The Immune System

Abstract

The immune system consists of a large number of different types of cells and proteins that function to distinguish between normal and abnormal cellular components and between 'self' and 'non-self'. As an example, when a thorn gets stuck in the body, the immune cells are able to recognized the thorn as a foreign object (i.e. 'non-self') and attack it. The same is true for bacteria, viruses or other organisms that can invade our bodies. A more subtle distinction between self and non-self occurs in the recognition of cancer cells by the forces of the immune system. The cancer cells are recognized and attacked because they differ from the normal 'self' from which they arose.