MATERIAL AND METHODS Materials Lipopolysaccharide (LPS; Escherichia coli, serotype R515) was purchased from Alexis (Lausen, Switzerland) and adenosine triphosphate (ATP) from Sigma (Deisenhofen, Germany). Tumor necrosis factor α (TNF-α) was kindly provided by the Knoll AG (Ludwigshafen, Germany). IL-1β was from Invitrogen/Biosource (Karlsruhe, Germany).