Mast cells release interleukin –
**Core Concept**
Mast cells are a type of immune system cell that play a key role in **inflammatory responses** and **allergic reactions**. They release various chemical mediators, including **histamine** and **interleukins**, which are a group of **cytokines**.
**Why the Correct Answer is Right**
Mast cells release **interleukin-4 (IL-4)**, which is a cytokine that promotes the production of **IgE antibodies** and the differentiation of **naive T cells** into **Th2 cells**. IL-4 is involved in the regulation of **immune responses**, particularly in the context of **allergic reactions** and **parasitic infections**.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because IL-1 is primarily produced by **macrophages** and **monocytes**.
**Option B:** Incorrect because IL-2 is mainly produced by **T cells**.
**Option D:** Incorrect because IL-6 is produced by a variety of cells, including **macrophages**, **T cells**, and **fibroblasts**.
**Clinical Pearl / High-Yield Fact**
Mast cell-derived IL-4 plays a crucial role in the development of **allergic diseases**, such as **asthma** and **atopic dermatitis**.
**Correct Answer:** D. 6 is not among the options given, however, mast cells are known to release IL-4, which isn't listed, but based on available data: **Correct Answer: C. 4**