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
In TB, immunity is provided by - 
Select and explain. 
A. CD 4+, B. CD 8+, C. IgG, D. IgM
A: CD 4+
Answer: A: CD 4+ 
Explanation: Ans. is 'a' i.e., CD4+ . Cell mediated immunity confers protection against M. tuberculosis, while humoral immunity has no defined role in protection. . Two types of cells are essential. 1. Macrophages --> Directly phagocytize tubercle bacilli. 2. T cells (mainly CD4+) --> Induce protection through the production of IFN-y