So the majority of the white blood cells in our immune system are able to differentiate normal cells from abnormal cells as well as communicate with one another. As a result of these special protein complexes found on the immune cells and our normal cells of our body known as the major histocompatibility complex MHC. And we have several classes. For example, we have MHC class One and we have MHC class two. Class one is used to differentiate abnormal cells from healthy cells. And class two is used to actually communicate between the white blood cells.