And so in diagram two we form this phagosome, this vacuole inside our macrophage. And these lysosomes fuse with this vacuum and they begin to break down that bacterial cell. Now, as they break down the bacterial cell, they essentially take some of those pathogenic proteins or antigen and the cell places our antigen onto our MHC class two complex. So the major histocompatibility complex class two, as shown in the following diagram. So, now that the macrophage actually contains this MHC class two complex, along with this complementary antigen that came from our bacterial cell, it can basically release special types of chemicals known as interleukin one. And what this chemical does is it goes on to recruit, it calls upon helper T cells.