But macrophages are much, much larger than the neutrophils. Now let's move on to our lymphocytes. So lymphocytes are those specialized wide blood cells that make up our specific immune system, our acquired or adapted immune system. So remember, we have three different types of lymphocytes. We not only have B lymphocytes and T lymphocytes but we also have natural killer cells which basically looks something like this. Now, natural killer cells are those cells that essentially bind to antigens on other cells and they can either kill off infected cells or they can kill off cancer cells.