So basically, once the binding process takes place, the T cells can stimulate our immune system in two different ways. They can either stimulate the humoral immunity or they can stimulate the cell mediated immunity. So let's suppose the CD four T cell that binds onto the APC is a helper T cell in such a case when this binding process takes place. And let's suppose the APC is a B lymphocide. In such a case, the helper T cell, which is our CD four T cell, will stimulate that B lymphocyte, our APC to actually begin to undergo mitosis and create more clone cells, identical cells that contain the same exact B cell receptor. And they can also stimulate those B lymphocytes to actually undergo the process of differentiation and differentiate into plasma cells and memory B cells.