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Glossary of Current Seminar Terms

Allergic cascade--the body's response to the binding of antigen to the mast cell-bound antigen specific IgE. This binding, which causes activation of the mast cell, has been extensively studied by scientists and acts as the trigger which starts the "allergic cascade." The allergic cascade is like a string of dominoes: once the first domino is pushed, or IgE/allergen bond is made, it sets up a chain of chemical reactions which eventually result in release of histamines and other toxic chemicals from the mast cell.

Allergen--Foreign macromolecule which does not belong in the host body and which triggers an immune response.

Allergy--hypersensitivity to substances which are foreign to the body. Such substances can include pollens, foods, dust, microorganisms and so forth.

Anaphylaxis--a potent allergic reaction, characterized by vasodilation and smooth muscle contractions, which can result in death within seconds after exposure to the allergen.

Antibody--protein found in the blood serum which is formed in response to the presence of an antigen.

Antigen--Foreign macromolecule which does not belong in the host body and which can be bound by antibody or by T-cell receptor.

Antihistamines--drugs which block the action of histamine, thus preventing or alleviating the major symptoms of an allergic response.

B cell-- a type of lymphocyte which can differentiate into plasma cells.

Desensitization therapy--treatment in which minute amounts of antigen are injected into an allergic individual in an attempt to cause a decrease in the allergic response directed against that antigen.

Dust mite--

Epinephrine--also called adrenaline. Hormone synthesized by the medulla of the adrenal gland. responsible, in part, for the "fight or flight" response.

Histamine--Chemical which, when released from mast cells, cause vasodilation and an increase in permeability of blood vessel walls. These effects, in turn cause the familiar symptoms of allergy including tearing eyes and running nose. Histamine can also cause other symptoms: when released in the lung histamine causes airways to swell shut in an attempt to close the door on offending allergens and keep them out. Unfortunately, the ultimate result of this response is the wheezing and difficulty in breathing seen in people with asthma - another occasionally deadly allergic complication which kills 4000 Americans yearly.

Immune system-- the components of the body, including cells and chemical messengers, which work in a coordinated fashion to protect the body from invasion by foreign agents.

Mast cells--cells which contain histamine-filled granules and which patrol the body's tissues, playing an important role in allergic reactions.

Plasma cells-- cells which develop from B cells and which produce antibodies

Pollen-- grains that contain the male reproductive cells of seed plants.

T cell--a lymphocyte which underwent maturation in the thymus, and which plays an important role in control of the immune response.

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