Interleukin‐8 processing by neutrophil elastase, cathepsin G and proteinase‐3

Abstract

Activated neutrophils secrete two forms of IL‐8 with 77 and 72 amino acids, IL‐8(77) and IL‐8(72), along with proteinases that could process these cytokines. Significant conversion of IL‐8(77) to more potent, N‐terminally truncated forms was observed upon incubation with neutrophil granule lysates and purified proteinase‐3. IL‐8(72) was considerably more resistant to proteolytic processing than IL‐8(77). The present observations indicate that neutrophil proteinases released in inflamed tissues convert IL‐8 to more active forms and therefore tend to conserve or enhance, rather than decrease IL‐8 activity.