How Alergies Work

A properly functioning immune system is a well-trained and disciplined biological warfare unit for the body. The immune system is really quite amazing - it is able to identify and destroy many foreign invaders. The immune system can also identify cells that are infected internally with viruses, as well as many cells that are on their way to becoming tumors. It does all of this work so the body remains healthy.

As amazing as the immune system is, it sometimes makes mistakes. Allergies are the result of a delusional and hypersensitive immune system. Delusional in the sense that the allergic immune system misidentifies an otherwise harmless substance as harmful, hypersensitive in the sense that it attacks the substance with the ferocity far greater than required. The problems this can cause range from mildly inconvenient to the total failure of the organism the immune system is supposed to be protecting.

In this edition of How Stuff Works ,we'll examine the most established school of thought on what makes up the condition referred to as allergy. A defining premise of this school of thought is that allergic symptoms are always triggered by a protein.

Terms to know

In order to discuss allergies, you need to be familiar with several vocabulary words. The following is a list of terms defined as they relate to allergies.

- Allergen: an allergy causing substance.

- Antibody: A B-cell produced protein molecule made in response to, and reactive with, a specific antigen.

- Antigen: a substance capable of causing the production of antibodies and then reacting specifically with these antibodies.

- B-cell, (a.k.a. B-lymphocyte): A type of white blood cell capable of producing antibodies.

- Basophil: a white blood cell containing histamine and other allergy mediators.

- Histamine: a chemical present mainly in mast cells which, when released, causes many of the symptoms of allergy.

- IgE: the type of antibody most instrumental in allergic reactions.

- Lymph nodes: small organs within the lymph system located at the intersections of lymph channels.