Immediate reactions begin within minutes of contact with the eliciting dose of antigen

Immediate reactions begin within minutes of contact with the eliciting dose of antigen

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Immediate reactions begin within minutes of contact with the eliciting dose of antigen. If antigens are  introduced directly into the tissues, such as by insect sting or injection, the result is a systemic  reaction such as anaphylactic shock. When the contact is a superficial one involving the epithelial  tissues, the reaction is more localized, as occurs in asthma or allergic rhinitis (hay fever). These local  reactions are commonly referred to as allergy. Another term used is atopy.  The antigens eliciting an immediate hypersensitivity are called allergens, particularly when they are  involved in local allergic reactions. Hapten molecules such as penicillin molecules may be involved  when they are bound to larger protein molecules. Foods, feathers, pollen grains, animal dander, and  dust may be allergens. Animal sera, bee venoms, and wasp venoms are also allergens. 
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Unformatted text preview: The antibodies involved in anaphylaxis reactions are of the type IgE. In cytotoxic and immune complex reactions, IgG and IgM are involved. Anaphylaxis. Anaphylaxis, or type I hypersensitivity, is a whole-body, immediate hypersensitivity also known as anaphylactic shock. The allergens are introduced to the body directly to the tissues in a concentrated form (intramuscular or intravenous injection, for example). After the sensitizing dose has been administered, IgE is produced by the plasma cells. The antibodies circulate in the blood and attach at the Fc end to mast cells of the tissues and basophils in the bloodstream (Figure 1 ). This activity occurs during the latent period. When the eliciting dose of allergen is later administered, the antigens combine with antibodies on the surface of the mast cells and basophils....
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