>>Clin Chem. 2006 Mar 30; [Epub ahead of print]
Quantification of Fragments of Human Serum Inter-{alpha}-Trypsin Inhibitor Heavy Chain 4 by a Surface-Enhanced Laser Desorption/Ionization-Based Immunoassay.
Song J, Patel M, Rosenzweig CN, Chan-Li Y, Sokoll LJ, Fung ET, Choi-Miura NH, Goggins M, Chan DW, Zhang Z.
Center for Biomarker Discovery, Department of Pathology.
BACKGROUND: Several proteolytically derived fragments from the proline-rich region (PRR) of human inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4) have been identified by surface-enhanced or matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS or MALDI-TOF-MS) as potential disease markers. METHODS: Previously, we developed a SELDI-based immunoassay that can simultaneously distinguish and quantify multiple isoforms/variants of a protein/peptide of interest. In this study, we used this high-throughput approach to quantify and characterize the extensive fragmentation within the PRR of human serum ITIH4 and determined its association with different disease conditions. The ITIH4-related fragments were first immunocaptured by use of beads coupled with peptide-specific antibodies. The eluates were then studied by SELDI-TOF-MS. In addition, freshly collected and immediately processed serum and plasma samples were used to analyze the ex vivo stability of these ITIH4 fragments. RESULTS: Human serum ITIH4 was shown to be extensively proteolytically processed within the PRR, and its fragmentation patterns were closely associated with different disease conditions. Fragmentation patterns were generally consistent with cleavages by endoprotease followed by exoprotease actions. Observed fragments changed little under different assay conditions or blood collection and processing procedures. CONCLUSIONS: The fragmentation patterns within the PRR of human serum ITIH4 are associated with different disease conditions and may hold important diagnostic information. These fragmentation patterns could be useful as potential biomarkers for detection and classification of cancer.<<
Interesting stuff. Diagnostic utility relies more on the pattern of fragmentation than the presence of the fragment itself. I had wondered about this, because of the many abstracts that mentioned fragments of this and other molecules as disease markers. They never went into much detail, and I figured they couldn't all be the same fragment. But that was all I could figure. This abstract enlightens me a bit. And note the author ET Fung. I believe he's actually an employee of Ciphergen, like their CSO or some such. Z Zhang is very familiar, as well, having been the lead author on the papers regarding validation of the ovarian assay. And, of course, Dr. Chan from Hopkins, who came up with assay biomarkers.
In the previous post, I mentioned Gaucher's as a CDG-1 disorder. I think that's wrong. It a disorder of glcosylation, but not that kind. Sorry about that.
Cheers, Tuck |
