Advancing the immunoaffinity platform AFFIRM to targeted measurements of proteins in serum in the pg/ml range

PLoS One. 2018 Feb 13;13(2):e0189116. doi: 10.1371/journal.pone.0189116. eCollection 2018.

Abstract

There is a great need for targeted protein assays with the capacity of sensitive measurements in complex samples such as plasma or serum, not the least for clinical purposes. Proteomics keeps generating hundreds of biomarker candidates that need to be transferred towards true clinical application through targeted verification studies and towards clinically applicable analysis formats. The immunoaffinity assay AFFIRM (AFFInity sRM) combines the sensitivity of recombinant single chain antibodies (scFv) for targeted protein enrichment with a specific mass spectrometry readout through selected reaction monitoring (SRM) in an automated workflow. Here we demonstrate a 100 times improved detection capacity of the assay down to pg/ml range through the use of oriented antibody immobilization to magnetic beads. This was achieved using biotin-tagged scFv coupled to streptavidin coated magnetic beads, or utilizing the FLAG tag for coupling to anti-FLAG antibody coated magnetic beads. An improved multiplexing capacity with an 11-plex setup was also demonstrated compared to a previous 3-plex setup, which is of great importance for the analysis of panels of biomarker targets.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blood Proteins / analysis*
  • Chromatography, Affinity / methods*
  • Humans
  • Limit of Detection
  • Tandem Mass Spectrometry

Substances

  • Blood Proteins

Grants and funding

This work has been financed by Fru Berta Kamprads stiftelse, Sweden. Grant no BKS53/2015 to SW. There was no additional external funding received for this study. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.