metchnikoff has done pioneering research in immunology and is best known for it. The first process discovered by him was the engulfing of the cell by using its plasma membrane in 1882. Macrophages are an example of such a cell.

Complete answer: Ilya Ilyich Mechnikov who is also called Élie Metchnikoff is a Russian-born zoologist and microbiologist. He was born on 15th May 1845 and expired on 15th July 1915. Being a zoologist and microbiologist he discovered many things. One of his discoveries is the process of phagocytosis which was discovered in 1882. This discovery done by him led to the major defense mechanism. Phagocytosis is the engulfing action of the cell by using the cell membrane. Engulfing particles in the cell forms a compartment called a phagosome. The cells which perform the phagocytic action are called phagocytes. In innate immunity, phagocytosis forms a major defense mechanism. The infection is responded by the action of phagocytosis. The major mechanism of phagocytosis is the removal of pathogens and cell debris. Professional phagocytic cells include neutrophils, monocytes, macrophages, eosinophils, dendritic cells, and osteoclasts. Neutrophils, macrophages, and monocytes play an important role in the immune response to infections.

So, option A is the correct answer.

Note: Phagocytosis is used as a means to obtain nutrients in some protozoa. Canadian physician William Osler was first to note phagocytosis but it was later studied by Élie Metchnikoff and named after him. Examples of objects that can be phagocytized are small mineral particles, dead tissue cells, and bacteria. Phagocytosis also plays a vital role in adaptive immunity.