The Immune System Protects and Defends the Body
The immune system is made up of an army of many different cells that work together to protect the body from getting sick. In a healthy body, the immune system targets and helps to eliminate threats. Threats can come in many forms, like bacteria or viruses. Sometimes, the body’s own cells change and become harmful. Cancer is an example of this, where either because of genetic or environmental causes, normal cells become harmful. Sometimes they live longer than healthy cells, and can multiply quickly.