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Comment by fastaguy88 | Hacker News Reader

The claim that mirror molecules would not be subject to immune surveillance makes no sense to me. The immune system is happy to react to non-biological molecules. It reacts to shapes, not chirality. It is a separate question whether the immune response could break into mirror membranes and break down mirror molecules.

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The pMHC-TCR complex, which is the cornerstone of the adaptive immune system, has evolved to bind peptide epitopes.

Most D-amino acids are known to bind MHC poorly and lead to reduced TCR recognition. I imagine this could increase the chances of evading immune surveillance.

Are you certain? The immune system detects molecules partly due to their shape, i.e. where binding points are on the proteins. I can imagine it being the case where the immune system's proteins no longer match up with the invader's because of the mirroring.

If you 3d print a mirrored house key, the bitting may line up with the original, but the warding wouldn't fit anymore. I think that's a reasonable analogy to the way proteins match up.

Early studies (1970's and earlier) used the antigen (hapten) di-nitro-phenol (DNP) to explore antibody diversity (how many different antibodies might be raised against a simple small molecule). DNP is very simple (non-chiral) structure that generates a diverse set of antibodies.

Whether an antibody raised against one structure interacts with a different structure is irrelevant to the question of whether an antibody can be raised to the other structure.

Most parts of the innate immune system recognize specific shapes like nucleic acids, while the adaptive immune system is more flexible in what it can recognize.

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