Cells that are infected by a virus or carry a
carcinogenic mutation, for example, produce proteins foreign to the
body. Antigenic peptides resulting from the degradation of these
exogenous proteins inside the cell are loaded by the
peptide-loading complex onto so-called major histocompatibility
complex molecules (MHC for short) and presented on the cell
surface. There, they are specifically identified by T-killer cells,
which ultimately leads to the elimination of the infected cells.
This is how our immune system defends us against
pathogens.
