And what this CD Four glycoprotein does is it actually binds and interacts with MHC class two. We'll see that there is another type of CD glycoprotein we call CD eight glycoprotein. And that glycoprotein only interacts and binds with MHC class one complexes, as we'll see in just a moment. So we have an inactivated helper T cell, a type of Lymphocyte, T Lymphocyte that can now go on and bind to this MHC class two complex that contains that antigen. So we have the binding process takes place and when they bind and form this entire complex, the macrophage begins to release a special chemical known as interleukin one. And the interleukin one essentially goes on to and interacts with this inactivated helper T cell.