Unformatted text preview: n kill it quickly and efficiently if we are exposed to the same disease
• Immune system problems
• Allergies: Sometimes our immune system attacks foreign proteins that are harmless, such as pollen
proteins or protein fragments from digested food. (Usually fragments that large are not absorbed by the
digestive system, but some conditions, such as certain illnesses, can make the intestines “leaky.”) The
next time the protein is encountered, the immune system attacks it, and we feel ill.
• Autoimmune diseases: If something goes wrong with the T cells’ ability to distinguish “self” from “notself,” the immune system may decide that some body tissues are “not-self” and launch an attack.
Rheumatoid arthritis, lupus, and multiple sclerosis are examples of autoimmune diseases.
• Cancer: The immune system is able to recognize and destroy cancerous body cells. But cancers can
grow too rapidly for the immune system to keep up with.
• Immune deficiency: Some children inherit a defective gene for one or more enzymes needed by the
immune system, and are born without an immune system (Severe Combined Immune Deficiency, or
SCIDS). The HIV virus specifically attacks T cells and disables the immune system, making its victims
vulnerable to the symptoms of AIDS (Acquired Immune Deficiency Syndrome). Research on AIDS has
yielded a great deal of new information on how the immune system works and has benefitted research
on cancer and autoimmune diseases.
• The word “immune” is often misunderstood or misused to mean, “Something one no longer reacts to.”
Vaccines and other types of exposure give us immunity not by suppressing the immune response, but
because the immune response is so swift and efficient that we do not notice its effects. An example of
misuse of the term: “Flies that are sprayed with pes...
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This document was uploaded on 02/25/2014 for the course BIOLOGY 103 at Western Oregon University.
- Winter '09