Well, a healthy cell will bind one of its normal proteins, peptides that it creates inside the cell onto this clef portion of our MHC class one complex. So if we take a look at the following diagram, we have a healthy cell of our body. We have our major histocompatibility complex, class one. And some type of protein that the cell produces inside our cell, it brings out and it binds onto this region right here. So when a leukocyte essentially approaches this healthy cell and it recognizes this peptide as a normal peptide, as a normal self antigen, so we call this a self antigen, which basically means that it's an antigen, it's a protein that is formed by this cell. So when the leukocide recognizes a self antigen, it basically leaves that cell alone.