(Science: cytokine) a soluble protein (17 kD: 152 amino acids) secreted by monocytes, macrophages or accessory cells involved in the activation of both t-lymphocytes and b lymphocytes and potentiates their response to antigens or mitogens.
Its biological effects include the ability to replace macrophage requirements for t-cell activation, as well as affecting a wide range of other cell types. at least two il-1 genes are active and alpha and beta forms of il-1 are recognised.
It is released early in an immune system response by monocytes and macrophages. It stimulates t-cell proliferation and protein synthesis. Another effect of il-1 is that it causes fever.
See: catabolin, endogenous pyrogen.