Autoimmunity

Step 5 of 7. It is possible to make a lot of different peptides.

20 amino acids can produce a lot of combinations of peptides

It is possible to make a lot of different peptides from 20 different amino acids. There are over 1,000,000,000,000,000,000 different peptides that are 14 amino acids long alone. Our T-cells are able to recognise any foreign peptide that binds to MHC. If this were not the case then germs could quickly evolve to change their proteins so that they produced peptides that could not be recognised.

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