Inside your body is an army of cells ready and waiting to fight off infection. This amazing video shows a group of white blood cells attacking a parasitic worm. Your blood is made up of red blood cells, white blood cells, platelets, and plasma. White blood cells account for only about 1% of your blood, but their impact is big. White blood cells are also called leukocytes. They protect you against illness and disease. White blood cells are made in the bone marrow and found in the blood and lymph tissue. White blood cells are part of the body’s immune system. They help the body fight infection and other diseases. Types of white blood cells are granulocytes (neutrophils, eosinophils, and basophils), monocytes, and lymphocytes (T cells and B cells).