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
A 25-year-old man is exposed to Ascaris but does not develop clinical signs of infection. Which of the following mechanisms is likely to be responsible for his resistance to infection? 
Select and explain. 
A. Antibody mediated destruction of worm infected host cells, B. CTL induced apoptosis of worm infected host cells, C. Complement mediated lysis of worm attached to host tissues, D. IgE mediated type I hypersensitivity disrupting worm attachment
D: IgE mediated type I hypersensitivity disrupting worm attachment
Answer: D: IgE mediated type I hypersensitivity disrupting worm attachment 
Explanation: Ans. (d)Local inflammatory responses such as that induced by IgE can inhibit attachment of roundworms to the intestinal wall. Ascaris is a large worm and is not damaged by antibodies directed at it or by complement, CTLs or phagocytes.