Peptide-MHC (pMHC)

A pMHC is the assembled complex of one short peptide sitting in the groove of an MHC/HLA molecule on the cell surface. The T-cell receptor doesn't recognize the peptide or the HLA alone — it recognizes the combined shape of the two together.

Modeling the pMHC complex (and whether a given TCR will engage it) is a fast-moving area where structure prediction and foundation models are increasingly applied — the goal is to predict not just binding, but actual T-cell recognition.