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': 'IL_2 is secreted by - \nSelect and explain. \nA. CD4 lymphocytes, B. CD8 cells, C. Macrophages, D. Neutrophils', 'role': 'user'}, {'content': 'Answer: A \nExplanation: IL-2 produced by activated T cells, which induced T cell proliferation and enabled their maintenance in continuous culture REF:Ananthanarayan & Panikers Textbook of Microbiology 9th Edition pg:155', 'role': 'assistant'}]