The Biology Project: Immunology

Introduction to Immunology Tutorial

Discrimination of self from nonself

The success of the immune system depends on its ability to discriminate between foreign (nonself) and host (self) cells.
Survival requires both the ability to mount a destructive immune response against nonself and the inability to mount a destructive response against self.
-David Huston, Biology of the Immune System, JAMA 278 (22)

When an organism is threatened by microorganisms, viruses, or cancer cells, the immune response acts to provide protection.

Normally, the immune system does not mount a response against self. This lack of an immune response is called tolerance.

In some cases, the immune system does mount an immune response against self. If an error is made, and an immune response is made against self, tolerance to self is lost. This condition is called autoimmunity (from Greek, "self-immunity"). Examples of autoimmune diseases in humans are: asthma, lupus, and arthritis.

The nude mouse cannot mount an immune response
The nude mouse has a defect in its immune system, and can only live if protected from pathogens. The mouse to the right has a transplant of rabbit skin, and can't reject the foreign tissue. Mice with immune deficiencies are very useful in cancer research because human cancer cells can grow into tumors allowing new ways to test cancer therapy.
Used with permission

The Biology Project
The University of Arizona
Tuesday, June 3, 1997
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