PROTEOME SCIENCES EVALUATES BIOMARKERS OF KIDNEY TRANSPLANT USING SIX-PLEX TANDEM MASS TAG (TMT®) TECHNOLOGY

06 September 2006

Proteome Sciences yesterday presented data showing the utility of its proprietary ProteoSHOP® platform for discovery and evaluation of novel rejection markers in renal transplantation at the 7th International Siena Proteomics Meeting in Italy. This is the first public demonstration of the power of the proprietary TMT® six-plex isobaric mass tags for optimising the performance of mass spectrometry in biomarker discovery.

In the presentation Dr. Josef Schwarz, Head of Laboratory at Proteome's Frankfurt facility described the analysis of a well defined cohort of plasma samples drawn at three timepoints pre- and post-transplant from 40 kidney transplant patients who have rejected their organ and an appropriately matched group of 40 patients whose graft remained healthy.

Using 2-dimensional gel electrophoresis Proteome Sciences identified 29 regulated proteins of which 12 have been previously reported as being associated with renal transplant rejection and/or kidney disease and 17 represent new candidate biomarkers for the early detection of renal transplant rejection.

In a parallel arm of the study two pools of 20 samples from both the rejecting and non-rejecting cohorts at each of the three time-points (a total of six different pools) were labelled with one of Proteome Sciences proprietary, six-plex TMT® isobaric mass tags. The six-plex TMT® tags are the first commercially available mass tags allowing the relative abundance of all proteins in up to six separate complex biological samples to be quantified in a single tandem-mass spectrometry experiment. A preliminary analysis of this data shows that the six-plex TMT® provides highly accurate relative quantitation across several hundred proteins revealing a number of differentially expressed candidate biomarkers.

In a comparison with the 2-DE study of the same samples the six-plex TMT® took considerably less time, provided a direct quantitative comparison of relative protein abundance linked to protein identification and identified a greater number of candidate biomarkers of renal transplant rejection.

This data is the first report of the six-plex TMT® isobaric mass tags and clearly demonstrates the potential and utility of isobaric mass labels to rapidly discover and validate biomarkers and the impact they will have on the future of proteomics.