This family contains interleukin 11 (approximately 200 residues long). This is a secreted protein that stimulates megakaryocytopoiesis, resulting in increased production of platelets, as well as activating osteoclasts, inhibiting epithelial cell proliferation and apoptosis, and inhibiting macrophage mediator production. These functions may be particularly important in mediating the hematopoietic, osseous and mucosal protective effects of interleukin 11 [1]. Family members seem to be restricted to mammals.

1: Interleukin-11. Leng SX, Elias JA; Int J Biochem Cell Biol 1997;29:1059-1062. PMID:9416001