The chemotactic activity for granulocytes produced by virally infected fibroblasts is identical to monocyte‐derived interleukin 8

Abstract

So far, the role of fibroblasts in inflammatory processes has been underestimated. We have previously shown that stimulation of fibroblasts with viruses or bacteria results in a simultaneous production of several cytokines, including interferon‐β, interleukin (IL) 6 and colony‐stimulating factors. We here report that virally infected fibroblasts produce also a chemotactic factor for granulocytes. The activity is inducible not only by measles virus but also by IL 1β and the double‐stranded RNA poly(rI) ˙ poly(rC). This factor, when purified to homogeneity, occurs as a 6–7‐kDa protein doublet upon sodium dodecyl sulfate‐polyacrylamide gel electrophoresis. The pure protein is serologically related to a fully characterized granulocyte chemotactic peptide (GCP) from monocytes, designated IL8. Furthermore, the chemotactic factor from fibroblasts has an NH₂‐terminal sequence identical to that of GCP/IL 8, small differences in NH₂‐terminal processing being observed. Finally, in addition to diploid fibroblasts, the osteosarcoma MG‐63 cell line is also a producer of GCP/IL 8. It can thus be concluded that GCP/IL8 can be produced by several cell types in response to infection and that fibroblasts can contribute to chemotaxis in inflammation.