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: Microbiology
IL-1 is produced by - 
Select and explain. 
A. Macrophage, B. Helper T lymphocytes, C. B cells, D. Cytotoxic T-cells
A: Macrophage
Answer: A: Macrophage 
Explanation: It is principally secreted by macrophages and monocytes but can be produced by most other nucleated cells as well REF:Ananthanarayan & Panikers Textbook of Microbiology 9th Edition pg:154