"The recent technology is peptide–MHC microarray or artificial antigen-presenting chip. In this technique, recombinant peptide–MHC complexes and co-stimulatory molecules are immobilized on a surface, and population of T cells is incubated with the microarray. The T cell spots act as artificial antigen-presenting cells containing a defined MHC-restricted peptides. The advantage of using peptide–MHC is that it can map MHC-restricted T cell epitope."

These few lines are from Chapter 3 of Immunoinformatics, De, Rajat K., Tomar, Namrata (Eds.).

What is recombinant peptide MHC? What is MHC restricted peptide? How did the advantage get derived?

  • $\begingroup$ you might need to clarify what you are struggling with here $\endgroup$ – rg255 Sep 19 '14 at 10:08
  • $\begingroup$ The entire paragraph. What is MHC peptide complex? What is MHC restricted peptide? $\endgroup$ – girl101 Sep 19 '14 at 10:09
  • $\begingroup$ Have you tried Google searches? You've already asked similar questions to this before, did you learn anything from those answers? I highly recommend obtaining a good introductory immunology textbook and reading it. $\endgroup$ – MattDMo Sep 19 '14 at 14:48
  • $\begingroup$ @MattDMo completely agree about reading good immunology books. But I doubt peptide:MHCs are covered in any general immunology book. $\endgroup$ – ddiez Sep 19 '14 at 15:02
  • $\begingroup$ @ddiez they were in mine... $\endgroup$ – MattDMo Sep 19 '14 at 15:57

According to this paper (Yoav Soen et al. PLoS Biology 2003), peptide:MHC microarrays are a type of cellular microarray (a microarray designed to identify cell types; Wikipedia). These microarrays have attached a MHC molecule bound to a peptide, which allows them to work as artificial antigen presenting cells (APCs) that activate specific subpopulations of T cells.

Another recent paper is here where they specifically use the word recombinant peptide:MHC.

The expression MHC restricted refers to the positive selection (in the thymus) of T cells that recognize MHC molecules of the host but not other self-antigens (Wikipedia).

  • $\begingroup$ T cells grows in thymus. So what does "in the thymus of T-cells" mean?? $\endgroup$ – girl101 Sep 22 '14 at 4:18
  • $\begingroup$ @user3237995 sorry about that sentence, not very clear. I added some parenthesis that hopefully improve readability. Let me know if it is still unclear. $\endgroup$ – ddiez Sep 22 '14 at 6:26

This is an important topic in immunology, especially for vaccine development.

MHC or HLA is a molecule expressed by some cells of the immune system which acts like a "catcher's mitt" and "presents" short snippets of protein to other immune cells. Other molecules act alongside MHC to provide co-signals which promote or suppress immune attack against the peptides that MHC presents.

Basically, it's a protein that holds out chunks of other proteins in order to educate the rest of the immune system. Here's the catch: different people have different genes for MHC which do a better or worse job of presenting certain peptides. This is one reason why different people can respond to different vaccines or different pathogens or cancers: they have different MHCs which may or may not present peptides from the relevant targets.

Thus, one big challenge in medicine right now is to develop good models for which peptides are best to include in a vaccine. The right answer depends on the genetics of the vaccine target (ebola, a tumor, e. coli etc) and also on the genetics of the person being vaccinated (does this person's MHC gene properly present this vaccine?)

So, to datafy this, people sometimes make arrays which allow us to quantify which peptides bind to which MHC genes in high throughput. Then we can use that data to learn which factors are most important for P:MHC binding. "MHC restricted" means that we are talking about a specific genetic subtype of these molecules.

Hope that helps. Bion Alex Howard


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