Optimization protocol for amyloid-β peptides detection in human cerebrospinal fluid using SELDI TOF MS

Purpose: The aim of the present work was to set up an optimized protocol for human cerebrospinal fluid amyloid-β (Aβ) profiling. Experimental design: We devised an immunoproteomic assay that employs monoclonal antibodies (mAbs) on Preactivated Surface (PS20) chip array followed by SELDI TOF MS. A comparison of a number of factors was performed, and the impact of these differences was noted. Each variable was tested using in parallel two different mAbs, 6E10 and 4G8. In addition, we tested whether the combined use of these two mAbs could improve the capture of N and C-terminally truncated Aβ peptides and then the quality of spectra. Results: The best results were obtained using a mixture of Aβ mAbs (0.125μg/μL 6E10+4G8): 15 Aβ peptides (including 3 N-terminally truncated forms) were detected. Conclusions and clinical relevance: This approach has many potential advantages in speed, sensitivity and economy of reagents and could be helpful in order to define the role played by specific Aβ truncated forms in cognitive decline.