Question

Transplantation of tissues/organs fails often due to non-acceptance by the patient's body. Which type of immune-response is responsible for such rejections?

• A. Autoimmune response
• B. Cell-mediated immune response
• C. Hormonal immune response
• D. Physiological immune response

Answer 1

The Correct Option is B

When considering the transplantation of tissues or organs, one significant challenge is the potential for rejection by the recipient's immune system. This can lead to the failure of the transplant. The primary type of immune response responsible for the rejection of transplanted organs is the cell-mediated immune response.

Here’s a detailed explanation of why the cell-mediated immune response is involved and not the other types mentioned:

1. The cell-mediated immune response involves T lymphocytes (a type of white blood cell), which play a crucial role in identifying and destroying cells that they recognize as foreign, such as those of transplanted tissues or organs. T cells can directly kill transplanted cells or recruit other parts of the immune system to attack them, leading to rejection.
2. Autoimmune response occurs when the immune system incorrectly targets the body's own cells as foreign and begins to attack them. While this is a harmful situation, it is not typically related to transplant rejection, which involves foreign tissues.
3. Hormonal immune response is not a recognized category of immune response with respect to organ transplant rejection. Hormones do play various roles in regulating immune responses, but they are not directly involved in the rejection process in the manner of cell-mediated mechanisms.
4. Physiological immune response might refer to the general function of immune responses in protecting the body but is not specific to the mechanism by which transplanted tissues are rejected.

Thus, the rejection of transplanted organs is primarily due to the cell-mediated immune response. Immunosuppressive drugs are often used in transplant patients to reduce the activity of T cells and prevent rejection.