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: Pathology
Cytokine for activating macrophage and conveing to epitheloid cell or giant cell ? 
Select and explain. 
A. IL2, B. IL 17, C. TNF alpha, D. IFN gamma
D: IFN gamma
Answer: D: IFN gamma 
Explanation: Ans. is 'd' i.e., IFN gamma Granulomatous inflammation is a form of chronic inflammation characterized by collections of activated macrophages, often with T lymphocytes, and sometimes associated with central necrosis. These granulomas are type IV hypersensitivity reaction that involves CD4-helper T-cells. Helper T-cells are activated by IL-2 and produce IFN-y (interferon gamma) the major cytokine of granulomatous inflammation. IFN-y induces formation of granuloma by conversion of activated macrophages into epitheloid cells and formation of giant cells by fusion of epithelial cells.