They flow through your bloodstream to fight viruses, bacteria, and other foreign invaders that threaten your health. When your body is in distress and a particular area is under attack, white blood cells rush in to help destroy the harmful substance and prevent illness.

How do white blood cells fight infection?

Your white blood cells lock on to the germs in order to absorb or destroy them. They have antibodies that latch onto the germs. Experience makes your immune system stronger. The first time your body comes into contact with a certain type of germ, your immune response may take a while.

How are white blood cells made?

Stem cells in the bone marrow are responsible for producing white blood cells. The bone marrow then stores an estimated 80–90% of white blood cells. When an infection or inflammatory condition occurs, the body releases white blood cells to help fight the infection.