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
TNF and IL1 are produced by - 
Select and explain. 
A. Neutrophils, B. Monocytes, C. Activated Macrophages, D. Lymphocytes
C: Activated Macrophages
Answer: C: Activated Macrophages 
Explanation: Tumor Necrosis Factor (TNF) and Interleukin-1 (IL-1)

TNF and IL-l serve critical roles in leukocyte recruitment by promoting adhesion of leukocytes to endothelium and their migration through vessels.
These cytokines are produced mainly by activated macrophages and dendritic cells; TNF is also produced by T lymphocytes and mast cells, and IL-l is produced by some epithelial cells as well.
The secretion of TNF and IL-1 can be stimulated by microbial products, immune complexes, foreign bodies, physical injury, and a variety of other inflammatory stimuli.