This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
About interferon true is: 
Select and explain. 
A. It is a synthetic antiviral agent, B. Inhibits viral replication in cells, C. Is specific for a particular virus, D. None
B: Inhibits viral replication in cells
Answer: B: Inhibits viral replication in cells 
Explanation: Ans. is 'b' i.e., Inhibits viral replication in cells(Ref: Ananthanarayan, 9th/e, p. 448 - 449 and 8th/e, p. 447 - 448)* Interferon by itself has no direct action on viruses but it acts on other cells of same species, rendering them refractory to viral infection.* On exposure to interferon, cells produce a protein (translation inhibiting protein TIP) which selectively inhibits translation of mRNA.