Question

You are studying transplant rejection in a wild and genetically diverse population of mice. You have captured some of the mice for laboratory studies. You have four mice from a family. Mouse 1, mouse 2, and mouse 3 are littermates, thus they all share the same mother and father. Mouse 4 is the father of the other three mice. You transplant a small patch of skin from mouse 2 (the donor) onto mouse 1 (the recipient). There is a delayed inflammatory response and two weeks later the skin is necrotic due to transplant rejection. You decide to attempt another transplant. Which follow-up transplant is LEAST likely to be rejected?

a. skin from mouse 1
b. skin from mouse 2
c. skin from mouse 3
d. skin from mouse 4-incorrect

Answer 1

When transplanted tissue expresses MHC molecules different from the recipient, the immune system may reject the tissue. In this scenario, skin from mouse 2 is the least likely to be rejected in a follow-up transplant because of the similarity in MHC molecules between the donor and recipient.

Step-by-step explanation:

When a transplanted tissue expresses MHC molecules that are different from the recipient, the recipient's immune system may mount a cytotoxic T cell response to the tissue, leading to rejection. The MHC molecules act as markers that allow the immune system to distinguish between self and non-self cells. If the MHC molecules on the transplanted tissue are recognized as foreign, the recipient's immune system will initiate an immune response to destroy the foreign tissue and protect the body.

In the given scenario, since mouse 2 (the donor) and mouse 1 (the recipient) are littermates, they will likely have similar MHC molecules. As a result, skin from mouse 2 (option b) is the least likely to be rejected in a follow-up transplant. This is because the MHC molecules on the skin from mouse 2 will more closely resemble those of mouse 1, reducing the chances of an immune response and rejection.