Mass spectrometry based qualification ofantibodies for plasma proteomics

There is a strong need for procedures that enable context and application dependent validation of antibodies. Here we describe a high-throughput approach for the detailed assessment of the selectivity of antibodies in plasma by PLasma Immunocapture Mass Spectrometry (PLIMS). The utility of PLIMS is demonstrated by determining the enrichment profiles of 157 antibodies targeting 120 proteins in EDTA plasma. Applying four classification categories (ON-target, CO-target, OFF-target and NO-target), it was found that 60% (44/60) of antibodies directed against denoted plasma proteins qualified for plasma assays. Among these, 85% (60/71) co-enriched another protein besides their respective target. As shown for several antibodies against IGFBP2, PLIMS was furthermore capable to describe known and explore novel protein complexes in plasma. In summary, PLIMS provides detailed insights into antibody selectivity in the context of plasma, thus will contribute as a valuable procedure towards to the generation of more reliable affinity-based plasma proteomics data. not peer-reviewed) is the author/funder. All rights reserved. No reuse allowed without permission. The copyright holder for this preprint (which was . http://dx.doi.org/10.1101/158022 doi: bioRxiv preprint first posted online Jun. 30, 2017;