The immune system helps fight germs.it has a special cell called the white blood cells.it has something called a vaccine which is a medicine that helps your body fight a certain germ without making you fall sick.the white blood cells help fight germs they move around your blood and if they any bad germs like viruses or bacteria they will try to destroy it.the lymph nodes help trap germs and support the white blood cells.bone marrow which is in your bones and makes white blood cells