The Immune System
- Describes the lymph node pathways, organs and cells that are involved in fighting infection. Site explains how T cells respond to foreign organisms. Includes diagrams. From the National Institute of Allergies and Infectious Diseases.
- http://www.niaid.nih.gov/final/immun/immun.htm

Understanding the Immune System
- A detailed look at the enemies that the immune system fights, the way the immune system recognizes foreign objects, cancer, and technologies currently being studied.
- http://www.thebody.com/nih/immune_system.html

Cells of the Immune System
- Descriptions and pictures of the cells involved in the immune response.
- http://www-micro.msb.le.ac.uk/MBChB/2a.html

How Stuff Works: Immune System
- Describes the immune system and discusses related topics such as allergies and AIDS.
- http://www.howstuffworks.com/immune-system.htm

The Anatomy of the Immune System
- In depth look at the immune system and all its separate parts, including organs and cells.
- http://www-micro.msb.le.ac.uk/MBChB/2b.html