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': 'In TB, immunity is provided by: \nSelect and explain. \nA. CD4+ cells, B. CD8+ cells, C. IgG, D. IgM', 'role': 'user'}, {'content': "Answer: A \nExplanation: Activated CD4+ helper T cell\xa0is the speciﬁc immune mechanism eﬀective in TB.\nIt is a ‘cell-mediated' type\xa0of immunity (since it is intracellular).", 'role': 'assistant'}]