This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
[{'content': 'Which of the following principally mediates delayed type hypersensitivity? \nSelect and explain. \nA. Cytotoxic T cells, TH1 cells, and macrophages, B. IgE, basophils, and mast cells, C. IgG and complement, D. IgG, IgM, neutrophils, and macrophages', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Cytotoxic T lymphocytes, helper T1 lymphocytes, and macrophages mediate the delayed-type hypersensitivity reaction, which develops in response to viral, fungal, and intracellular bacterial antigens. Antibodies do not play a significant role in this type of response. IgE, basophils, and mast cells are involved in the production of type I hypersensitivity. IgG and complement is a mechanism of toxicity in type II cytotoxic hypersensitivity. IgG, IgM, neutrophils, and macrophages may be involved in types II or III hypersensitivities. Ref: Levinson W. (2012). Chapter 65. Hypersensitivity (Allergy). In W. Levinson (Ed), Review of Medical Microbiology & Immunology, 12e.', 'role': 'assistant'}]