Which type of innate immunity is exhibited by interferons secreted by virus infected cells to protect non infected cells?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Cytokine barriers
Innate immunity is the defence a person has from birth. It is non-specific and works through four kinds of barriers. Interferons are proteins, and they work by protecting the cells that the virus has not yet reached.
Option (1) Physical barriers — Incorrect. These are skin and the mucus coating of the respiratory, digestive and urogenital tracts. They block the entry of microbes; they are not secreted proteins.
Option (2) Cytokine barriers — Correct. Interferons are cytokines released by virus-infected cells to protect the healthy cells around them.
Option (3) Physiological barriers — Incorrect. These are acid in the stomach, saliva and tears, which stop microbes from growing.
Option (4) Cellular barriers — Incorrect. These are white blood cells such as neutrophils, monocytes, natural killer cells and macrophages, which swallow and destroy microbes.
NCERT Extract:
Innate Immunity – “Innate immunity is non-specific type of defence, that is present at the time of birth. This is accomplished by providing different types of barriers to the entry of the foreign agents into our body. Innate immunity consist of four types of barriers. These are —
(i) Physical barriers : Skin on our body is the main barrier which prevents entry of the micro-organisms. Mucus coating of the epithelium lining the respiratory, gastrointestinal and urogenital tracts also help in trapping microbes entering our body.
(ii) Physiological barriers : Acid in the stomach, saliva in the mouth, tears from eyes–all prevent microbial growth.
(iii) Cellular barriers : Certain types of leukocytes (WBC) of our body like polymorpho-nuclear leukocytes (PMNL-neutrophils) and monocytes and natural killer (type of lymphocytes) in the blood as well as macrophages in tissues can phagocytose and destroy microbes.
(iv) Cytokine barriers : Virus-infected cells secrete proteins called interferons which protect non-infected cells from further viral infection.”