this is a million dollar question probably nobel prize winning.

keep in mind this is not proven but is a promising angle, CRSPR as made popular is a hijacked mechanism used to edit DNA sequences. normally this mechanism is used in prokaryotic organisms as an immune system. there are tags in the prokaryotes DNA that are used to match with foriegn DNA and signal it for destruction.

this type of arrangement MAY, possibly exist in eukaryotes as well and may be the basis of self/nonself recognition.

i have yet to talk to anyone else in professional context, this is inference on my part but it the best answer i can suggest for now.

you would want to look at antigen presentation and antibody production mechanisms, in deep detail .

This has been an AWESOME thread to follow. Thanks for taking the time to answer through the thread.

Yes. Reading the thread you quickly realize what a natural wonder our immune system is, and how much more there may be left to learn about it.

They are made by https://en.wikipedia.org/wiki/Thymic_epithelial_cell (see the section on Positive and negative selection) as part of the selection process.

It does not. All index entries that correspond to body are filtered out during aging process. If some are missed or close enough to the body proteins past puberty, you would get an autoimmune reaction

look back in the thread and you will see this part is about an autoimmune question. other than that yes you have the concept.

“The body stores this index of components recognized as self in the thymus” / gtp3 gets more specific

There is a guy living in a house inside a tree with huge library. The first responder cells will call him by phone and he will check the library for what to do.

Disclaimer: All I know about this comes from Cells at Work/Hataraku Saibou.

(https://en.m.wikipedia.org/wiki/Cells_at_Work!)