What Is Immune

In a narrow sense, immune refers to the human body’s resistance to the pathogens (virus and bacteria) and harmful substances. In a broad sense, immune is a kind of special protective physiological function. Depending on this function, the human body can recognize and reject or eliminate the foreign substances to maintain the balance and stability of the internal environment.

Human body has the ability to keep prevent the foreign pathological substances invading into body referred as immunity.

The human body realizes the immune function depending on a systemic immune system. Every one has a powerful immune system that is composed of innate immune system and back-up immune system to keep the human body in a healthy state. Innate immune system is also called non-specific immune system. It is a natural defense function and is built up during the human evolution. In order to guarantee the safety of the innate immune system, the human body builds up the back-up immune system consisting of alternative pathway of complement activation system and adaptive immune system. The innate immune system and the back-up immune system work together to keep the body remain in a healthy state.