True about cytokines are all except:
**Core Concept**
Cytokines are small **proteins** important in **cell signaling**, involved in the immune response, and include **interleukins**, **interferons**, and **tumor necrosis factors**. They are crucial for the coordination of the immune response, facilitating communication between different cell types.
**Why the Correct Answer is Right**
Without the specific options, it's challenging to pinpoint the exact correct answer. However, cytokines generally act through **receptor-mediated mechanisms**, influencing various physiological and pathological processes. Their dysregulation can lead to **inflammatory diseases** or **immune deficiencies**.
**Why Each Wrong Option is Incorrect**
**Option A:** Would be incorrect if it stated cytokines are exclusively produced by immune cells, as they can be produced by a wide range of cell types.
**Option B:** Might be wrong if it suggested cytokines only have pro-inflammatory effects, as they can also have anti-inflammatory properties.
**Option C:** Could be incorrect if it claimed cytokines are not involved in non-immune functions, as they play roles in **tissue repair** and **endocrine regulation**.
**Option D:** Would be incorrect if it proposed cytokines do not have a role in disease pathogenesis, as they are implicated in numerous **chronic diseases**.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that cytokines can have both local and systemic effects, and their imbalance can lead to various diseases, making them targets for therapeutic interventions. Understanding cytokine functions is crucial for managing **autoimmune diseases** and **cancer**.
**Correct Answer:**