When a person becomes sick, it is because a foreign invader or pathogen has entered their body. A pathogen is anything that enters the body that is not supposed to be there.
I attack invaders inside the cells.
I'm a phagocyte!
To prevent us from getting sick, our bodies have an immune system to protect us. For example, if you get a paper cut B-cells, T-cells and phagocytes come to try and reduce the chances of getting an infection.
I'm a germ!
B-cells are one type of protector, they are also called antibodies. Each cell acts as a guard to keep you from getting sick.
A T-cell is also a protector in our bodies. The 3 types of T-cells are killer t-cells which kill germs, helper t-cells send out signals to call more killer t-cells to get rid of germs, and regulatory t-cells which tell the b-cells when to stop making antibodies.
A phagocyte is another type of protector. Phagocytes have the job of killing germs by eating them. If they ever need help when they are trying to kill all the germs, they just call more phagocytes to come help!
Now it was Lily’s 2nd line, phagocytic cells turn to fight the virus. The virus quickly defeated the 2nd line, and it was up to the 3rd line of defense to save Lily. The 3rd and last line of defense was her body’s specific resistance, it is specific because it targets specific antigens that are foreign to Lily’s body.