Which of the following substances is an immuo-suppressive agent ?

Options

A. Statin
B. Streptokinase
C. Lipase
D. Cyclosporin - A

Explanation

**Step-by-Step Solution:**

1. **Understanding Immunosuppressive Agents**: Immunosuppressive agents are substances that reduce the strength of the body's immune system. They are often used in medical settings, particularly for patients who have undergone organ transplants, to prevent the body from rejecting the new organ.

2. **Identifying Cyclosporine A**: Among various substances, Cyclosporine A is recognized as a potent immunosuppressive agent. It is specifically used to help organ transplant patients by suppressing their immune response, thereby reducing the risk of organ rejection.

3. **Source of Cyclosporine A**: Cyclosporine A is derived from the fungus Trichoderma polysporum. This natural origin is significant as it highlights the role of microbes in producing important medicinal compounds.

4. **Differentiating Other Substances**: In the context of the question, it is important to differentiate Cyclosporine A from other substances mentioned:
- **Streptokinase**: This is used as a clot buster in treating heart attacks and is not an immunosuppressive agent.
- **Statins**: These are used to lower blood cholesterol levels and are not related to immune suppression.
- **Lipase**: This enzyme is used in detergent formulations and also does not have immunosuppressive properties.

5. **Conclusion**: Based on the information, the correct answer to the question "Which of the following substances is an immunosuppressive agent?" is Cyclosporine A.

**Final Answer**: Cyclosporine A is the immunosuppressive agent.

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