Molecular Studies on Murine Interleukin 1

Abstract

Our understanding of IL 1 biology has been accompanied by dramatic advances in IL 1 biochemistry and molecular biology. In 1981, murine IL 1 was first purified using standard chromatographic procedures (1). Subsequently anti-IL 1 antibodies were generated and used to purify murine IL 1 with a significant increase in overall yield of active protein (2). Using anti-IL 1 antibodies, Giri et al. (3) demonstrated that murine IL 1 is initially synthesized as a 33,000 molecular weight precursor that is enzymatically cleaved to the lower molecular weight forms detected in the culture medium of stimulated cells. More recently, human IL 1 has been purified from the conditioned medium of cultures of stimulated peripheral blood mononuclear cells (4–6) as well as a monocytic leukemia cell line (7). However, a major breakthrough in IL 1 research was achieved with the cloning, sequencing, and expression of cDNAs for murine (8) and human (9–11) IL 1. These studies revealed the existence of at least two forms of human IL 1, termed IL 1α (pI 5) and IL 1β (pI 7).