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
[{'content': 'Prausnitz-kustner (PK) reaction was used to demonstrate - \nSelect and explain. \nA. IgA, B. IgG, C. IgM, D. IgE', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., IgE o IgE is homocytotropic i.e. species specific. Only human IgE can fix to the surface of human cells. This is the basis of the Prausnitz-Kustner (PK) reaction, which was the original method for detecting atopic antibody.", 'role': 'assistant'}]