Induction by transforming growth factor-beta 1 of the interleukin-1 receptor antagonist and of its intracellular form in human polymorphonuclear cells.

The aim of this study was to examine the expression of interleukin-1 receptor antagonist (IL-1ra) in human polymorphonuclear cells (PMN) treated with transforming growth factor-beta 1 (TGF beta 1). TGF beta 1 induced IL-1ra transcripts in human circulating PMN and the induction was not blocked by protein synthesis inhibitors. Actinomycin D blocked induction by TGF beta 1 of IL-1ra transcripts, suggesting the involvement of gene transcription. The half life of IL-1ra transcripts was prolonged by TGF beta 1. By reverse transcriptase-polymerase chain reaction, TGF beta 1 was found to augment the transcripts coding for both the intracellular (keratinocyte type) and the secreted form of IL-1ra. TGF beta 1 induced the production of IL-1ra in PMN. Induction of IL-1ra by TGF beta 1 in PMN may represent a further mechanism by which this molecule can counteract the potent pro-inflammatory properties of IL-1.