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: Pathology
[{'content': 'The following interleukin is characteristically produced in a TH1 response? \nSelect and explain. \nA. IL-2, B. IL-4, C. IL-5, D. IL-10', 'role': 'user'}, {'content': 'Answer: A \nExplanation: After coming in contact with antigen presenting cells, CD4+ helper T cells secrete IL-2 and expresses high-affinity receptors for IL-2. IL-2 is a growth factor that acts on these T lymphocytes and stimulates their proliferation, leading to an increase in the number of antigen-specific lymphocytes.', 'role': 'assistant'}]