A recombinant therapeutic agent which is chemically identical to or similar to the endogenous cytokine interleukin 11 (IL-11). Secreted by bone marrow stromal cells and a number of mesenchymal cells, IL-11 binds to and activates its cell-surface receptor, promoting primary and secondary immune responses, modulating antigen-specific antibody reactions, and preventing apoptotic cell death. This agent also stimulates the T-cell-dependent development of IgG-secreting B-cells in spleen cell cultures and may be an important regulator of megakaryocytopoiesis. or The place in the brain where some of the optic nerve fibers coming from one eye cross optic nerve fibers from the other eye. Also called optic chiasma.