Transplantation of tissues/organs to save certain patients often fails due to rejection of such tissues/organs by the patient. Which type of immune response is responsible for such rejections?

Options

A. Auto-immune response
B. Humoral immune response
C. Physiological immune response
D. Cell-mediated immune response

Explanation

**Step-by-Step Solution:**

1. **Understanding Transplantation**: Transplantation involves transferring tissues or organs from one individual to another to replace damaged or non-functioning parts in a recipient's body.

2. **Identifying the Problem**: Often, the transplanted tissues or organs are rejected by the recipient's body. This rejection is a significant challenge in transplantation medicine.

3. **Immune Response Mechanism**: The human immune system is designed to protect the body from foreign substances. When a tissue or organ is transplanted, the recipient's immune system may recognize it as foreign.

4. **Role of Antigens**: The transplanted tissues or organs are perceived as antigens (foreign substances) by the recipient's immune system. This triggers an immune response.

5. **Antibody Production**: In response to the recognition of the transplanted tissue as foreign, the immune system produces antibodies aimed at destroying these foreign cells.

6. **Type of Immune Response**: The specific immune response that leads to the rejection of transplanted tissues or organs is known as the **cell-mediated immune response**. This involves T-cells that attack the foreign cells.

7. **Conclusion**: Therefore, the correct answer to the question regarding the type of immune response responsible for the rejection of transplanted tissues or organs is the **cell-mediated immune response**.

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