Immune System

The immune system protects the body from infection by pathogenic organisms. It does this by creating barriers and mechanisms to prevent bacteria and viruses from entering the body (for example, the skin, saliva and sneezing). If pathogens breach these barriers, the body's innate immune system uses specialised cells that detect, and often eliminate, the invader before it is able to reproduce and cause damage to the body. Any pathogen that manages to evade the innate immune cells must face the adaptive immune system. The adaptive response has the ability to recognise a pathogen, and to launch stronger attacks each time that pathogen is encountered.

Occasionally, the body can develop hypersensitivity, which is an immune response that damages the body's own tissues. This leads to an allergic reaction, which can range in intensity from mild discomfort to the most severe form - anaphylactic shock - which can lead to death in minutes if left untreated.

To learn more about the medical conditions involving the immune system, select an item from the menu below.