EndoLISA[reg]: a novel and reliable method for endotoxin detection

Abstract Abstract• Introduction• References• Acknowledgments• Author information A new test for the sensitive detection of endotoxin has been developed, based on a lipopolysaccharide-selective, precoated microplate and a factor C–based detection reagent and presented in a complete kit format. The selective capture of lipopolysaccharide (LPS) is achieved using a phage-derived receptor protein exhibiting high affinity and high specificity for the conserved core region of LPS. After binding of sample-LPS to the microplate as the first stage of the assay, the original sample matrix is washed off, thereby eliminating potentially interfering components. In the second stage of the assay, LPS is detected by factor C in a process whereby the principal receptor of the Limulus amoebocyte coagulation cascade reacts with a fluorescence substrate. The new endotoxin test EndoLISA has a detection range from 0.05 EU/ml up to 500 EU/ml. At a glance Figures View all figures Figure 1: Standard curve of the EndoLISA test: concentrations of the LPS standard are plotted against the relative fluorescence signal. EU, endotoxin unit. Full size image View in article Figure 2: Correlation plot of EndoLISA versus LAL assay. Multiple LPS preparations and dilutions from different sources, including LPS of mutant strains, were compared. The tested LPS samples were E. coli O55:B5, E. coli O111:B4 (phenol extract and EDTA extract), E. coli O128:B12, E. coli O45, E. coli K235, E. coli EH 100 (Ra mutant), E. coli J5 (Rc mutant), E. coli F583 (Re mutant), Salmonella enterica serotype Minnesota (wild type and Re mutant), S. enterica serotype Enteritidis, S. enterica serotype Abortus equi, S. enterica serotype Typhimurium, Klebsiella pneumoniae, Serratia marcescens and Pseudomonas aeruginosa serotype 10. Individual dilutions of the LPS samples were prepared in water. The coefficient of correlation (R2) was determined by linear regression. Full size image View in article