PYROGEN TESTING OF LIPID-BASED TPN USING MONO-MAC-6 MONOCYTE CELL-LINE AND DELFIA

Objective: Measurement of lipopolysaccharide (LPS) induced interleukin -6 (IL-6) secretion in Mono Mac 6 cells. Method: Dissociation-enhanced lanthanide fluoro immunoassay (DELFIA), a technique based on time-res olved fluorescence. Results: A comparison of DELFIA and the B9 bioassa y showed a correlation between the results of the two assays. DELFIA d id not show any crossreactivity with the human cytokines TNF alpha, IL -1 beta, IL-1 alpha, IL-2, IL-4, IFN gamma, murine IL-6 or LPS. In aqu eous solution the detection limit was 2.5 pg LPS/ml, and in a 25% dilu tion of a lipid-based total parenteral nutrition (TPN) product it was 25 pg LPS/ml. TPN did not interfere with the DELFIA assay, but the IL- 6 secretion from the Mono Mac 6 cells was inhibited at TPN concentrati ons above 25%. Conclusion: A combination of Mono Mac 6 cells with DELF IA was found to be a reliable method for detecting LPS, but further va lidation by independent laboratories is justified.