This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
Allergic hypersensitivity is mediated by - 
Select and explain. 
A. IgM, B. IgG, C. IgD, D. IgE
D: IgE
Answer: D: IgE 
Explanation: Atopy or allergic hypersensitivity is type I which is mediated by IgE. Atopic sensitivity is due to overproduction of IgE antibodies. In normal individuals , the inhalent and ingested antigens are delt with IgA lining the respiratory and intestinal mucosa and thus do not come in contact with IgE producing cells. When IgA is deficient, antigen cause massive stimulation of IgE forming cells leading to overproduction of IgE. Reference : Anathanarayan & paniker's 9th edition, pg no:165 <\p>