Inhibitory action of cytokine preservatives on chemiluminescence assays.
Huang-H; Hubbs-AF; Lewis-DM; Brower-PS; Vallyathan-V
Toxicol Methods 1996 Jan; 6(3):157-161
An in-vitro model was used to investigate the early biological effects of tumor necrosis factor alpha (TNFa) on free radical generation during the particle stimulated respiratory burst by rat alveolar macrophages. While TNFa did consistently change cell free hydrogen-peroxide induced chemiluminescence (CL), the effect was dependent on the source of the cytokine. Azide free recombinant murine TNFa further enhanced hydrogen-peroxide associated CL, while recombinant human TNFa which contained sodium-azide was an effective quenching agent for CL. Dialyzed TNFa had less of a CL quenching effect than the sodium-azide preserved TNFa. The low molecular weight fraction of the dialyzed TNFa also quenched hydrogen-peroxide associated CL, but was less efficient than the azide preserved TNFa or the high molecular weight fractions. The authors conclude that small amounts of sodium-azide and/or bovine serum albumin (BSA) may interfere with these assays. This interference is expected when cytokines are used in experimental protocols. Not only did low concentrations of sodium-azide or BSA interfere with the CL assay, but this interference was not completely eliminated when the TNFa was dialyzed.
Mammalian-cells; In-vitro-studies; Alveolar-cells; Free-radicals; Luminescence; Chemical-analysis; Analytical-methods; Azides; Lung-cells