Perforin is released by :-

Options

A. NK–cell
B. T–memory
C. `T_(H)`–cell
D. Macrophage

Answer

**Step-by-Step Solution:**

1. **Understanding Perforin**: Perforin is a protein that plays a crucial role in the immune response. It is primarily involved in the destruction of infected or cancerous cells.

2. **Identifying the Cells that Release Perforin**:
- **Natural Killer (NK) Cells**: These are a type of lymphocyte that can recognize and kill infected or cancerous cells. NK cells are known to release perforin to induce cell lysis.
- **T-Cells**: Specifically, cytotoxic T-lymphocytes (CTLs) also release perforin. However, the question does not mention CTLs directly.
- **T-Memory Cells**: These cells are formed after an infection and are responsible for providing a rapid response upon re-exposure to the same antigen. They do not release perforin.
- **T-Helper (TH) Cells**: These cells assist in the immune response but do not directly kill infected cells or release perforin.
- **Macrophages**: These cells are involved in phagocytosis and do not release perforin.

3. **Conclusion**: Based on the functions and roles of the mentioned cells, the primary cell type that releases perforin is the Natural Killer (NK) cell.

4. **Final Answer**: Therefore, the correct answer to the question "Perforin is released by:" is **NK cells**.

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