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: Medicine
[{'content': 'IL-2 is secreted by: \nSelect and explain. \nA. CD4 and lymphocytes, B. CD8 cells, C. Macrophages, D. Neutrophils', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Answer is A (CD4 and lymphocytes) : IL-2 is produced by T helper (CD4) lymphocytes', 'role': 'assistant'}]