The plasma proteome profiling with monoclonal antibody based protein chips is a promising new tool in biomarker discovery that can be used to identify novel plasma markers in a wide variety of diseases. Recently a novel system – QuantiPlasm69 (QP69) – has been introduced by Randox Laboratories using 69 monoclonal antibodies (mAbs) – developed by BioSystems International – that can recognize different human plasma proteins. The mAbs are immobilized on 9x9 mm ceramic chips and a biotinylated plasma protein tracer is competing with plasma proteins in the tested sample for mAb binding. The amount of the bound tracer is determined by a streptavidin-peroxidase conjugate and a chemiluminescence substrate. We aimed to evaluate the analytical properties of QP69.
The performance of QP69 system was tested by the Evidence Investigator analyzer. In order to find the optimal dilution 10-fold dilution series of control plasmas were trialed. As the 100- and 1,000-times dilutions seemed to be optimal for most of the antibodies, these have been used in the reproducibility measurements. The intra- and interassay variability was determined in one plasma sample using six parallel determinations repeated three-times in three experimental days. An interoperator variability was also calculated as the 6 replicates per day were prepared by 2 operators.
The optimal plasma dilution has been determined to be 300-times, with which 57 of the 69 mAbs can measure both a decrease and an increase in protein concentration. At this dilution 4 of the remaining 12 mAbs will measure an increase in plasma protein concentration, while 8 mAbs will measure a decrease in protein concentration. The maximal relative light unit (RLUmax) – in the presence of the tracer alone – changed from 400 to 35,000. The intra-, interassay and interoperator %CVs were typically <15%. In the presence of the tested plasma sample when the RLU signal was within the optimal inhibition range (30% to 70%) the intra-, interassay and interoperator RLU %CVs were also typically <15%.
This work was supported by the National Office for Research and Technology of Hungary (TECH-09-A1-2009-0113; mAB-CHIC).
Péter Antal-Szalmás1, József Lázár2, Róza Földesi1, Zoltán Steiber1, Amy Bradley3, Stuart McGregor3, John V. Lamont3, S. Peter Fitzgerald3, László Takács2, István Kurucz2, János Kappelmayer1
1University of Debrecen, Medical and Health Science Center, Department of Clinical Biochemistry and Molecular Pathology, Debrecen, Hungary
2Biosystems International Ltd, Debrecen, Hungary
3Randox Laboratories Ltd., Crumlin, United Kingdom
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