THE PRODUCTION AND CHARACTERIZATION OF A MODIFIED RECOMBINANT INTERLEUKIN-1 RECEPTOR ANTAGONIST

The increasingly complex cytokine network involves both positive and n egative regulatory pathways. Natural inhibitors of cytokines are of gr eat importance both as analytical tools and as, potential therapeutic agents. Interleukin-1 (IL-1) inhibitory bioactivity including a specif ic receptor antagonist of IL-1 (IL-1ra) has been described both in cul tured cell supernatants and in human body fluids. In the current studi es, the cDNA of IL-1ra from human monocytes was obtained by the techni ques of mRNA isolation and reverse transcription/polymerase chain reac tion (RT/PCR). The IL-lra cDNA/pET-15b was transfected into DE3 cells and the recombinant protein expressed. The purified protein was demons trated as a single band with molecular mass of 20KD by SDS-PAGE; it ha d strong IL-1 inhibitory activity. This IL-1 inhibitor competed with I L-1 for their receptor as assesed by flow cytometer. The existence of this naturally occurring specific cytokine receptor antagonist may lea d to a different perspective of the cytokine network. The availability of this recombinant IL-1 receptor antagonist allows us to test its ro le on the cytokine network, and on possible disease modification.