Type I hypersensitivity is mediated by which of the following immunoglobulins?: (A) Ig A, (B) Ig G, (C) Ig M, (D) Ig E
Answer is D. Type I hypersensitivity reaction is IgE dependent. Cytotoxic IgE antibodies are fixed on the surface of tissue cells ( mast cells and basophils) in sensitized individuals. The antigen combines with the cell fixed antibody, leading to release of pharmacologically active substance that produces the clinical reaction. Reference : Anathanarayan & paniker's 9th edition, pg: 162 <\p>