Antibody-free, targeted mass-spectrometric approach for quantification of proteins at low picogram per milliliter levels in human plasma/serum.


Sensitive detection of low-abundance proteins in complex biological samples has typically been achieved by immunoassays that use antibodies specific to target proteins; however, de novo development of antibodies is associated with high costs, long development lead times, and high failure rates. To address these challenges, we developed an antibody-free strategy that involves PRISM (high-pressure, high-resolution separations coupled with intelligent selection and multiplexing) for sensitive selected reaction monitoring (SRM)-based targeted protein quantification. The strategy capitalizes on high-resolution reversed-phase liquid chromatographic separations for analyte enrichment, intelligent selection of target fractions via on-line SRM monitoring of internal standards, and fraction multiplexing before nano-liquid chromatography-SRM quantification. Application of this strategy to human plasma/serum demonstrated accurate and reproducible quantification of proteins at concentrations in the 50-100 pg/mL range, which represents a major advance in the sensitivity of targeted protein quantification without the need for specific-affinity reagents. Application to a set of clinical serum samples illustrated an excellent correlation between the results obtained from the PRISM-SRM assay and those from clinical immunoassay for the prostate-specific antigen level.

  • Camp DG
  • Fillmore TL
  • Hossain M
  • Jones N
  • Kagan J
  • Kim JS
  • Liu T
  • Moore RJ
  • Pasa-Tolić L
  • Qian WJ
  • Rodland KD
  • Schepmoes AA
  • Shi T
  • Smith RD
  • Sun X
  • Tang K
  • Wu S
  • Xie F
  • Zhao R
PubMed ID
Appears In
Proc Natl Acad Sci U S A, 2012, 109 (38)