UNIT 3-Module 8-Ch17, 18_ Immunological Disorders and Applications of the Immune Response.pdf

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UNIT 3­Module 8­Ch 17, 18: Immunological Disorders and Applications of the Immune Response Ch17: Immunological Disorders Describe the difference between hypersensitivity, and allergy
Describe the difference between autoimmune disease and immunodeficiencies
Describe the immunologic reactions involved in type I hypersensitivities. Type I hypersensitivities→ immediate and IgE mediated effector → B cells type of antigen → soluble inhaled substances (e.g., pollen, pet dander, mold) ingested substances (e.g., peanuts, milk, seafood) injected substances (e.g., insect venom, drugs) type of antibody → IgE other immune cells involved → basophils and mast cells mediators → histamine, leukotrienes, prostaglandins time of reaction after Ag encounter → immediate to 30min skin reaction→ wheal and flare mechanism of action → functions as captured antigen receptors allowing basophils and mast cells to detect invaders First exposure to Ag→ induces an IgE antibody response leading to sensitization (i.e pollen grains contact mucous membrane of respiratory tract, triggering IgE production, which sensitizes individual to pollen) 1) B cell binds to allergen and is activated by helper T­cell 2) B cells differentiate into IgE producing plasma cells and memory cells. B cells under mucous membranes initially programmed to produce IgM molecules often switch to IgE production (especially if prone to allergies) 3) Sensitization→ after the primary exposure to an antigen leads to an allergic reaction if and when that same antigen is encountered again an antibody response is induced Fc portions of IgE Abs accumulates and bind to mast cells and basophils 1
UNIT 3­Module 8­Ch 17, 18: Immunological Disorders and Applications of the Immune Response Once attached IgE molecules are stable for weeks with their antigen­binding sites available to interact with allergens subsequent exposure to Ag → occurs if antigen is encountered again 1) cell bound IgE molecules react with specific antigen, the IgE molecules cross­linking causing mast cells to degranulate 2) degranulation→ the release of mediators (i.e histamine) from a cell’s granules which cause: capillary dilation, smooth muscle contraction and increased mucus secretion 3) allergy symptoms (i.e sneezing, runny nose, itching, swelling and pain) begin minutes after exposure to allergen: examples

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