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
Classical pathway macrophage activating molecule 
Select and explain. 
A. IFN gamma, B. IL 4, C. IL 13, D. ILI
A: IFN gamma
Answer: A: IFN gamma 
Explanation: Answer- A. IFN gammaThere are two major pathways of macrophage activation:Classical macrophage activation- induced by microbial products, which engage toll like receptors & other sensors, by T cell derived signals, impoantly the cytokine IFN-yAlternative macrophage activation - induced by cytokines III & ILl3 produced by T lymphocytes & other cells. Their main function is tissue repair & secrete growth factors which cause angiogenesis, activate fibroblasts & stimulate collagen synthesis.