In xentoransplantation, a protein that causes graft rejection usually comes from transgenic

Options

A. Cow
B. Mice
C. pig
D. Sheep

Answer

**Step-by-Step Solution:**

1. **Understand Xenotransplantation**:
- Define xenotransplantation as the transplantation of living cells, tissues, or organs from one species to another. This is important to understand the context of the question.

2. **Identify the Problem of Graft Rejection**:
- Explain that during xenotransplantation, the recipient's immune system may recognize the transplanted tissue as foreign and mount an immune response, leading to graft rejection.

3. **Role of Proteins in Graft Rejection**:
- Discuss that the immune response is mediated by proteins, specifically antibodies, which are produced by the immune system in response to foreign antigens present on the transplanted tissue.

4. **Transgenic Animals**:
- Define what a transgenic animal is: an animal whose genome has been altered by the transfer of a gene or genes from another species or breed.

5. **Identify the Source of the Rejection Protein**:
- Explain that in the context of xenotransplantation, transgenic pigs have been genetically modified to reduce the likelihood of rejection by humans. However, the proteins that still cause rejection often originate from these transgenic pigs.

6. **Select the Correct Answer**:
- From the options given (cow, mice, pig, sheep), conclude that the correct answer is "pig," specifically referring to transgenic pigs.

**Final Answer**: The protein that causes graft rejection in xenotransplantation usually comes from transgenic **pigs**.

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