Which one of the following Immunoglobulins cause type 1 allergic reaction?
Which one of the following Immunoglobulins cause type 1 allergic reaction?
Select an option to attempt
Correct Answer: Option C
Explanation
Immunoglobulin responsible for Type I (immediate) allergic reactions:Type I hypersensitivity (immediate / anaphylactic type) is mediated exclusively by IgE:1. First exposure: allergen stimulates B cells to produce IgE antibodies.2. IgE binds to FcεRI (high-affinity IgE receptor) on mast cells and basophils — 'sensitisation'.3. Second exposure: allergen cross-links IgE on mast cells → degranulation:• Releases histamine, leukotrienes, prostaglandins• Causes vasodilation, bronchoconstriction, mucus secretion4. Clinical manifestations: allergic rhinitis, asthma, urticaria, anaphylaxisOther immunoglobulin classes are NOT involved in Type I hypersensitivity:• IgG: Type II (cytotoxic) and Type III (immune complex) hypersensitivity• IgM: agglutination, complement activation• IgA: mucosal immunityAnswer: IgE (Option 3).