The neutrophil-activating protein (NAP-1) is also chemotactic for T lymphocytes

Monocyte chemotactic protein gene expression by cytokine-treated human fibroblasts and endothelial cells

A number of cytokines are active during the evolution of an inflammatory response, including tumor necrosis factor-alpha, interleukin-1, and novel chemotactic cytokines. This latter group of mediators belong to supergene families of inflammatory signals that play a key role in the selective recruitment of immune cells. In this presentation, we present data demonstrating, for the first time, endothelial cell expression of monocyte chemotactic protein (MCP) mRNA induced by LPS, interleukin-1 or tumor necrosis factor. Human fibroblasts were also found to express monocyte chemotactic factor mRNA in response to interleukin-1 or tumor necrosis factor, but LPS was not effective. In addition, neither primary cultures expressed MCP in response to interleukin-6. These studies demonstrate that non-immune "bystander" cells can play an active role in the recruitment of inflammatory cells via the production of novel chemotactic cytokines.

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

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-beta, 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 1 beta 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/IL8, 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/IL8. 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.

A Novel Cytokine That Activates Human Neutrophils

A novel neutrophil-activating peptide was recently characterized by different laboratories and named NAF (neutrophil-activating factor) (Walz et al., 1987) MDNCF (monocyte-derived neutrophil chemotactic peptide) (Yoshimura et al., 1987) and MONAP (monocyte-derived neutrophil-activating peptide) (Gregory et al., 1988). The peptide detected in the culture fluids of stimulated human mononuclear phagocytes consists of 72 amino acids. Minor amino-terminal truncation variants are also found (Lindley et al., 1988). The major form was now obtained by recombinant methods and was shown to be biologically equivalent to purified natural NAF (Lindley et al., 1988).