Question

Interferons are
a) Protein products of macrophages which destroy microbes.
b) Allergens
c) Antibody molecule
d) Proteins secreted by virus-infected cells which protect non-infected cells from further viral infection.

Answer 1

Hint: As the name indicates, interferons have the ability to interfere with viral proliferation.

 Complete answer: Interferons belong to the large family of cytokines. Interferon is not a toxin designed to poison a key molecule in the cell. Instead, it is a message that is read by human cells. Interferons have various functions: they activate immune cells, they increase host defences by up-regulating antigen presentation by virtue of increasing the expression of major histocompatibility complex antigens. When the immune system is activated due to the viral infection or other immune response the white blood cells and virus-infected cells. Interferons do not directly kill dangerous cells, they reduce the growth of dangerous cells by regulating the activity of several genes. Hence, interferons are proteins secreted by virus-infected cells which protect the non-infected cell from further viral infection.
The protein product of macrophages transport chemicals across the cellular membranes. They do not protect non-infected cells from viral infections. Allergens are the substances which often eaten or inhaled that are recognized by the immune system and causes an allergic reaction. Antibodies are produced by plasma B cells. They are not produced by any microbe infected cell especially virus-infected cells.


Thus, the correct option is D. i.e., Proteins secreted by virus-infected cells which protect non-infected cells from further viral infection.

Note: Interferons were identified more than 50 years ago by Isaacs and Lindenmann during their studies of the phenomenon of viral interference, the ability of an active or inactivated virus to interfere with the growth of an unrelated virus.