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Delayed - 3 Lymphokines a Transfer factor –...

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Delayed-type Hypersensitivities (Type IV) 1. General Characteristics: a. Allergens - whole cells, haptens that complex with skin proteins b. Route of exposure - subcutaneous tissues, internal tissues (organs) c. No circulating Ab. involved, due to development T DH lymph “sensitized” d. Reactions delayed - ave. 24-48 hrs. after exposure to Ag. e. Reactions milder, persist longer period of time 2. Development of Delayed Hypersensitivities a. Primary Exposure: 1). Macrophage a). Processes antigen b). Presents antigenic determinants on cell membrane c). Secretes Interleukin I – attracts lymphocytes and macrophages 2). T H Lymphocytes a). Reacts with antigenic determinants b). Secretes Interleukin II – stimulates T DH lymphocytes 3). T DH Lymphocytes a). React with antigenic determinants b). Multiply clone immature lymphs c). Differentiate “sensitized” T DH lymphocytes b. Subsequent exposure: 1). “Sensitized” T DH lymphs react with allergen 2). Secrete lymphokines adverse reactions
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Unformatted text preview: 3). Lymphokines: a). Transfer factor – “sensitizes” additional lymphocytes b). Lymphotoxin – cytotoxic factor → destroys host cells c). Macrophage Chemotactic Factor (MCF) – attracts macrophages to site of reaction d). Macrophage Migration Inhibition Factor (MIF) – keeps macrophages localized at site of reaction e). Macrophage Activating Factor – increases activity macrophages → “angry” macrophages 3. Types of Reactions a. Contact dermatitis 1). Allergens – haptens complex with skin proteins 2). Absorbed through skin → subcutaneous tissues 3). Reactions → skin (red raised areas, itch) 4). Ex.: poison ivy b. Infectious allergies 1). Allergens – intracellular bacteria (TB bacillus), systemic fungi, protozoans, helminths 2). Invade tissues → delayed hypersensitivity c. Autoimmune disorders 1). Allergens – host tissue cells 2). Destruction host tissue cells...
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Delayed - 3 Lymphokines a Transfer factor –...

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