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': 'Macrophages are major source of? \nSelect and explain. \nA. IL-1, B. IL-5, C. IL-7, D. IFN- y', 'role': 'user'}, {'content': 'Answer: A \nExplanation: IL-1 REF: Jawett\'s microbiology, 24th edition chapter 8 Immunology Table 8-3 See APPENDIX-19 for list of "CYTOKINES"', 'role': 'assistant'}]