This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cells and Tissues of Immune System, Subject name: Pathology
Mast cells release? 
Select and explain. 
A. IFN-g, B. IL-5, C. Histamine, D. Lysozyme
C: Histamine
Answer: C: Histamine 
Explanation: Ans. is 'c' i.e., Histamine o Mast cells reside and mature in tissues. They are the most important cells in immediate hypersensitivity and are also the most important source of histamine.o Other secretions are : Serine proteases, Carboxypeptidases, Glycosidoses, Proteoglycans, Sulfatases.