Now, we have a variable portion on our T cell receptor, the protein. And this basically varies from one cell to a different cell. And that's because this is the portion of the T cell receptor that contains that specific sequence of amino acids that can bind to some particular antigen. So it contains the antigen binding site. The constant region of our T cell receptor on the gamma delta T cell basically does not change too much when we go from one cell to a different cell. And this is the portion of our T cell receptor that actually binds onto the cell membrane of the gamma delta T cell.