And now this stackosome contains these digestive enzymes and acidic environment, as well as the bacterial cell. And inside the phagosome, we begin the process of the breakdown and digestion of that bacteria. So the macrophage essentially engulfs that bacterial cell and begins the process of digestion. Now, the macrophage is actually a type of cell we call APC, or antigen presenting cell. And what that means is, after it kills off and breaks down that cell, it takes one of the antigens, one of the proteins or nucleic acids or polysaccharides from that bacteria, and it places it onto the surface of that cell. But it places it onto a special type of complex of proteins known as MHC, which we spoke about previously.