Chapter 17&18 Notes.docx - Chapter 17&18 Immunological...

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Chapter 17&18: Immunological Disorders and Application of Immune Response/Immunization Chapter 17 Hypersensitivity- immune response that causes injury; can be categorized into one of four major groups according to mechanisms and timing of response Autoimmune disease- targets body tissues Immunodeficiency- lack of adequate immune responses Type 1 Hypersensitivities: Immediate IgE-Mediated o Occurs within 24 hours often within minutes, o IgE binds to mast cells or basophils, o Functions as captured antigen receptors, allows mast cells and basophils to detect invaders o IgE is specific to a foreign particle (allergen) o Binding triggers release of inflammatory mediators o Binding to allergens sets off system o Tendency to have type I reactions inherited o Specific allergen is due to environmental exposure o Sensitization: contact induces antibody response 1. B cells under mucous membranes normally produces IgM but often switch to IgE production, especially in those prone to allergies 2. IgE accumulates, attaches to mast cells and basophils 3. Cell-bound IgE molecules react with antigen, cross-link 4. Mast cell releases histamine, other inflammatory mediators 5. Yields rapid reaction including hives, hay fever, asthma, anaphylactic shock o Localized Allergic Reactions: Hives: skin condition characterized by wheal (swelling) and flare (redness) Hay Fever: itching, teary eyes, sneezing, runny nose following inhalation of airborne antigen Asthma : respiratory allergy o Systemic Anaphylaxis : Rare but serious form of IgE-mediated allergy Antigen enters bloodstream, spreads throughout body Binds to IgE on basophils, which release mediators Extensive blood vessel dilation results in fluid loss, severe drop in blood pressure

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