Mice whose immune systems had previously rejected a tissue transplant from a cer
ID: 208964 • Letter: M
Question
Mice whose immune systems had previously rejected a tissue transplant from a certain strain of donor mouse received another transplant shortly afterward, either from the same donor strain or a new one. All of the recipient mice eventually rejected the transplant. However, one group did so more quickly than the other group. Do you think this group received the graft from the original mouse strain or the new strain?
Explain why. Make sure to include two main types of immune cells that mediate this rejection response in your answer.
Explanation / Answer
One group (A) which rejected the transplant more quickly received the graft from the original mouse strain.
Because this strain has already rejected the transplant so it backup the memory cells. Memory T helper cells has a CD4 receptor which binds to the MHC class II molecules which are expressed on the surfaces of the transplanted cells quickly and reject the graft tissue. Cytotoxic T cell destroys the transplanted cell CD8 receptors that dock to the transplanted tissue by MHC class I molecules matching.
In group B which rejected the transplant lately received the graft from the new mouse strain.