Hi everyone. I'm sorry but I just can't seem to get the relationship between these 2 right.
I've heard that human leukocyte antigen are antigens that help the immune system to distinguish proteins of an individual against those of pathogens. If the transplant HLA doesn't match, it provokes an immune response and is rejected.
I've also heard that antigens define unique tissue types of individuals based on their genetics and if the tissue types of a transplant doesn't match the recipient's tissue type it also provokes an immune response and rejection.
So does that mean HLA shows tissue types as well as defining the protein, and if not why do they both provoke an immune response please.
Thank you for answering, I'm sorry for my stupidity
Answers (1)
Never apologize for stupidity when asking a question. Well, ok there are some exceptions. But academic questions like this are rarely stupid.
You seem to be asking whether the HLA antigen varies between tissue types within one individual. That is, are the HLA's presented by the liver different from those presented by the skin? As far as I can tell, the answer is no for the most part. There are some types that are only presented by immune cells, some presented only by anucleated cells (red blood cells), and some presented only by the placenta, but it looks like all the other cell types have uniform HLA's within an individual. It's actually an interesting question that I never thought about; can the body tell what kind of cell a particular cell is based on surface markers? I'd think so...but that seems to be a separate question and probably not related to HLA's.
So, your first and second statements are two ways of saying the same thing. Tissue type can be thought of in regards to what kind of cells make up the tissue, or it can mean comparing my blood cells to your blood cells and looking at the differences in their HLA's. By the way, another thing that is likely to confuse you is MHC vs. HLA. HLA is just the human version of MHC's; all animals (plants? hmm, I wonder) have MHC's.
Reference: Wikipedia, Google, etc.