What are interferons? Name one disease controlled by them.

Explanation

**Step-by-Step Solution:**

1. **Definition of Interferons:**
Interferons are a type of antiviral protein that are produced and secreted by cells that have been infected by a virus. They play a crucial role in the immune response against viral infections.

2. **Function of Interferons:**
When a cell is infected by a virus, it releases interferons to signal neighboring cells about the viral infection. This signaling prompts the neighboring cells to activate their own defense mechanisms, thereby enhancing their ability to resist the virus. Interferons can also inhibit the replication of viruses within the infected cells, limiting the spread of the infection.

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