This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunity, Subject name: Pathology
[{'content': 'Which interleukin is T-cell growth factor? \nSelect and explain. \nA. IL-3, B. IL-7, C. IL-11, D. IL-5', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., IL-7 * T-cell growth factors (TCGF(s)) are signaling molecules collectively called growth factors which stimulate the production and development of T-cells. A number of them have been discovered, among them many members of the interleukin family (IL-2, IL-4, IL-7, IL-9, IL-15 and IL-21). The thymus is one organ which releases TCGFs.", 'role': 'assistant'}]