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': "The immunoglobulin which exhibits 'homocytotropism' is - \nSelect and explain. \nA. IgA, B. IgE, C. IgG, D. IgM", 'role': 'user'}, {'content': "Answer: B \nExplanation: Immunoglobulin E (IgE) A type of protein in blood plasma that acts as an antibody to activate allergic reactions. REF: Ganong's Review of Medical physiology; 24th edition; page no:77", 'role': 'assistant'}]