Interleukin-1: amino acid sequences, multiple biological activities and comparison with tumor necrosis factor (cachectin).

Interleukin-1 (IL-1) now refers to a family of polypeptides which are produced by the host in response to injury, infection, and various immunological reactions. To date, two forms have been cloned but there are likely others. Recombinant IL-1s confirm the multiple and diverse biological properties that had been described previously using natural IL-1s. In this review, the cloning approaches for are discussed; in addition, the molecular control of IL-1 synthesis and processing are considered. The various biological activities of recombinant IL-1s are presented and are discussed regarding their clinical relevance. The multiple biological activities of recombinant tumor necrosis factor (cachectin) are compared to those of recombinant IL-1s.