The vast majority of T-cells that
is the alpha-beta (αβ) T-cells,
need to see antigen that is processed and presented to them.
So let’s explore together exactly what is
meant by antigen processing and presentation.
So T-cells recognize protein antigens
that are processed into peptides.
And what that means is that protease enzymes chop up the
polypeptide chain into short
stretches of amino acids - peptides.
These peptides are then shown to the T-cell receptor
or presented to the T-cell receptor by MHC molecules.
So the peptide is put together
with the MHC, and this combination
of peptide-MHC is what the αβ T-cell needs to recognize.