And what that means is they're involved with forming and storing antibodies. So the plasma cells form antibodies that are complementary to these specific antigens that we spoke about earlier shown in red. So these antibodies are complementary to the antigens found on this bacterial cell. And these plasma cells form a bunch of these antibodies that can now move around our blood system and lymph system and they combine to the antigens of this bacterial cell. Now, memory B cells, instead of forming these antibodies they essentially store these antibodies within the cell and they can essentially react with a bacterial cell of the same type that reinfects our body at some later time. So it's the memory B cells that essentially allow our immune system to be adaptive.