Synergistic induction of tumor necrosis factor ? by bacterial lipopolysaccharide and lipoteichoic acid in combination with polytetrafluoroethylene particles in a murine macrophage cell line RAW 264.7

Abstract

The induction of tumor necrosis factor α (TNF‐α) by polytetrafluoroethylene (PTFE) particles (5–50 μm) and by bacterial lipopolysaccharide (LPS) and lipoteichoic acid (LTA) was examined in RAW cell cultures. Twenty‐four‐hour culture supernatants from the treated and control cells were assayed for TNF‐α using a mouse L929 cell cytotoxicity assay. Untreated RAW cells produced low levels of endogenous TNF‐α in the culture supernatants. Addition of 0.5 ng to 1 μg/ml LPS or 1 ng to 1 μg/ml LTA increased the TNF‐α production by 7‐3570‐fold and 2‐815‐fold, respectively. Addition of 1–5 mg PTFE increased the TNF‐α production by 6–17‐fold over the untreated control cell levels. The cells exposed to PTFE and 0.5 ng/ml LPS or 5 ng/ml LTA produced TNF‐α levels that were significantly higher than those produced by any inducer alone. Thus, both LTA, a Gram‐positive bacterial cell wall component and LPS, a Gram‐negative bacterial cell wall component, can induce TNF‐α production, which is further enhanced by PTFE particles in RAW cells. © 1996 John Wiley & Sons, Inc.