Which substance is produced by a cell in viral infection that protect other cells from further infection?

Interferon

The correct answer is Option (3) → Interferon

Interferons are proteins produced by cells in response to viral infections. When a cell is infected by a virus, it releases interferons, which act as signaling molecules to warn neighboring cells , acting as a crucial part of the innate immune response.These interferons help activate immune responses and make other cells more resistant to viral infection, thus providing protection against the spread of the virus.

The other substances listed do not play this specific role:

• Serotonin: A neurotransmitter involved in mood regulation, not related to viral infection response.
• Antigen: A molecule that triggers an immune response, typically a protein on the surface of pathogens, but it is not the protective substance produced by infected cells.
• Histamine: A chemical involved in inflammatory and allergic responses, not directly involved in protecting cells from viral infection.

The substance produced by a cell in response to a viral infection that protects other cells from further infection is interferon.