Question

The viral RNA inducible interferon system provides the molecular defense against

• A. RNA viruses
• B. Single stranded DNA viruses
• C. Double stranded DNA viruses
• D. Bacteria

Hint:

Double-stranded RNA (dsRNA) is a molecular signature of RNA virus replication. The host cell recognizes dsRNA as a "pathogen-associated molecular pattern" (PAMP) to turn on the interferon system.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Interferons (IFNs) are host glycoproteins secreted by cells in response to viral infections, serving as a vital component of the innate immune system.

Step 2: Detailed Explanation:
1. During the replication cycle of most RNA viruses, double-stranded RNA (dsRNA) is produced as an essential intermediate.
2. Host cell pattern recognition receptors (PRRs), such as TLR3, RIG-I, and MDA5, detect this foreign dsRNA structure.
3. This detection triggers a signaling cascade that induces the synthesis and secretion of Type I interferons (\(\text{IFN-}\alpha\) and \(\text{IFN-}\beta\)).
4. The secreted interferons bind to neighboring cell receptors, upregulating interferon-stimulated genes (ISGs) that inhibit translation, degrade viral RNA, and halt viral replication.
5. Thus, this inducible pathway is primarily targeted as a molecular defense mechanism against RNA viruses.

Step 3: Final Answer:
The system provides molecular defense predominantly against RNA viruses.