The probability of the immune system attacking a transplanted organ as opposed to transfused blood is higher.

Question

Answer the following statement true (T) or false (F)

Answer 1

True

Clarify Question


• What is the key concept addressed by the question?
     o The question asks about organ and blood rejection.
• What type of thinking is required?
     o You are being asked to analyze statements to explain if organs would be rejected more than blood following a transplant.


Gather Content


• What do you know about rejection of organ transplants? What other information is related to the question?
     o The major obstacle to successful transplantation of tissues and organs is a reaction called graft rejection, in which the immune system recognizes the transplant (also called a graft) as foreign and attacks it as it would any other foreign cells. Although B cells and macrophages play some role in graft rejection, cytotoxic T cells and helper T cells are mainly responsible. To minimize this possibility, transplant patients are given drugs that suppress immune function, a procedure that is associated with some risk.
     o Except for grafts from identical twins, the class I MHC proteins on graft cells differ from those on the recipient's cells, as do the class II MHC proteins present on macrophages in the graft cells. Consequently, the recipient's T cells recognize the MHC proteins in the graft as foreign, and cytotoxic T cells (with the aid of helper T cells) destroy the graft cells. All nucleated cells in the body contain class I MHC proteins on their surface.


Choose Answer


• Given what you now know, what information is most likely to produce the correct answer?
     o For organ transplants, cytotoxic T cells and helper T cells are primarily responsible for rejection. They attack cells with different class I and II MHC proteins. Since only identical twins share the same class I and II MHC proteins, almost all organ transplants would be rejected without drugs to suppress immune function. For blood transfusions there are no class I MHC proteins on their surface, so they will have a smaller immune reaction from the host receiving the blood transfusion than a person would receiving an organ transplant.


Reflect on Process


• Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
     o This question asked you to analyze statements to explain if organs would be rejected more than blood following a transplantply. If you got the correct answer, great job! If you got an incorrect answer, where did the process break down? Did you think that red blood cells had class I MHC proteins on their surfaces? Did you recall that class I and II MHC proteins were the target for rejection of transplants by the host immune system?