An immune response to a tissue graft will differ from an immune response to a bacterium because ________.
A) MHC molecules of the donor may stimulate rejection of the graft tissue, but bacteria lack MHC molecules
B) the tissue graft, unlike the bacterium, is isolated from the circulation and will not enter into an immune response
C) a bacterium cannot escape the immune system by replicating inside normal body cells
D) the graft will stimulate an autoimmune response in the recipient

Question

Quizplus · Accepted Answer

The main difference between an immune response to a tissue graft and an immune response to a bacterium is that MHC molecules of the donor may stimulate rejection of the graft tissue, but bacteria lack MHC molecules. MHC molecules play a crucial role in antigen presentation to T cells, which triggers an immune response. In the case of a tissue graft, the donor's MHC molecules may be recognized as foreign by the recipient's immune system, leading to rejection of the graft. Bacteria, on the other hand, do not express MHC molecules and are recognized as foreign by other mechanisms.

An Immune Response to a Tissue Graft Will Differ from an Immune