And what it also does is it takes the antigens of these pathogens and places the antigens on the surface on the membrane of the macrophage. The question is what for? Well, because as it turns out the B lymphocytes as well as the T lymphocytes as we'll see in just a moment contain these receptors on the membrane of the lymphocytes. So the B lymphocytes contains the B cell receptors and when the B lymphocyte approaches our macrophage, if the B cell receptor complements this antigen we can have the binding process take place. They will form a complex and that will ultimately call upon a cell involved in the cell mediated immunity known as the helper T cell. And what the helper T cell does is it releases a special type of chemical or special types of chemicals which basically help the B lymphocyte undergo mitosis and differentiate into two different types of cells.