Extracellular Hsp72 does not induce or inhibit cytokine release from pleural mesothelial cells.

The ability of a highly purified, recombinant Hsp72 preparation to induce inflammatory cytokine release from pleural mesothelial cells was determined (A and B). MeT-5ACells were treated with the indicated doses of Hsp72 or PMA as a positive control, and MCP-1 (A) and VEGF (B) release measured 24 hr post-treatment by ELISA. In separate experiments, the anti-inflammatory effects of extracellular Hsp72 were examined (C and D). Cells were pre-treated with Hsp72 for 2 hr, followed by treatment with TNF-α (C) or thrombin (D) for an additional 24 hr to induce MCP-1 release. In contrast to PMA stimulated MeT-5A cells, treatment with Hsp72 had no impact on cytokine release. The data are presented as the mean ± SEM of three independent experiments performed in triplicate. NS, not significant.