Which interleukin is T-cell growth factor?

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.