And recall that memory cells are those white blood cells that actually store a copy of that antibody for that specific antigen. And the reason the memory b cells store that antibody is in case reinfection actually ever reoccurs actually ever takes place again. So what happens when the body is reinfected by the same type of pathogen? In this case, the immune system will elicit a secondary response and it will be different than the primary response because of the presence of these memory B cells and memory T cells. So let's redraw this diagram as shown. So we have first infection taking place and then we have the end of our primary phase, our primary response.