Which of the following antimicrobial substances is commonly released by the skin and mucous membranes as part of the innate immune response?

• A. Histamine
• B. Immunoglobulin G (IgG)
• C. Lysozyme
• D. Interleukin-2 (IL-2)

Answer: (C)

Verified step by step guidance

1. Understand the role of the innate immune system, which provides the first line of defense against pathogens through physical barriers like skin and mucous membranes, as well as chemical substances they release.
2. Review the functions of each listed substance: Histamine is involved in inflammation and allergic responses; Immunoglobulin G (IgG) is an antibody involved in adaptive immunity; Interleukin-2 (IL-2) is a cytokine that regulates immune cell growth.
3. Focus on Lysozyme, which is an enzyme found in secretions such as tears, saliva, and mucus, and is known for its ability to break down bacterial cell walls, thus acting as an antimicrobial agent in the innate immune response.
4. Recognize that the skin and mucous membranes release Lysozyme as a chemical barrier to inhibit bacterial growth, making it a key antimicrobial substance in innate immunity.
5. Conclude that among the options, Lysozyme is the antimicrobial substance commonly released by the skin and mucous membranes as part of the innate immune response.