If a foreign invader, like a bad microbe, gets into your body, your immune system jumps into action!  Your immune system responds with all of its defences to make sure you don’t get sick.  Your white blood cells (leukocytes) make antibodies which are very special – a new antibody is made for each different type of invader! 

Antibodies help to fight the microbes that may make you sick and then they hang around guarding your body in case that microbe comes back!