interleukin Definition

any of various cytokines of low molecular weight that are produced by lymphocytes, macrophages, and monocytes and that function especially in regulation of the immune system and especially cell-mediated immunity

an interleukin produced especially by monocytes and macrophages that regulates immune responses by activating lymphocytes and mediates other biological processes (such as the onset of fever) usually associated with infection and inflammation

an interleukin produced by antigen-stimulated helper T cells in the presence of interleukin-1 that induces proliferation of immune cells (such as T cells and B cells) and is used experimentally especially in treating certain cancers