Discuss the roles of antibodies and antigens in an incompatible tissue transplant.

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Hi, everyone. Welcome back. Our next question says, which of the following may result in tissue transplantation rejection. A, the MHC molecules of the donor and recipient match B the recipient's immune response is suppressed. C the recipient has antibodies against the donor antigens or D all of the above. Well, let's recall what's going on when a tissue transplant is rejected. It's when the recipient's immune system recognizes the donor organ or tissue as foreign and thus attacks the donated tissue. Well, since we're talking about attack by the immune system, when we look at answer choice C the recipient has antibodies against the donor antigens. This one's pretty obviously correct. If your recipient has actually already made antibodies against antigens in the donor tissue, that will absolutely result in the immune system attacking and destroying that donated organ or tissue. But we know we have this option of all of the above. So we need to evaluate our other choices as well to see if they're correct. So let's look at choice. A, the MH C molecules of the donor and recipient match. Let's recall that MH C class one molecules are present on the surface of every nucleated cell in the body. They have an important role in the immune response. In that if the cell is infected by a virus or bacteria or has a TU or a tumor cell, the MH C class one molecules will present antigens to help the immune system recognize these cells and destroy them. But they also present peptides, just normal peptides from the cell's own contents. And as a result, they serve as sort of a self recognition system. They are very polymorphic, have many genetic variations. They're inherited, they're inherited in a codominant fashion. So you present MH C molecules inherited from both parents. And so they vary widely among different individuals. If a donor organ or tissue is presenting MH C one molecules that are very different from the recipient's own, those cells are much more likely to be recognized as nonself. So if you're transplanting tissue from another individual, you try it and excuse me, try and match as closely as possible when you're doing transplants, the MH C molecules that are present in humans, these MHC molecules are referred to as HL human leukocyte antigen. So that's why genetically related people are more likely to be capable of being an organ donor to someone because they're more likely to have matching MH C one molecules. So when the MH C molecules of the donor and recipient match as in choice A that is the least likely scenario where you'll see tissue transplantation rejection. So choice a not our correct answer as this will greatly reduce the likelihood of rejection. Well, we already have one incorrect answer so we can rule out choice D all of the above. And if we were in a hurry, we'd go ahead and pick Choice C as our correct answer. But to be thorough, let's just take a look at choice B, the recipient's immune response is suppressed. Well, even if the MH C molecules match, there's still some other molecules going on there that might cause a donated tissue to be recognized as foreign. So any recipient of a donor organ has to take immunosuppressant drugs for their entire life to reduce the likelihood of rejection. Since it's the immune system that would attack the donate tis donated tissue and cause rejection. So since suppression of the immune system helps to prevent rejection, choice B would not be our answer here. So once again, the answer choice that may result in tissue transplantation rejection is choice. C the recipient has antibodies against the donor antigens. See you in the next video.

Discuss the roles of antibodies and antigens in an incompatible tissue transplant.

Verified Solution

Key Concepts

Antibodies

Antigens

Tissue Compatibility