Diapedesis is the characteristic feature of

Options

A. Monocytes
B. B - lymphocytes
C. T - lymphocytes
D. All of these

Answer

### Step-by-Step Solution:

1. **Understanding Diapedesis**: Diapedesis refers to the process by which white blood cells (WBCs) move out of the bloodstream and into tissues. This is crucial during an immune response, especially at sites of infection.

2. **Mechanism of Diapedesis**: During diapedesis, WBCs squeeze through the endothelial cells of blood vessels. This movement allows them to reach the site of infection or inflammation where they can perform their immune functions.

3. **Identifying the Type of Cell**: The question asks about the characteristic feature of diapedesis. While several types of white blood cells can undergo diapedesis, it is particularly associated with monocytes.

4. **Characteristics of Monocytes**: Monocytes are the largest type of lymphocyte and they are phagocytic in nature, meaning they can engulf and digest pathogens and debris. They play a significant role in the immune response.

5. **Conclusion**: Based on the understanding of diapedesis and its association with monocytes, we conclude that diapedesis is a characteristic feature of monocytes.

### Final Answer:
Diapedesis is the characteristic feature of **monocytes**.

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